I’m posting this in response to Allen’s referencing of the speakers I’m building in another thread as an example of what can be wrong with a mtm! 😱

I'm building a $4000 speaker kit ... Which one?

Allen I’ll link the crossover for the speaker in question and maybe you can help me understand how to improve on it? Drivers are…..
https://www.eminence.com/pdf/Delta_10B.pdf

https://www.bcspeakers.com/en/products/hf-driver/1-0/8/de250.pdf

http://gpoint-audio.com/wp-content/uploads/2013/03/seos10.jpg

Despite my total ignorance, I plan to refurbish the electronics in my old Meridian DSP5000.2 active speakers. I have a list of recommended parts to solder in place, but can't find two items:


Ansar "Supersound" caps, 3.3uF and 2.2uF 400V
UK distributors are instead selling a brand called Monacor?


Nichicon 100uF 63V caps #UFG1J101MPM which are out-of-stock


I visited Humble Homemade Hifi to learn which 400V "audiophile" caps are out there today, and now wonder if I should simply replace the Ansar with Audience Auricap XO but don't understand anything about component electronics parts compatibility for Meridian amplifier boards.


Please help a confused Newbie.

Hey folks 🙂

Not strictly a DIY query but I thought you guys are so knowledgeable as to be very well placed to answer it.

I have recently acquired a pair of Def Tech ST-L towers that have replaced Focal Domes for L/R duty in my 5.2.1 setup.
I'm currently still using a Dome as center speaker and was wondering if I could connect the other spare two with it (in my understanding, a mix of parallel and series should get me ~6ohm).
Below is a rough mockup...


Edit : Focal Dome white-paper (PDF)

What I'd hope to achieve is better dispersion, clarity (less "distortion" at higher volume?) and maybe even better/lower bass response.

The speakers have a base that can be used to fix them to a wall but I would fix them to a plinth of some kind.
They could be next to each other, separated by any amount of distance, straight inline, positioned in an arc (either inward or outward), etc etc...
They could even be vertically angled differently if it had any benefits.

Bad idea or a possible noticeable improvement to my "center channel"?

For sale a pair of Lundahl LL1660S/18mA
Perfect condition, all windings checked for continuity.
Ratio 1+1+1+1:2.25+2.25

Asking 160€ for the pair.
I'm based in Luxembourg/Europe.

Shipping inside Europe (with tracking): 12€
Shipping outside Europe (with tracking): 16€

20210218_213550-1660S.jpg - Google Drive

Kind regards,
Yves

Hello guys,

Please feel free to move this thread if this is not the correct place,

I have been asked by a friend to check his SPL Goldmike preamp which he accidentally overvolted by changing the voltage settings... he blew the fuse so the overvoltage was not long, but there are issues...

Everything seems OK (voltages are correct) but there is a heap of noise and a lack of gain... I guess the temporary overvoltage did not pass through the solid state regulators (classic 7812/7912/LM317 phantom) so the low voltage circuitry should be fine, but I have some doubt about this, signal on first stage (mic preamp) seems nice enough so I think this part is OK...

It could also be the input zeners which saw a big overvoltage and are now producing more noise than input has signal, but it doesn't explain gain loss...

Would the high voltage part be damaged from the overvoltage during such a short time as a fuse blowing? It should be around 700V during a couple hundred milliseconds, would it be enough to damage the 12AX7 from the valve stage? (this is in combination with a SSM2017 or SSM2019)

I'm in the process of trying to get the schematics, found it on GroupDiy but the archive is not existing anymore and I'm waiting account activation to be able to contact the original poster...

Anyone would have some idea to point me in the right direction? The friend in question is a music artist and as anyone would guess the funds are not good these times with no events, so I'm dedicated to find a solution and help him not to spend on another preamp... (even if there is way better than this model)

Hello Everyone,

Just got hold of a Peak Atlas DCA55 which is quite neat, but after running some test of the bunch of transistors I plan to use in my current project.

There are 2 sets of NPN/PNP at the output stage and I plan to use TIP41A/TIP42A and BDW93C/BDW94C.

Running the tests, the Vbe seems to be find and all well within +/-10%.
The issue is with hFE, while within the same batch they are all closed, but the hFE of NPN and PNP deviates a lot. eg. the hFE of TIP42s are approx 200 but the TIP42s are around 630; the BDW94C are about 26 and the BDW93Cs are all 37.

I did some reading on various forums and seems like matching hFE of NPN to PNP is not critical and almost impossible.

Is my understanding correct?

I thought I owed it to those involved in two of my larger builds to give a longer term review of these two speakers having lived with them for a few years, and over the last few weeks having done level matched, sighted and unsighted AB comparisons (which was hard work but fun!).


If you are unfamiliar with these two builds here are the threads:
The XBush Mark 2. A synergy/Unity horn of spherical proportions
Great Balls of Prestige

The differences are fairly obvious. One is a two way synergy horn with good controlled directivity, excellent measurements and using SB acoustics middle of the road (but very good) drivers. The other is a four way high output low diffraction, but more typical design using extremely high end drivers from VOLT, scanspeak and SB acoustics.

The four way system does have better than average directivity as the volt dome VM752 is horn loaded and hands over to the the scanspeak 7000 ring radiator which also has narrower directivity than a 'normal dome' almost like it is in a shallow waveguide, but it is obviously not as well controlled or tight as the synergy horn.

This is my newly completed listening room. The two large 'pictures' behind are 200mm fibreglass slab behind acoustic printed cloth. And you can see some of the ceiling treatments which are similar but with a 100mm gap behind to enhance low frequency absorption. I also have bass trapping in two corners to reduce some of the room modes. The room is 4mx5m with a listening distance of 2.80m. This photo is slightly 'fisheyed' and taken behind the listening position so don't worry about the apparent 'toe-in'.

Hi I am busy making speakers as in pic but due to limited space in the design I need to put my mid range port at top of the cabinet on the side (cabinet is wider than it is deep) for adequate clearance to the rear of port.

The lower port for the bass I want to put on the front under the bass driver it won't have enough clearance to back of cabinet either but I have room there to put a 90 degree elbow in it

Is it OK to have a side and front firing port on the same cabinet?
Please ignore marks it has been altered a number of times.

Oh no, another Zintolo's thread about that ####### Baby Huey?
Yes. This time with building notes.

As some of you probably know, before assembling the pcbs I decided to study the project and I got bored alot of you with silly questions and pedantic arguments. I'm sorry for that, but I'm glad it helped me understanding (partially, as I'm sure I'm still missing alot) the circuit and the design process that lead there.

Everything started from Yves Monmagnon "Dissident Audio" ECL86 amp:
Push Pull ECL86/6GW8

Then it has been further developed by Ian "Gingertube" by substituing the ECL86s with a 12ax7 and two EL84 (that are equivalent to the ECL86 indeed).

Then UL has been integrated (instead of the original and preferred by Ivesm pure pentode) to reduce the THD of the EL84s, but with Hammond trafos with 43% UL taps, the ratio is not the right one (see here: http://www.oestex.com/tubes/Rudolf Moers - Appendices.pdf and here: UL for EL84. 22-24% is better than the dogma....40% is lowest distortion.... ).

Then it has been modified the CCS on the tail of the PI to increase the AC impedance and so improve the balance of the phase inverter. Total current of the CCS passed from original Yvesm value of 1 mA to 1,2 mA and no more than 1,4 mA (700 uA per side).

Then it has been applied the trick to reduce 3rd harmonic content: EL84 Amp - Baby Huey

Then the output tubes have been switched from cathode bias to fixed bias to improve the recovery when overloaded.

Then powerdrive has been applied, with a simple resistor on the mosfet.

Final developement has been to increase the driving capability of the powerdrive by applying a CCS instead of the simple resistor to load the mosfet of the Powerdrive.

About R33 and R38:
to fully drive the EL84 I need around 25 Vpp (a bit more if I want to reach AB2) up to ten times (to be conservative) the bandwidth, so 200 kHz, so slewrate will be:
2 x pi x f x V = 2 x 3,14 x 200 kHz x 25 = 31,4 V/us

One EL84 has an input capacitance of 11 pF (let's say 15 considering wiring?).

C = i x dt / V
dV/dt = 31,4 V/us

then
15 pF = i / slewrate

so
i = 15 pF x 31,4 V/us = 470 uA

The current of the CCS is 0,7 / R33 (or R38), so we'll need that resistor to be less than 1.5 kOhm. I will keep the original 390 Ohm.

Powerdrive AC voltage supply
Being the negative side of the PI's CCS connected with the negative rail of the Powerdrive circuit, the voltage is set by this one at 3 times the bias voltage ( EL34 Baby Huey Amplifier ).

So for a EL84 amp with approximately -12 Vdc it will be around -35 so, multiplying by squared root of 2, a 50 Vac winding is needed to supply it (it's called BIAS on the pcb).

About R16 and R17:
On the BOM and the PCB they are shown as 1.6 kOhm and 1 kOhm respectively, but this is due to a very early version of the Baby Huey, not the current one.
The guideline is to keep the current of the led of the PI's CCS between 2 and 5 mA, preferibly towards the lower value. In both versions, EL84 and derived EL34, R16 is around 1.5 times R17. I still don't know why, but I'll keep this proportion.
So considering the small losses in D5&R28 plus the drop due to the led, we have around -33 Vdc to be dropped by R16 and R17 with around 2 mA.
Then R16 + R17 becomes 33 Vdc / 2 mA = 16.5 kOhm. Then I decided to have R16 = 10 kOhm and R17 = 5.6 kOhm. This leads to around 2.1 mA.

About R3 and R4:
On the BOM and the PCB they are shown as 1 kOhm, but this is quite low as a value.
The old guidelines for triodes were to use 8/gm to set the grid stopper value, so with a 12AX7 which gm is 1.6 mA/V the value would be around 5 kOhm. In my guitar amps I always use at least 10 kOhm because gm of the tubes goes down with age, and I want to be sure there are no issues even when tubes are almost gone.
With an avarage value of 12AX7's input capacitance (Miller included) in the order of 150 pF, 10 kOhm gives a low pass filter with -3db point at 106.1 kHz. I would say it's plenty acceptable.
IMPORTANT NOTE: carbon comp here is the best choice, because they are the resistors with lowest capacitance and inductance, and that is what is needed in this position. I used carbon film, the second place in the choice.

About R7 and R8:
In the BOM they are 600 mW resistors, but they need to be 1 or 2 Watts, because of the voltage they see across them (remember that they are connected to the shunt feedback system that is directly connected to the primary of the output transformer.
Of course I noticed it only after I soldered all resistors, so by now I decided to install 2W metal oxide resistors on a pair of pcbs and keep the BOM ones on the other two pairs, in order to be able to check the differences.
On my experience with guitar amps, higher wattage on plates of preamps gives more dynamics and more definition to the sound (over there there's need to get higher THDs with specific harmonics), I'm curious to see if it applies to this scenario too.

About R14 and R15:
On the pcb they are shown as 270 Ohm, on the forum someone suggested to raise that value to 1 kOhm to be on the safe side. I'll start with 270 Ohm (originally gingertube used 33 Ohm) and I'll see how it will react. I would say that this value depends also on the working conditions of the tubes: with pentodes they must be higher (because screens have higher potential than anodes, so secondary emission is higher), then optimal 23% UL is in between, and 43% distributed load will need them lower. I'll use 23% UL connections and 270 Ohm by now.

About R20 and R21:
They are shown as 470 kOhm on the pcb, but I used 1 MOhm instead.
The reason is these resistors are part of the load seen by the PI (detailed description here: EL84 Amp - Baby Huey even if it refers to the old schematic without powerdrive), and even if the difference between 470 kOhm and 1 MOhm when in parallel with 64 kOhm is small, why make it worst?
I think the 470 kOhm value comes from the pre-Powerdrive indications, because that was the grid-leak maximum allowed resistor for EL84. Now it is no more, so 1 MOhm is better.

About C1 C2 and C5:
Here the value shown on the pcb is 220 nF. For C5 I remember it's the 1/100 rule based on the main power supply cap, so C6 in this case.
As for C1 and C2, this value is very high. I used 100 nF for all three because the coupling caps with 1 MOhm load will have an high pass filter with -3dB point at 1.6 Hz, so one order of magnitude lower than what can be heard.
I used the suggested Vishay Ero 1813 because I already used them for my guitar amps and I liked them, then I've seen some suggesting them for Hi-Fi as well, so before investing 10 € for a cap, I give them a try.
Suggestion on it?

In attachment you can see the boards with the standard R7 and R8 resistors, and with the 2W metal oxide ones.

Not something I have ever seen before! Came from a Pioneer amplifier. The schematic is not really readable but a capacitor with 3 legs?

Hello,Guys🙂

I am a newbie to diy audio. I started my audio life last year. I purchased a pair of W3-1878 to build my first speakers and asked my father to build a amp for me. He built a JLH 1969 int. amp for me and I started to enjoy my music. I built up a raspberry pi streamer with 9038dac hat and picoreplayer for tidal. It is a good experience to me to enjoy the music. However, I have heard another system this few week and it is surprising me. I heard a same song which is a Japanese female vocal but it was more balance and more low frequency compared with my system. Thus, I want to upgrade my system. In my limited budget, I would like to upgrade my speaker first and there are two ideas.

First, I would like to purchase another pair of speaker. My budget is around HKD 3000 and I am looking for a 2nd hand speaker in Hong Kong. I found the monitor audio gold MA700 mkII and Tannoy oxford on the 2nd hand market which are closed to my budget but I had no experience to these two. In the meanwhile, Tannoy is too large for my limited area.

Thus, my second idea is to upgrade my speaker into a 3-way bookshelf speaker. I would like to use my w3-1878 as mid-range driver and purchase another tweeters and woofers. In my view, 5” woofer is the max. size of my home.

Therefore, which option is better? If I build a new 3-way speaker, which tweeter and woofer are the highest C/P for me? Thank you so much.

The problem with piezo guitar pickups and piezoelectric crystals is that they are not well matched to typical audio inputs. By their nature they can generate a lot of signal, but they cannot drive a 50 kilohm typical line input. The pickup needs to work into a much higher impedance, typically 1 megohm or so.

So what to people do? They go and plug a piezoelectric disks output directly into the line input of their recorder, typical impedance 50k, or the plug-in-power mic input of their recorder, typical impedance about 7k, and they start to bitch and moan that this damn thing sounds tinny. Which is does ! But they don't understand why!

The reason why these devices often sound tinny is because the piezo sensor presents its signal through a series capacitance which is small, typically 15nF or less. When wired to a normal 50 kilohm line input this forms a high-pass filter, which eliminates the bass.

One of these can be used for a reverb plate, listening to the insides of a engine,recording the sound of vibrating things.

Mechanics may even use one of these to discover trouble with bearings or other mechanisms not easily opened or stopped.
That includes engine Knocking (also knock, detonation, spark knock, pinging or pinking) in spark ignition internal combustion engines.

They should also work nice with hydrophones. PZT-5H tubes is best for that.

In case of a hydrophone it's possible to have the hydrophone attached with a long cable and the amplifier/buffer circuit close to the piezoelectric elements.
It's of course extremely important that the circuit board and connections are absolutely waterproof.

Commercial ones uses kerosene oil, so olive oil or sunflower oil is a great alternative as it will not pollute the environment if any leaks occurs.
Plant based oils is actually possible to use in high voltage transformers:
https://pdfs.semanticscholar.org/56b6/36870fac68b1bb6e343eee914002195b8a61.pdf

All PCB boards and components are easy to solder, one just needs basic skills and knowledge of the right direction to put in the diodes.

Some PCB boards has SMD components, but Aisler and other companies offers SMD assembly.

There may be components that has lower self noise,better common mode noise rejection and so on, -but finding the best choice of components that handles from 0 to 48 volts DC power, uses maximum 10 milliamperes total, minimum self noise, has 8 pins DIP package is not a easy task!

If you know components that is superior in regard to the intended voltage range, please fork the GitHub page and make the changes you want.

PCB board for 48 volts phantom power, with balanced input and output using op amps, gain set with two resistors. It's the easiest to solder because it has no SMD components:
GitHub - Supermagnum/double-gain: A small PCB that uses two TL082BCP op amps to amplify a signal from a contact microphone.

With switches to set the gain:
GitHub - Supermagnum/double-dip: A small PCB that uses two TL082BCP op amps to amplify a signal from a contact microphone.

SMD version, gain set with switches:
GitHub - Supermagnum/balanced-smd: A small PCB that uses two TL082CDE4 op amps to amplify a signal from a contact microphone.

PCB board using ultra low self noise components, balanced input and output, 48 volt phantom power. It's a little harder to solder, because some of the solder points are quite close together:
GitHub - Supermagnum/piezo-balanced: A small board that uses a LSK389B, for preamplification and impedance matching of two piezo electric crystals. It has balanced input and output.

PCB board for 9V battery, mono audio out and single input. Easy to solder:
https://github.com/Supermagnum/piezo-9v

48 volt phantom power supply with mono headphone output. Has one SMD component:
https://github.com/Supermagnum/48power

All these links has links to Aisler, that offers PCB boards and components:
Just register and import the
PCB and part list.

Made with: http://www.kicad.org/

KiCad uses an integrated environment for all of the stages of the design process: Schematic capture, PCB layout, Gerber file generation/visualization, and library editing.

KiCad is a cross-platform program, and of curse free!

Hi all, I picked up 2 Yamaha DBR10s to make a small PA for my mom and her acoustic performances, as well as to have something for jam nights, my helix, etc. I love the size and price of the DBR10s, but Im not too crazy with how they sound. I think I should have tried the QSC cp8 before buying these... But they're hard to find these days! I decided to test them outside in the backyard with my UMIK-1 and REW. I realize this isn't very scientific, but it gave me a decent idea of what they're doing.

The orange line is averaged from 5 tests, on the ground, on it's side, in monitor mode, and the hpf is set to 120hz. Red is the same but the hpf is set to 100hz. Blue is the same but the hpf is off. Green line is the same but no hpf and the speaker's DSP was set to off.



This is the speaker about 7' off the ground and about 7' away from the nearest wall... so I assume anything below around 180hz will be screwy if we're just testing the actual speaker. But I still think this info is useful since there will always be walls/ground where ill be using these!



I think it's kind of neat that my tests are pretty spot on to what Yamaha published:



Well it was a fun experiment. Hopefully someone finds it interesting/useful. I definitely had to EQ A LOT of lower mids out and boost some highs. I can see why I've seen a lot of complaints that this speaker can be muddy. Cheers

Post 373 in the The " 'Circles of Doom'.....Open baffleless full range speakers" thread appears to contain an attachment that is stopping all following images to load. Could a mod please try removing the offending attachment? TIA.

I just found a really old speaker plan.

It is a folded horn that is tuned for 22 Hz, and have an efficiency more than 20%

Any idea of it?

Can someone tell me some pros and cons of it?

Is it really tuned for 22Hz ?

THX

FS: JVC EX-1A receiver, NO SPEAKERS: $80 (SOLD)

JVC EX-A1, near mint. No speakers. I am the original owner. Hardly used but when played I used my custom-made fullrange-speakers (last picture). Plays audio CDs and DVD movies (no HDMI). Comes with the original remote, power cord, and FM antenna. As can be seen the unit is near mint, and everything works as expected. Will ship within US only, please add shipping wt 15lbs. From zip: 92101 to your address.

I've got a pair of custom Sowter's for a Baby Huey EL84 build.

I didn't get a spec sheet, but this one looks fairly the same:
https://www.sowter.co.uk/colours/8378.pdf

There are 8 secondary wires, red/blue pairs numbered 1-4.
I'm having trouble understanding how to wire these given the drawing above.

The 1ohm and 16ohm diagrams are less relevant for me.
Ideally, I'd like both 4 and 8 ohm options, so either:
* Wire in parallel with multiple binding posts
* Or switchable via toggle switch.

Thanks for your help.

Im thinking of using a Class D unity gain buffer ( which is meant purely for current gain basis ) and not using too much of feedback. Is there any way that I can do that in SI8244?

Op Amp Advice – RQ970BX Phono Preamp Andy Grove Mod

Hi
I recently bought a Rotel RQ970BX phono preamp. I wish to try an upgrade of the Rotel based on the "Andy Grove Modification" which was printed in the Nov 1994 edition of HiFI World. Please bear with me as, although I am an engineer, I have a very rudimentary understanding of electronics. I can read a basic circuit diagram and can wield a soldering iron but I am very much a “monkey see, monkey do” hifi enthusiast.

I need help with the substitution of the op-amps. The mod called for replacement of the NE5534 op-amps and replace them with the AD744’s being used in the front end. The gaps left by the AD744’s were to be filled with AD743’s.

There is still a live link to the mods on:

https://www.hifisentralen.no/forume...w_nov_94.pdf&usg=AOvVaw3AeXdNNih-x87CkDBkt1ym

There are also handy discussions of the mods below which have helped my understanding of audio circuits:

Rotel RQ970BX phono preamp mods? | Audiokarma Home Audio Stereo Discussion Forums

Dumb op-amp question from complete newbie

I would still be able to use the AD744 but I believe the AD743 are expensive and hard to come by. Op-amp tech has also moved on. On another discussion OPA627’s (output) and LME49710’s (input) were also successfully used. I have researched some alternatives and the OPA627’s successor (which are eye-wateringly expensive) is the OPA828 but its specs are quite different eg
slew rate – OPA627 is 55: OPA828 is 150
GBW – OPA 627 is 16MHz: OPA828 is 45MHz etc.
I am way out of my depth here as I have almost no idea what would be appropriate. What characteristics are important and what should I be looking for?
I would like some advice on what op-amps I could use in the circuit that aren’t too expensive or do I bite the bullet and order original. I will be putting in DIP sockets so I can test alternatives. HELP please!!!

I am currently running a TPA3116D2 using a 19.5v 4.7amp PSU. All speakers are 4 Ohm.

It all works fine.

However, a 24v. 10.4 amp PSU has come into my possession.

Blocked

I've no idea why it's been blocked CCM250PS24.


Are there any benefits in using this PSU, or should I discard it?

I have sent a package containing a wooden amplifier case and an amplifier DIY-kit, consisting of PCBs, capacitors, transistors, ...
to a DIY-friend (chiily) in the UK.
I have created the UPS label delivery via UPS Online services.

Today I have received back the package.
Reason: I did not include an invoice, but this is needed, since the UK does no longer belong to the EU.
I did not know, when I filled the delivery sheet and the UPS shop, where I took the package, did no tell me either.

Can anybody assist me creating a pro-forma invoice for the UPS package?

Thank you - Rudi

The year 1968, I was just 18 years old when I started the construction of the Mullard Seven -watt Stereophonic Amplifier. With limited funds and other distractions that grabbed the attentions of an 18 plus year old, the construction was very slow. Marriage, children and building a home further added to the delays in the build progress. During the mid-1970’s an attempt was made to complete the project. Gathering all the items together after 7 years on one work table was a challenge but at last, I was able to slowly power up the amplifier section by section. All appeared well until the ECL 82 output stage was connected to the power supply. At this point I was confronted with massive instability. This came in the form of motor boating which started within 15 seconds of power switch on. After a lengthy period of checking and rechecking some of which resulted in an almost complete rebuild centring around the tag board provided no resolution. The obvious areas were checked such as the phasing of the feedback loop but all seemed correct. The amplifier was again boxed and put into storage for some 43 years. During 2020 the amplifier was taken out of storage with the intention of finally identifying the problems. All electrolytic’s were replaced, a selection of critical resistors were replaced and all coupling capacitors were upgrade to audio grade versions. No success. Output stage still remained unstable on both channels.

At this point I made up my mind to dispose of the project and in June of 2021, plans were made to place it on eBay. While photographing it, I concentrated on the wiring from the tag board and there I thought I saw a possible cause of the problem.

Although the passage of time is long, I vaguely remember receiving the Main Transformer and Output Transformers. Where these items were obtained from has been lost but I do remember that the Main Transformer came with complete wiring identification but the Output Transformer came with nothing. As an inexperienced young person, I did not consider requesting information from the supplier. I attempted to identify the primary and secondary winding by visual inspection and taking resistance measurements. As a result, I came to the conclusion that the

• Red and Black wires (13 ohms) were the secondary winding with the yellow and green as the centre tap.
• Red & Orange anode (1056 ohms), Blue and grey 20% feedback and white as centre tap of the primary

It was with these identifications that the construction was built way back 44 years ago. I now question whether this identification was correct?
If I was wrong, then it is likely that I have used the primary winding as the speaker output while the Secondary connection were connected to the anodes of the ECL82’s using the Blue & Grey connection as the 20% taps.
Have I got it wrong? If yes then the supplier supplied an output transformer without any 20% taps on the primary and the additional wires Blue and grey are simply different speaker impedance outputs.

Attached is an image of one of the transformers, is anyone able to offer advice.

Before I consider moving on, I would be very grateful for any comments regarding my identification of the wiring that took place some 44 years ago

Hello y'all! I am hoping somebody out there can shed some light. I bought a pair of CMS8s (8" driver) and put them (& crossover) into floor-standing cabinets (Phase Tech 7T). But - something is not right with the sound. I can't put my finger on it but it kinda sounds like there's a large tube in front of the driver. Like the midrange (1 KHz?) is bumped up maybe? It's quickly apparent when switching from a Thiel CS2. I previously put a CMS6 into a ported bookshelf box and didn't notice this problem. I tried each channel individually, and at low volume as well. Tannoy uses different size wire lugs so I'm sure the phase is correct, and I compared a photo I took of the CMS6. I traced the crossover wiring & components, comparing it to a System 800 schematic. Seems identical except for the smaller cap/larger series resistor for the tweeter used in the System 800 (higher crossover frequency?). The 800 uses 2.2uF / 4.7 Ohm; the CMS uses 3.3uF / 2.7 Ohm. Thanks a bunch.

I'm currently in the process of choosing opamps to try in our I/V circuit for an ES9038Q2M in mono mode. My gut tells me that for most of the opamps that are on my list, noise will be of no concern, but let's see if I got my numbers right.

For the following calculations please see attached schematic.

So the noise contribution of the circuit shown are as follows:
- input voltage noise from the opamp
- input current noise from the opamp
- resistor noise

Regarding input voltage and current noise I assume that the noise gain of the I/V converter is 1 - ist that correct? otherwise my calculations will fall apart before they even began...

So let's add things up in an example - I'll use the OPA1611 as it's widely used for that purpose. Let's assume an I/V resistor of 500 ohms and the DAC has an output impedance of 774 ohms

current noise:
The datasheet shows a input current noise density of 2.8pA/sqrt(Hz). That corresponds to 396pA RMS noise current in the range of 20Hz-20kHz. As far as I can see Rdac and Rf are parallel in this case (299ohms) and this will yield a RMS noise voltage of 0.12uV

voltage noise:
Voltage noise densitiy is given as 1.7nV/sqrt(Hz) which calculates to a RMS noise voltage of 0.24uV in the range of 20Hz to 20kHz

resistor noise:
According to Sengpiel's noise calculator a 500 ohms resistor has a RMS noise voltage of 0.4uV in the ususal audio frequency range

Adding these up (taking the square root of the sum of the squared components) gives me 0.48uV RMS noise contributed by the opamp and the resistor, resulting in a 138.4dB SNR for a 4V RMS reference level.

I'd be very thankful if somebody would take the time look over my calculations as I have no formal education in this field and every bit of wisdom used was extracted from the internets 🙂

IF all that is correct I deem the noise contribution of a modern opamp to be almost neglible compared to resistor noise and most likely noise from the DAC itself.

In my continuing quest to do things slightly differently to everyone else, I've come up with some ideas to improve on the capacitance multiplier. I'm developing it to use with the horn subwoofer I'm planning, which being very efficient will want the lowest possible ripple to keep hum down. I've rejected the idea of a normal voltage regulator on the grounds that they are boring.

The improvements were inspired by R.G's thread on amp output protection where he mentioned using P-channel MOSFETs on the positive rail as switches. This made me realize that the same idea could be applied to a capacitance multiplier to lower the dropout voltage (NPN BJTs need a couple of volts; N-channel MOSFETs need even more), further improving what is already one of the main benefits of capacitance multipliers.

The extra drive circuitry necessary to accomplish this also has the benefit of increasing the effective multiplier due to high input impedance. This allows the use of a smaller 'base' capacitor (what was the base capactor anyway - it's not connected to a base now); small enough to make a film cap possible here. Base capacitors can of course still be large for ridiculously low ripple, but it will then take quite a while for the output to ramp up to full potential.

Using low on-resistance MOSFETs, such as IRF5305/IRLZ34N, dropout voltage can be really very low. As low as 0.1V is possible, but more is needed if very high currents are required. This means vanishingly small power disipation, which is nice.

With appropriate component choice this circuit should be able to provide tens of amps with only mV of ripple and very relaxed heatsink requirements. Regulation is not good, but that's because it's not a regulator. It's a bit more complicated than the standard design, but still has a reasonable component count.

I can't find many designs for standmount speakers with waveguide tweeters.
Most of the ones I find use discontinued waveguides or ones that require modifications with a router table or such. A tweeter with a built-in waveguide would be ideal or at least a still available commercial option that needs minimal modification.

Does anyone have recommendations for sub $1000, 8 ohm, 87+dB standmount speaker plans with waveguide, that would work well 1-2 feet from the wall in a medium sized room.

The Hamlet is tempting but I'd prefer US sourced parts since overseas delivery can be such a pain now.

The ER18DXT is one of the few I can find as an option.

- I also forgot to mention, the simpler the build the better. I only have a circular saw and a router. With time and patience I can build a really good box but complex internal supports or external shapes are a bit much.

Hi,

Does anyone have any information on the availability of DML modules for the Luxman 5M21 amplifier.
An email address was provided of a potential supplier but this does not work as all emails to this address bounce back.

I would also consider diy kits to assemble myself if necessary.

thank you.

Here are some pics of my build and my recent experience with this driver. The SOTA 11R is a fullranger from Markaudio with a diameter of ~ 110 mm. I picked up a pair of the raw drivers along with some diy folks for a nice price from a dealer looking to blow out his inventory. We couldn't get any TS parameters or raw measurements from the dealer and were only told that they were similar to the Pluvia 11 drivers. So I took him at his word and built a CGR designed for the Pluvia 11 designed by Planet 10. The SOTA 11Rs look like they are built to a high standard and come with a sturdy stamped steel frame. I ran the drivers for about 20 hours in free air before mounting them in the new enclosures.

I wanted to try one of Markaudios larger drivers and was hoping for a smallish set of fullrangers that could be as nice as the old Dayton budget bookshelf speakers designed by Wayne Jaesche that I had built about 20 years ago, the cost of the two builds is about the same. Unfortunately so far this has not been the case. The CGR enclosure seems to be doing its job well enough and delivers some punchy but not deep bass, after all it is a small enclosure. My disappointment so far is with the drivers apparent lack of detail and its uneven frequency response. With some decent electronics (aleph J, aikido pre) the budget 2 ways sound pretty impressive, on the same system The SOTA 11Rs are clearly lacking. I'm going to let them run in for a few days and then experiment with some BSC filters to see if I can improve the sound.

From a friend I got for repair a diy motor control for Linn's LP-12.
Compared to the X-tal versions with divider from Linn model "Valhalla" and "Lingo" is here a sine wave generator in use - similar to Linn's AXIS motor control - go to
http://www.turntablepsu.com/images/Axis Schematic.pdf
In the attachment you will find the schematics, which I have drawn out.
Who can give a description, how the circuit of the sine wave generator works or can give an advice, whether this circuit was based on an existing commercial product.
Thank you very much therefore.

P.S.: The reason for not correct working condition you will find in the fifth image.

Go to post #16 for news and new schematic, which I have drawn out.

Hello everybody.

It is hard to find 63/37 solder in the Philippines. So far, this has been one of the cheaper alternatives by mail order.

Has anybody used it? Is it any good?

https://ph.element14.com/duratool/spc22138/solder-wire-63-37-sn-pb-1lb/dp/1539841

Please forgive me if any of this is stupid or ignorant.

A home burglary has put me in the position to assemble a HiFi system from scratch, and after looking at the available amplifier options I thought "why not make one myself?
I have some half-decent soldering skills and enough knowledge to get me into trouble, but no experience with building audio devices, so I'm hoping someone will point out any glaring errors I've made.

I don't know yet what speakers I will pair with this, though I liked my old Paradigm 3SE's. I figure once it's built I can take to to my local HiFi store and they'll let me audition some speakers with it.

Here's my terrible photoshop layout. The red rectangles are to scale with the given internal footprint of the case.



My parts list (in $AUD) is:

Ncore NC122MP 4Ω-125w/ch 8Ω-75w/ch $544 85x170x40mm
(probably shucked from Audiophonics build if I can't find the module by itself)

KHADAS Tone Board $135 82x75x25mm

Relay volume control $140 100x65mm
Is this unnecessary overkill?

Case $45 w182xD200x48mm 8mm front plate
Or vented version

I intend to replace the side panels with some lovely Redgum and countersink the volume knob into the aluminium faceplate. These are things well within my skillset. I like the compact size TypeD will allow and I'd like for it to have a sleek, minimalist look.

Questions:
Is there any reason I can't desolder the RCA outputs on the DAC and solder cable in place to send the signal straight over to the volume module?
What cable should I use (in general) and are there any hints for routing to reduce noise or the like?

I guess they need to be twisted?

Is 60/40 cored resin solder okay or do I need something special?
Any suggested options for adding a sub-out?
Am I cutting it too close with the size of this case? Should I be going slightly larger?
Is there anything I've missed?
I truly appreciate any input.

In the attached pictures you will find the wanted switches.
Who know the manufacturer (Made in France) ?
Maybe the brand COSMOS are replacements:
https://datasheet.octopart.com/81-10101-00-EAO-Switch-datasheet-8497360.pdf
https://download.siliconexpert.com/pdfs/2006/09/29/c/cs/eao/ds/cosmos key switches.pdf?
But I don't know exactly
Thanks for an advice.

Purchase via EBAY a Distortion measurement set HP 339A from an supplier from Israel. This morning it arrived an I did some quick tests. It is a good functional set and I am now very happy with it to test the THD of my tube amp designes. Oh yes, the Forum will shout to me " but there are very good software tools to do that job" and, yes, I agree. But anyway I am glad to have a set that will do that job also.
Here a picture of my set:

I just built an amp with 27dB of gain and I'm building a preamp with 18dB of gain. So total system gain is 45dB.

Is this adequate or excessive gain for a 2V line level DAC source? I don't know what the input sensitivity is.

I don't have a feel for this since I'd been using an integrated amp forever.

I just received a used new 2017 Intel NUC7PJYH (with an optic sound port 1/8).

-I try to swap my Daphile already installed and working HD in the NUC. I received a error message : no device bootable. I set the Bios in different way, with Linux setting without automatic on graphic..., I reset to default, nothing to do. I can boot with this HD a Lenovo micro and a old Dell ATG.

- I reinstalled fresh the last version of Daphile, nothing change, always the same error message.

-I try to install Linux Mint cinnamon v. 18 and the NUC was working very well. I booted also from my USB key.

Regards,

Jean

new arrivals , pcb and more...😱
https://www.ebay.it/sch/scafas/m.html?item=274403855777

Hi ll, I have a naim AV2 and want to see if I can re purpose an unused HiCap for the analogue board,

I have measured the four LM317T's in the AV2 and I believe they are feeding 2 x 5V and 2x 8V supplies (I was expecting the analogue board voltages to be higher ?)

The Hi-Cap is running 2 x 24V supplies, I have originally thought that I might be able to fit two Avondale TPR2's in the HiC-Cap then feed these to the two 8v points on the AV2 board after disconnecting the two 317's in the AV2. I can make up suitable cables and run an earth link to ground the AV2 to the HiCap as well

Any thoughts ?

hi- anyone know a good place to buy vu bulbs- specs are 6VAC @ 14 ohms 20mmx3.75mm- thanks

Hi All,

Does anyone know what size screw thread is used on the securing bolt for the case.

I know it's not metric. is it BA BSF or something else?

Thanks
Andy

Greetings to all.

My name is Marian, i'm new here and I'm sorry to bother you with this but i'm kind of desperate, i have a problem with an EV 7300A power amplifier and i'm in great need of help.

The problem is with channel 1 with is silent, the protection LED on the front pannel stays on permanently, so the power amp inside is closed, this would seam to be cuse of some DC ofset voltage at the output that i have found but i cannot find the reason why it is, i have removed all the power transistors and checked them out and they all are ok, as are the other transistors on the board, then i have checked the other active components ( diodes, zenners ) and they are ok as well, i did found R31 to be foulty ( interupted ) and replaced it, and the power on LED on the board CR21 shorted out, i've replaced it either, now as i was nosing around i found what it first seam to be the the problem with OP Amp NE5532, i found a big difference of voltage between the rails at it's pins, as the negative one was ok at -15Vdc, the possitive one oscilating around +5Vdc, since all other components seam to be ok i have removed the OP and with it removed the voltage rails returned to good working size, +/-15Vdc, then i replaced the OP with a new one but the problem did not go away, i have put the old OP on the working module and it is ok there, but here every time i put the IC in the socket the possitive rail goes down allot, throug thoroughly verification i have found that the main positive rail goes down in fact ( that is measured against the ground ) so i have changed the power line with the one from the working module but still the same, with the NE5532 in it's socket the main positive voltage rail goes way down at a slow but steady rate, that i cannot understand why, i have also found an strange ( to me that is ) voltage difference between the power lines of the modules, i mean that as the working one has a +78/-53 Vdc the foulty one has +59/-72Vdc, i also verified most of the capacitors, searched for blown or defective resistors and came up empty..🙁

Now i came here to you askin for help of any kind, i realy need to solve this amp as it's one of my best friend's amp, so any help is greatly appreciated.

Here is the link to the manual http://archives.telex.com/archives/EV/Amplifiers/Owners%20Manual/7300A%20Owners%20Manual.pdf, and thank you all for your time.
Marian.

Hi,

My decade old Creative Inspire 5.1 5300 started to show problem recently; the popping comes out randomly.


I am thinking of replacing the amplifier board, is there any recommendation on the board?


Alternatively is to do build standalone amplify, using back the existing speaker. For the sub-woofer, I think I will just make it a passive speaker. Any pointers for the board, and the necessary casing?


I am ok with doing some soldering.


Regards.

Looking up something else I stumbled across something on the TI site suggesting with an active second order filter the second stage filter should have wildly different component values, say 10x the capacitance and 1/10 the resistance, or the other way round (it would help if I could remember which).

I've never heard this before or seen it on examples. Anyone know anything about it? As I said, I was looking for something else and at the time what I reda didn't sink in (I was looking for advice on feedback resistor values).

Hi unfortunately I have all my music as downloads to my PC from itunes at there best quality download. I realize this is subpar quality for many of you but I am wondering what is best way to play it through my home stereo for best audio quality?

There are so many options available. I usually just plug my USB stick in my Sony Blu ray player and it does a reasonable job but should I get some music dedicated device instead now I have upgraded my speakers? What about a DAC are they used for this purpose?

I know itunes have a big upgrade to lossless planned. But currently I only have the 256 format.
Regards Tim.

Selling my highly modded Naim CD5i.
Time to say good by to this nice player, as I it collect dust and someone may enjoy his gorgeous sound.

It has a huge number of modifications that I'll not list here. Worth mentioning Burson opamp, Schottky diodes, BHC capacitors, lot of oscons, silver-mica and regulators.


Will go for 700euro.
Shipping 22 euro to EU.
contact me @ tiberiu _ vicol at hotmail dot com

Regards,
Tibi

Hi all,
I recently posted for help designing a tube output stage that would exploit the unused power from my preamp PS. Several contributors helped identify the current limits of my supply, and shared advice on what output tubes might meet my design criteria. I have been reading up on amp basics, limited yet to SE triode mode configuration.

I took two recommended tubes and plotted some load lines. The 6l6 will be underutilized in my build, and the ECC99 maxed out. I am attaching a schematic of my PS which should allow me to continue to supply my 4x6sn7 Aikido preamp with the 40mA it requires, leaving an optimistic 100mA for the output stage, given my transformer is rated at 150mA, and is capacitor loaded. Furthermore, it has a 5A 6.3V secondary, which should be enough for 2 6l6 or ECC99 tubes.

I have modeled the PS in PSUDII, and my voltages are somewhat higher than estimated, probably due in part to my house supply frequently surpassing 121V. Using the software, I have determined that as it is shown gives me 390V with a 40mA load and 4uV ripple, and at 150mA, voltage dips to 340V and 15uV ripple. This seems pretty good to me.

Would you be kind enough to look at my load lines and offer advice on which will likely be a better fit given the PS limitations. I should add that I am not intent on squeezing as much wattage as possible from this amp, and I plan to listen only at modest levels close to the speakers, which are relatively efficient. With this in mind, preserving the character of the preamp (low distortion) is preferable. Another thing I should mention is that the Aikido gives a voltage gain of 9. I plan to use it with a CD player that quotes its output at 2Vrms. Given these, I calculate that I might have max voltage to the output of +-25Vp-p.d My choice of grid swing reflects this, and with the ECC99, I realize that I will not be using the full output of the preamp. 25 V seems really high to me, am I figuring that correctly or is that too literal?

I realize there are many details I have neglected, but thanks for any help with this.

I am not going to profess to being an expert or anything when it comes to electronics or especially audio circuitry, so I was hoping to get some feedback and/or that some people more knowledgeable than I would "check my homework", so to speak.

Here is the current draft of a schematic on which I am working, based on the examples in the datasheets for the LM1875, LM1876, and LM3886; Scott Campbell's "A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier"; and various information gleamed from this forum, particularly the advice of AndrewT.

I have tentatively selected the LM1875 (for its low distortion) — though it is otherwise a bit of an overkill, as I do not anticipate ever exceeding 2～4W.

Bipolar capacitors are film (my best guess as to what AndrewT meant by "MKP"), the polarized ones are audio-grade electrolytics, and the resistors are metal film (preferably with ≦0.5% tolerance — though that is my own preference).

I explain my high-band/low-band cutoffs in grey near their applicable parts in the schematic. Mouser was referenced for a rough idea of cost and availability of less common sizes. (9.98kΩ, for example.)

Source will be a computer's line-out, so I am guessing that a 10kΩ input impedance would be optimal, and a gain of 10 or 11 should more than suffice. (Also should help with reducing Johnson–Nyquist noise, compared to the values used in the datasheet, per my understanding.)

Question #1:
From a theoretical standpoint, does anyone see anything wrong with my numbers, or am I on the right track? Is anything absent that I should add?

Question #2:
In the case of a pure DC voltage source (batteries, for example), C3, C4, C6, and C7 are unnecessary, no? To the extent of my understanding, their purpose is to "fill the void" between peaks of one polarity of the AC voltage swing, no? Therefore, with a steady DC source, unnecessary, no? (There is also a discrepancy in the datasheet regarding the size of C6 and C7, with the typical application schematic saying 100μF and the recommended board layout showing 1000μF... And I also see people on here adding a third...)

Question #3:
I have seen suggestions of using large polarized capacitors in series with the speaker, as a means to protect it in the event of catastrophic failure of the LM1875. However, such nullifies the advantage of the split supply, no? (Perhaps a reason to opt for the LM1876, instead, I wonder?)

Question #4:
For the sake of breaking free of the two-layered, two-dimensional constraints of a PCB and minimize traces between components (with placement not addressed in the above schematic), would it not make sense to build something like this in free-form/dead-bug style?

Hello to the Forum


I own this little good sounding Cyrus Q Power amp that I used for a while as a power stage for my TV. This amp is just intended for high quality AV systems since it has an auto power feature.
Now I've moved it to a music only desktop setup that I mainly use during working hours at very (very) low levels. Unfortunately when using it in this way it sometimes switches to standby and it needs me to slightly raise the input level or press the front power button to awake it back. The auto-poweroff input level is a bit lower than the auto-poweron (hysteresis), most probably in order to avoid continuos power cycles.


Does someone know if and how the circuit can be modified in order to disable the auto-power feature? I have jut verified that keeping the power button always pressed does not keep it always-on; the auto-poweroff has precedence. The button can only awake the amp if already in standby.


Cheers


Raf

So I've built some cheapo party / garage speakers! Cheap, big, and loud were the design goals, and after hearing the woofer run full range I think I'm on the road to success. The box is together, but I still need the crossover. So here I am looking for help. 😀

Here's what I got:
A big, cheap, MCM 12" part no. 55-1745
12'' Professional Woofer | MCM Audio Select | 55-1745 (551745)
Claims response out to 4.5 khz

Cheapish Pyle compression driver
Tweeter Titanium Horn Driver Threaded Compression 150w RMS | Pyle | PDS221
Fs 800 hz (claimed)

I haven't found any frequency response graphs for these inexpensive drivers. I don't have frequency response measuring stuff, though I can do an impedance sweep.

Dayton 10" waveguide for the pyle
Parts-Express.com:*Dayton H10RW 10" Round Waveguide 1" Threaded | horn lens horn tweeter horn bell horn compression driver DaytonAudioWaveguides070109
loads down to 1,600 hz.

My simplistic plan at this point is to hear from some one what kind of acoustic slope is going to come out of the tweeter / WG combo, then add maybe 2nd order electrical (prolly around that 1.6 khz from the WG) to keep me from toasting the tweeters. Then whatever would match that on the woofer. Plus impedance compensation. BSC will be considered after the woofer and tweeter are playing nicely together.

But this is the first pair of speakers I've built w/o someone else's plan to follow, so maybe someone else will have a better idea. Whadya think?

Is anyone familiar with the transformers on ebay listed as Finemet? They say they were sold through Noguchi in the past. JELabs mentions the Noguchi ones on his blog. But I haven't seen anything else on them and the ebay ones seem like more recent arrivals.

On the data sheet what do the different frequencies next to the primary resistance mean? does that mean it bottoms out at 60Hz on the 5K taps?

I 0nly find sheets that are in some foreign language I can´t read.
Anyone have one in english?

Has anyone purchased any Kartesian drivers recently or dealt with THLP? I've been trying to create an account at THLP and can't get past the confirmation.

Both the Wom120_vMS and Mid120_vHE look very interesting to me as midranges covering, say, 400 Hz to 3k.

Hi folks, I’m Duane and I’m about to put together my first set of open baffle speakers. These will be used mostly for some classic jazz and acoustic guitar music and played at low-medium volume.

Baffles are from an old oak table that’s 1-3/4” thick and it measured 48”x30”. I’ve cut it diagonally and the two pieces are 20” at the base and 10” up top - sort of triangular. I have already cut holes for woofers 18” up from the bottom and chamfered the back sides of the holes with a generous half-round radius. That oak table was a curb find from 30 years ago, BTW, and I’ve wanted to do something fun with it. Now’s the time.

What I’m wanting to do is use a pair of 12” Cerwin-Vega woofers I picked up (also free, off a curb) which I re-foamed, along with a pair of Dayton PS220-8 “point-source” full-range drivers. I was planning on running the PS220 drivers straight from the amp - but limiting the upper response of the 4 ohm Cerwin-Vegas.

Sadly, I don’t have a low power SET or similarly low power SS amp; I’ll be trying these out with an old monster, Krell KSA-100 - until I can pick up something more suitable. Another issue for me is that these speakers will go in front of a large living room with a ceiling peak of 26’. Not sure if that will be a problem. I can get the speakers about 3’ out from the wall without the wife getting too upset.

Can anyone suggest a simple to build low-pass filter that may work OK with the 12” woofers I have and cross smoothly to those Dayton PS220’s?

Thanks for your help. 🙂

All reasonable offers considered when buying in bulk.

The following 4 boards from Ableconn for Raspberry Pi:

1.Raspberry Pi USB to 4 Ports USB Power Hun Board. Jumper selection either 2 pin external 5V or Pi USB power. This is a hat with standoff mounting hardware. Retail $28. Asking $10

2. Pi USB to SATA converter board. SATA III, II or I device. USB micro-B and USB 5 pin header. Retail $25. Asking $8

3. Pi USB to M.2 SATA SSD Converter. Accepts 2280, 2260, 2242 ans 2230 SSD. micro-B and USB 5 pin header. Standoff hardware included for Pi. Retail $25. Asking $9.

4. Pi USB to mSATA. SATA I, II, III SSD. Pi or external 5V jumper. Retail $27. Asking $10.


If you want all 4 boards I'll consider a discount.


TP-Link TL-POE150S POE injector. New in Box. These are $17 with free Amazon Prime shipping. Asking $10 with free media mail shipping.

The 2 units listed below sold together. This will power the DigiAmp+ and Pi to power Passive speakers using DietPi, Volumio or m00de Audio. Great for a small bedroom, hallway or kids room system.

2a. IQ Audio PiDigiAmp+ Specs: Access Denied New in Box with pigtail for external power.

2b .Meanwell brick power supply GSM60B18-P1J. 18V 3.3amp output. Good for small Class D amps. 2.1x5.5 center positive. New in box

Asking $55 for both with shipping included and no PayPal fees.

--- Power supplies. All new in box.

Cosel PBA75F: 75 watt 15V 5A. MFG part number PBA75F-15 Purchased directly from mouser: https://www.mouser.com/ProductDetail/Cosel/PBA75F-15-G?qs=7%2B9h8EK%2Bkysa4hy3GMwxYg==

Only asking $28 with free shipping.

https://www.mouser.com/productdetail/mean-well/rs-75-12?qs=pqZ7J9Gt/mo1O2E%2b2%2byO/g== $15 with free shipping.

-- Meanwell RS-50-12. Link: https://www.arrow.com/en/products/rs-50-12/mean-well-enterprises $12 free shipping.



-- Meanwell RS-75-12 12 Volt 6 amp power supply. Link

Looking for a pair of LL1692A or LL1660, 18ma or 25ma.

Hi, I recently came upon this thread
Ribbon mic (DIY) - Bigger gap to shorten front to back path. | GroupDIY
where PRR mentioned that the magnetic strength of a ribbon mic can affect whether it is resistance driven or mass driven. But it was my understanding that magnetic strength only affects the sensitivity.

If X amps are being run through Y magnetic field, the effect on the ribbon should be the same regardless of X and Y as long as X is sufficient.

So why did PRR say that the magnetic field can negate the effect of mass on a ribbon?

I have decided to clean out my workshop and sell a lot of drivers, amp parts and eventually my tube collection. I have way too much stuff and after suffering a stroke in February my life is going in a different direction. Time to make space for new projects.
I am open to offers as long as they are reasonable. I have used my meter on all of the drivers to verify they are good.

1. Tangband W5-704s pair minor use
2. Tangband W5-704d pair minor use
3. Tangband W6-789e pair new in box never use
4. Vifa DQ25SC16-04 pair brand new no use
5. Fostex FT207D minimal use
6. JBL LE20-1 I have 3 salvaged from various speakers
7. JBL LE10a pair one has a small water stain on the cone
8. JBL LE 5-2 pair in nice condition
9. JBL 123A-3 I have 3 in good condition
10. Dayton RSS315HF-4 rand new never used
11. JBL LE14a pair in nice condition in nice cabinets if you want them
12. Hammond 1620 PP output transformers pair
13. Hammond 166L5 pair brand new in box
14. Hammond 166G30 brand new in box
15. LM3886 amp board stuffed brand new never used
16. 41hz amp6 kit brand new never assembled
17. Bash 300S subwoofer plate amp in great shape

Make me offers. Just be reasonable. Buyer pays shipping.
I have pictures of everything. I will send pics upon request.

I have been wondering for some time about adding or making my speakers 3 way. First off I am running JBL D130's with LE175 horns and drivers referred to as potato mashers. My crossovers are JBL N1200.

I built these in the mid 80's I think my crossovers were beginning to get tired, They have the old paper and wax cap's and they were sounding muddy and I purchased some inexpensive 2way crossovers from amazon and it seemed to bring these speakers back to life. Blew me away how much better they sounded, which brings me to this.

I was thinking about buying new tweeters and use the LE175's as midranges and getting new 3 way crossovers. Ideas or suggestions. I will probably try to rebuild my JBL N1200's and maybe just leave it at is if rebuilding makes them sound as good as it does now with the cheap 2 way crossovers. I know the N1200 are completely filled with wax, and would like suggestions on getting them apart

Rocky

Hi, Im new here and Im here looking for a little help. I recently acquired some lovely vintage Toshiba 330 Hi Fi components. I have the sc-330 amp and matching tuner and pre amp. Iv been using them every day. They look and sound amazing! I have the sytem driving some lovely old Wharfdale E30 speakers.

The whole system belonged to my girlfriends dad who passed away a few years ago so they have sentimental value to her.

Yesterday was listening to some music when I the amp developed an awful static sound - something akin the sound of a Vinyl record in between songs, coming from the left channel.

I have tried removing everything that was plugged into the line in's, fiddling with all the switches on the amp and pre amp, making sure all the speaker cables are attached properly and unplugging all other electrical devices int he room all to no avail.
Also I tried headphones and the static is evident in the same channel through these too.

I would like with your help and advice to perhaps attempt a repair. I have only a very basic understanding of electronics but I probably know more than your average man on the street.
People have suggested contact cleaner for all the pots and switched so Iv ordered some from ebay and Il try this first.

If you have any information or input Id love to hear from you.

There is a post from a guy with the exact same amp and what seems to be a similar issue on another forum. The thread ends without an outcome but non the less it may be of use to someone offering help to me, so here is link:
Toshiba 330 Rack - Tapeheads.Net

any help much appreciated.

Thanks 🙂

Hello, first post here.
I am considering building a sub with a Pioneer TS-W312D4 as the driver for home theater. I cant understand how to build the port or the total enclosure volume through WinISD ; by trying changing values of the tuning frequency it is giving me the proper response in the Transfer Function Magnitude, but I cant figure out what structure needs to be changed to reach the lowest frequency in about 15-20Hz with the highest SPL possible?

I'm looking to make myself a set of "mix cube" type studio monitors. Typically known for being single-driver, sealed, and light on bass/treble so one can focus on mixing midrange content. Most attempts to clone the prototypical Auratones end with the need to find an identical driver. I'm not interested in a clone, just making a small, sealed, let's say "mid-focussed" speaker from a full range (or I guess good mid range) speaker driver as a complement to my "big" monitors. I actually already made a prototype with a $1.95 speaker from a DIY electronics site in a 3D printed enclosure. It's a bit to distorted at low volumes to be the finish line but it was close enough to make me think a real swing is worth the time.

So, I'm looking for driver options. Right now the best looking driver I've found is the Audax 13LB25AL with its flat midrange and gradual role off in a small sealed enclosure. The sensitivity is a bonus too. I also have a pair of Mark Audio Alpair 10p but they look to need a bigger sealed box to prevent a bass bump from over damping. The smaller alpairs all look to have a little bit of a scoop in the mids that would be undesirable. Surely there are other choices if anyone can make a recommendation. I'd pay about $150/driver max or thereabouts.

Hi guys
I am recapping my mark levinson 33H
As I star with the output stage board I have looked for week links
I wish to upgrade the emmiter resistors to non inductive and non magnetic ones and if it's possible to ultra low noise ones.
I don't have any experience in this specific point of upgrade so I don't
Know what to expect by sound characters.
I have heard great things about vishay mils resistors and ohmite audio gold resistors.
Did any one compare between those 2 ones ?
What are the sound characters did you got by upgrading emmiter resistors?
Values that I need are:
0.22 ohm 5w now installed cw5 resistors)
0.33 ohm 10w (now installed cw10 resistors)
10 ohm 5w (now installed vishay NS-5 non inductive)

Best regards

Nehoray

During installation a small piece of wire fell into the amp (the rca side). After that all 4 leds light, and consumption is 250mA at 12V.
A local technician tried to repair it and replaced R30 with a 2K2.
Then they send it to my shop.
I removed the transistor switch of the power supply driver board, injected 12V, and managed to turn on the power supply. The audio section has no rail to rail oscillation, probably muted.
Any help is highly appreciated as the amp seems quite complex.
I dont think the class D audio section is faulty, i believe its the turn circuitry.

Same of us experiences really hot summer know and miniDSP 2x4 HD

runs quite hot.
If you have a 3D printer welcome to print vented shell.
www.thingiverse.com/thing:4902183


I have added fans for vented shell as well
www.thingiverse.com/thing:4912339

this Focal Solid 1 is stuck in protection .there are no bad psu or output transistors ,no dc on the speaker terminals .nothing appears burned
Pwm is tl494cn

Pin 1:0.00
Pin 2: 1.35
Pin 3: 0.07
Pin 4: 1.53
Pin 5: 0.21
Pin 6: 0.45
Pin 7: 0.00
Pin 8: 13.97
Pin 9: 0.00
Pin 10: 0.00
Pin 11: 13.98
Pin 12: 13.98
Pin 13: 1.55
Pin 14: 1.55
Pin 15: 1.55
Pin 16: 0.00

hi- pressure pad has disintergrated- wondering what to replace it with

Hi amigos,

I don't know if you've heard of the Poppulse T180, in its MD version for the German market. But I was lucky to be able to have one)
The MD version was specially made for the German market with best caps and some improvements (wiring, OP amps etc).

I discovered this amp on a German discussion thread and was very skeptical of its praise. This amp has been compared to many amps above the 10,000 euro mark, including the ASR Emitter 2.

I am one of the people who prefer to test rather than read too much .... I am quite pragmatic in my approach so here is a small review of this beautiful amp

You can see my reviews from ASR and Diyaudio, I own many amps : Purifi / Hypex Ncore / Dual Merus Infineon / Top level TPA3255 etc...
So I have a good basis to be able to compare this Poppulse)



Spec :

Poppulse T180 MD version
Dual Mono Tripath TA2022 chip
Update : OPA1656 for Output path (XLR) + OPA1692 for the preamp section
Linear PSU
Full Balanced inputs
Unbalanced inputs
ALPS motorized volume controller
Anti RFI/RMI filter
2x120W / 8R
Full aluminium case
412 x 340 x 80 mm
8 KG

My setup :

Gustard AK4499 Dac (full balanced)
HD Audio stream source
DACS 33 floor speakers with Ribbon Tweeter 3 way


The amp already seems very well built and robust, it is quite heavy given its toroidal power supply (8KG). It is assembled in a black aluminum case and the connectors are of good quality.
By opening the case we discover a fairly simple but very clean circuit which highlights the two Tripath chips in a dual Mono configuration, so one chip per channel. Basically it comes with two genuine OP5532 that I updated.
Everything is well made in and it's readable enough to understand that we are dealing with a well finished amp. In this price range it is also very rare to find a motorized volume controller, the amplifier comes with a small remote control.

I have a small downside concerning the automatic protection mode: indeed a chip resets the volume controller to 0 each time the amplifier is turned on.
But in the end it may be a good point to protect the speakers
The manufacturer recommends a 40-hour break-in to polarize the components; I am still far from it because I barely did ten hours of listening.

I listened to multi styles in HD Audio to see the potential of the amp and I can already tell you that the amp has enormous potential!
You have the option of bypassing the internal preamp via two small switches. (bypass preamp 0db or use preamp 12db)

I made the test with the preamp only for the moment. The OPA1692 update on the preamp section allowed me to considerably improve the soundstage and refine the highs.

Here is my feeling:

Highs :

Tripath is well known for its definition, especially at the top of the spectrum. On my jazz register, the ride "chabadas" are sublime! The hi-hat, cymbals and effect cymbals come out beautifully and the Tripath / Ribbon Tweeter combination works wonderfully.
The higher-pitched voices come out extremely well in the mix in most of the albums listened to and the amp is in no way aggressive in the treble, the listening is very musical and muffled.

Mediums :

With the OPA1656 the mids are straight and very neutral. Compared to the 5532, I found that the OPA1656 brought a lot more warmth and "naturalness" to the vocals.
Here we keep the analytical dimension of class D with the advantages of class AB.
all the voices come out wonderfully, the baritone, soprano and tenor are really well transcribed.

Bass :

I never liked amps with bass transcribed too far forward. Here the bass is balanced, fair and round as it should. in the Pop to Rock register, it's clean and it doesn't bleed.
The delicate bass acoustic articulations are reproduced very well. I refer in particular to the mix in the rhythm section double bass / drums which stands out to me in the Jazz register.

Conclusion :

I was very skeptical when I read the German forums. But I can tell you that this amp is a killer considering its price. I was able to compare it to my Dual Merus reviewed recently on ASR and even against my Purifi, this amp is probably the most "musical" of the class D that I have been able to test. It is silent, very dynamic and absolutely warm in all registers.
This amp has everything a big one, a huge soundstage, enough power to drive big speakers and above all flexible with the possibility of personalizing your sound with your favorite OP amps in DIP8 format and even the possibility to bypass the internal preamp.

I have not tested the ASR Emitter 2 highlighted on the German forum (Kellerkind-Audioforum - "MD"- PopPulse T180) and which has been compared to this Poppulse but in my humble opinion this amp will overshadow much more expensive amps. I had the pleasure of testing a bunch of amps much much more expensive but really less efficient than this Poppulse! If you find one, go for it!

Demo Video :

In progress. Will share later

Pictures :



envoyer des photos gratuitement par internet








envoyer des photos gratuitement par internet

envoyer des photos gratuitement par internet

Hi all
Amp using 4 transformers using 4 set of IRFP064N mosfets. The driver transistors are KTN2222A and KTN2907A.

I would like to know the good replacement for driver transistors. Thank you.

Good day/night to you all! I've been thinking of building a pair of CHN-50 enclosures to use for my desktop setup, now that I'm hooked on MarkAudio from my 7MS build.

After looking through all the vented and mass loaded and horn designs, I simply don't know the advantages and disadvantages to each within the context of my particular setup...

Being that they will be on a desk, they will be both near the rear wall of my room, and each speaker will be sharing "baffle" with part of the computer monitor to the left and right.

Quite a loaded question, but what would be the sonic advantages in this use case to going with a horn loaded design, versus simple vented or mass loaded, other than taking advantage of getting the drivers higher and closer to ear-height when sitting on the desk?

Does it even matter? If not, might as well go with a Tozzi One kit? That'll save me time and effort.

I appreciate your insights. 🙂

Hi,

I have a brand new Hypex NC502MP module + cable kit to sell
Free shipment to Europe, can't ship outside !

Last version (2021).

Perfect to build a clean reliable powerful amp.
See ASR to check the NC502MP great performances )

PRICE : 450 euros free shipping (but UK)
Paypal only please


Hypex NCore NC502MP twin Channel Module
PSU SMPS integradted 1500W
Auto sensing 100-240V mains input operation
0.5W standby operation
47K Ohms Input Impedance, low output impedance
THD 0.0018%
S/N Ratio 116dB
26dB Voltage Gain
2 x 350W 8 Ohms
2 x 500W 4 Ohms
2 x 450W 2 Ohms
Fully loaded flat frequency response
92% efficient

Two years ago i purchessed a broken DD Dual turntable for its tonearm which was in good condition. I also have a B&O MMC20E cart that was never used from a broken B&O turntable , some Easton archery Jazz arrows made out of 7075 aerospace alloy and a a broken Garrard whose counterweight needed to be used too...Now i need to wire it , put the phono pre inside the wooden box and listen to the damn thing.

I'm tired of designing in high voltage and having a lot of spares and components. My method will help get the best performance. I hope those who believe in me will receive good things. when building a class d filterless high voltage system.
[double H Bridge]
[Sorry, the circuit I posted still crashes.]

Hello there!

I am a member on this forum for quite some time now. I just thought it would be great to introduce myself. 😀

I started building my own radio when I was ten. My father is an electrician and he always collects electronic boards from garbage(I came from a poor family). One day I found this fm tuner board and an amplifier board from a toy piano, with the help of my dad, I have built my first fm radio. Since then I fell in love with building audio electronics.

I am now an electronics engineer for more than 10years. Sadly I didn't got any opportunity to work for an audio electronics design job. But at least I am working for research and development for electronic products which is still I love.

I have created a website tataylino.com to post some of my work during my free time. Most of my post there is about audio electronics. This is my way of continuing my passion in audio electronics since my day job is not about audio electronics.

Cheers,
Glenn

I would like to share my DIY turntable plinths with you

I refer to the thread title which is IMO inaccurate. If accuracy in knowledge is required, to visit this set of forum pages then we should know firstly what analog line level is, and what equipment analog line level actually relates to. Our sub list of equipment presently reading as Preamplifiers , Passive Pre-amps, Crossovers, etc.

Will after a few pages here hopefully be seen to be quite inaccurate, and collectively be asked to aspire to greater accuracy to assert the pages knowing what line level actually is and only include equipment in discussion that actually uses Analog Line level.

As example would if we adopt the AES guidelines, would include as well as consumer line level and professional level equipment, also microphones and musical instruments.


Can we have firstly perhaps seek consensus on the definition of Analog line level

1. Consumer line level, can we agree this is the majority of audio equipment forum
members use.

expressed as -10dBv or nominal level 0.316V
RMS , or Peak amplitude V pk 0.447v or Vpp 0.894 ,

2.Professional equipment expressed as +4dBU , or nominal level 1.228V RMS
Peak amplitude Vpk 1.736 or Vpp 3,472

We should find in our understanding that consumer line level is bound already to the manufacture of CD's DVD's and the same same standards are used by streaming services. historically there was break away from this called the Loudness wars, but was sensibly brought back into line, when someone woke up that, dynamics were unable to be reproduced. ( this does not discount the inevitable use of companding that awaits )

Professional level is different in that DAW's and the like are constantly trying to achieve as high a dynamic range as possible at the recording stage,( Companding is the answer for everyone ) however professional level still applies to equipment in recording studios, and some equipment that can be used in domestic settings, but is typically balanced audio, and may have much incompatibility if used with consumer line level.


as a reference the AES ( Audio engineering society ) define line level here:
Pro Audio Reference (L)

"levels Terms used to describe relative audio signal levels: (Also see decibel).
mic-level Nominal signal coming directly from a microphone (before any digital conversion if present). Very low, in the microvolts, and requires a preamp with at least 60 dB gain before using with any line-level equipment.

line-level Standard +4 dBu (pro) or -10 dBV (consumer) audio levels. See decibel.

Instrument-level Nominal signal from musical instruments using electrical pick-ups. Varies widely, from very low mic-levels to quite large line-levels.'


There is scope already for DAC's to have amplification stages in them altering line level ... but this I invite blurs discussion of analog line level itself , if we base ourselves on accuracy going forward.

Over to you.

Hi folks


My Apart Concept1 amp started sounding distorted a couple of weeks ago, so I replaced all the large electrolytics and it cured the issue, I suspect the three caps next to the voltage regulator heatsinks had dried out.

However, there is still a problem, the amp has four inputs labelled A, B, C & D. It works great on B, C & D but A sounds distorted.

I also changed the 2.2uF electrolytic caps on the inputs to 2.2uF polyester ones, I don't have a service manual or a schematic, otherwise I'd replace all the caps in the signal path.

So, anyone got any bright ideas as to how to diagnose and fix input A? The only thing I can think of is to trace the channel from the input jacks, replacing all the caps along the way. However, I'm dubious that just a change of caps will do the job as the other 3 channels sound fine.

Just got my hand on a Thorens TD 160 and need to get a phono stage for it. If you have one for sale or thinking selling feel free to ping me.

I have installed bookshelfs with empty space in the corner (IKEA Billy). I have room for some absobers of some kind. From the corner out to the back of the bookshelf set at 45 degree angle from the walls there is about 35 cm distance. There is room for both some fibrous damping material and 25 cm/10" pipes.

The easy way out would be to stuff the whole compartment with some fiber material. An other would be to utilize a part of the space for quarter wave traps. Is that useful for say the 100-150 Hz range? If so should the open ends be placed near the corners (pressure maxima) or away from the (higher velocity)?

Hi,
I need some help.
I have a 1200AS2 module that stopped working.
Auxiliary and stby switching PSU is trying to start but after less than a second stop. That is all that I've found out without schematic. No visual demage is present on the board.
Is here anybody who has any experience in repairing this modules or has a service documentation to share?