2 x 10H/20ma
2 x 6H/40ma
$ 160 per pair

Buyer responsible for shipping cost

Eminence DeltaLite 2515 II 15” Neodymium bass speakers, 8 ohms, very light weight.

They are used in some of Gravesens Open Baffle speaker projects, and they are also very good for subs or electric bass use.

New price is about Euro 400 for a set, without shipping.

I will ship to EU countries by pre payment for Euro 220 including shipping.

OK, it's up.

FIRST WATT

Hello everyone in this chat!

My name is Danila, I am from Saint Petersburg, Russia.
I work in the field of technical support of events, I am interested in pro-audio.
In my free time I write and mix music.
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Hello.
Those of you with a Icepower 700AS1: Hot hot are your heatsinks ?

I´ve got a Icepower 700AS1 up and running since 2 days.
Balanced input, driven by a SPL Volume 8, powering a 2*18" subwoofer (R DC = 2.7Ohm)
The heatsink HS1302 (the one next to the speaker output) gets quite hot.
Testsetup is on a flat board right now. Allround ventilation / free air / no case.

I know you can mount the heatsinks to the casing for heat dissipation. Which I will do lateron when putting it in a case.

Even with low power after a couple of minutes the heatsink HS1302 is getting very hot. I can only touch it for like 3 seconds, maybe 60°C I guess. Seems strange to me.
The amp works normal, protect LED is never on, its never shutting down, music sound real good.
The other two heatsinks on the board feel like 40°C.

I´m wodering if it´s normal for HS1302 to be "cooking" even with low power levels.

Before the 700AS1 the subwoofer was driven by Hypex FA251 or 501.
The plate of the Hypex Modules never got noticably warmer than body temperature.

What´s your experience with the 700AS1 ?
The 700AS1 shoudn´t be so hot with the same levels that the Hypex 251 handled while staying cold, should it ?

I have two Icepower 300AS1, those stay abolutely cold while playing music for several hours.

Cheers, Michael

Hi Hugh,

It appears that the Aspen homepage is not available.

Is it in the process of being updated?

Cheers,

Jens

Have a T7V >
Looking for Adam Audio T7V Power Supply Board schematic

Speaker not functioning

Does the monitor’s LED light up? No
Have you tried a different power source? Yes
Did you select the correct input at the back of the monitor? (RCA/XLR) Yes
Does the issue migrate to the partner monitor, after you swapped the audio cables between the two speakers? No


I'm not the original owner.
There is power coming into cream colored board but no power leaving. (red / black leads)
Thank you for your time
D

Hi Moderation Team!
Please let me post in this forum, I have been diy amps for 50 years....

Hi guys, long time lurker here. Am trying to modify an old audison amp (SRx-4 - the early model with the silver-and-blue color scheme) which has a rather narrow range of crossover frequencies, namely 50-220 Hz for LP and HP, offering the choice of HP for Channels A L/R and HP/LP for ChB L/R. I'd like to use it to actively drive my mid-woofers and tweeters separately using the active crossover, as I have another amp for the subwoofer. Which means, modifying that active crossover frequency - the later model of that amp has a "10x" switch which does change the filter range, something like that is what I want to do (although permanently).

Since I'm not that experienced with amp modification, I'd like to ask here first before making potentially money- or time-consuming mistakes. As I understand it (haven't been able to trace the dual-layer SMD PCB yet), the circuit resembles what is shown in Elliott Sound Products Project 148 - some variable resistors combined with a capacitor to set the filter frequency. So my approach would be to solder in new caps of much smaller size, basically going ~1/25th C to give me 25x the crossover frequencies (1200-5500Hz). I'm 99% sure the 56nF 100V caps here are the ones in the HP filter section, the sliders on the bottom of the image are the ones controlling the frequency. However since there are clearly lines going from the sliders to the set of 4 caps (82nF 63V types) on the bottom right of the image, I could easily imagine the 56nF being used in the high-pass sections, and the 82nF ones for the lowpass section (which doesn't quite explain why there are different values on these than on the others).

Does anyone have the schematics available? It's a bit of a daunting task to retrace this PCB for an amateur like me.

Does anyone foresee any problems with replacing them with either 2.2nF film caps (~1/25th) for the 56nF ones, and 3.3nF for the 82nF caps?

Also, to protect the tweeters when driving them actively, would you guys recommend installing a large cap (basically a 6dB HP filter active below the working range, like 100uF~400Hz xo frequency), or does that seem like overly protective and not strictly necessary on a better-quality amp like the audison?

So thanks for reading through, looking forward to any replies!

Hello!

Could you guys comment on the methods I followed for the 3-way projects I use to build?

Along the last 2 decades, I've built some loudspeakers for my self, family and friends, all 3-way port based with extended bass response down to 30Hz at least.
Always "old style" relatively big (>60 liters) with 8" or 10" woofer, 4" mid range and 1" dome tweeter.
I've used to electrically model the speakers on Pspice (eletronic circuit emulator) to get an idea of the real impedance.
I have a reasonable knowleadge of analog eletronic circuits.
I've always started with a theoretical LR aligment frequency cuts and slopes crossover and adjusted the crossover elements based on the circuit emulation result.
After building the final box, lots of intuitive adjustments always needed to be done playing with resistors/inductors/capacitors.
I understand that the speaker modeling I used to do only models the "piston" range of the speaker and not the rolloff range.
I basically compared the loudspeaker with a headphone and adjusted the elements by ear with reasonable results, not intended to have high-end units.

Last month, I've got a calibrated mic and decided to rebuild the 3-way loudspeaker crossover of my own pair of loudspeakers using REW to generate frequency response and impedance files for each speaker already seated in the loudspeaker baffle. I've loaded the 6 files in XSim.
Starting with a theoretical LR 12dB/oct circuit, I've got the usual result with lots of deeps and peaks and cancelations between speakers , which I used to more or less resolve inverting polarities here and there intuitivelly. I know in LR, we should invert the polarity of just the mid-range speaker.

This time, playing freely with the inductors/capacitors/resistors in XSim, I ended up with a good result (for my standards) both in the XSim simulation as well as in REW real measurements at the first try. Took a lot of iterations, since I fixed a certain range and got troubled in others.

See the attached curves and schematic. These were indoor measurements at 25cm main axis, so disregard frequencies below 100Hz due to standing waves.

Just the tweeter frequency upper range didn't match much comparing simulation (XSim) and real measurement (REW).
I've made the adjustments (notch filter) for the real measurements, of course.
The only care I took was to observe the final minimum impedance (>4ohms) and the minimum frequency protection for the mid (>500Hz) and tweeter (>3kHz).
Looking at the schematic, it's completelly off from the theoretical LR aligment I've started with.
Mid-range ended up being just first order 6dB/oct with a notch to attenuate its breakup frequency peaks around 5 to 6kHz.
Woofer/tweeter 12dB/oct with a notch for the tweeter and a Zobel for the woofer.

Main question: what method you guys follow to adjust the crossover elements in XSim if the initial theoretical schematic doesn't get you a flat response at the first try?

Thank you!!

I'm working on a design for a preamp with a phono stage. The phono stage is based on 2 EF40/86 and 2 5814A/12AU7 set up as amp -> RIAA -> amp -> cathode follower which then feeds into the main pre. The pre is all 12AU7s and 12AX7s. I'm running DC filaments across the board, so I settled on a parallel 12.6V to all tubes to reduce the current load on the regulators. Split supplies for the phono stage and the preamp stage. The issue is the two EF86 heaters at 6.3V each. My initial thought was to just run them in series, but after looking at some comments in other forum posts, there seems to be some concerns about heater mismatch and one tube pulling more current, so I thought I'd ask the hive mind.

Is there any way to balance the voltage across the two tubes? Virtual ground using 2 100R/5W power resistors? A current limiting resistor between the 2 filaments? Dropping resistors to turn the 12.6V to 6.3V (32R/2W)?

Any help would be appreciated!

Early schematic can be found here: https://www.diyaudio.com/community/threads/preamp-design-feedback.417521/
That thread apparently didn't get any traction. Probably the wrong forum section for that.....

Filament power supply below.



Thanks,
Chris

I am new here after lurking for years. I am making an attempt to rebuild one or both of my Parasound HCA-1205a. I have all the replacement caps on order as they are all leaking brown goo and the amps don't produce sound. As I was giving the individual amps a visual inspection, I noticed what I thought was a temperature sensor attached to the heat sink that also had the brown goo. This sensor is on Jumper 2, and the wiring diagram lists the part number as "TO-T95AR1U1" I can find no such part online. Anyway, the part has brown goo, but it may be adhesive. I am leaning away from that as it is in random places on all 5 of them. They are attached with a metal clip that screws into the heatsink, and thermal paste. I am attaching a few pictures.

Any thoughts on if these need replacing based on the brown stuff, and if so, what are they? Even Digikey tech support was stumped. Thanks

Is there any reason not to use dupont flashing tape as a gasket between the driver and the baffle. I have some left over.

thanks

Hello, I am a complete beginner in speaker and amplifier schematics. I want to build a 6-inch down-firing subwoofer as a replacement for my old and worn-out 2.1 speaker subwoofer. For the L/R channels, I am using 4-ohm 2.75-inch 15-watt Harman Kardon full-range speakers and 1.5-inch 3-watt tweeters for treble.

Here are the parameters I am using and the design for the subwoofer:
-Box size: 25x25x25 cm made from 15mm MDF (30mm board at bottom for stronger driver mounting)
-Amplifier: ZK-TB21 TPA3116D2 Class D (32-pin original)
-Subwoofer driver: 6-inch Legacy LG 696-2 (parameters are attached)
-Ventilation port: 5 cm diameter with a 16 cm long port

There are a few questions I would like to ask, and I hope you can help me determine the answers:

1. How much power supply wattage do I need for this setup? Is using 19V 2.37A = 45 watts enough?
I have this adapter from an old Asus laptop charger with a DC port.

2. With these subwoofer specifications, is running at 2 Ohms better than 4 Ohms?

3. Is my box design suitable for achieving a soft and deep bass character? I will place the subwoofer under my computer desk.

4. My subwoofer box design is inspired by the Audioengine S8, but dimension-wise, I followed the Audioengine S6, which has a 6-inch driver and similar box dimensions around 25 cm. Is this good get smooth and deeper bass profile?

Good explanation really help me figuring this issue, thank you.

Hey -

I'm willing to pay a few bucks for a copy of a Vestax 46 repair/Service manual. Please let me know if anyone has one.

Mike

Hi All,

I just acquired a pair of JBL L20 (European model, made in Denmark), photo attached.
I would like to change the capacitors in the tweeter's crossover (schematics attached) to Jantzen capacitors but there are 2, C2 1uF in parallel with R1 3R9 resistor and C1 in series, now I want to use the Jantzen superior Z cap but the 6.8uf cost more than what I'm willing to spend so my idea is to get a 1uF superior Z cap and a Jantzen standard Z cap for the 6.8uF capacitor.
I would like to know please what's the reason for the 3R9 resistor in parallel with the 1uF cap?
why not just use 3R9 in series with 7.8uF (or 8uF) capacitor?

Thanks

First we have the high tech 'keyless' entry and start on cars
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Then we have the low tech, basically a Slim Jim on a hotel door.
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I can’t find a schematic for an L-Pad on a second order series crossover for a woofer and tweeter. Every source I have uses a parallel crossover as an example. Can someone point me to a schematic or post an example? Thanks!

Hello! I'm prepping for a build of this Nobu Shishido 2A3 DC amplifier. I should note that it's my second non-kit build... That said, I have a question about the power supply in the attached schematic and specifically why there is a 50 Ohm resistor before the first filter cap. From what I understand the first filter cap for a 5AR4 should be around 47uF. Is the 50 Ohm resistor serving as a buffer after the rectifier? Maybe I'm completely missing something obvious. Thanks in advance!

Good evening,
I need help choosing a power amplifier for an all-in-one two-chassis system I'm building. In the lower section, I will include Teddy Pardo and Salas Shunt power supplies with Mundorf capacitors, while in the upper section I’ve already set up an R2R DAC with a discrete component output and the Buffer B1 preamplifier by Nelson Pass.
What kind of project could I use for the power amplifier? I will be using Harbeth M30 speakers, and I am intrigued by the Hypex ucd180hg hxr, but I am unsure if it is a good match or if there are better alternatives.
Thanks to anyone who can help!

Hi everyone and thanks in advance for suggestions.

New to all this, so happy to accept any type of feedback.

I’ve purchased a faulty Sony WMSP85 active subwoofer. The unit powers on but no sound comes out.

I’d read on another thread that one of the ICs (STK-404-130S) fails very regularly, so I’ve desoldered that and replaced it to no avail.

I’ve also replaced 3 capacitors that looked like they’d burst, and I must confess I am probably responsible for some or all of these, because I think I created a short while voltage testing the old STK-404-130S.

When replacing the capacitors, I had come under the impression that the capacitance and type (film in this case) need to match however the voltage rating can be different, so long as it’s at least as high as the capacitor being replaced. Please correct me if I’m wrong on this. For reference, they were C203, C204 and C208 from the data sheet.

I’ve taken voltage readings across the PCB where the datasheet specifies the expected voltages, and they do seem to be a bit out.

The voltages across the STK-404-130S are as follows, with the data sheet expected voltage in brackets:

1: 0v (0)
2: 0.25v (0.3)
3: 0.14v (0.1)
4: 0.15v (0.1)
5: 0v (0)
6: -51.8v (-42)
7: 11.9v (12.3)
8: 0.64v (1.1)
9: -1.1v (-1.1)
10: -51.9v (-42.5)
11: 51.9v (42.5)
12: 0v (0)
13: 0v (0)


There’s 2 other smaller ICs (NJM4565DD), with voltages as follows:

IC202:
1: 40mv (0)
2: 40mv (0)
3: 23mv (0)
4: -11.9v (-12.3)
5: 5mv (0)
6: -1.8mv (0)
7: 11.6mv (0)
8: 11.97v (12.3)

IC203:
1: 5.8mv (0)
2: 5.9mv (0)
3: 5.2mv (0)
4: -11.94v (-12.3)
5: 34.2mv (0)
6: 35.3mv (0)
7: 35.6mv (0)
8: 11.93v (12.3)


The data sheet also has expected voltages for each of the 5 other transistors on the circuit, so I’ve tested these and they are as follows, again with expected voltage in brackets:

Q501
B: 0v (-3.8)
C: 0v (21.5)
E: 0.5v (not specified)

Q502
B: 0v (0.7)
C: 52.2v (1.3)
E: 0v (not specified)

Q503
B:0v (not specified)
C: 0v (21.5)
E: 0v (0)

Q504
B: 0v (0)
C: 0v (21.5)
E: 0v (not specified)

Q505
B: 0.25v (0.3)
C: 11.96v (12.3)
E: 0.014v (0)

Thanks for any input!
Cam.

Hello,
using my sacd player Lindemann 822, that has a balanced output of 4,6v/100 ohm, into the P1.7 preamp is it better theorically to use some attenuation with the internal switches and 'open' the front double gain pots or go 'straight in' without any resistance switch and 'close' the pots maybe at 9 o'clock?
Thanks,
Stefano

Hello, I have developed and optimized these circuits for commercial purposes, their thermal stability is very good, oscillations are prevented with a minimum capacity,
It is very enjoyable to listen to, I use it myself.

Good evening,
I am a big Hi-Fi enthusiast, and for a few years now, alongside purchasing commercial products, I have also been working on my own projects, which I find very rewarding.

Hi
Does anyone on here fabricate tone arm weights?
I need one for a Toshiba SR 300c
Thanks

Briefly mounted for testing and forgot about them. Will ship in factory box + whatever you are comfortable with, at actual cost, USPS only. Any reasonable offer for one or both.

This amp has no output.When I power it up the first time I saw oscillation on the high side but nothing on the low side.Now am not seeing no oscillation on the outputs.Rail and low voltages look ok.I didn’t spot any bad part yet.

Any suggestions?

I calculated a 30-liter box for my woofer, but the box will have 33 liters because of the internal box of the midrange that I will install. Doing the math here, the height of a round box for the midranger would be 35.7 cm, taking as a base the 4 inches that it has...
Therefore, the main box which would hold the woofer and the tweeter would have the measurements of Final Dimensions of the Box:
Height: 47 cm (0.47 m)
Width: 30 cm (0.30 m)
Depth: approximately 23.4 cm (0.234 m)
The height of the midranger box completely exceeds the depth of the box, and I wanted the speakers in the front to be arranged one above the other, as I think it is more aesthetically pleasing...
Any idea of how I can do this?
The midranger will operate between 400Hz and 3200Hz
I don't know if I should reduce the size of its box... for me, I think it's a great choice for it to be around 3 liters

I have with me two units of Nakamichi CD4. Bought next to nothing because one of them doesn’t work but the case is nice. This unit is 230V, no voltage selector
The other unit works (as claimed by seller) but the case is all rusted to heck. This unit has a voltage selector.
So we know they’re from different markets.

Opening both of them I realised not just the transformer side is different; the main boards are also different.
While the layouts are the generally the same, the components are different. And the 230V unit has all the components soldered willy nilly and canted as if rushed.


The multi voltage unit board with nice components


The 230v unit board with not so nice components.

On the multi voltage unit we can see near the analog out section, there are rows of green Nichicon Muse capacitors. The 230v unit only has two of them.

230v unit also has a mixed bag of capacitors from different brands. The four power supply caps has 2 different pairs but all four are 3300uf 25v.

C122 near spindle motor is orange which sticks out, probably a better (?) one since if it fails the cd will only spin half a rotation and stops.

This fault actually happened to the multi voltage unit and thankfully someone here pointed out in an old thread that replacing C122 will help with the spindle motor issue.

Multi voltage unit now runs well and my friend will be picking it up soon after I’m done testing (playing, hehe) with it.

The 230v unit is dead for the most part. No display, buttons do not respond. But the cd motor and tray does jerk a little when turned on so there’s something going on there.
Voltages seem correct and all semis tested ok on diode mode.

Pulling hair a little but that’s how it goes.

Oh yes I’m using the Nakamichi CD Player 4 service manual since I can’t find one for the CD4. Internals look the same when compared to the service manual.

**minor edits for clarification.

Hello,
ial
I am modifying my Spatial Audio M3 Turbo S speakers and would like a little crossover help. I used to modify and build speakers many years ago before software and DSP was even a thought. I added a horn and a SB Audience 65CDNT and and designing a new crossover for it to integrate this new driver and horn. I have the woofer figured out and am trying to integrate the tweeter. I currently have a contour circuit on the tweeter with a 2.2 uf cap and 10 ohm resister to bring down the horn rise to flatten the response. The compression driver in the horn starts rolling of at around 550 to 600 Hz which is good but a little to low to properly integrate with the woofers. When I try to install a cap on the tweeter before the contour circuit the added capacitor does not crossover the tweeter it just changes the contour circuit! How do I keep my contour circuit and add an additional crossover to the tweeter without either one being effected and letting me cross the tweeter over higher? I put a hand drawn diagram in this post to show what I mean.

I'd like to replace the 2sc2240 BL differential pairs in the driver board of an Adcom GFA-555. These are getting pretty scarce and i'll need quite a few to find some that are close.

Can someone suggest a current production equivalent?

Pair of ACA Racams built with boards from Mark Johnson includes the heatsinks. Forget what I built with but think I used IRFP140s. Also a few mods added as per the ACA with premium parts thread. Running slightly higher bias than standard too.

Asking £75 plus postage

I am following this forum now for some time and I am amazed how many people with little or no knowledge or experience dare to open and work on discrete (that is with transistors) audio equipment.

When it comes to transistors many people can recognize it as a transistor but assessing if the part is not defective is more of a challenge. A happy few have a transistor tester and some even know how to interpret the readings.

If not, using a multimeter to measure the 2 diode junctions is not sufficient to assess the correct working. This method below I learned over 40 years ago and never failed on me.

1. Connect the lead of your multimeter carrying the positive voltage to the collector and the negative to the emitter for an NPN transistor. The other way around for a PNP.
2. The reading should be (close to) infinity for Si and "large" for Ge
3. Moist the tip of your finger just a little bit. I say "moist", not "wet". Moist like you want to turn a page.
4. Press your moisted finger against the collector and base
5. The resistance reading should drop to a few hundreds or few tens of kilo ohms.

If you obeserve near infinity without touching the base, and a considerable drop while touching the collector and base, the transistor is good. As simple as that. If you want to double check, the resistance reading must be considerably less than touching the collector and emitter in the same way with the same finger.

Note on lead polarity: For analog, not-electronic multimeters the positive voltage is on the common (black lead). For digital multimeters I have no clue. I don't know if that is even consistent for all types. Just find out using a diode.

Note on Hfe: different transistor types have different Hfe. Small signal transistors like BC550 have quite some gain. So pressing on the lead ends might already give the reading. For larger transisitors like TIP42 you have to press on the flat sides of the wires. For TO3 transistors, put your entire finger tip on the housing and the base stud. That is why those large transistors came in that case: more area to put your finger during testing. Just kidding!

Note on collector and emitter leads. Fortunately there are 42 different standards for lead position on the various transistor housings. Transistors, especially small signal transistors have gain when you swap collector and emitter leads and do the described test. If you are not sure what is C and what is E, test the transistor in both ways. The measurement showing the highest gain has is connected correctly.

Note on meters: Analog meters are preferred over digital meters for this test and in general. Even the cheapest functional analog meter gives you better information about what you measure compared to digital. If this becomes a discussion, start a new thread.

For power transistors the Hfe is quite low. But because the collector current is also very low during testing generally Hfe > 10 and you will get a usable test reading.

I'm the owner of an old McIntosh MA230 tube/solid state hybrid amp and 4 Klipsch mid 70s Heresys. My electrical/electronics knowledge is limited at best. Looking for some support. Thanks for having me.

Hello,

I have BMW CD54 Professional Radios sitting around. For hobby project I dissembled one of it to see how it is working. I quickly realized that cd drive outputs audio to mainboard via I2S. There are 12 IO and power pins + 6 pin connector for I2S lines. Same Becker design used in different car brands as well, thats why I thought that if I can find out how is it working, it will be so easy to integrate an ESP32 for bluetooth music streaming.

I2S lines are connected to the SAA7325 however control lines and SAA7325 I2C lines are connected to the other proprietary Philips chip CM30430 that I cannot find the datasheet. So far the pinouts that I can traced are like this:



Do you have any suggestion for me to find out how the control working? Should I get an oscilloscope? I am adding CD Drive PCB and mainboard too.

I'm going to use one-half of a PAM8403 module as a part of a larger system. Its job is to produce short bursts of a fixed tone. I have two questions about this:

1) Is it OK to leave the unused output pins open?
2) Is it best to short the unused input pin to ground?

Hello Everyone!
I'm Raimonds. Thank You for accepting me in the club. I'm electronics Hobbyist designing electronic circuits mainly analogue synthesizer stuff. I came across this forum while looking for Amber 4400A test set service manual. Hope to learn something new from diyAudio members. Thank You!

Product chars :

Input method: SPDIF & I2S

Support sampling rate: SPDIF 44.1khz 88.2khz 96khz 192khz

I2S:44.1khz~384khz



I`m trying to modify this board to accept pcm56, but without any success, as the datasheet states both dacs are pin compatible, but when trying direct swap, the pcm56p is playing music but with noise. Should I assume that the WM8805 is the main issue in this configuration or something else? Another question, can I use the I/Out of the pcm`s in parallel? Removing the single op amps and feeding to valve output?

The RD-75 is extremely rare, no longer in production. It is the late David Graebener’s “ultimate transducer” magnum opus. 88dB sensitivity, 100Hz-17KHz response; they combine incredibly low moving mass with the surface area of a 12” woofer and 200 watts power handling. They play very loud with no visible excursion, and have a light, transparent, fast sound with large presentation and big stereo image.

For 12 years these Bohlender-Graebener RD-75 ribbons were the centerpiece of my “Ultimate 2 Way System”.

These RD-75s are mounted in a closed-back box (monopole, not dipole). The speakers are in excellent condition, built in 2005. Well cared-for. The cabinet was custom made for me, matte black finish and has no significant scratches or blemishes. Baby grand piano not included 🙂



They need no crossover in the ultra-sensitive 2-5K region where the ear is most sensitive. This is why the sound is so top-to-bottom coherent.

These line-source handcrafted ribbon drivers deliver transparency, resolution, and transient ability. The proprietary RD-75 ribbon driver uses an ultra-lightweight aluminum foil diaphragm suspended between powerful neodymium magnets.

Properly integrated, the response is smooth and level everywhere throughout the room. You can stand up, sit down, or even lay on the floor, and sound is consistent everywhere. This design minimizes floor and ceiling reflections. As soon as your ear rises above 6 feet elevation, the high frequencies vanish. That’s because the ribbon emits a cylindrical wave that does not reach the ceiling. You clearly hear every layer of detail in the recording. Vocals are lush and full and transparent. Percussion has clarity and drive. Plucked strings are almost visceral, when they need to be.

One of the most remarkable aspects of the RD-75 is its ability to capture the attack and decay of musical notes with startling realism. The ribbon drivers' lightning-fast response, combined with their exceptional linearity, ensures that even the most dynamic passages are reproduced with effortless precision and authority.

Measurements and photos I took this morning:


Above: Frequency response, several distances, on axis, left and right channels averaged together.


Above: Step response. Extremely clean with no phase reversals.


Above: Impulse response.


Above: 2nd and 3rd harmonic distortion.


Above: Phase response, which is +/-30 degrees from 200Hz-15Khz. Unheard of.


Above: left/right responses overlaid in real room. I'm 95% sure the differences below 500Hz are because of the different position of the speaker in the room, not differences between the drivers; which match to within 1dB for great imaging.

Impedance is 6 ohms, resistive and almost straight-line flat. Super easy to drive.

I used these in biamp configuration with active DSP crossovers. You can also use these with passive crossovers. If so, they need a notch filter to pad down the area around 5K. The schematic is online https://techtalk.parts-express.com/filedata/fetch?id=1317741

I recommend using them above 200Hz with 12dB/octave crossovers. I wrote up the system I used these with, you can read all about it here:

https://www.perrymarshall.com/articles/ultimate2way/

If you have a couple of subwoofers with good midrange response and a DSP, it's pretty easy to put together a fantastic sounding system that rivals commercial designs costing 10-20X the price. If you wish to use these dipole, you can take the backs off of the enclosures or take the RD-75’s out of the enclosures. Any mods are up to you.

As you can see from the article, I was easily able to attain near perfect frequency, impulse, step and phase response with a 2-way system - at listener position in a real room with no crossover voodoo (no exotic FIR filters, just standard 12dB slopes). Not easy to pull off with almost any other driver.

DIMENSIONS:
Main part of enclosure: 76.75H x 14"W x 5.5"D
Base: 18"W x 14"D

Price: $1950 OBO for the pair. Pick up from my home in Chicago. Estimated shipping (continental USA via truck, will take time to arrange): $1000.

Here is my first attempt at a mini (actually an micro-amp) using the Russian equivalent of the 6BM8. I have an octet of tubes on the way, and a a pair of bitty output transformers in fab at Edcor. The boards are in process at PCBway. I plan to power the amp using a DC-DC converter run by a 12V, 3.5A switching adapter. The amp takes its inspiration right from the Sylvania data sheet, with the power pentode being running full tilt at its 7W dissipation rating. I am running the input triode at 1ma plate current with an LND150 current source load. This will go into a proletarian bud box (so not all that pretty), with transformers on the bottom to keep the thing from tipping over. They will drive a set of Klipsch speakers that are actually pretty efficient (they have no problem making lots of noise with the 20W/channel Class A amp currently driving them). The amp will get a full characterization on the bench for frequency response and gain-phase, as I have a gain-phase analyzer available at work that goes up to 5 MHz. The values on the output Zobel network will be adjusted so as to keep the output gain from going back up through 0dB (gain margin as well as phase margin).

I’ve been into Hifi for a looooooooong time, and still loving it!

I have way too many amps. Willing to part with one of my wolverines. Its in 4U modushop, with massive external power supply. Its ef3-3. Perfect sound. I will not ship it, but i can deliver within 100 miles of metro DC area. Asking $2000.

Hi, I hope it's ok to open a thread here to cover more basic issues. As I'm used to building speakers for hifi use (and taking the room into consideration!), I'm constantly feeling a bit, let's call it, "philosophically alienated" when entering the car audio world. Perhaps someone with a similar background can help me increase my understanding...? In general, yes I know and have experienced myself that car systems can sound decent. So there must be reasons why that is in spite of the issues I have in my mind, and guess it might actually be useful to find some answers as to what these reasons are. Those issues would be:

a) everything is off-axis, the individual chassis are far removed from each other, the listeners are sitting very close to the speakers (extreme near-field), and basically always outside of the stereo listening triangle. How does one come up with a proper sound setting for that, which works well and creates a stereo illusion for all occupant numbers, and also not a noticable change in response from different passenger heights/positions? I can only guess, does one routinely use speakers that have basically non-linear frequency responses on-axis (rising treble), to have a linear response at the off-axis listener position?

b) is a point source characteristic, and with that, stereo imaging and "virtual stage size" even a consideration? apart from coax speakers, which rarely are positioned anywhere near to creating an acoustic stage (in front of the listeners), I'd say there are very few system configurations that would allow for a classical point source (generous rule of thumb: distance between speaker centers less than the wavelength at crossover frequency - meaning about 17cm between tweeter and mid/woofer at 2kHz)?

c) since there are no regularly shaped acoustic baffles, various predetermined speaker positions, and a lot of hard, acoustically reflective surfaces including glass of varying curvature, which are pretty much acoustic mirrors for any mid-high frequency waves and therefore highly influential - how (apart from creating complex 3d models including the acoustic properties of seats and dashboard lining) does one even have a concept of a plan to find out how a given system might sound when installed in a different car? I guess that will also be the reason why just about no manufacturers publish any sort of frequency response charts for their systems, right?

Hello everyone!! I never build a speaker before, but I have some experience with DIY stuff. For the sake of simplicity and acoustical characteristics I first decided to build a voight pipe, but the size was a problem, so I settled on the single folded design, with front facing port. I have a pair of Lii Audio Fast 8 but I am struggling to get the right dimensions for the build. I thought that the online calculators were enough, but I saw that is heavily recommended to use hornresp for modeling. The problem is that I use a macbook, so I need to borrow a windows pc first, to then try figuring out how to use the software. Furthermore, based on what I saw of hornresp on youtube, I'm not exactly confident that I will get the dimensions right that quickly. That said, I thought of getting help here first, because maybe some wise kind soul could roughly estimate that for me, if that is not asking too much.
For placement sake, I can not afford a width larger than 30cm and a depth bigger than 36cm. The height is more flexible, but it is preferable to be around 100~115cm. I imagine that it need to be taller, but I rather sacrifice some bass extension (I live in a apartment with leaky bass problem)

The image bellow its one of the recommend designs from Lii Audio, with aprox. 136L of volume (its actually less because of the fold)

Technical data of the driver:
1. PMSE-Free 0.42 Ohms
2. Fs 47 Hz
3. Re 6.33 Ohms(dc)
4. Res 64.66 Ohms
5. Qms 7.10
6. Qes 0.69
7. Qts 0.62
8. L1 0.10 mH
9. L2 0.68 mH
10.R2 3.73 Ohms
11.RMSE-load 0.36 Ohms
13.Vas(sd) 69.7 liters
14.Mms 10.28 grams
15.Cms 1084 uM/Newton
16.Bl 5.15 Tesla-M
17.Splref(sd) 94 dB(Re)
18.Rub-index 0.02

Area (Sd): 213.82 sq cm

I do not need a perfect speaker cabinet for my frist build, just a 'good enough' so I can at least start to burn in the drivers. So if anyone at all could help me with that I would be forever grateful. But again, if that is too much to ask I will proceed trying out myself. I'm only asking because from my point of view, it seems that for those already used to the software, its not that hard of a task, but could be just my sheer ignorance of the subject. Thanks!!

We have an apartment in Azerbaijan which is a bare concrete core & shell, so we will fit out everything including a suspended plasterboard ceiling, around 15cm below the concrete that defines the floor/ceiling levels. I'm planning to put ceiling speakers, but have never really used them before, though I am familiar with building (but not designing) speakers in cabinets.

We have two bedrooms and a living room, the idea is to have one pair of Polk RC80i in each of the bedrooms and two pairs in the living room, all powered by 3x WiiM amplifiers (60wpc) which can be linked in-app to provide multi-room capability.

So my question...if I fix a speaker in the ceiling, it if effectively in a cabinet that is around 15cm x 5m x 4m - which doesn't feel like a good size of cabinet for an 8" speaker. Since we are building the ceiling from scratch, it occurred to me that I could make an in-ceiling speaker cabinet behind the speaker using a double-layer of plasterboard, that is a more appropriate size for the speaker. And I'm wondering if this is a good idea, or not?

At the moment I've no idea what size of cabinet it would be (except 15cm deep) or the Thiele Small parameters for the Polk RC80i.

Good day. I am working with Stetsom HL1200.4. The amp is totally dead without any light. I found out that the 4 power supply Fets are shorted, It has the IRFB448 mosfets in the power supply. This mosfet is hard to source from reliable sources. Did anybody tried for a similar substitiute of this mosfet that is available in reliable sources. Please share if you had luck replacing it. Thank you.

Translated from Mr Ohashi's Blog (Google translator)​

True Frequency Response​

October 1, 2024
Today I would like to show you the frequency characteristics of vacuum tube amplifiers, which you basically do not know (usually manufacturers do not provide them).

The data I will publish today is the data stored as in-house records at the time of shipment of the assembled products, converted into a semi-logarithmic graph, and all of them are true frequency characteristics without any corrections.

Catalogs often state "frequency characteristics 20Hz~20kHz", but this only indicates the standard -3dB point and is not a document to evaluate the performance or actual state of the amplifier. This is because what has the greatest impact on sound quality is "behavior within the audible range", which can be said to be the individuality (character) of the amplifier.

Now let's take a look at the frequency characteristics of our representative model.

SV-S1616D/KT150 Specifications

SV-S1616D / PSVANE WE300B Specifications

The reason there is no big difference between these two models is that they share the same basic platform and use the same output transformer. Please note that the 300B has a slightly "sloping shoulder" on the high-frequency side.

Next, we will show the difference in push-pull. This is the difference in sound between multi-electrode and triode amplifiers, and it is a big difference.

SV-P1616D/KT170 Specifications

SV-P1616D / Western Electric 300B specifications

I think many people will be surprised to see how different they are. The KT170 specification is super flat, while the 300B specification has a natural roll-off at both the top and bottom. This roll-off is actually closely related to the plot position on the voicing chart, and to put it simply, we tend to feel that the flatter the response of an amplifier, the more to the upper right (sharper and cooler), and the larger the roll-off, the more to the lower left (softer and warmer), which coincides perfectly with the frequency characteristics.

Next is the transmitting tube amplifier.

SV-S1628D/845 Specifications

SV-S1628D/211 Specifications
These two data were obtained when two types of vacuum tubes were delivered on the same machine, so they are quite similar, but they match the frequency characteristics of a typical triode amplifier. However, please note that there is a "shoulder" on the higher frequency side than the 300B. In this case, the PSVANE WE211 has a higher high frequency extension than the regular 211, so it should be noted that the roll-off point of the regular 211 is often a little lower.

Next, let's look at the SV-8800SE.

SV-8800SE / KT170 Specifications
What I want you to pay attention to here is the difference with the SV-P1616D / KT170 specifications above. Basically, it has a wonderfully flat response, but while the P1616D is flat down to 10Hz, the 8800SE is flat up to 100kHz (and above) and actually extends to 200kHz and above.

The reason why the P1616D is positioned towards the top right of the chart in terms of tone is that the 8800SE has a gentler (or, if you will, more natural) roll-off at both the top and bottom ends. As mentioned above, this roll-off has a sensitive effect on the sense of hearing, but it is the "coupling capacitor" that filters the DC component superimposed on the signal that gives the sense of density to the ear. It is safe to say that this difference in frequency characteristics has a major impact, and that is why many people feel that it is particularly effective with multi-electrode amplifiers.

Finally, the SV-91B.

SV-91B / Western Electric 300B specifications
One of the features of our amplifiers is that they are slightly higher at around 35Hz, which is actually the lowest frequency we feel, slightly above 20Hz. However, what is important in voicing an amplifier is not how far it is extended numerically, but the overall balance.

If there is a "swaying balance" of sound, what Hz would be the center?
Generally, the audio world considers 1kHz as the standard, and we also set many reference points at 1kHz in our measurements. On the other hand, when it comes to creating sound, if humans can perceive 20Hz to 20kHz, 5 octaves above 20Hz is 640Hz, and 5 octaves below 20kHz is 625Hz, so I personally create sounds with the idea that the center of gravity of sound is at 600Hz to 650Hz. As the

audio industry has moved from vacuum tubes to semiconductors, flat sounds have become the norm. However, without even taking the example of wood used in guitars, I think it's fine and should be possible for there to be amplifiers with a clear, bright tone like maple, and a warm, rich tone like mahogany.

The rich musical quality of a vacuum tube amplifier is ultimately achieved by bringing out the inherent resonance of the material. We always aim to create an amplifier that has a "good sound" rather than just "good characteristics."

Hi all,

Firstly, please forgive me if this has been discussed (or beaten to death) elsewhere.

Way back in 2011 I made this post (https://www.diyaudio.com/community/...lrangers-help-me-pick-a-design-please.184703/), looking for recommendations for my second speaker build. I never ended up building anything, but I'm itching to now.

I'm a fan of diyAudio primarily because I believe it allows for a "high value" listening experience without the corresponding cash outlay. To put it more clearly, I am much more into listening to diyAudio than building diyAudio, and I'm hoping I can leverage the incredible experience of those on this forum to help me decide what to build next. Because ideally whatever I build lasts me a good long while!

Can you please recommend full-range enclosure designs (and sub designs if you have recommendations!) which prioritise sound quality, WAF, and which are tolerant of "sub-optimal" room placement? I really like clean, detailed bass with good extension. In fact I would say that bass performance is a little more important than imaging to me, particularly as this setup will often be enjoyed from the adjoining kitchen, or otherwise "not in the sweet spot". Ease of build would be nice too. I'm just looking for a shortlist of enclosure designs that I can exhaustively research on my own hahaha. And maybe some "explain like I'm 5" wisdom on diy subwoofers and integration with a pair of full range speakers. I've done a tiny bit of reading on calibration/REW corrections with a USB mic & DSP... but still have much to learn.

Proposed signal chain:
Tidal - Wiim amp or Wiim streamer into a <$800 DAC + AMP bundle (like SMSL DA9 + SU9n). I want to keep it simple and relatively affordable on the amplification side of things. EQ/DSP would be nice.

Use:
100% music. I listen to (truly) everything, but these days a fair bit of techno, IDM, DnB, deep house, hip hop, motown, jazz, and a little classic rock. Volumes are restrained, I live in a townhome/rowhouse and love my neighbours.

I've been leaning towards the Frugelhorn XL or Joan plus a sub, but wondering if I'm going to run a sub or two if I can get away just fine with the standard Frugelhorn? The Pensil and variants have also caught my eye. In my 2011 post, I was recommended the Castle microtower as well. And how about a sub(s)? What would work best with the full range enclosures you recommend (and isn't too picky about room placement)? Should I run one or two?

-----Boring and long-winded background/history-----
Years ago I built some B0FU BIBs and loved them for 6+ years before they succumbed to a slowly climbing WAF threshold. I drove them with a Sonic Impact T-Amp and ran them both alone as well as with a B&W 10" sub (which I loved, taking a little bass load off helped the BIBs shine even more imo).

Since, I've been using an old pair of cheap Polk bookshelves (driven by the same trusty T-Amp) in conjunction with the same older B&W sub and it's been okay, until my sub decided it'd had enough and packed 'er in.

The signal chain I've been using will make most of you groan. It's been chromecast HDMI - TV - RCA line out - sub (w/ crossover) - RCA-1/8" - T-Amp.

I have a headphone setup at work with a standalone DAC and headphone amp. I used to listen to lossless and high-bitrate rips before I succumbed to laziness and spotify. Spotify has been driving me nuts though, I just tried Tidal and I'm loving it. Now I want to stream high bitrate to my home stereo.

Between determining whether my sub can be repaired or not and switching to Tidal (and hence looking into better streamers than a chromecast plugged into my TV) I started thinking about the entire system. I'm planning to keep the TV paired with my old bookshelves and build a music-only system from scratch, with the goal of bettering the SQ I enjoyed with the BIBs + sub.
-----background history over------

I appreciate everyone's feedback and suggestions - mainly I'm looking for a short list to research to death on my own and select a design from.

Thanks a million!
Cheers,
Cam

Has anyone tried using fleece like maybe the thickness of a blanket to use as sound deadening inside a sub enclosure. Seems to me it would work. I'm curious because I have a couple of old blankets that I've used for storing various items. I thought maybe I could repurpose them into lining the inside of an enclosure

My speakers are designed to be used with a 100 Hz first order high-pass filter. A pair of these RCA filters were included with the speakers: https://www.vandersteen.com/products/m5-hp

I want to design and build my own version of this filter, adding the ability to accept balanced and single-ended inputs/outputs, and maintaining the ability to adjust to match different amplifier input impedances.

The spec from the manual is a signal measuring 1v at the filter output at 1000 Hz should measure 0.707v at 100 Hz. The filter should be adjustable so that this attenuation can be achieved with a variety of amplifier input impedance values.

I know the basics of designing an RC filter, but I need help picking the resistance and capacitance values, and designing switchable loading.

I have an Orion cobalt 2100 that has a similar issue to problems that have been discussed here before. Problem is it doesn’t look like it was ever solved in the other threads.

This amp started taking out speakers then the magic smoke came out. Opened it to find a fried rail cap that also took out a trace. A couple of resistors desoldered themselves too.

I replaced all electrolytic capacitors. I tested the output fets and found one to be very leaky. I replaced all output fets with some equivalent parts that were recommended on a different thread. I also replaced all resistors that looked burnt in the middle.

The problem is the amp draws too much current at idle and heats up rapidly. The output fets get warm. I placed my meter in series with the source resistor and got about 60mA before the current limit on my power supply kicked in.
The driver transistors get really hot. I have already replaced them with no luck. They are marked with silver on top.

Any suggestions on what to check next?

Cheers

Has anyone played with the SUOS (Stream Unlimited Optical Systems) Blue Tiger CD Drives? They seem to be an affordable option. I have used many of the old now defunkt Phillips CDpro2 drives and there are still currently many options for those and Infact there is a guy in germany that has cloned the drive and will start remaking them again, but they are VERY expensive. nearly 3x the cost of the SUOS drives. So I am curious if anyone has played with them. built their own transport/player etc. or if there would even be any interest in a DIY drive???

So, thanks to a very generous forum member I got some fostex 208 sigma drivers for a great price, and decided to build the kirishimia cabinets (should have gone to the gym for 6 weeks!)
Already having the fostex t90a (as the 208 sigma is a 'wide range driver, not full range it needs upper support imo)
So.
I am lucky that I work for a small furniture company (I am no maker!) And have access to some very expensive saws etc.
Cut a long story short here are some pics.
They are progressing in an American black walnut veneer finish with plain grey sides.

Any questions please let me know.

For the veneering I only (now) use contact adhesive, the evostick thixatropic is just a joy to work with, and any bits that don't stick, nothing that a hot iron won't sort.

Hi,
Hope you all are well. I need some help with converting my BenQ DLP projector lamp from halogen to LED. Am I right saying that I need to bypass the ballast to trick the mainboard to say stock lamp is connected?

There is a vertical circuit board connected to main power supply board and 5 wires coming from that to mainboard (connection port J13). Do I have to connect one of these wires to the ground and then I can use LED directly connected the ports?

I know this has 2 step converions:
1. Bypassing or fooling the ballast
2. LED lighting source

Any advice would be highly appreciated.

Cheers

Zaky



from Schematic diagram...







Mainboard...
The Lamp cover switch (thick red and black wires) should be depressed to power up the system.

Sold

Hey guys

Recently I picked up a Krell KRS 2 preamplifier that had supposedly been sitting in storage for the last 20 years. It looks brand new both inside and out but upon further inspection it appears that a few of the electrolytic caps are cracking. I've seen caps bulging before but never cracks, one would assume this unit is due for a re-cap? I have not yet tested any of the caps with a meter.

I did take a quick look around Mouser and Digikey for the cap values but I'm having a really hard time finding anything in 14.5MM diameter. If it does indeed need a re-cap I'd like to keep the form factor the same as factory if possible.

Ignore the broken phono ground in the last 2 photos, Shipping wasn't kind.

I was......Loving these speakers until the drivers started failing. I have listened to new JBL monitors and klipsch r7iii that cost over 10k AUD. Came home and the IMF's were better in every way. Wow. the xo has been redone but the b139 has gone and now the hp1300 is crackling and spitting. I'd love to keep them and upgrade with all falcon drivers but am not sure if I will gain anymore headroom . I think the falcon b1399 can handle higher spls but not sure about the tweeters . I know they are not party speakers but they should be able to rock up to 100db without failure. Goddamn they sound good but reliability is the line. Has anyone done the falcon kit upgrade or should I search for a JBL or klipsch that sounds like an imf but handles higher spl? Under 10k AUD?
Thanks for any insights or guidance going ahead.

Guys,

For plywood (I will not use MDF)
What router bit or bits do you use and or recommend for sub and top cabinets building.

Baffle ,handles and back plate jacks or plate amps.

I just scored a budget router that was in clearance to be my beginner training tool.

Hello, my name is Chris. I live in Kerrville, Texas. I'm a complete newb amateur, determined to learn the art and science of designing and building a tube hybrid headphone amplifier by doing it. I am using AI to teach me what I need to know: how to read and understand and create schematics using kicad, how to read and understand datasheets, how to make sure the parts we are wanting to use will work together, how to use kicad to create a schematic, assign footprints, and design a pcb. I'll save technical questions for the specific thread I intend to create to document my progress with this project.
I am coming here mostly for community, to talk about my design with people who are interested in such things.

Let me try to address some concerns up front:

You should not begin by designing your own amp. You should get a bottlehead crack or similar kit, and build that first.

Click to expand...

Yes, probably. However, I have looked all over the internet for a tube hybrid amplifier that will supply at least 1W per channel into 32 Ohm headphones, and also at least 300mW into 300 Ohm headphones. An OTL design just won't work for me. Also, I prefer to use only tubes and mosfets, no opamps. I'm going for a very old-school sound. I don't see any point in wasting my time and money building an amp that I won't want to use. I just want this one, specific amp. If I tried to buy something like this already made, it would cost thousands of dollars. I hope to build this amp for less than $500, not including tools and test equipment.

You are going to fry yourself, you fool!

Click to expand...

No, I won't. I'm going to build it such that the PS connects to the pcb through screw terminals. I will not connect the PS. I'll build and test it as best I can without ever plugging it into the wall. Then, I will take it to my local electrician / electronics repair shop, show them the schematics, and let them test it if they feel safe doing so.

If you got it all sorted out, coming in here like you're not going to even listen to people who are legitimate experts, why are you even here?

Click to expand...

I will listen to people encouraging me to do things differently, if their suggestions are clearly going to get me where I want to go better than what I had planned. I just don't want blanket discouragement, which is what I had encountered on another website, which just removed my posts. I don't mean to disrespect or devalue anyone's expertise or advice. I just want to be sure that your advice will get me closer to my goal of owning a tube-mosfet stereo amplifier that can give a lot of power to both high and low impedance headphones.

Thanks for reading! I look forward to engaging with this community, and working on my project, and learning-- really learning-- everything I need to know to end up with the amp I want.

Hello all. I am new as a member here but have used this place as a reference many time. I am from Phoenix, but England originally. Got the audio bug working at Circuit City in the early 90's. I don't have anything outlandish for equipment, but am always trying to upgrade. Currently running rebuilt Infinity Crescendo 3008s with a Def Tech Supercube. Onkyo Flagship receivers have changed out a few times. I am a novice, but my father is an electrical engineer, so I know enough to be dangerous.

Hi guys.
This regarding a Kurzweil PC1x keybord.
A few days ago I asked for a replacement for the TLC2272CP.
Today I inspected the pcb on the pitch / mod assembly once again and it turns out that trimpot R15 is missing its tiny adjusting wheel...
To all Kurzweil PC1x users out there:
Can anyone tell me the value of this R15 trimpot? Please?

Just wonder is someone has pictures of the boards ( component/solder side ) from this amp.
Asking for a friend😉

I have a polk psw11 sub. Recently hooked up to my 6LU8 tube amp. I use the speaker level inputs. After a bit of trial and error, I have the frequency and volume adjustments where I think they sound best.; Here is the problem. With low level bass there is often a bit of noise on top of the bass. At higher levels, like playing loud, or with bass heavy modern not acoustic, there is no noise. It sounds like a dirty pot, but does not come and go with turning either vol, or freq knobs. Speaker wires are all hooked up solidly.

My question is whether this is a repairable problem or not. If not, is there a 'replacement' sub amp that is very affordable?

Roger

This was one of my first veneering jobs a number of years ago. I've done quite a few cabinets and counter-tops using plastic laminate (Formica) so had plenty of experience using water based contact adhesive. The paper-backed veneer was very easy to work with, much easier to install and trim than p-lam but there are obviously extra steps involved in the final finishing.

The client inherited the console from his grandfather who had it stored in a basement. Hope this inspires someone to save an old piece of audio gear that may otherwise be sent to the dumpster.

Here is the finished product, I'll follow-up with some "before" images as well as the process.

The amp on my powered sub psw10 is crapping out, I thought I could do a cheap diy fix with a 40W mono tpa3116(8?) Board from China. Add a 24vdc smps, and an op amp low pass preamp. Total cost would be around $15.

Am I crazy? I really like my system with the sub. I am using a DIY 6LU8 tube amp, without any sub out. I was using speaker level inputs on the powered sub.

I have a source selector that I built that holds my DAC board, and phono board. I can easily fit the low pass subpre amp inside the selector, and provide a mono combined line out to the sub. I would like to rip out the faulty amp in the sub and install both the smps and class D amp on the plate, use the e listing 120vac input to the sub.

Questions:

Will my phono and dac boards drive BOTH the sub low pass pre-amp?
Will the smps 24vdc/3A get too hot for installation inside the sub?

I know there are not a whole lot of specificshere, but in general, is this doable? I know it is likely not going to be high end, but I listen at very moderate levels.

Anyway, any feedback is welcome.

Roger

Hello I'm Tony and hope I can find help here in repairing my class D amp and look foward to learning a thing or two along the way <3

Hello,

For sale is an Allo usbridge signature. currently running ropieee.

Please note that the USB Clean port does not work. Only 2 usb ports work. This is how i got it. It seems like there was a repair made on the usb port. I never bothered repairing it since i used the module using its i2s from gpio.

This will not come with the power supply.

Im asking $100.

Buyer pays shipping and paypal fees.

Thanks for looking

I have the phono board of the DMC-20 and I’m planning to run it by itself. I don’t have the actual preamp, just the phono pcb.
Anybody who knows the +/- feed voltages for the DMC20 phono board?


Never mind the attached photo☺️

Hello all! I’ve been stalking the threads here for a while now and I’m finally ready to start asking some questions to the talented people here. I started building speakers about two years ago. So far, I’ve made about 9 or 10 designs. 3 of these were boomboxes made with 2.1 amplifiers, full range drivers and small “subwoofers”. The rest have been several bookshelf speakers, 2 floor standers, a beefy wtmw center channel, and surround speakers for a 5.1 matching set, oh and two subwoofers. I’d like to build me a set of rs225-8 FASTs using ps95-8 in the future and I hope you all will be able to help me out a bit with that! Thanks!

I have a Marantz CDR-500 and 2) CDR-510. All produce static at certain points in certain songs and it is pretty consistent. There is static on both CD and CDR drive outputs. The components for left and right channel are the same but are done with separate components. That the distortion appears on both channels, means two units manufactured months apart, are exhibiting the same issue.

Elton John "Blue eyes"
01 seconds "Blue"
18 sec "On a"
27 sec "Blue"
39 sec "Morning"
46 sec "Far"
1:11 "Alone"

• Lady Gaga "Enigma" when she starts singing at 4 seconds has the static.
• Harry Styles Daydreaming" the opening has static

There is no static when used as a transport with an outboard DAC.


So I sent it to the repair guru who had a CDR-510 on hand. Once he was aware of the static, he could replicate it on his CD R-510 and was not there on his Denon CD Player nor did it occur in the headphone.

He pulled the main PCB and checked the output circuitry (including caps) and connectors with nothing found.

Any thoughts? Is this a design flaw or am I missing something?

They were some Gb with this regulators. Does anybody have empty pcbs to sell ... 10x for lt3045-42 and 5x for lt3094. Eu please.
Thank you.

stigigemla is my nickname and it is derived from my name Stig Ljunggren and the place where I live, Gemla in the south of Sweden
I build my first amplifier in 1960 (with a schematic of my own) and used my first transistors in amplifier 1967.
Since then I have had a problem all my life with schematics just bubbling out of my head. I am very fond of reducing the number of components in circuits without degrading performance.
I have been working in electronic service and as an electronic teacher.
I retired about ten years ago and now I have my little home lab with SMD equipment. I use 90% SMD in my constructions because it is so much easier with low temperature solder and a controlled hot air gun.

Went to post to comment on this years Burning Amp Festival but was stopped because apparently I need to introduce myself first.
I started my audio design journey in 1971 after university, never looked back and now I am a semi-retired Engineer/Executive getting back into analog audio design.
Some people put ships in bottles, I love researching, designing and building audio stuff that I really have no use for.
I find the diyAudio forum very interesting for observing and learning from knowledgable individuals as well as for a perspective into the minds of individuals who are serious about building audio gear but really have no background to help them along.

The path to the ultimate LM317 is well trodden with the VRDN, the D-Noizator, etc. Inspired by Pa's F5m I'm going
to ponder and post a minimum LM317 that has maximum performance with a minimum number of parts. Perhaps ten?

Quick notes on using 3-Pin Voltage regulators

Feel free to offer your thoughts.

Regards,
Dan

Hi all,

This is Takomania from the Netherlands. I'm not a newbie in vintage electronics home audio. But I'm not a technician. Don't own a scope etc. yet etc. I trouble shooted till date mainly by reading forums and on the eye and ear. But I can handle a soldering iron well etc. It's only recent I try reading schematics etc.

Dear Audiofreaks
I am very motivated to build some Loudspeakers in the next month to come.
So i come up with a Backloaded Horn based on a coax driver wich serves my needs perfect.

Login to view embedded media Is there someone who can provide a Drawing on a German design called Cobra Horn 2?
Thanx in advance: Marti

The slew rate you need is always at least 15-20% more than the slew rate of the op-amp you have.

I've recently had the idea of making a portable (quite compact) bluetooth speaker and after a bit of research I'd like to think I've come to a nice set-up that'd give decent-ish results (no way anything up to "audiophile" standards of course).
I'll be using 2 DMA45-8, one for each channel and 2 ND65 passive radiators. After playing a lot around in winISD I've found that if I pair one of each in an enclosure opposite of each other with 0.3L air I'd be getting best results. I've found a BT module from TinySine I'll be using for connection and for power I'll be stripping down a xiomi powerbank for the power supply.
The amplifier is an issue. I've found one small amp I can source locally, based on the TPA3110 chip. I understand this most likely is not a good option, and so I was also looking at the BVS25 with which I could drop the BT chip entirely, or the TA2024 which also looked good and compact enough for my application. Do I keep the one I've already chosen, or do I want to look into the other options.

Regarding the drivers and PRs, so far the set-up makes sense in my head. Am I missing something here? Should I look into getting other drivers and/or radiators? Should I perhaps not be placing them opposite of each other?

In conclusion I know there are a lot of things to cover and the science behind designing these things goes very deep, but I'd like a general overview of the project as a whole.

Hello.

I've been digging around and trying to know more about making an amplifier. I have decided to make something, that is hopefully not too big of a mouthful for me. We all have to start somewhere, and for me, that somewhere is here.

I hope i can get some feedback of the parts list and possible some recommendations for changes to the parts list. As soon as I, hopefully, have received some feedback, and corrected the parts list, I will try to make the PCB layout and post it in here.

The end goal is to have a couple of boards for my own use.


What do i want out of this project:
I want a PBTL mono amp (switchable to BTL Stereo if possible), that also has a build in 5v 1a output for an Arylic Bluetooth Receiver.
Be somewhat on a budget.
Has to play clean, but I do not need something over the top.
Possible a change of OPamps if it is worth it, to spend some extra
A reliable amplifier, that can be used for a party speaker and/or some nice mono speaker for the living room.


... I considered adding PFFP to the board, but i honestly do not think it is worth it for this project. Correct me if I am wrong.

I also dreamt about having 3 chips on the board, and DSP, making it real easy for crossovers for my projects, but unless I have a schematic I can follow, this will be too complicated.


Parts list:
I listed my parts list below. That is including the schematic and parts list for the voltage converter for the 5V 1A.
All the green markings are items, that have been changed from the reference design schematic. If you have any tips of changes in values, parts etc., please let met know.