Good morning from Fredericksburg, VA. I am

Is this the ultimate multiway design, feel free to critique the design draft

Hello all. After very long I am posting & this time I want help for making a dual rail high current variable power supply for testing projects. I already have a dual supply with Lm317 and Lm337 supply but the current is insufficient for testing projects upto 3 Ampere so I want to know how can I increase the current upto 3 Ampere or more upto 5 Ampere in future. I also made a variable power supply using switch mode buck converter with XL4016 but it's only single output that's positive and ground but I want positive ground and negative output which is not available readily and I can't buy those expensive bench supplies like from Siglent so please advise me

You know how you to want to DIY something and it keeps getting put on the back burner? Well, this has been the case for me for over 30 years. Having some free time on my hands (thank you open heart surgery) I finally sat down at the computer with my hand drawn schematic and after many failed attempts arrived at a design and layout which might actually work. I will enclose a picture I took of the computer screen.

I did click the save as button so I probably do have the design on the computer. Now, what do I do. What files do I look for to send to PCB WAY?
I have absolutely no idea what the heck I'm doing just the thought that I would like to try to DIY one project in my life.

I apologize in advance if I've put this in the wrong section. Can anyone help me?

I want to disable the over current shutdown of this little 500w china amp.
As per the datasheet I can remove R11 and R12 and connect pin 8 (OCSET) to VCC to disable the low side but it doesn't say how to disable it for the high side. The datasheet states that the CSD (pin 16) has max of VS to VB. Which should it be connected to? I'm thinking remove R16 and R17 and connect it to VB (pin 15)

hello everyone.
up to now I have used an old laptop combined with REW, E-mu USB sound card, power amplifier and microphone. little by little I have transformed a small unused room into a simple unpretentious laboratory to do my experiments in the audio field.
the time has come to retire the old laptop and replace it with something else. unlike what I have done up to now the new hardware will always remain in the room without ever leaving it and therefore I am not forced to buy another laptop. for the moment I only use REW, ARTA and spicyTL, I can not know if in the future I will use particularly demanding programs. I intend to buy another sound card to use alongside the one I already have. one to measure the impedance with LIMP and the other to measure the frequency response with REW. this way I do not have to continuously assemble and disassemble the connection circuit every time I want to change the type of measurement. I would like an RME 9632 HDSP but it only works with the old legacy PCI slot that has been banned from most recent motherboards. Apparently the best choice is a socket chip with native PCI legacy 32-bit/33 MHz support. So I come to the point: I would like to choose hardware that is sufficiently suitable for this type of audio software but that has at least two (in case of failure I can change slots) legacy PCI slots. I could orient myself towards a computer already assembled and ready to use or buy a motherboard, CPU and accessories, power supply, RAM, video card and screen but there is a problem, I have no idea which product I should orient myself towards.
what do you recommend? .
bye and thanks

Hi after using the Ciúnas USB converter for about 5 hours the output becomes very distorted after turning the devise off/on it works fine but then the same can happen after an hour,ive replaced the Lifpo4 battery and the psu still the same with a steady voltage 3.45v. Inside is a modified amanero combo 384 my question is, is it ok to upgrade the firmware and will this resolve the issue or should i be looking else where ?

LTSpice can export schematics in other formats besides its own. I tried to understand how the various formats available represent a schematic and found that schematics exported in Accel format are not that difficult to decipher. This format seems quite straightforward to understand. The bad news is ngspice does not support Accel format. So, I decided to write a software tool to convert Accel format into ngspice format. I already achieved some results, but the connections are disordered. This means, that my algorithm needs to do another pass to order the component pins. The format for ngspice to represent a component is "component pin1 pin2 pin3 .... model_number". In my application nets represented by pin1, pin2, pin3, etc are not in order which means to give an example the emitter of a transistor may be mixed with the collector or the base. Although at first, this seemed to be an easy task, this is proving to be quite hard to achieve.

The coding is in Delphi (or Lazarus) Object Pascal. I will post the source code when I am ready. The first version will be limited to a few component types but hopefully the source code will be extensible. I plan to post the code in this thread when it behaves better than it is at this moment.

Some of the code follows. This is only a snippet.

This thread provides a purchasing option for the 1-inch compression driver DFM-2535R00-08.



The driver is not available anymore in single units and hence unobtainable for consumers. With this group buy in cooperation with a Tymphany distributor from Germany DiYers can once again purchase a pair of the much discussed and HiFi-optimized compression driver that has some special properties.

The price for one driver DFM-2535R00-08 will be around 40 Euro excluding VAT. As an example, for buyers from Germany with 19 percent VAT, the end price is about 48 Euro total. Plus shipping from Germany to your destination. In general, it is possible to ship world wide, depending on your willingness to pay the costs. EU shipping is standard.

Please enter your contact details and the amount of drivers you want to buy in this google forms link: https://forms.gle/zszS5UC68y8xskvJ6

The condition for the distributor to stock the lot is an order of a minimum of 50 pairs / 100 pieces.




When the necessary amount of buyers is reached, we will proceed with transaction. This can be done via bank account or PayPal.


- - - - - - - - - - - -


Some facts on the compression driver DFM-2535R00-08:

The compression driver is optimized for high quality sound reproduction, combining a polyimide surround with a coated titanium diaphragm. Thus it equally provides the benefits of a TI diaphragm, that is detailed high frequency reproduction, while also enabling the smoothness of a polymer surround. Additionally, it enables a low crossover frequency of 1 kHz LR24, making it a perfect fit for 2-way home audio speakers with waveguides. This compression driver is not optimized for high SPL.

[1] Distortion measurements. A crossover at 1.1 kHz LR24 promises <1 percent distortion for 96 dB at 1m throughout the passband (HD2):


-> source

[2] Burst decay. The main resonance of the diapragm is pushed to the very high frequencies:


-> source

[3] Detail images of the driver construction courtesy @Zvu:


-> source

[4] Review from audioxpress

https://audioxpress.com/article/peerless-by-tymphany-dfm-2535r00-08-compression-driver

This thread is not to discuss the driver, please use the technical threads instead. If you want to share this group buy on another board, you are welcome. Please send me a message so that I know.

Starting to come here more and more to expand my horizons further. Who else is here?

Hi, I want to use a schematic like this TNT-Audio but i have a 3 wires transformer 25-0-25. Is it possible?
I can't modify schematic because pcb is just made.
Thanks

The shunt was shown as a brother of Iron pre and Iron pumpkin and was partnered with a capacitance multiplier.

http://www.diyaudio.com/forums/pass-labs/293169-whats-wrong-kiss-boy-19.html#post4883680

I would like some help discussing its Vout range and load current limits to see if it could fit any other projects like the B1, the BA-3 or even digital stuff.

I'm looking for a pair of Fremen edition of LM3886 amplifier boards latest (1.08) version from EU.

Celestion SL6s restoration: Part I​

Celestion SL6s restoration: Part II​

Celestion SL6s restoration: Part III​

Some measurements of the speakers with and without crossover:

Celestion SL6s Spkr A impedance no xover red=woofer white=tweeter

Celestion SL6s Spkr B impedance no xover red=woofer white=tweeter

Celestion SL6s Spkr A impedance+xover red=woofer white=tweeter green=speaker

Celestion SL6s Spkr B impedance+xover red=woofer white=tweeter green=speaker

Low frequency nearfield measurement
Red = Mic in baffle plane
White = Mic nearfield, few mm from cone


Celestion SL6s A Low freq resp nearfield & baffle plane


Celestion SL6s B Low freq resp nearfield & baffle plane

Simulations with Basta:
I made a set of simulations based on the measured woofer data, including the baffle response.

• Closed box 10,9 liter
• Damping fill 80%
• Baffle 20x37cm

Basta simulation - spkr A&B freq response-impedance-max output with xover


Basta simulation - spkr A&B freq response-impedance-max output no xover


Basta simulation - spkr A&B freq response-impedance-max output no xover - show group delay


Basta simulation - spkr A&B freq response-impedance-max output no xover - show effect of damping

And just for fun a simulation of the Celstions with the OB sub (see Part I). Probably more a fantasy than a realistic simulation, but it shows that the combination is at least possible.
The OB sun woofer is a Redcatt 154FINDX8-298 15" woofer with TS data from the German Hobby Hifi magazine. Crossover is @120Hz, 24dB/oct Linkwitz-Riley.



Part IV describes my experiences with the Celestions, some comparisons, and at a later data, when the wheather improves, more measurements. I plan to do a full set of FR and polar measurements.

My Error-Correction/Composite F5M thought.
By simulation:
1. PPM THD
2. uV output offset
3. H2 dominant

I can't find a bigger case.

I'm working on a Rockford Fosgate R600-4D Prime and need to replace 2 Zener Diodes on the underside of the board D14 & D15 (picture)
While I’m here, I tested everything I could but maybe someone that had this problem where all 4 resistors and the 2 diodes blew. Resistors R59, R60, R61, R62.
With those blown the amp gets really hot to touch. Is there anything I should test?

Celestion SL6s restoration: Part I​

Celestion SL6s restoration: Part II​

Celestion SL6s restoration: Part III​

Some years ago I purchased a pair of Celestion SL6s for €80,- I have listened to them on and off over the last few years, and, although I liked them, the wow factor was mostly absent.

Technically they are in good condition, the same cannot be said for the cabinets.




So I decided to try to repair some of the damage done to the cabinets. I also wanted to mount the crossover outside the cabinet, and create the option of bi-amping or use of an active crossover. Currently it looks like this:





I still have to find a good solution for the lower part of the front.

Another project relating to the Sl6s speakers that I am working on is a dipole subwoofer. The first iteration of that subwoofer uses a single Redcatt 15 inch driver mounted in a 44cm wide frame.




Crossover is active, at 120Hz / 24dB/oct.

Stands
The Celestion SL6s is a bit of a weird speaker in the sense that the optimal listening height of the speaker is not the usual tweeter axis on ear height. Celestion recommended a stand height of 18” (45 cm). That means that from a normal listening distance you can just see the top of the speakers, and ear height is actually slightly above the speaker. The subs have a height of 46 cm, and for normal use I build myself a pair of low stands (Height 45cm/18 inch).




The Tweeters
As can be seen in the pictures the tweeter is in integral part of the frontplate, the dome is actually attached to the back of the frontplate. The magnet can be removed, but you have to be very carefull while doing that. It is easy to damage the voice coil. Likewise I did not try to remove the wiring, because that too seems to me quite risky.
The airtight mounting of the tweeter is done with a putty like sticky substance around the mounting hole between the cabinet front and the metal frontplate of the tweeter. You have to take care when you assemble the tweeter to spread the stuff evenly, to create an airtight fit.



The bolts are corroded, but they are easy to replace.





Dome and magnet separated





The woofers (Celestion T3507 165mm (6.5″) PVC Diaphragm)
The woofer is a well build 6,5” model, designated T…

Based on the 100W 3-Way DSP Amp board, I made these modules on a plate radiator.





Performance parameter:

• Output power: 100 W per channel, R load = 4 Ohms.

• Speaker impedance: 4 - 8 Ohm (2Ohm – max 50W)

• Frequency response: 20Hz - 20kHz

• THD -3dB: less than 0.005% on 8Ohm load, and less than 0.01% on 4Ohm load

• SNR: 106dB(A)

• Spdif Input: 16-32bit 44.1-96kHz

• Spdif Output: 16-32bit 44.1-96kHz

• I2S Input: 16-32bit 44.1-192kHz

• Power supply: 100V-240V, 32V/11A

• Consumption power: Idle mode 12W, sleeping mode 4.5W

• Efficiency - 80%

More detailed parameters of the 3-Way DSP board can be found in this topic. https://www.diyaudio.com/community/threads/3-way-dsp-amp.415065/#post-7734899

The DSP board are flashed with a starter program called 3Way FIR 48kHz. The folder with the starter projects is attached to the message..

The plates come with a programmer on the CYC68013A chip and an optical receiver for remote volume control.

Those wishing to purchase such plates, write in private messages.

The price of the entire set is 370 US dollars.



Delivery to Europe and America is at my expense. Delivery to islands or other distant places is negotiated separately.

Payment via Payoneer.

Celestion SL6s restoration: Part I​

Celestion SL6s restoration: Part II​

Celestion SL6s restoration: Part III​

TS parameters of the Celestion SL6s woofers
I measured the woofer driver TS parameters with the Clio Pocket. Before I did that I run the drivers for about 36hrs on a 15Hz signal at close to maximum excursion. Just out of curiosity I measured the impedance and TS parameters before and after burn in.




There is some difference between the two woofers, but what do you expect. They are about 40 years old.

Impedance woofers A&B


Spkr B (only) woofer impedance response red=1volt white=3,46volt.

The cabinets
Outside measurements (HxWxD) 376mm x 201mm x 250
Inside measurements (HxWxD) 351mm x 174mm x 195mm

• Baffle thickness 19mm (HDF/MDF)
• Backpanel thickness 12mm (HDF/MDF)
• Sidepanels thickness 13mm multiplex
• Internal brace 19mm (HDF/MDF)

Internal brace 351 x 174 x 19mm; Holes 100mm x 140mm and 150mm x 140mm; Volume of the brace approx. 0,5 ltr.



Internal volume of cabinet 1,95 x 1,74 x 3,51 -1 = 10,9 ltr (0,5 ltr for the drivers).

The cabinet is simple, made form a combination of MDF (HDF?) and multiplex. The construction is very rigid, and heavy for such a small cabinet. Note the back panel, which is mounted 22mm inside the cabinet. This is done in order to better supress cabinet resonances.


Cabinet sketch and crossover schematic


The crossover mounted on the inside backpanel, and some of the pulverized damping material.

The crossover
[Correction]
The crossover is simple, with a 12dB/oct lowpass for the woofer and a 18dB/oct highpass for the tweeter. Tweeter and woofer are connected in phase. The drivers are connected out of phase. The reason for that is the tweeter response (all measurements in room, ungated).


Woofer=Yellow, Tweeter=White, measurement distance 50cm on tweeter axis, ungated.

Between abott 2k-6k the tweeter shows a falling response of about 6db/oct. This response is compensated in the crossover, resulting in an effectively 12dB/oct crossover response.


Tweeter on axis 50cm 1/12oct smoothing ungated. Red=with xover White=no xover Yellow=drivers out phase Green=drivers in phase.


Freq response tweeter & woofer on axis 50cm 1/12oct smoothing red=tweeter green=woofer with xover



All capacitors are originally (as shown here) Alcaps. I checked the capacitor values.


Not bad for 40 year old capacitors. I still repaced them with Visaton 10µF MKM, and MCaps.

Cabinet damping
The cabinet is almost completely filled with damping material. There are three layers of two types of foam stacked from the backpanel up to the back of the woofer magnet. On top of that there are pieces of foam along the sides up to the baffle. The three top layers of foam, like the green type in the picture below, are in good condition, the bottom layer (of a different type, see the grey foam in the picture below) was essentially reduced to dust, and fell apart when I touched it. This foam layer had to be replaced. It is a sort of reticulated foam, widely used as packaging material, and for water filters.




Part III to follow.

Been working on the new store amp.

The old "Honey Badger" is a nice amp.
But , it was such a long time ago. Like Windows XP 😀 .

It's 2021 , time for ....

- EF3 (like a leach amp - or HK680) goodness.
- Ripple cancelling rail traces.
- P/N/P/N/P/N alternating output device genders - consistant thermals and
NFB takeoff nodes throughout.
- 2 X 2W-.47R per output device Re , or single MOS 5w 220mOhm ones.
- Cap multipliers.
- .5A +/- 12v aux. supplies with external output built in.
- Servo.
- And , A SIP connector for the ability to add any 20th century classic input
stage to this project. I you don't use the connector , the original Wolverine/
Badger (blameless) topology is default.

ALL these designs have not only been tested .... but some sell them on the
internet. I did a search of the "Slewmaster" WOW ! , there were a lot of images ! 😱

I have heard of the suggestions for left and right versions of the project boards.
It would be up to management to decide on 2 board runs ???

The tiny hole problem was unfortunate 😱😱 , but now I am researching the
parts individually as I do layout.

Any drawbacks ???

- Caps multipliers , you lose 2.1V per rail .... but gain 30db+ PSRR over
most of the audio spectrum. A quite simple circuit - needed for a CFA input stage.
- EF3 - lose another volt off the rails.

Any and all suggestions welcome ....

PS - if anyone has the EXACT output device spacing for the Badger store boards ... please share. I had to reverse engineer from the store PDF and
a simple toner transfer image I had . I lost my original artwork.
OS

The last few years I notice a sharp increase in installation of home automation. People that can't even use/charge a smart phone correctly buy cartloads full of expensive stuff only to be dependent on that brands technology, Internet connection and people that do know this stuff. People that do know are not found in abundance.

When helping out the elderly I notice that these are a sales target and buy such "necessary" devices to improve their situation which it does not as they can not master the devices. Reality is that they bought extra stuff that they can not configure when it refuses one day. If the brain starts to become foggy home automation and apps are not understood while switches even are understood by people with dementia/Alzheimer. Internet dependency is IMHO not a blessing but a curse certainly when one does not want to know how stuff works and is interconnected. I mean we can all say: "I have no knowledge of that" but that does not solve issues. Even TVs and audio devices are connected to each other wirelessly....while cables work without configuring, maintenance, security issues and software updates as long as you live and longer. Also age does not really help when starting to buy a can of worms as you won't get younger. Reliability of electronics is laughable compared to old stuff as found in houses. Only when 100% LED light is implemented switches start to wear out faster. I recently replaced light switches installed in 1971 and the lady said that it was bad that stuff breaks down so fast 🙂

Just to learn how working in technical retail is I worked a day for free in one of the largest stores that sell such stuff and was astonished how much was sold on a day. To people of which the majority had absolutely no clue 😀

So why would one buy such stuff and think things will improve? What is exactly negative when needing to use a simple switch to switch on the light? My hard opinion is that it almost all is superfluous garbage one can do without (we did till now) and I deliberately look for classic and sturdy non internet connected stuff that just needs mains voltage.

Please tell your view.

I've been here for a while but never posted anything.
I love this place.

Simple Full Complementary Simetry +/-80V. Voltage amplifier/driver biased with 30mA. This driver circuit stabilized BIAS in output stage. Exelent stability without oscilation, hum and noise, sound great.
RMS Power: 240W 8ohm, 350W 4ohm

Go to post #470 for schematic and PCB
http://www.diyaudio.com/forums/solid-state/162043-mosfet-amplifier-irfp240-irfp9240-47.html

Hello all I'm new to diyAudio - My main interests vacuum tube amplifiers and transmission line speakers

Illustrated build guide for the BA-3 amplifier (With complimentary output stage)

The “Burning Amplifier” series is a selection of modular amplifier pieces designed by our technical, spiritual, and menu advisor, Nelson Pass. The pieces can be mixed and matched, used with a range of PSU voltages and scaled up or down as you desire. (The limit, as always with class-A amplifiers being how much heatsink you have…)

There are two gain stages or ‘front-ends’, The BA-1&2 gain stage is a differential pair voltage amplifier with CCS, using some feedback. It can accept a single ended or balanced input. The BA-3 gain stage is a complimentary pair voltage amp with no feedback. There is no ‘better’ between the two stages, just different. You are encouraged to try both and report back your findings.

This guide uses this PCB - P-BAGSN-1V20 - Burning Amplifier Gain Stage for BA-3 (Requires bias boards and output stage; Makes 2 channels; Rev 2.0) - Circuit Boards


The output stages are Complimentary (Push-Pull) and Single-ended. Both these stages can be scaled to hold as many pairs of output Mosfet as you desire, the PCB have provisions for daisy-chain links to add as many boards as you like. (Heatsink and physical area of your case being the limit.)
The Complimentary output (push-pull) is identical to the F4, without the F4’s input buffer, and with the ability to add more Mosfets.
The Single-ended stage is similar to the Aleph amps, the difference being a fixed Constant Current Source instead of the Aleph CCS (which dynamically tracks the output) and the ability to add more mosfets.

This guide uses this PCB set - P-BAC-S4V20 - Burning Amplifier Complementary Bias and Output Set for the BA-2 & BA-3 (Requires a gain stage; Makes 2 channels; Rev 2.0) - Circuit Boards

Either gain stage can be used with either output stage. So not counting the PSU voltage or number of output mosfets there are 4 versions of this amp;

Differential FE, Complimentary output (BA-2)
Differential FE, Single-ended output (BA-1)
Complimentary FE, Complimentary output (BA-3)
Complimentary FE, Single-ended output (BA-3 SE)

Acceptable PSU voltage is from 20-32V, a bipolar supply is needed, you may utilize the diyAudio PSUv3 board or something similar. —

Universal PSU V3 - Circuit Boards

Of course, you will get more output power with higher voltage, at the expense of more heat. (Do you see a trend here…? 🙂 ) There is an upper limit to voltage, approximately 32V, as the input Jfets will start to become very unhappy at voltages much higher. (Of course, you can add a cascode circuit to the front-end to protect the Jfets from higher voltages, but there is no provisions on the PCB to do so.)


Anyway, this guide will show the construction of a BA-3 — a complimentary FE with one PCB of complimentary outputs. PSU will be +/- 32V .

If you haven’t yet, please read this article before continuing. If you have read it, might as well skim over it again, it has lots of great information —

Nelson Pass BA-3 article - Burning Amplifier BA-3 - diyAudio


And as we are using the output stage from the BA-2, this article is quite informative and instructional to read as well -

Nelson Pass BA-2 article - Burning Amplifier BA-2 - diyAudio


Now the one question you will have when reading the articles is this - “How much power does this amp have?” Well, it’s a very fluid design, remember? (So Nelson never said any numbers in his articles, although the information is in the graphs…) But an educated estimate is as follows -

Complimentary output, 24V rails - 25WPC, 8ohm. More into 4ohm
Complimentary output, 32V rails - 40WPC, 8ohm. More into 4ohm.
Single-ended output, 24V rails - 25WPC, 8ohm. Less into 4ohm.

More output devices doesn’t necessarily make more power, but it does provide more current, making difficult speaker loads easier to drive.


Schematic


Front-end

In this schematic note that the Mosfets types are not shown. The suggested pieces are Toshiba 2SK2013 / 2SJ313 (hard to find) and Fairchild FQP3N30 / FQP3P20 (easy to find). I’ve built using both types and can tell no real difference between the Toshiba and the Fairchild. If using Fairchild, use 1K pots for P1, P2. These Mosfets do not need to be matched.


Bias and output.

Schematic Changes (Suggested)


On the Front-end board P1 and P2 can be increased to 1000ohm to help accommodate different Mosfets. (As mentioned in the BA-3 article)

On the bias board I strongly suggest changing R25 to approximately 12K, and P2 to 5K. This will give more range to the circuit to zero the offset, using Fairchild output Mosfets I found it impossible to zero the offset with the original values. Those two minor changes made everything work as designed.

If you have well-matched Mosfets the source resistors (shown as 1.0 ohm 3W) can be reduced to 0.68ohm 3W or 0.47ohm 3W. You will get more output power with smaller source resistors.


Construction


BA-3 gain stage (Front-end) PCB. Note that there are PSU connections (V+, V-, GND) for each channel.
Also raise resistors R10 and R11 as shown, you will need to clip test lead there to set this stage’s bias and DC offset.


As the 5U chassis has enough space to fit the Fe board as shown, I decided to do so, it took only 4 holes drilled in the back. It has the advantage of keeping the input leads very short and away from the power transformer, and also keeping all the PSU wiring located in the same general area of the chassis.


Completed FE board.




FE board wiring. The PSU connections to the FE board are on the back, to keep those wires closer to the chassis. Then can, of course, be in front if you wish.


The completed and installed FE board. Note that the output from the FE to the output boards is not yet connected and shown. (Nor is it visible in this photo, it’s blocked by the bottom of the film caps…)


The diyAudio chassis is modular to the point that it’s easy to loosen a panel and make more room when construction get tight.



Complimentary output PCB.


Complimentary bias PCB.


The two resistor network is 10K+2.2K as I had no 12K in a single resistor. Also visible is a 2K pot in position P2. in the end I used a 5K.


Complimentary board and bias board on 4U heatsink.


Bias board connections - please note the extra washers raising the standoffs and PCB to clear the resistors underneath.


The bias/output connections are visible here - the black and red twisted pair is V+ and V- from the PSU, the white wire is the signal from the FE, labeled “D”, and pink is the speaker output positive (+). Speaker negative (-) is from the PSU GND.


Top view bias board.


It’s a bit busy, but not too bad back at the PSU connections.





Looking into the completed amp.
(Some may be asking, were did the big blue film caps go? Well... In a moment of extreme clumsiness I touched the iron against one of them while soldering another connection, and burnt a hole through. Whoops! Not having a direct replacement, I reached into my box of bits to see what I could come up with, and found some 10uF Silmic II and 0.10uF Rel-Cap film for bypass. That combo sounds great!)


The diyAudio soft start PCB. Not strictly necessary, the CL-60 thermistors in the primary circuit found in the original PSU work great, but this is kinda cool as well… Use the thermistors or the SoftStart.


If you center the LED and use bright blue ones, the glow comes out of the vents without shining out too bright… It's a nice look.

Power Supply

A stereo BA-3 requires a bipolar power supply from (+/-24V) to (+/- 32V). For 24V rails you need a 18V+18V (or 36V Center Tapped) transformer of suitable VA for your number of output devices. (a good rule of thumb is 50VA minimum per stereo pair of devices) and capacitor bank of 60,000 - 80,000uF per rail or more. I.E., a single output board, holding 3pr of Mosfet per channel (12 devices total) will need a 300VA transformer at the minimum. Most people will sure a 400VA. That’s fine. If you have more devices, you must have a bigger transformer. The other rule of thumb is you don’t want more total bias (in watts) than 1/2 of your transformer VA. More about that in the bias section.

The 32V PSU needs a 24V+24V (or 48V Center Tapped) transformer, and PSU capacitance of 60,000 - 80,000uF per rail or more.

Although not the exact PSU as shown in the Nelson Pass article, the diyAudio PSUv3 circuit board can be used to make a suitable power supply for the any of the Pass/Firstwatt amplifiers.

Using the PSUv3 board allows an easy addition of dual diode bridges, which will help keep the transformer mechanical noise to a minimum, and other benefits such as LEDs on each rail, room for (8) capacitors of up to 35mm diameter, the ability to use many different styles of connectors on the board itself, and not to mention the convenience of having everything on one PCB.

The diyAudio universal PSU v3 was made with the requirements of this very amp when it was designed.

The PSU shown in this guide has 50V caps of 18,000uF each, and a 24V+24V, 600VA transformer. (This happens to be the same PSU as used in the F5T guide.)

A build guide for the PSU itself can be found here - http://www.diyaudio.com/forums/powe...circuit-board-v3-illustrated-build-guide.html

Chassis

This is a high-wattage Class-A amplifier. It has lots of excess heat that needs to be dealt with. The 4U chassis can mount one PCB (6 devices) per heatsink. The 5U can mount 2 PCB (12 devices) per heatsink with a little creativity. But with 12 devices you will need to run at a bias amount (slightly reduced) that won’t overwhelm the heatsinks. (No worries, it will still sound fantastic!)

The 5U and 4U Deluxe chassis from the DIY audio store are basically identical except for size and that the 5U heatsinks are 2 pieces per side, so the guide for the 4U chassis is suitable for the 5U as well.

An illustrated guide to building the Deluxe Chassis (4U) can be found here - http://www.diyaudio.com/forums/parts/245959-illustrated-guide-4u-deluxe-chassis.html#post3704810

Testing and Powerup

Bias

Front-end

The procedure for setting bias on the BA-3 FE is almost identical to setting an F5, so this might seem familiar...

The Front-end bias and offset is separate from the output section. Do the FE first. Heck, you don’t even need to connect the output section to bias the FE.

Adjustments (Bias and Offset, set with P1 and P2)

This is easiest with three DMM.

Shorting the input jacks is very helpful, although not strictly necessary.

Before power up, dial pots P1 and P2 to 0 ohms . DON'T adjust P3 during bias

Place one voltmeter (Set to DC volts) across R12 - to observe DC offset

Place a voltmeter (Set to DC volts) across R11 another across R10.

For test - slowly dial up Variac ( presuming that you have one , as man with many skills) up to full mains voltage , observing rail voltage at PSU ....... thinking about max cap voltage ( 25V as in FW ? ) , because with 0 Iq PSU is unloaded and voltage is maxed (It’s useful to have another meter for this…) If nothing is smells bad, and the magic smoke is still in the circuit - leave Variac at full mains ;

IF you don’t have a Variac, you must build a lightbulb mains lead. (with a 25W bulb)

What's important - Iq (measured as the voltage across source resistors; the Mosfet bias) must be very low , offset is irrelevant in this moment .

Now turn one pot one turn ( assuming that you have multiturn pots) then turn other pot one turn. Continue, one turn at a time on each pot until something happens.

Observe voltage across resistors and output DC offset.

Proceed one then second pot , again just one turn

Observe Iq and offset

Again one turn + one turn

Now you are probably in range when you can see which pot is pulling offset in right direction - to 0 . It will feel like one of the pots is controlling the bias on both sides, and the other is controlling the DC offset.

It’s best to increase the bias a bit, and then zero the offset. As you zero the offset you will decrease some of the bias, so it will be two steps forward and one step back. That action is normal.

As you increase the bias and zero the offset, remember to always keep the offset near zero. If you run out of turn on the pots, determine your max bias, with zero offset. (It’s useful for troubleshooting)

Proceed iteratively with pots , while you set - say - 75% of desired bias, with zero offset. Remember, full bias is 1V across R10 and R11, with zero offset BEFORE the capacator. If you measure after the cap there should always be no DC.

Now - put lid on box and let it cook for a while - until you get thermal equilibrium on heatsinks

It's best to use wire/clips to leave those voltmeters in place ;

Open the lid , up bias to - say - 90% of desired one ,while maintaining offset

Put lid on , let it cook.

Check again.

If all is OK - move voltmeters for Bias and offset to other channel and repeat procedure.



Output section -

Do this only after the Front-end is set.

DC offset is adjusted by pot P2 on the bias board. Place a DMM set to DC volts on the speaker outputs and adjust for zero. If you have DC offset that drifts rapidly, it’s likely the TL431 is faulty. Replace.

Bias is adjusted by potentiometer P1 on the bias board. It’s measured by a DMM set to DC volts placed across any of the Mosfet source resistors. To start, set 0.25V measured across the 1.0ohm source resistors.

Use it few days at 90% of desired bias , then check and set to 100%

Remember - temp. equilibrium with lid on is important.


How much bias you can run is determined by a few factors, the most important being heat - the heat of the heatsinks, and the heat of the mosfets themselves.

The simple rules of thumb are -

HEAT = No more than 55C heatsink and 65C Mosfet. (The best place to measure Mosfet temp is pin 2)
TRANSFORMER = The amplifier’s total bias (in Watts) should be no more than 1/2 the VA of your transformer.

How do you determine watts? Simple - measure your bias current, the voltage drop across the 3W source resistors. Let’s say you measure .3V . Divide that by the value of the source resistor. If using 1.0 ohm, your answer is then .3A (.3 / 1 = .3) — but if using 0.47ohm resistors, a voltage drop of .3 is now .64A (.3 / .47 = .637) Back to the example using the 1.0 ohm resistors, multiply by your rail voltage, 32V, so each device will have a bias of 9.6W (.3 * 32 = 9.6) then multiply by the number of devices - 12 in this amp, (12 * 9.6 = 115W)


Setting P3

BEFORE installing and soldering P3 it’s best to adjust the pot so you have equal resistance from pin 1-2 and pin 2-3.

If you didn’t set it, determine how many turns the pot has. Run the pot all the way to one limit (they usually click) and then turn the adjustment the other way for 1/2 of it’s turns. (I.E.,if a 25-turn pot, adjust it 12.5 turns.)

Assuming well matched Jfets the neutral position is going to sound really nice, with 2nd harmonic dominant at the 1W level. IF you have access to a distortion analyzer, or a high-resolution FFT (or both…) give the amp a 1K test sine wave that outputs 1W into your load resistor. Then adjust P3 as necessary for the harmonics you prefer. If you adjust for minimum THD, you will likely have nulled out most of the 2nd harmonic and made it 3rd dominant, which in my opinion makes it very fast and clean, at the expense of soul. YMMV.

Anyway, if you DON’T have a distortion analyzer or similar, take careful notes and turn the pot a few turns (or more) in whatever direction you want and see what it sounds like. It’s a subtle change, but I think you will sense something. You can refer to you notes and see where you like the pot the best. And if you ever get lost, set it back to neutral, (with the power off) just bottom the pot in one direction and set it back to 1/2 it’s travel.


Lightbulb Mains lead notes -

If the bulb ever turns on and stays bright, you probably have a short.

Normal operation when turning on a cold amp will have the bulb glow bright for a second or two, then dim, perhaps off. (this is the capacitors charging, then full)

As you increase the bias of the amp the bulb will glow brighter, and this is linear with the bias amount. A fully biased amp can get the bulb to glow very bright.

You cannot set full bias with the bulb in place - as it increases the bulb will glow more, limiting the voltage to the amp and all the readings will be wrong compared to when the bulb lead is out.

You can, however, set the initial bias with the bulb in place. Start the procedure, turn the pots until something happens, and set, at maximum, 0.1V across the source resistors and zero offset. Getting the pots started this way is a good idea. Remember, this is with a reduced voltage, and the pots will make the circuit draw MUCH more bias when the normal mains lead in used. Expect to measure 0.2V or more with a normal cord. Continue biasing in small steps, always trying to keep the offset near zero.

Hi Folks; Minor panic here; A VOX Escort Bass 50 landed in my lap and is quit sick.
It is a capacitor coupled amp so the voltage between the output transistors should be half of B+. (80 V) It was around 19 V until some probing and now it is closer to only 1 volt.
All the transistors seem to test OK in circuit. It is a very simple amp but it has me stumped at the moment. Here are my voltage measurements;

Tr 1 E 2.1
B 9.4
C 0.0

Tr 2 E 0.7
B 0.0
C 0.9

Tr 3 E 1.5
B 0.0
C 0.9

Tr 4 E 2.3
B 0.9
C 72.0

Tr 6 E 0.01
B 0.58
C 1.4

Tr 7 E 1.8
B 2.3
C 72.5

I have got a HK audio lucas nano 300 in for repair. The issue was the unit not powering up, no indicator lights. Opening up the unit I found that something was shorting out +15V and -15V power rails. The culprit was 2 tantalum capacitors on the preamp board. There were actually 4 capacitors and it seems to be that 2 capacitors are in parallel with the 15V and -15V rail.
After removing the two shorted out capacitors I powered on the unit. This time the unit sprung to life but the amp is on mute mode. The indicator light is red and the LED on the main board labeled 'mute' is also lit. I measured the power rails and everything was ok and stable.
During troubleshooting one of the remaining tantalum capacitor on the preamp board shorted. So I have replaced all the capacitors now, there are no shorts now but the amp remains in mute mode. I tried playing back audio thinking that amp was in idle mode or something. No change, no sound but I heard very faint audio from the small satellite speakers.
I couldn't find any service manuals online, which makes the troubleshooting that much harder. I emailed the manufacturer but they are not willing to hand out the service notes unless its their authorized re-sellers, even for their legacy products. Any help on getting the service manual would be really appreciated.
The amplifier chip is LM4780. Nothing seemed to be shorted there. One thing I would remark is that the -VEE pin is tied to ground. I thought it would be connected to the -15V.
I traced the mute pin track to a SOT26 package transistor, the markings on it is '1Ft'. I couldn't find the pinout, knowing this would also help to figure out why the amplifier chip is mute.
Any help on this would be really appreciated.
Thanks in advance.

hi fellows, have been reading the original A75 publish and got a few questions wondering if i can find consultation here.

my electrical engineering study experience went no further than high school level.
DIY audio-wise, have successfully assembled and run AMB β22 singled-ended and balanced in these past 3 years.
started reading and assembling an A75 these 2 months.
can sense my understanding for audio amplifier components and circuits growing, but still won't say i am knowledgeable a all.

1. output stage circuit
   so i see in the amplifier wiring figure depicted in Part 2, it has speaker+ output connecting line coming from 'right in front of' the output stage circuit, rather than having OUT going through the output stage and then connect to speaker.
   i understand that the output stage is common drain mode in parallel, and it takes signal input from DRV+ and DRV-, right? so what would OUT be comparing to DRV? because in the complete amplifier circuit in Part 1, the OUT goes in to and through the whole output stage, and comes out as input to speaker terminal.
2. gerber drawing of power supply board
   is there an error with the section of where transformer secondary output goes into regulated circuit? R3 and R4 should definitely be between C4, C5 and AC, right?
   same thing with transformer secondary + and - marking in the wiring figure. (but probably most DIYer can make out these typo so no big deal?)
   after reading the article in these 2 months, i am 'guessing' there are minor errors with the gerber drawing but circuit diagram of amplifier and power supply are correct.

Would appreciate guidance on both A75 as well as suggestion on reading/studying direction to solve these questions.

Hello everyone, these last months I started designing a more accomplished NAP250 clone, I may have been too ambitious and suddenly I end up with a small problem of oscillation of the main regulator.

I respected the Naim audio diagram with the difference that I placed the amplifier and the regulator (NAPS) on the same PCB, routing level it was complicated to do.

After wanting to improve the amplifier I replaced the MPSA56/06 transistor references with ZTX753/653 which are more robust

the drivers and output transistors were also replaced by
TTC3710B/TTA1452B
and MJW18020 at the output.

The output filtering capacities are at good esr for stability and those at the input too.

everything else works fine the amp the phase compensation etc I even added the TGM10 speaker protection which works and also a front regulator (like the NAP250 DR) but for the moment I dismantled the front regulator to focus on the NAPS which is faulty.

I specify that on laboratory power supply everything worked without problem and the oscillation was therefore not present, I think it is the ripple of the symmetrical power supply which is not supported by the regulator.

do you have any ideas as to the cause of the problem compared to the original design? or do you have a modification to make that could stabilize this problem?

thank you in advance I put you pictures of scope and the new design.

the oscillation is a 150Khz component which makes 100 mv on the negative rail and 50 mv on the positive rail.

Dear all,

Recently acquired a Sansui Sr525. It was spinning very fast and with high wow and flutter as measured by an Android app.

Did these and managed to bring the speed down to 43rpm on the 33rpm setting:
1. Replaced the fine pitch controls and VR1 and VR2 on the motor board.
2. Opened the microswitch and cleaned it as much as possible.
3. Replaced all electrolytics caps on the power and motor control boards.

It is the slowest speed I could get by putting the fine pitch control and the trim pots to the slowest setting.

I have since replaced the zener 5.1v and 2 ceramic caps near the dual transistor at the motor circuit, to no avail as well.

Any suggestions? Thank you very much!

looking forward to learn everything that i can from fellow users

As part of an experiment I am looking into how best to replace the clocks feeding an Intel C222 chipset on a PC motherboard. The idea is to replace the crystals with XO clocks with separate power supplies. The power supply with be a 3.3v lifepo cell.

The suitable 25MHz XOs that I can find (eg https://uk.farnell.com/jsp/search/productdetail.jsp?SKU=2394158) appear to have an output signal voltage (high) of a minimum of 90% of VDD. Seeing as the lifepo outputs around 3.3v this means around 3v o/p signal voltage. However the chipset documentation states that the voltage should be no more than 1.2v.

I have read through a few threads on the subject of replacing clocks here and elsewhere but none seem to mention this issue. Is it a non-issue that I can ignore? Or, as I'm guessing that I shouldn't, how can I reduce the output of the clock with as little disruption to the signal as possible?

Many thanks,
Crom

I'm currently working on a high-power amplifier and I'm exploring different input stage designs. I'd love to get your insights on the performance and sonic characteristics of op-amp based input stages versus discrete transistor-based input stages.
I would greatly appreciate it if you could share your experiences and attach one best input stage schematic for each category that you believe excels in performance.

Looking forward to your valuable inputs!

I have made two surround ”eggs” to complement my chn110 tower speakers , using the similar looking but much smaller chn50 driver in a small cabinet.

Two IKEA 12 cm wooden bowls and a 3 inch 22mm Mdf ring was glued and painted in black. I used a round black cable and making the drilled hole in the speakers very tight so they dont need any connectors. Inside there is sheeps wool and no crossover at all.

These speakers will be mounted on two speaker stands with a round base.

The reason I made these speakers is the new software in WiiM ultra , allowing dolby digital 4.0 with the help of my older WiiM PRO and my Hypex ncore 125 amplifier.

Feel free to chip in

Hi friends, a while back I built this amp for a friend(with some changes). He's been using it for several years without any issues. A few weeks ago, he told me he was hearing a noise on the right channel. I thought it was the 6v6s running out. I set up the oscilloscope and detected a noise/oscillation in the negative part of the sine wave that I can't detect. Can you give me any clues on how to locate the fault? Could it be the OPT? I've already tried another 12ax7 and re-soldered it.

The red marks are where I placed the oscilloscope and found the noise.
The other triode of the 12ax7 and the other 6v6 work ok, to eliminate the potentiometer.
I inverted the 6v6 too.

thanx a lot guys!!



https://diyaudioprojects.com/Schematics/DIY-Push-Pull-PP-6V6-Tube-Amplifier/

This is a group buy for circuit boards to make a diy clone of the First Watt F3 amplifier. This board set is designed to work with the diyAudio store UMS mounting pattern making life a little easier for those having UMS chassis.

The design is about 80% done and now it is time to gather input and make refinements before ordering a test set of boards to validate the layout.

The images below show the basics, and the .pdf has more details about the boards, preliminary pricing, and a tentative schedule for the group buy.

Here is a link to the F3 UMS Pattern Group Buy Sign Up Sheet

I will make every effort to post weekly status updates to share progress.

Need some help to repair a bad channel on Crown 400CSL power amp. Need a little help where to look. I seem to have a good signal up to C100 but signal after R101 seems bad. I made a couple videos:

Output off speaker terminals.

Signals at C100 input and R201 output.

Here is schematic: https://schematicsforfree.com/files/Audio/Products/Consumer/C/Crown CSL 460.pdf

Any suggestions appreciated.

A new wood enclosure in perfect condition, very solidly made of high quality plywood (no voids) with beautiful veneer, brass screen on top, vent opening on bottom, four pointed brass feet.

Overall outside dimensions 21" wide x 16" deep x 7-1/4" high, not including feet, 8-1/4" high with feet. Internal dimensions 19.5" x 14-3/4" x 6". Front opening 17" x 5-1/2". Screened top opening 14" x 7". Bottom opening 11" x 6".

$200 plus shipping.

So I am a DJ and occasionally do live shows corporate work as well. Our typical event is 300 people or less, mostly indoors but occasionally outdoors. I am looking to really make my load in/out as simple and easy as possible. Dragging VRX subs and SRX tops in and out of venues by myself is doable but I am getting older now and it seems like it just gets a bit more painful every year.

I would like to go with a Passive rig that can be run by two QSC GXD8 amplifiers or something similar. Keep the processing in the amps and have a simple 5U case at 35lbs. For subs, I have built two of single 15 enclosures using Beyma 15LEX1600nd. The enclosures are complete minus the handles. Waiting for the drivers to come in so I can get the COG right. They should weigh in at right about 55-60 lbs and are very compact. Supposedly they get decently loud. I guess we'll see. If they perform well I intend to build two more for outdoor work.

I am struggling a bit with a design for a lightweight 2-way top. But ultimately I would like to us an RCF HF94 coupled with 2 B&C 8MBX51 mid/low drivers. I would like to hp them at 80 to 90 hz and crossover at 900 - 1000. I spent several days in winISD and the attached screenshots are what I came up with so far. In this design I have baffle between the low and high frequency section to keep my volume down. Ultimately, I would like to achieve a true 125db and be under 40lbs.

So besides and suggestions you might have, I have two questions:

1. Is there anything wrong with using a rear port on a PA speaker? I really struggled to find a balance in enclosure volume and port dimensions that were reasonable without exceeding cone excursion parameters. And I could save a few inches in height if I could move the port to the back.

2. Is there a particular compression driver you would recommend pairing with the HF94?

Here they are, both K and K2 diagrams, may the interwebs never be void of them again!




For those who want to remove the Lpads on the Ks, here is an altered diagram:




Thanks to all who have contributed to this thread and a special thanks to @chrisng for his tracing and diagram skills! 🙂


--------- Original Post Below ----------

Hi,

I am after the crossover diagram for the Goodmans Magnum Ks.

In this post here: https://www.diyaudio.com/community/...sovers-and-potentiometers.112926/post-1971834 user alspe had previously uploaded the crossover diagram to google drive. It was some time ago though and the link is now dead. It’s not listed in the way back machine either.

I was hoping to contact alspe, but it looks like they are no longer a member here and I can’t tag them.

I have attempted to trace it, but these old xovers are a mess and I’m finding it difficult.

I thought it would be similar to the K2 but it’s not. Not only because of the Lpads, but the filters are different too.

Anyone got it or able to help?

Hi All, been offline for quite a while, since i finished my major build. Despite it being a year long learning experience and trying to use best-practise on every aspect (within the limits of my requirements for a compact system) honestly ive never been totally happy with the sound. the subwoofers particularly have never really satisfied me, and the whole system seems to be missing something. The subwoofers (compact things with slot ports) do crank out bass, but its a bit resonant and boomy, and overall the system is missing "slam!"

i remember at the time, i had a laugh when somebody here described my chosen subwoofer drivers (https://www.daytonaudio.com/product/120/rss265ho-4-10-reference-ho-subwoofer-4-ohm) as "mud-shovels" and i assume the criticism was spot-on. i chose them since a) i got them for an amazing price and b) they allowed me to build the subs small (also they did have great reviews so im not a complete idiot)

so anyway, im evaluating options. specifically, im wondering if some other enclosure type might allow these sub drivers to sound better.. ideally also reaching higher to improve the punchiness of the sound. (they claim to go up to 600 hertz, id be happy with kick drum range at 2-300hz.) at the moment they cross over to my dual driver alpair fullrange cabinets (also ported enclosures) at around 85 hz.

Id not go higher with the current cabinets as first, they are not positioned well for stereo imaging if they go higher, second, the drivers are down-firing and third, with a 210 gram cone, they have a habit of jumping off the floor despite weighing close to 20kg.

i was playing with the idea of some kind of transmission line (pvc pipe?) or tapped horns, placed under or behind the fullranges, with the drivers forward firing.

i do vaguely remember however that these drivers were not well suited for tapped horns.

itll break my heart to replace the very pretty (imho) translam cabinets i spent months designing and building, probably with something 3x bigger and ugly. but if it doesnt sound good, whats the point?

any suggestions most appreciated.

Hate to see it go, but it's been gathering dust in the closet since I switched to an active monitor setup. I built this amp in 2016 and it sounds great. It has XLR inputs, but can easily be converted to RCA. It is quiet even with sensitive speakers.

Asking $500 obo. Local pickup preferred, but willing to ship within ConUS. I am located in San Francisco. Sold

Plan on post #83
latest sim and hr file on post#121


###########################
On my quest for a PA sub design that will let me reach 140dB SPL with 4 cabinets and do not use the 700+ Drivers from Beyma, 18sound and B&C that are staples
in high output PA cabinets
i looked for modest options and found a car driver that fits the criteria

since my hornresp skills are very modest, i can not simulate from scratch but punch in different drivers in to existing designs.
i think i found a winner combination.

i will take 2 sheets of ply and 2 skar drivers
143 a piece per driver is 286usd for 3kw power per cabinet
the original design costed about 325 bux in 2013, i calculate that this will cost about 400 to 450
wood plus , handles, casters, paint.

do you guys remember this LAB12 based design ?
https://www.diyaudio.com/community/threads/325-lab-12-based-pa-tapped-horn-35hz-extension.232219/



BP1 was very kind to help and do some mods to the original design that can only house a LAB12
he made S1-S2 baffle length longer so to accommodate 2 skar 12" drivers inline
using 4 cabinets with 2 skar 12 DDX drivers @1.5kW per driver (3kw per cab) we get this









with HP and LP applied we get this


what you guys think?
tweaks ,mods, and improvements are welcome
Max.

To spice up my boring 2 way build I am going to try some 3d printed edge diffraction pieces to see what difference they might make.

I will be starting with this aerofoil/teardrop shape. This is a pretty small one but I can make it wayyyyy bigger which is probably what I will try next.

Does anyone else have a shape they would like me to test? Let me know. Let's do some science!

Hi folks, I've noticed a lot of misinformation about people using ferrite (Fe2O3, or commonly referred to as rust) resistors in audio electronics and other electronics. It's actually a horrible choice of material for a resistor. Ferrite is used in antennas! If you want to get hacked offline or to pick up interference from random crap, ferrite is a great choice of material in your resistors.

I think a lot of you are making your own electronics specifically to avoid talentless hacks screwing everything up. If that is the case, you are perhaps better off with some sort of ceramic material for resistors, just make sure your power rating has sufficient watt throughput capability.

The benefit to using ferrite is that the resistors are very small. If you are shielding everything or are not worried about talentless hacks ruining your fun, ferrite is a great choice. Otherwise, choose resistors made out of a different material -- especially if you are in aerospace.

I just got a VPI SDS but I don't think it's operating correctly.

I connected it to my VPI TNT Jr and it worked but pressing the rpm button woudn't do anything nor would the up/down arrows. I messed around with it and was able to change speed by simultaneously pressing rpm & down arrow. I could change the frequency by pressing rpm & up arrow. This would lower the frequency but I can't figure out a way to raise it. I also can't get into setup. The output voltage & frequency match the display.

I assume this is a firmware issue?

Thanks.
Kevin Looker

I‘m trying to simulate the LM3886 with the LM3886.lib from Texas Instruments in LTspice XVII. The schematics is from the datasheet. When I run the simulation, the error log is telling me:



I assume that something is not connected properly but I can‘t figure out what it is?
I renamed the LM3886.asy to LM3886.asy.txt and the LM3886.lib to LM3886.lib.txt, so they can be uploaded with this post.

The Texas Instruments Support can't help with LTspice XVII, because they support only TINA-TI or PSpice.

Dear members,

I'm looking for a Krell KAV-400Xi KAV 400 XI schematic / service manual.
left power amp is broken.

This build thread associated with this GB:

http://www.diyaudio.com/forums/group-buys/229358-my_ref-fremen-edition-interest-group-buy.html

On the project's OneDrive folder it's available a PDF version of the tutorial, in addition to schematic, BOM, etc..

Also on 7/2013 I've added a video on YouTube of the SMD soldering part:

Apart support and sharing place for builders, goal of the thread is to generate content to complete the tutorial.

Builders, please post your experience, problems, pics and whatever related with your FE build... 😉

Good day,

Anyone happen to know what diode was in place at location D6? It was completely melted out of the amp when I got it. The MJD32C burned the pad up pretty good.

Thanks in advance!

I have a strange setup I'm looking to update. I do the bulk of my music listening in my kitchen and the only place to put speakers to get decent soundstage around the whole room is on the ceiling. So I stumbled on DML speakers and made some 2x2' panels from styrofoam. With some heavy DSP and a sub they sound great honestly.

However I am just kind of bored and looking for a change so I want to keep the same ceiling hung config but build new speakers that address the shortcomings of the DML panels. The shortcomings are basically general inefficiency, high LF rolloff (about 200-250Hz from what I remember) and the heavy handed DSP to flatten the response. The great thing about them is the imaging- there is basically no beaming, at least to my ears, which is great considering how much I move around the kitchen.

So I am looking to make new 2x2' panel speakers with conventional drivers that have minimal beaming/max dispersion all the way up the frequency range. My gut says to just pair an in ceiling speaker with a high QTS 10-12" driver and call it a day. But I'm also open to running a WMT 3 way setup as well. Imaging doesn't have to be perfect.... I just don't want any high frequency hot spots in the room. What do you recommend?

Great day guys, this amp keeps blowing out the rail caps mainly the negative side, what could be the issue why it’s doing that, power on ok, then even with low volume it’s just pops the caps, I’ve change them but there seems to be an issue otherwise.

Good Morning. Here’s my Second post to clean out some stuff I don't need.

1. I have a lot of Gotham Audio wires and connections I bought from swisher land and shipped to my house. Never used.

2. I have a few Belden speaker wires and so on for sale. Never used.

3. I have some Canare Wires all speaker wires and the 4S11 (O.F.C.) I paid more for per. Foot and the regular 4S11 cables. Never used.

4. I have some whirl wind speaker wires and cbi Speaker wire and West penn wire as well. I have Redco’s only House brand speaker wire too. I have very little Dayton Audio wire but, I have some.


I have some Binding post from Dayton Audio and Gotham Cables and RCA plugs as well.

I have quick connections Gold and silver ones for speaker cable and driver hook ups.

I can take pictures and send them to anyone who wants to see pictures of the products.

I would love to sell local it would be a lot of little things to ship out. I also Have the wire in a sealed container.


E mail me with Questions about things for sale. I can be reached at Jmboo1922@gmail.com. Thanks Jeff

I’m recently new to the hifi hobby and have always been intrigued by building things yourself. I’ve studied electronics and embedded systems in schools even though IT was always my major. Now I’m looking to re-ignite my interest in electronics via hifi. 🤓

Hello.

I have two couple of speakers with altec lansing 409-8c coaxial drivers, each of them driven by an integrated tube amp. One couple of these altec goes first through the speaker level imputs of two vintage Yamaha subwoofers. A couple of pictures, so you will understand:






These Altec speakers have a sensitivity of 97 db, nominal impedance 8 ohm and minimum impedance 6 ohm, and an advertised frequency response of 50 hz/14 khz.

I would like these speakers to be driven in parallel by just one amplifier, each channel going first through one active subwoofer, then two coaxials in parallel and, in order to have a higher impedance as a result, I would like to add a 16 ohm vintage compression driver and horn for each channel, with a crossover like EV c35.

Do you think it will work? What kind of impedance will I have? What vintage compression driver and horn do you recommend? What crossover?

(I can't build a crossover myself, I'm quite a novice)

What kind of sensitivity will I have with two 97db speakers in parallel for each channel? 100 db?

In short, each channel, after the amplifier, there will be a subwoofer, two coaxial drivers Altec 409 in parallel, then a crossover and a compression driver and horn. The horn will go on top of two speakers.

In short, if this is feasible, what I lack is compression drivers, horns and crossovers, and also the knowledge. Compression drivers and horns should not be very heavy. I've got fibromyalgia and can't lift heavy weights.

Thanks in advance.

Hello Everyone how are you all 🙂. My diy Lampucera has arrived. It has not come with any instructions. It has two power supply transformers I don't know where the one with yellow wires connects. As I look at everything to do with the dac it's starting to become clearer what to do and one of the things is ask a friend of mine who solders better than me to help me. To test it to see if it works do I need a metal case first and is everything I need to get it working in this kit I know I need a power cable to connect it to the on off power connector that comes with it.

https://www.ebay.co.uk/itm/18672783...46UT_E9QjS&var=&widget_ver=artemis&media=COPY

Hi All,

Im a hifi enthusiast from Malaysia with limited DIY experience. I picked up hifi during my university time in the mid 90s in the UK. It seems the bug is still with me until now. I run 2 sets of stereo separates, one with ole chrome and the other with olive naim amplifiers at the heart, sources are Arcams and Audiolabs and speakers are Epos and Mission.

3 days ago, my trusty 30 year old Arcam Black Box 50 stopped working. One thing I notice is that the sync lock light is stuck ON all the time (cannot be switched off) and there's no red light at the sync lock terminal at the back of the unit. My go-to CD player repairman asked if I can get a hold of the correct circuit schematics. He's got the repair manuals, but its not sufficient it seems.

I was wondering if anyone here can assist me on this issue, or even help with the circuit schematics of the Arcam Black Box 50. I can be contacted via WhatsApp at +60123827078. Thanking all in advance and looking forward to making your acquaintances and sharing of ideas here.

I recently published an article in audioXpress (September 2024) about a new family of loudspeaker crossovers that I call "DFE Crossovers". The filters that make up these crossovers are derived from elliptic filters (giving rise to the DFE name) are characterized by:

• steep transition bands, up to ~150dB/octave
• a stopband that is finite in depth, typically 40dB-50dB but sometimes more
• excellent LP+HP summation with very low ripple
• low group delay (below the threshold of audibility reported in the literature)

The elliptic filter is described by more parameters and has more degrees of freedom compared to all-pole crossovers. This provides additional degrees of freedom, making it possible to trade off steepness, stopband depth, ripple, and group delay. I used an optimization technique combined with an objective function that attempts to balance all of these characteristics of the crossover and its constituent filters. These crossovers make use of two lesser-known notch filter responses: the highpass-notch and the lowpass-notch. When expressed as a series of first and second order stages, an elliptic filter uses only the LP-notch or HP-notch 2nd order stages, with odd order filters having a single additional all-pole LP or HP filter. I described the LP-notch and HP-notch in an aricle in the August issue of AudioXpress. It includes a suggested circuit for an analog-active implementation as well as a C++ code to calculate the IIR transfer function coefficients that can be plugged into a DSP processor that can accept them.

The DFE family consists of over 30 examples, having order from 3 to 8. Variations such as "squared" crossovers (like the Linkwitz-Riley crossover) and combinations of all-pole and DFE crossovers (AP-DFE), are included in the "family". The AP-DFE type can be implemented as a mixed passive+active hybrid, with the all-pole part implemented as a passive crossover and the DFE part using analog active or IIR DSP means. This has the advantage of suppressing harmonic distortion within the LP filter passband (see this Purifi tech note for more information).

The audioXpress article provides full details on the DFE crossovers, but I will provide a couple of examples below. I typically present the lowpass filter response, a zoomed-in view of the LP+HP sum, and the group delay of the crossover. The highpass filters is simply the lowpass mirrored about the crossover frequency. Please see the following attachments:

The elliptic-like response of these crossovers is well suited to loudspeaker crossovers because stopband attenuation of more than about 50dB is not necessary. Instead it is better is to quickly transition between passband and stopband (e.g. the transition band is narrow). Most non-FIR filters with such narrow transition bands would produce excessively high group delay that would cause audible phase distortion, but I have used the extra degrees of freedom to design the DFE Family filters to have sufficiently low group delay as to not give rise to audible distortion in the time domain signal.

Overall these filters offer an interesting mix of capabilties that has not yet been available except through FIR filtering. The DFE filters can be implemented with analog active circuits or IIR DSP, and remain easy to use and relatively lightweight. You can download information about the complete DFE Crossover family at the following link:
https://audioxpress.com/files/attachment/2777




.

As spin-off of thread below I build a unbalanced tube input board for my hybrid purifi modules as mentioned in the thread below.
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-3#post-7027789



Picture from Jasper84

I made a PCB for the unbalanced version, a 6n6p tube with mu-follower topology.
The preamp has a gain of 9 times and no problems to drive the 2k2 input impedance of the 1et400a modules.
Timing circuit around Q1 has a 13 seconds delay. This gives the tubes time to heat up without getting a big thump and shutdown the amp modules without strange noises.
Led D2/3 is on the “amp on” signal and can be mounted in a B9A socket with a hole in the middle. Tube bottom will light up when amp is on.







Combined this input board with 2 x 1et400a Purifi amp and Hypex smps1200a400 and smps 265v/6.3V then you get amp in picture below.



This amp is a pleasure to listen to.

Would anyone have a Dynakit z565 output transformer, either a new or a used one in good electrical condition that you would be willing to sell?

Forgive me while I learn these full bridge amps.

This amp powers on, makes rail voltage but has clip light on.

Output doesn't seem to be switching. I believe if I lift Diodes 10/11 that will force the MIC8280 (U7) to send pulses? The driver ICs are CSC3127's? Can't find much of anything on them. They then seem to feed 2 pair of 1797/4672 buffers.

What's the best plan of approach here?

Outputs don't seem to be shorted.

One 1 set of outputs I have G(55v) D(124v) S(55v)
Other set of outputs I have G(0V) D(55v) S(0v)

Same on both sides of the amp.

I bought this massive transformer several years ago and never realised this project. It is the 15 watt OTL with EL509 Tubes.
It is made by a very well regarded German company, it also has a magnetic shield.
Some parts come with it, see Photo.
I also can add eight 6s45p tubes for 70€, they should work fine.
Preferably shipping to Europe, as it is pretty heavy which will drive shipping cost up.
Price 200 Euro for the whole package including tubes, 130 without.

(update) Wellers solding station not sold. Thanks everyone. Good Afternoon. I have the Following Items for sale. Fell feel to make me in offer even after I put what am asking for? I can also send pictures. Here is my
E mail. Jmboo1922@gmail.com

Items for sale.

Sold1.Bass box and Crossover pro programs with books cd and both product numbers. Asking $50.00 and You pay shipping. Books in excellent condition.

Sold/2.Dayton Dats v3 mint condition comes with everything and even the original box. I also thrown in the mass scale new and the Probe that slows down your speaker and so on and the original woofer test 2 from Smith and Larson with everything it comes with and even the box. and The winspeakerz and the subwoofer tool box program. Am asking $120.00. You pay for shipping. (If you do local pick up I will Give away a tripod and a 4x8 piece of acoustic foam to put around the tripod).

(Not sold yet)A. I have a digital Weller a soldering station with a soldering smoke fan. I’m asking $100.00. Brand new never used any of them. I have paper work on both. You pay for shipping.

I will only ship to the 48 United States. Thanks Jeff

2" Peerless by Tymphany - nice driver, right ?

https://audioxpress.com/article/test-bench-peerless-by-tymphany-full-range-2-pls-50n25al01-08

wait what is this ?



20% THD ? how ???

well ...

"For the distortion measurement, I mounted the Peerless by Tymphany 2” rigidly in free air"

he always does that ... FREE AIR ... WHY ??? he had it mounted in an enclosure for his other tests:

"I mounted the PLS-50N full-range in an enclosure, which had a 9” × 4” baffle and was filled with damping material (foam)."

but for distortion measurement it is now in free air ... "rigidly mounted" ... he says it like it's some kind of an achievement ... as if mounting it flexibly would produce a different result ...

that makes no sense ... of course without enclosure the low frequency of fundamental will get cancelled out by the back wave while the higher frequency of harmonics will not, causing the measured ratio of harmonic to fundamental to shoot way up to something absurd like 20% THD ...

does anybody actually believe that a driver from a major manufacturer would have 20% THD in the middle of the passband when measured correctly ?

why does he keep doing this ? isn't he the guy who wrote the loudspeaker design cookbook ? surely he knows better ?

what is going on ?

Omicron is:

• A compact, ultra-low distortion headphone amplifier that we developed jointly with @Rus2000 from the RCL-electro.ru forum
• Designed to work with 32 to 600 ohm headphones and tested with a range of over-the-ear and on-the-ear cans from AKG, Beyerdynamic, Grado, Klipsch, and Sennheiser but proved to be equally at ease with lower impedance headphones, such as 8-ohm AKG's K3003 3-way in-ear monitors and 18-ohm HIFIMAN's planar magnetic HE5XX; the ubiquitous white Apple EarPods (tethered ones, both 1st and 2nd generation) sound great with Omicron, too!
• Very musical, with pure, clean, liquid sound and perfect clarity even in the most harmonically complex pieces. Those who built the Omicron often report that its sound is addictive, and that it is hard to put the headphones down when listening to music.

First hand experiences:

The sound immediately fascinated me so much that I began listening without adjusting the quiescent current. You want to turn up the volume, no mess, even the quietest sounds are clearly heard, but at the same time the sound is very comfortable, not harsh, a beautiful three-dimensional scene. Very nice bass. In short, top notch!

Click to expand...

donovas said:

... sounds flawless and works equally well. [...] The claimed <140db probably holds true because this design sounds cleaner and smoother than anything ive built and that includes single opamp setups and well known discretes.

Click to expand...

bloqhed said:

This amp is fantastic, I've been listening away and taking notes for a better review, spent a few hours last night playing games with it, worked wonderfully. It really blows all of my other headphone amps and line amps out of the water. The clarity is surreal.

Click to expand...

Last night compared Omicron with my composite LT1210 based headamp. At first, it seemed that the LT1210 sounds softer and more beautiful, but after listening to Omicron for about an hour, I switched back and realized that now I want an Omicron for myself! With the same tonal balance, it gives an accurate, fast, assertive bass and better conveys space. Sounds great on good recordings.

Click to expand...

Will2226 said:

...the sound really is fantastic. [...] It's a huge step up from [...] bottlehead crack with the speedball upgrade.
The soundstage is really amazing with my hifiman cans and there's a wonderful amount of detail. Very liquid sounding and the amp just seems to do everything right. The amp runs very cold too, the case never even gets warm.

Click to expand...

jwchen119 said:

The Omicron is a fantastic headphone amp and preamp, the background is more black and bass is more deeper and punchier. Also the clarity is absolutely amazing, the vocal is no doubt much clear from the track "Mistakes from Lake Street Dive" than before.
And the crossfeed did something, especially from older track or some track that the musical instrument sounds are more biased toward the left and right channels. Toggle on the crossfeed makes the soundstage a bit wider and the sound is no more at the front but a bit lay back, more natural.

Click to expand...

I have the feeling my old Beyerdynamic DT-880S from 1984 in combination with the Omicron never sounded that good.

Click to expand...

Sounds good! [It has] no sound of its own. The resolution is there, and so is the bass. Highs and mids are very clean. I have been using it for a month, will put it in a case now.

Click to expand...

danbmellow said:

This little amp is something else. Listening last night it really started to open up after a couple of hours. Bass goes deeper than any of my other headamps. Very black background. Smooth yet detailed. I ended up listening much later than I had planned. Very musical. Definitely a keeper.

Click to expand...

ElArte said:

Easy to build and excellent.

Click to expand...

Features:

• Vanishingly low distortion: with THD and IMD better than -140dB (0.000 01% - that's only 100 parts-per-billion), Omicron is orders of magnitude more linear than other "high-performance" and "ultra-high performance" amplifiers
• Compact: Just one IC and two transistors per channel
• Inexpensive, commonly available parts (NE5532, BD139, BD140; under $40 at Mouser for the whole BOM)
• Easy through-hole construction (NEW: a smaller board with easy-to-hand-solder SMT parts has been developed, see its photo above)
• Functionally complete: One 80×110mm (60×90mm for the SMT version) board carries two amplifier channels, a sensitive DC protection for your headphones and an optional (switchable in the SMT version) cross-feed circuit, which helps create a realistic soundstage in headphones

Simplified schematic (links to the full schematic are below):

IMD 19+20kHz, 5Vpp @32ohm (see post #11 for more measurements):

Theory of operation:

• Schematic design: post #2
  • Mod: increasing input impedance: post #67 (this mod is now the stock version and part of the BOMs linked below)
• Loop gain (simulated): post #27
• Crossfeed schematic and frequency response: post #33
• DC protection: post #34
• Power supply: post #35

Measured performance:

• Distortion, clip, frequency response: post #11
• Distortion and clip for the SMT version with no heatsinks and half the quiescent current: post #109

Schematics, board outlines and other reference information:

• Through hole Omicron board
  • Schematic: post #295
  • Board outline: post #142 - includes a discussion of how to fit Omicron into 1U enclosure
  • Part list: post #155
  • Winding the output inductor: post #71
  • Mod: crossfeed switch board by @gajira: post #334
  • Mouser shared project - order all parts for this board in one click
• SMT Omicron board
  • Schematic: post #297
  • Board outline: post #299
  • Part list: post #298
  • Mouser shared project - order all parts for this board in one click
• Power supply board
  • Schematic and board outline: post #300
  • Part list: post #301
  • Mouser shared project - order all parts (except the power transformer, see post #174 for what's recommended) for this board in one click
• Assembly guide: post #225
• Choosing volume control: post #170
• Mod: running Omicron from +/-12V rails
• Opamp substitution: one, two.

Build examples:

• Post #173 - yours truly
• Post #226 - @bloqhed
• Post #287 - @ElArte - Fallout themed!
• Post #311 - @ElArte, another build
• Post #330 - @Will2226
• Post #393 - @Mulburg - in a vintage toaster!
• Post #402 - @emuffler
• Post #425 - @Mulburg, a more conservative build
• Post #479 - @jwchen119
• Post #545 - @namghiwook

Hi - The Undearm Incident here.
Never forget

Hiya, I'm joining this site in an attempt to learn how to fully fix my beloved NAD 7240PE and also just absorb more knowledge on audio amps in general 🙂

I am new to this site. From Australia. I have signed up to talk with audio professionals about live PA systems. I have built a 20hz tuned tapped horn, and a FLH line array kick bin for drum and bass/ house rave parties. I currently have an event startup for rave parties within my state. I am also a software engineer and have some ideas I'll be developing over the next few years. Id love to chat with individuals and share ideas I have.

Hi All,

Im a hifi enthusiast from China with limited DIY experience.

I’m from Montana and I’m here because I have a unique Rockford fosgate amp that nobody locally appreciates and so I’ve been having issues selling it for even half what it goes for. It’s a vintage t1000bd from what I can tell it’s a 25 to life edition and it works with no issues. Any help pointing me in the right direction would be neat oh and I’m looking to get somewhere between 3-500 out of it.

Hello,

i am embarked on my first DSP/Amp trial and ran into some issues regarding the gain structure with this board. While programming and measuring it with REW i got the board very easily into clipping (REW output measured at 1.5 Volts Output) without getting even full power on the outputs of the board (was not trying to anyway). So my question in general is, does someone have/had experience with tinysine boards and is able to tell, how to approach this whole topping of using an analog input without getting it into clipping/distortion whilst getting maximum output possible?
There are some dip switches on the board which i did not even touch and i am running it with a propper 36 Volts power supply.
Would be glad to getting pointed into some directions how to avoid clipping with the analog inputs!

Greets Swany

Hi.
I got the MF-A1 for repair.
Someone had tried to repair the beast before and has done some strange stuff.
I have tried to replace all suspect parts.
One side of output transistors were dead.

So now after replacing and recapping, the amp doesn´t work.
I have about 400mV on the outputs and my output transistors don´t work and are not turned on.
Output transistors are healthy and all other transistors too.
Anybody have an idea?
looks like I am missing something but I can´t figure it out...

Thx.

This is a new thread started from a rando post here: https://www.diyaudio.com/community/threads/headshakes-far-field-3way.382393/post-7434715

I've made a 3" ETON + t25b box before and this will be a reworking of the same setup. I like the idea of being able to swap out the HF/MF boxes.

The Seas L26ROY is in a PartsExpress box. It is by chance that it fits without any adjustment.

I will measure the drivers next and make an ideal sim to reference along the way.

The JA-0801 is in a foam baffle for now. I used some Loctite power grab and some wood skewers to hold the stand together. Metal screws are holding the driver down.



The hypex FA123 can be seen at the bottom of the image.

The tweeter will be picked later.

A translated info sheet about the dome:

I'm not really trying to transform the 'pi. I just to make it store and play music. I have the RPi 4 with 8gb ram. Is there any downsides to using it as a media player? The major upside for me is space. I'm using a big clunky PC in a ATX mid tower that is hooked up to my JVC Audio/receiver/dac/amp now. I'd really like to clean that area up nice and neat. I'd like to hear some dos/donts from people who are using one. I'm not looking to make chicken salad from chicken s**t but I would like a good sounding system. TIA

Hello,
You can make an offer !

I have a Nikko Beta II preamp (the D-TYPE) that has too much gain for modern sources.
Is there any way to decrease its gain by some 15dB?
Service manual attached.
Any input is appreciated!

Good morning,
I have an opamp in my hands, the OP27, possibly to be used as a reference for a regulator circuit. I later realized from the datasheet that an example circuit is also a phono stage in a preamp.
I was wondering out of curiosity if anyone has ever used it like this, and if it sounds good despite being a rather obsolete component. Thank you

Having just built a LM3886 chip amp and finding it too clean, I'm looking to add some tube warmness. I don't need any gain in a preamp, but a buffer with a cathode follower would probably be too clean. I need a grounded cathode stage. I whipped this up:



It seems to work on the bench, 2V P-P in, 2V P-P out. However, I have a very janky benchtop SMPS, and there's a lot of noise on the scope so I can't really measure anything. Is this thing a good idea, or an abomination? I would think the amount of feedback would squash a lot of the harmonic distortion. Should I go with a voltage divider at the input and AC couple the cathode follower without the feedback? Thanks, all.

Good Morning Everyone. I am cleaning out some of my Raw drivers that has never developed into projects I wanted to get done. So I have the following Drivers
for sale.They have never been used and are in a non smoke environment. They have been stored in a controlled environment and it never gets to hot or cold. They are in their original boxes. I will only ship to the 48 United States. I have the following for Drivers for sale. I will be moving into a smaller house Eventually and am going to get rid of everything I don’t use or needed anymore. Spring cleaning.

Mark Audio Drivers.

💥(Updates)1.MAOP 11- Driver’s. Original cost $589.00 a pair. Am asking $400. 00 for the pair . . You pay for shipping.

Sold/ 2.MAOP-5 Driver’s. Original Cost $277.00 a pair. Asking $200.00 you pay for shipping.


2. Puvia Seven HD in the gold color. Original cost $99.40 a pair. Am asking $60.00 a pair you pay shipping

Fostex Full Range driver.

1. FE126E speakers. Am asking a $100.00 A pair. You pay For shipping. New

2.FE126NV speaker. Original cost $140.00 a pair.New Asking $110.00you pay for Shipping.

(Updated)A. Dayton Audios RS125-4 5 inch reference 4 ohm speakers brand new. Cost per. Driver is $44.98. Asking $60.00 and you play for shipping.

Sold/ B. I have a pair of Vifa/ Peerless Ring tweeters the 4 ohm version. Model XT25SC90-04. $21.29 each. Asking 30.00 a pair you pay shipping .(Given away with Fostex speakers).

Sold/ C. I have some paper cone tweeters from Parts Express as a buy out. I think 4 of them at O.68 cents each. (Given away with Fostex Speakers).

I would like to sell for local pick up unless someone is willing to pay for shipping?
For these items listed below.

1. CHN-50P Driver’S. Original cost $40.00 a pair plus shipping was around $14.00. Am asking $25.00 a pair. You pay for shipping.

2.Auible Physics 2” inch speakers. (Newark Company and use to me MCM Electronics). Cost $22.40 each so $44.80 is the total cost plus $15.00 Shipping. So I would like to get $20.00 for the set. You pay shipping.

(Updated price)1. Used Am for sale. Dayton Audios
APA102 BT.Class D amplifier blue tooth. Cost. $184.98 I’m asking $80.00 and I will throw in a nice pair of Studio Master speakers for free. Local Pick up. Speakers

Speaker boxes for sale$

(Updated).A. Frugal Horn XL speaker boxes for sale. I have new Dayton Audio Binding post and Wire for these speakers. Pictures added now. Make me an offer for these boxes.

I can send pictures of speakers you are looking for or interested in. You can e mail me at
Jmboo1922@gmail.com with any questions and offers if you think it’s reasonable? Thanks Jeff

Sold ( Thank You) but, wasn’t in the selling post. Fostex FF166K ENAbled Drivers From planet 10 Hi-Fi.

Sold (Thank you) But, Wasn’t on this selling post. RCA ends. Sold. I have no more left of this item.