I have a wadia x64.4 dac that is acting up on me a bit. I have it working well now, but there's an issue with the sledgehammer output stage. Originally, the unit would not play from one channel via RCA outputs. The other channel worked perfectly. I fussed around a little, changed electrolytic capacitors and relays without any change. Then I realized my issue with the positive signal section of the output on one channel. I swapped the positive and negative input signal and the op amps and now it works.

I've been listening to it this way for months, but I'd like to fix it. Comparing side to side, the thing that sticks out is the resistance to ground. On the channel in question, I'm reading open from signal to ground where in the functioning channel I'm reading 220k ohms. It has been this way the entire time. I also swapped out film capacitors from side to side without any change. At this point I'm thinking I have a broken lead somewhere. Any help will be much appreciated.

So, the other part to this is: is this output stage worth fixing or should I put something else in? I'm sure there are better output stages, but not sure which would be a good match for my dac.

Smallest box with passive radiator for 25Hz F3.

We now know that in case of multi sub setup the individual sub's alignment doesn't matter, reasonably speaking. As long as the sub can reach the intended extension within its excursion and power handling limit, the alignment does not matter. So, lets not discuss driver parameters and alignments, from the plethora of drivers available from either home audio or car audio, just about any decent one could work fine.

Now, for the same tuning (Fb) a smaller box means increased added mass on the PR. It means that the added mass and size of the enclosure are the limiting factors. Because we cant add more mass, we cant make the box any smaller.

So, how small can a box get and how much mass can be added to 10"/12" PRs for 25Hz, F3? Pls note that for 25Hz, F3, a much lower Fb will be needed.


Related: Bose:Small enclosure, long port, how?

6.5" - keen to see someone use it.

In VG condition - can email photos. ONE driver only. Would need to be shipped from NZ.

Hi

20 NOS, unused 2SJ28 / KF33

Posting this here to help out a friend - he has 20 pieces all sourced as part of the same batch/tray from Acronman, aka circuitdiy. Selling unused due to some pressing health issues, hence unmatched as well.

Based in UK. 20 pieces for GBP 650 (approx $41 each I think)

Thanks for looking.

Cheers
cv

What are these screws called and where can I get them? They are used in securing output transistors on heatsinks. They seem much more user friendly than the machine screws i have been using. Those need to be tapped, which sometimes ruins the sink plus takes a long time, These on the other hand are just drill and screw types, no need to tap them ... I know they are self tapping, but what kind or where can I order them?

Hi guys....Rephrased question... I'm finally getting to my tu 8200. I just want to know if there will be any issues using wire jumpers instead of the vol pot, or should I put some resistance in there.? Thanks for advice. Cheers!

Anyone have any pics of the board ?

Or might be able to tell me the value of the resistors ?

This amp isn’t producing any positive regulated voltage.

I removed the opamps since 1 of them was defective and still couldn’t get the +15 volts .

All opamps for this amp still have voltage on all pads even after they have been removed from the board .

I removed the regulator also and all 3 pads for the regulated have voltage on them .

Any ideas ?

Hi everyone:


The terminals finally broke on my Klipsch Promedia 2.1 (original version with power swtich). I need a drop-in replacement. As I understand it, anything bigger would requiring cutting the metal on the backside of the Bash amp to fit. Does anyone know a source for a drop-in replacement?

So far, all I could find was this seller on eBay
NEW Klipsch ProMedia 2.1 Speaker Satellite Terminal Block module Plug; OLD Type – Speakers Geeks
However, by the time I convert to $CAD and add shipping and other fees, it will come out to $CAD 50.00. I'm not willing to pay that for $5.00 terminals.

Thanks in advance.

Suspend speaker by swing is best one can do.
🙂

Like to prove yourself ?

Hello,
I am about to built a pair of DIYSG HTM-12 speakers was wondering if there were potential ways I could maximize the quality of the speaker build. Reading around it does appear there are some potential things that could help but I am just wanting to make sure they are correct and ask for feedback.

1) I was wondering about the speaker driver / baffle interface. I have read that having some dampening material (such as weather stripping or neoprene etc) can help reduce the transmission of vibrations to the speaker cabinet. I could not get it to be a fully floating driver but I was wondering if instead of the driver being simply screwed into the MDF if this design would be beneficial:
Speaker driver -->
Dampening material -->
MDF baffle (drilled through, so no direct contact with the bolts)-->
Dampening material -->
1” plywood with T nuts for bolting the speaker to (the plywood could either be cut around the whole speaker cut out, or could be in smaller pieces for each individual bolt hole)

Do you think that would help isolate the driver from the baffle and be worth doing? Any room for improvement?

2) I was looking to minimize cabinet resonances and so I have read that the main way to do this is through adding more mass to the walls, adding more bracing to the walls, adding dampening material, absorption.

Mass: I have looked into constrained layer dampening and using green glue, and so I could potentially put another layer of MDF on the back wall. Would this be beneficial? Any other options / thoughts?

Bracing: I certainly can add more MDF bracing to the cabinet. Are window braces most effective? Any places that I should avoid putting bracing (i.e. right behind the main driver)?

Dampening: This is where I haven seen lots of opinions yet have not figured out what truly would be best. I have heard of people using dynamat, roofing felt, industrial floor tiling, rubber gym mats, memory foam, bubble wrap, etc. Would all of these be options? Any personal preferences people have? Also how does this affect the effective volume of the cabinet, like can one go too overboard with this stuff?

Absorption: The speaker design is a ported design and calls for ~3inches of absorption on the back wall and 1.5inches on the side and to keep the ports clear. I have read that the maximum velocity of standing waves is in the middle of the cabinet, so then hanging the absorption material ½ way through the cabinet would be most effective would it not? But are their down sides to this? Also if it was in the way of the direct path from the speaker to the ports would that change the port tuning, or is that all about the internal volume and should not be a problem? Also, more absorption would change the effective volume and thus change the port tuning so maybe not changing the absorption would be ideal? I have also heard that there are significant downsides with over stuffing a speaker yet I have not personally made any speakers so what should I be looking for if that occurs?

Ok, I think those were the main things that I was looking into to try and squeeze that final 10% of performance out of this DIY build. I would appreciate any feedback on the proposed alterations and also let me know if there are any glaring ways I could further improve on the cabinet making.

Thanks!

I've had these up for months, with a few watchers - I have two, actually, as someone purchased one w/o following the listing rules. They are in nice condition, originally out of a Kenwood mosfet amp.

Large 7.5 lb 200VA 40-0-40 (80V ct) + 10V Audio MOSFET Power Amp Transformer | eBay

When a speaker is connected amp will go in and out of protect continuously .signal on the outputs look good.I see 633mv offset on output terminals.

Any suggestions?

What normally goes bad on these driver boards?

So far only thing I find was a bad 5v regulator which supply Voltage to the driver board.

Found another vintage tube console that seems like a good candidate for converting into a standalone amplifier. I really like these old vintage consoles for honing my soldering and chassis modding skills. They usually come very cheap (sometimes free) and the accessible point to point wiring makes them fairly noob friendly.

Here's what I've done so far:
- removed the pre-amplifier / tuner section
- added polarized power cord, on/off switch, and fuseholder
- replaced all power filter caps (kept old capacitor cans for aesthetics)

Please note that all the tone controls, etc. are removed along with the pre-amplifer section. The pots and switches were not worth cleaning and using.

What should I do with the rest of the circuit to use it as standalone amplifier and have it sound good? Is it as simple as replacing the coupling caps as per the schematic? Or are other values or modifications recommended?

Any guidance much appreciated. Schematic attached.

For Sale - A single 16 ohm BMS 4592 coaxial driver. Used for testing a few years back, been sat gathering dust since. In full working order. £200 posted in the EU.

Hello,

Has anyone seen a simple on/off relay circuit for an SMPS without soft start?

I would like to have a low voltage Anti Vandal type momentary type switch that when pushed in for a few seconds lights up and turns the amp on and then when pushed again for a few seconds goes off and turns the amp off.

Anyone seen such a circuit?

Preferably a board I can just buy.

Looking around the webs, I didn't find anything suitable.

Thank you,

David.

Hi, apparently TI has decided to also make a free Spice simulator available to their customers.
You can ask to get access for their 'Pspice for TI' simulator, you get an email and can then download & install.
Should be of interest for those TI proprietary models of switching regulators etc.

Anybody using it?

Jan

Greetings.
I am a new member, I decided to try to build f5v2. I am now in the process of procuring and finding the materials needed to make it.
I have a request can any of you help me please.
I would like to have FQA19N20 mached quad, and FQA12P20 mached quad.
Or 2SK1530 mached quad, and 2SJ201 mached quad mosfets.
Please dear members can you help me on this.
I apologize for my poor English
Best regards.
Miha G.

Few months into the diy game and becoming obsessed, after some budget friendly failed ideas/designs I am looking forward for something better.

The options I have in mind these days are:

A. The Jeff Bagby's sb revolution mini (the sdac edition) plus the Jeff's woofer module featuring one SB29NRX75 per side (crossover @200hz)

B. Sb Rinjani OR troels gravensen's sba 761 (both 2.5 way with satori drivers) plus active subwoofer (peerless xls with passive radiator.

Surplus to needs,

$20. Plus Shipping.


ZHIXIANDA H0716 7 inch 1024*600 16:9 AV BNC VGA HDMI signal portable mini LCD screen monitor with two speakers|lcd screen monitor|portable lcd screenmini hdmi monitor - AliExpress

Hello everyone Tell me, what is the output of the amplifier and put the second circuit Cabela? Moreover, such a circuit is put only in amplifiers for the German market.

Hello,
I know everything can be run from battery, it is just a question of the size of the battery 🙂
So, with a reasonable battery, what amp would you recommend? With this, I would use my smaller, portable cans and plan to get some good Grado. Maybe I would use sometime with 300 Ohm cans, but it is not the most important.
Also, it may be important that I less care about the base, much more about wide and deep stage. I do not prefer ICs, but may try. Opamps I do not like at all however (maybe DC servo). I made with TPA6130 and it was not bad. Very detailed sound, but less the amp what I would listen to for hours.
Thanks a lot!
JG

Since I would like to build the 'ulti-amp' that was published in Elektor I need to get my hands on 4 x BFX36 and 4 x 2N2914.

As i felt like a deep unjustice to not even mention Lars's old design once in a decade, I start this topic with its schematic as it was once published on Olive audio.
It was the first high power amp i built, even modified it for use with complementary fets which is simply done by removing t14 and r29 and replacing all n channel tarnsistors with P channel ones, reversing the source resistors place of course .It worked flawlesly on a pcb i'd be ashamed to post...At the time there were the Holton amps in vogue, but having built both i was convinced that Lars's Zeta was the better one. it worked very well from +-90v to +-9 v .using only one pair of transistors and +-35v supply makes for a very good home amplifier .

As i don't find any explicit ban for posting its schematic anywhere i'll do it.

One thing I am trying to do is "future proof" a Class AB design with reasonable performance because many transistors become hard to source over time as commercial designs continue to advance. 2N5551/2N5401 have many alternate and generic sources and have high enough VCE for 200 to 300 W class amps with 60 to 70 volt +/- supply voltages.

However, they are probably not the best choice for many of the parts of the amp, and perhaps another part such as BC546C/BC556C might be a better choice and also easy to source. For example, the long tailed pair input which best has a low noise figure might have a low enough VCE so that a BC546C could be used. For constant current sources that have a low VCE, there might be changes in Hfe that cause nonlinearity that causes distortion for which BC546C/BC556C is a better choice as well. There are likely other issues I am not considering. How serious are these problems if 2N5551/2N5401 is used in these roles?

Also, other TO-126 parts seem to be becoming rarer such as MJE340/MJE350. However, TO-220 parts seem to be available, in particular MJE15032/MJE15033 or TIP47C/MJE5731, with MJE10532/MJE15033 having at least one generic available. So while it might be more slightly expensive, using MJE15032/MJE15033 in place of MJE340/MJE350 might help future proof a design. Increased gain-bandwidth might require extra compensation, and increased base and collector capacitance might be an issue here as well.

As for power NPN/PNP combinations there are fortunately still many choices. However, in the interest of future proofing, reducing the number of types of devices required and making the devices have many generic sources helps to ensure availability. Do the substitutions I am suggesting make sense and would not significantly compromise an amplifier?

Taken out from my retired player, the latest XO3.2 without XO is 179 euro

Low jitter clocks

Asking for 75 euro / USD85 with free shipping to Europe, USA and Asia, PayPal only.

Really niche but interesting ..
SIT(V-FET) 2SJ20A-2SK70A Power Amp & Power IVC

Does anyone know that strange looking part on in the pictures ?

Hi, I have recently come across a set of JBL 55VX speakers, the cabinets and tweeters seem to be in very good condition, however the woofers have the usual surround rot and need replacing. My question is how do I get these out? The plastic surround covering the screws seems to be very firmly attached and I do not want to damage it or the front of the speaker.

Thanks.

Hey Y'all.

I put together what I think would be a great enclosure for my Dayton Titanic 12" mkIII. Its been living in an old JBL enclosure power by a BASH 500. Please let me know if I missed anything here.

I entered the driver into WinISD



The only thing that was different from the spec sheet was Sd. It autocalculated and manually entering from the spec sheet would caused driver invalidation.

WinISD liked 130 liters tuned to just under 20 hz, SPL at 500 watts rms, 45 deg angle, 3 meters away.




Made this in sketchup to match:


Heres cone excursion and port velocity:



Looks like I'll need to filter under 20hz, but i have a DSP to help out.

Does that all check out? Did i make any mistakes?

I have a question regarding a combination of choke and line output transformer loading for preamp tube and I'd appreciate your answers.

I'd like to use a line output transformer for loading of my 01A tube preamp. The output transformer has only around 90H of primary inductance which I believe is a little short for loading 01A tube at low frequency.
Is it possible that I'd use an additional 50H choke (audio choke) in serie with the primary of the line output transformer, according to my understanding:

If I take the output at the anode of the 01A tube (via a capacitor), it should be Ok since in this case the primary of the line output transformer will act like a choke in serie with 50H choke (the secondary will be left un used), so total inductance of the two will be 140H and the low frequency will be improved albeit with high output impedance.

If I take the output at the secondary of the output transformer, I believe the output will be lower than before since there will be a voltage divider between the choke and the primary of the line ouput transformer, that's acceptable for me but my main concern is would the low frequency at the ouput of the line output transformer improved or not?

I used Tractrix _V1.4b to design a 185 Hz horn using Inlow sounds .inlowsound.com method of making a mold and building the cones out of paper mache. I am not connected to them in any sense. I have never communicated with him either. Although it probably would have been a good idea. I am just about to finish and pull the second horn off the mold. I do not have storage space for the mold and am willing to make someone a terrific deal. It has a 55mm mouth and is approximately 24" high and diameter. I have not progressed to the point where I can say how it sounds, and am about deaf so don't ask. I am using Dynaudio D54af for drivers but a low frequency 2" compression driver would be better. I hate to take a hammer to my covid 19 lock down work, but it has to go soon. I have learned a few things and can pass that along as well. I am located on the Southwest coast of Florida.

Hi,

I have this t.amp 1050 (380W / 8Ohm) specified cheap PA amp. I guess it is a copy of a copy .... and there are many similar amps around, I have attached a schematic I found. I would like to reuse at least the case and the transformer, but I need much better sound 🙂, it should be transferred into a good sounding amp for HiFi.
Do you have any suggestions/schematics for me how to modify it ?

p.s.: I think it needs more than another opamp...

Salas phono simplistic Preamp mounted on a bamboo table, gain set to MM or High output MC.
Supreme and EVO AG-AU oil Mundorf capacitors, Saligny synchronous rectifiers.
Price 500euro.

Ship only to EU due COVID restrictions.

Reason for selling - HMN



Regards,
Tibi

I am looking to buy NUFORCE HA-200 headphone amp in decent condition. I am in Chicago area. I want to give this amp a try.

Thanks

Is there any castle style MLTL designed for the Alpair 10p?

Hi ! if i understand well speaking of bjts more powerful ones have a bigger SOA than less powerful ones. Is this confirmed ?
I wonder which kind of issues i can encounter if i replace let's say a NPN 80W bjt with a NPN 200W bjt.
I know already that higher gain bandwidth product can lead to instability
and this is my main concern 😱
If i have to replace a 3 MHz part can a 10 MHz part be a safe option ? 🙄
The goal would be to have a more robust output stage (i.e. increase not the power but the soa)
Anyone who has done something similar ? is this a silly idea ?
If there is a more appropriate section please redirect my question there 😱
Thanks a lot and kind regards, gino 🙂

Looking for schematics for this dedicated amp for the Transar speakers of the late 70's.
Has a horizontal function power indicators along with voltage/current source output buttons on front.
Inputs for high frequency crossover and volume along with inputs for full range operation
Stereo amp at 250 watts ? 16 T03 total quasi outputs

Mine has a turn off thump annoying me. Negative rail sticks on after shut down . No bleeder resistors originally but then it didn,t have this issue years ago.
You might check out this Heil transar speaker project that never took off

Regards
David

Hi,

I wonder how its linearity is at ~400Vdc in triode mode/single ended. Any one has Triode curve of GU-50?

For single ended operation, how is this GU50 tube compare with KT88 and GM70?

Thanks.

Hey guys.
Do you guys know of any small 2.1 or 2ch amp boards that have reasonable power output? for what they are hahah🙄
I have a small amp board about the size of the palm of my hand with 2x tpa3116 chips on it and it is loud for what it is but I was hoping to get something a little better if possible as I know there’s a ton of different amp modules out there with various amp chips but it’s very hard to do research as you really have to try them…hummm…..but it’s worth asking the question.
Cheers

Hi Guys,
I am repairing a Optronica Amplifier SM-1616
it has a 60w Dual amplifier output on it S60w Output IC
the pre driver BJT transistors are Blown i cant seem to find a replacement for them the originals no longer are availble
2SC1628YL & 2SA818YL

i think i can use the following but not 100% certain
KSA1381ESTU & KSC3503DSTU
can someone please point me in the correct Transistor to use as a replacement that will be compatable for this

Thankyou
Wayne 🙂

I know its a long shot but.......

I was looking for a California Audio Labs ICON MKII CD Player (non-functional) but with functioning display.

I have both US & Canadian mailing addresses and I can pay via PayPal.

Thanks in advance,

EDIT: solved
Hello,

Can anyone tell me if there are going to be issues with this design?
I'm planning to build a ported enclosure with dual subs in it but they will both run on their seperate channels.
Can any problems appear regarding over excursion or distorsion.

The enclosure has 51 liters (with the port and drivers taken into account) and it is tuned to 30,95Hz.
The subs are Dayton Audio SD215A-88 and I'm planning on running them on 60W (RMS is 80W.)
Appreciate the help.
Here's a CAD of the design:

I found a weird design speakers from 80s. They were labeled 5-way floor-standing speaker systems. They had 5 drivers per cabinet consisting of a 10” woofer, a 5” midrange and 3 2” cone tweeters. I had opened up the cabinet to see the crossover network and was surprised that it was very minimal. The woofer had no any network while mid and tweeters had only a capacitor on each driver; 10uf on mid, 4.7uf, 3.3uf and 2.2uf on the tweeters, respectively. Yet, they sound not so bad. I’m wondering that should they considered to be 5-way speakers? Were they be low cost speakers design?

Dear Admins,

would you consider creating a new amplifier category like "Hybrids" ?

We have SS, Pass Labs, Tube/Valve, Chip and Class D categories but .. where to put questions or ideas about hybrid amplifiers ? (Valve input stage, sometimes even driver stage with mosfet or class D output for example).

These kind of old-new animals are slowly approaching into the Hi-Fi era, I think it would make sense to create a new category for them, under the Amplifiers section.

Cheers 😉

WTB SIT NEC 2SK70, 2 of them would be fine, more then 2 even better. If you like to sell pairs with 2SJ20, also welcome.
I own 2 pairs and like to have spairs just in case I damage one.

Hello , looking for a DLS5000 R Subwoofer , preferably in Canada .

I started TI TAS6422 2.1MHz Class-D Digital Amp Project.
An original designed board has PCM9211 for 24bit 96kHz ADC, Coax/Optical SPDIF, I2S and LVDS-I2S interfaces controlled with PIC16F1829. One-button & Rotary Encoder UI software is now under development. I will put my source code on my Github repository soon. I'd like to share my design information and impressions for all DIY'er members.

My Project Web Page: TAS6422 Amprefire Fix & Modification

Best Regards,
CyberPit

Hey folks. This is a followup to another post https://www.diyaudio.com/forums/tubes-valves/359369-amp-design-critique.html

I made a couple of adjustments to the schematic and breadboarded a prototype. It's working okay for the most part, but now I have this very low frequency ringing. Originally I thought it was motorboating, I was pulling down the PSU too hard with how I biased the KT88, but I bumped the resistor up and, while it became "better", it hasn't entirely gone away.

Here's my current schematic(sort of, will explain later)


Now the ringing isn't completely audible as before, but I can still see it on the scope and on the woofer cone. It's around 7.7Hz, and the amplitude gets much greater than this.



I think it's a ring, not an oscillation, because it's not always there and seems to get "triggered", especially during bassier parts, and after a few seconds seems to resolve without any intervention(other than the song moving on).

I'm almost completely positive that this is coming through my global feedback and back through the signal chain. It completely goes away when there is no feedback at all. The schematic has R6 as 1k, but in actuality I have a 30k in there. At this little feedback, I'm not getting the kind of frequency response that I want, but I can't make it much lower without increasing the chance of ringing.

LTSpice is even showing a large phase shift at sub-10Hz frequencies(not exactly 7.7Hz). I'm still an amateur and I'm not sure how to address this. Is this a common problem and is there a specific resource I can be pointed to to understand it better?

Thanks

Hi all,
Just thinking about speaker placement in my room…. Did some REW measurements and found all sorts of peaks and troughs when measured at my listening spot which I understand is quite normal. Before I start moving speakers I thought I’d get the thoughts of the learned team.
I set my listening chair 38% from the back wall as 38% from the front wall would never work, the speakers are around 800mm from the front wall and spaced to form an equilateral triangle. This was based on what an ideal room should look like (from my reading that is).

Is it worth moving the speakers to try and get a better (Flatter) response? If I move things around I get away from the rules. The room is 4.5mts x 5.7mtrs so not a big room by any means. I found once I eq’d a couple of the low freq peaks down a bit things sounded better, as can be expected bumping up the troughs didn’t do much.

Or……. As it sound really nice leave it and enjoy?

Hi to all!

I am having doubts about a project I am starting.

I have some drivers at home that I got this past months and would like to begin a project for a mixing/mastering 3 way speaker...

So far I have...

x2 Eton 11-612/c8/50 Woofers (8ohms 120w)
x2 PHL 2011 Midwoofers (16 ohms 120w)
x4 Peerles 850134 Woofers (8ohms, 150w IEC268-5) is this W RMS?
x2 Focal TC90 TD5B Tweeters (6ohms 75w)
x2 Peerless XT25TG30-04 Tweeters (4ohms 110w)

My Original Idea is to built a 3way Speaker System with Eton, PHL and Focal in a TMW Configuration.

But recently, I had the idea of building an MTM W design with the 4 Peerless and 2 Focal tweeters. And the Eton as a subwoofer.

What would you do? PHL or Peerless as Midwoofers?

Looking for the most transparent sound.

Thank you all!

Hello,

I bought a pair of Airpods through Aliexpress sometimes ago. It worked fine and had a good sound.Recently, I felt its sound has decreased than usual and music is also unclear.It's not physically damaged. I thought to reset it. But, I don't have its manual now.Does anyone know about Airpod resetting? Is there a common way to dit?

What do we have ?
Cheap.
For current around 5mA
No need for accuracy.
Voltage drop down to 1.5V

Hello,

can somebody please provide me a pinout for the 9-pin d-sub cable of the 2.1 Logitech X-230 system?
Four of the wires in my cable are shorted and I want to replace the whole cable.
I think the shorts are on the connector side. If I wiggle it a bit, everything works for a second or two 🙂

The cable is soldered to the pcb inside of one of the stereo speakers (pads on the pcb are numbered from 1 to 10 where #10 is not soldered).
I need to know which pad goes to which pin in my connector.

The system is now over 10 years old, but I love it and don't want to throw it away.

Thank you in advance!

Kind regards,
Leonid

As I am considering some of the amp choices available, I figured that there might be
someone who have already gone through some of the options and have a clear
understanding of the differences.

The first goal is to do an active system and for this reason, I will need a set of amplifiers.
The woofer will be driven by Purifi's class D which leaves me with the need for a
midrange and tweeter amplifier.

25W in 8ohm should be more than sufficient for a tweeter and midrange at less than
100dB listening levels. I am usually 85-90 dB maximum, and class A for its perfect transition.

Neutral, natural and relaxed clarity is the best description I can give. The amp should be able to
deliver lots of air and nice dynamic range without sounding too relaxed or "warm".

Which one of the Aleph J, M2x and F6 can be considered to get me closest to my need and desire ?

Many thanks for any reply.

There have been a few versions of the JLH Class A design around with MOSFET output devices, e.g. :

http://www.diyaudio.com/forums/solid-state/3075-jlh-10-watt-class-amplifier-44.html#post2836764

or a full MOSFET version :

http://www.diyaudio.com/forums/solid-state/2274-jlh-class-mosfets.html


I took on the mental challenge on the train this morning to come up with a JFET / MOSFET version of the 2003 circuit at Geoff's excellent website :

The Class-A Amplifier Site - JLH Class-A Update

This is just quick and dirty draft version which is by no means optimised.
But the performance is more than decent, with some -90dB 2nd at 1kHz 1W 8R output.
Bandwidth is beyond 10MHz, if you believe everything in Spice.

🙂

Will give it some more thoughts when I have time. Perhaps a PCB later.


Patrick

Hi, Friends.

Might be a silly question...

I have to use some capacitors on my drivers. I'm actively amplifying them and on the HF units, I want to have a cap in line with the driver in case of a surge it does not blow the driver.

I only need one cap of 10uF. Can I just zip tie this directly to the enclosure (using Solid Wood)? I haven't worked with passive components in a long time so I'm not sure how hot they get.

Thanks!
Joey

Offering only 1 bass driver. This is woofer, could be used in many different sealed or vented designs. High excursion, very low distortion. Very little used, purchased new from Acoustic Elegance a few years back. The TD Series woofers are low distortion, high Xmax, wide bandwidth, bass drivers designed for sealed or vented enclosure applications. The TDS use a 2 layer round wire copper coil for higher Qts. They are typically the option chosen for sealed box applications and larger vented box applications. They are often used in larger floor standing speakers. This is heavy driver.

Price $ 350.00 plus shipping


Specs:
TD15S-8ohm
Fs: 22.8Hz
Qms: 3.87
Vas: 467 L
Cms: .45 mm/N
Mms: 108 g
Rms: 4 kg/S
Xmax: 14 mm(peak)
Xmech: 20 mm(peak)
Sd: 855 sqcm
Vd: 2.4L (p-p)
Qes: .41
Re: 5.3 ohm
Le: .3 mH
Z: 8 ohm
Bl: 14.1 T/m
Pe: 500W (cont.)
Qts: .37
1WSPL: 93.4 dB
2.83V: 95.11 dB
TD15S-4ohm
Fs: 22.8Hz
Qms: 3.87
Vas: 467 L
Cms: .45 mm/N
Mms: 108 g
Rms: 4 kg/S
Xmax: 14 mm(peak)
Xmech: 20 mm(peak)
Sd: 855 sqcm
Vd: 2.4L (p-p)
Qes: .41
Re: 3.5 ohm
Le: .3 mH
Z: 4 ohm
Bl: 11.5 T/m
Pe: 500W (cont.)
Qts: .37
1WSPL: 93.4 dB
2.83V: 96.91 dB
Suggested Enclosures:
3.0-6.0 cubic foot sealed
5.0-8.0 cubic foot vented

Good day everyone,

I've got some questions with concerning 2.5 way designs -

1. I know that for a more standard 2.5 way, the 1/2 woofer can be used as the BSC. So if I were to have a design in the style of TM/MM (with 2 0.5 woofers to help supplement the low end), what would the increased efficiency be?

2. In reference to the 1st question, for a TM/MM style of design - what would the wiring be like?

3. For the woofers - would they all share the same cabinet space, or would each woofer be enclosed in their own chamber?



If there are any extra bits of information you all could share - that would be greatly appreciated as well!

Thank you all for your time and help!

A quick question. When I use Amazon Music on my iPhone to control the Alexa app on my PC, what is the audio quality that my PC feeds my DAC? This appears to be the only way that I can use my phone to remotely control Amazon Music.

I can run the Amazon Music app on PC, and then it gives me full "Ultra HD", but there isn't indication what the audio quality is when doing what works to have a remote control.

Tidal not having any remote capability was a deal breaker for me. If I want to listen to a high quality source and get up every time I need to change songs or volume, I'll use vinyl. In this day and age, Tidal not having this capability (Spotify does) is just not acceptable.

Any info that you may have would be much appreciated

1/ a previously working music player I wrote has stopped working. Debugged it and it wont open music files
2/ PC keeps blue screening with various error messages.
3/ Windows update doesn't work, keeps resorting back to older version.
4/ Strange version of Windows with odd power down button sequence required.
5/ Visual studio often blue screens.
6/ MPLAB X microcontroller programming IDE quite often blue screens on power up.

I ran disk checker and drives are fine. Ran memory checker and that is fine.
Tried to reinstall windows but trying to burn windows to flash drive fails at 8% every time.
Starting to tear my hair out at this point.
So pulled one DRAM module out and still blue screens.
So put it back and removed other one.
PC been fine since...………
Got another module on order so will be interesting to see if that fixes it or there is problem with having two modules in at the same time.

I've spent some time looking around and have found plenty of threads with different ideals or constraints but I haven't been able to find one who's main constraint is power.

I'm about halfway through a bus conversion with my girlfriend for full time off grid living. Our living space will be solar powered by 400w of Renogy solar panels and 2 200ah batteries. The bus is insulated like a Yeti cooler and we will have insulated window coverings with foam padding to block out light and heat and bring down sound reflection from the windows when we want. The space is roughly 600cu ft total.

I want to build a 2.1 system primarily for when the bus is at rest, so it won't need to contend with road noise necessarily. It's my first build and I'm fairly confident I can figure out the full range aspect but I'm a little stumped on the subwoofer. I'm looking to cap the RMS of the system at around 80w, probably about half to the full range/midrange+ and half to the sub. Space is a tiny bit less of a constraint, we have plenty of empty space that I can jam a good sized enclosure into, perhaps a maximum of 3-4cu ft depending on the shape. It will be used for music and movies, and our tastes run the full spectrum. War movies to reality TV and classical to EDM and everything between. I've got a great sounding set of 60w M-audio speakers paired with a small 32w sharper image sub that sounds pretty bad but pretty loud in our much larger current kitchen. I can deal with a bit of boominess, I'm open to turning the sub off, heavily EQing, or listening to headphones when SQ becomes my primary concern while listening to, say, classical or jazz. I just want low end extension when watching movies, or listening to EDM or modern orchestral compositions like soundtrack Hans Zimmer or Thomas Bergersen.

What T/S specs should I focus on when looking at low power subwoofer applications? Which will sort depend on the answer to the following question which is what type of enclosure might work for this application?
I'm quite likely going to go for some form of vented design, perhaps a transmission line or a folded bass horn of some kind with a smaller (<8in) driver. I'd love to deep dive into this but there are so many projects I'm doing at the moment, so a bit of guidance might go a long way for me.

I have revised my proposed Aleph J build to comprise monoblocks. My plan would be to place each amplifier adjacent to a speaker. In order to turn them both on from a single source, I would like to have a relay in each monoblock that, when activated, connects the mains to the power transformer. I would power the relays through a single low voltage (5 to 12 volts dc depending on the relay) power supply in its own chassis placed next to my line stage (I am not sure if it would require a linear power supply or if an SMPS would suffice).

My first question is whether my idea makes sense or is there some fundamental flaw with my thinking?

My second question is whether the cables running from the relay PS to each monoblock need only have two wires (V+ and return) or three (also protective earth). I would think that I would not need that third wire because the monoblocks will each be earthed, but would appreciate any insight anyone could give me.

Also, I thought I might as well run the current for the relay through a thermal switch attached to the heat sink on its way to the relay. That would provide a simple method of thermal protection, but is it overkill? Does the temperature of the heat sink pretty much stabilize over time, or might it increase if the amps were inadvertently left on overnight for example?

Finally, does anyone have any thoughts on what would be a good relay to use for this purpose? Would 10 amps be sufficient? I understand that SS relays require less current, but that they leak some voltage. Should I avoid that type for that reason?

Thanks for any help anyone can give me.

Jazzzman

Can anyone help me?
Cheers

Hello world!! I'm a complete newbie to loudspeaker design. I just want to ask, if you put a woofer meant for ported application into a sealed enclosure or vice-versa what would happen with regards to sound quality,efficiency e.t.c. Thank you so much.

One pair of NOS JX125.
One of the drivers has a small dimple on the cone. Please see the picture.
$150 a pair + sh&h
These are dual voice coil drivers.
I also have a used single JX125 if you interested.

Hi everyone

I have an Adam Audio Sub7 subwoofer that would not power on. After taking it apart and doing some diagnostics, I found a faulty rectifier on the SMPS secondary and blown TDA8950TH and one bulging cap. After replacing the rectifier and cap and removing the TDA, the PSU came back to life. A quick check of all voltages showed no problems so I put in a brand new NXP TDA8950TH. I also replaced the rest of the small electrolytics apart from the four 2200uf 25V caps as they seem fine. After powering the amp on there was about 7V of DC offset. Both with and without a load and both with and without the input connected to the power amp board. Connecting my throwaway test speaker showed that it pushed the cone out but seemed fine otherwise, there was still regular background hiss and the amp would pass audio. Due to a lack of time, I put the sub on my shelf and forgot about it. Now I had some time today so I pulled it back out and had another go at it. Interestingly I took it apart, measured some voltages and everything seemed fine. It had only about 10mV of DC offset and played just fine on my workbench and had plenty of power. So I put it back together and powered it on and again, pushed the cone out. Slowly and calmly, takes about a second for it to rise to 7V DC.

Now the weird thing is that after a while it starts to drop back down. I took some measurements and everything seemed normal. Supply voltages were okay, no significant DC on the input. During the time of poking around, about 10 minutes, the DC had dropped to about 1.5V. Only pushes the cone out slightly and plays fine. I have an old 16 ohm Turbosound driver to test bad amps. Then after some time it raised again, about 3.something V DC. Then dropped back down.

I checked my soldering and it's good, looks like new 😀 Don't think there is a problem there.

Any common problems that can make these behave weird? Or is the new chip defective most likely?

No schematics for this unfortunately but it's not a very complex amp. Regular SMPS with +-20V supply, chip configured to run in BTL mode, nothing more on the amp board but the SMPS, TDA chip and it's supporting components.

Hello I have qty 2 identical Tubelab Simple SE boards. They are about 10 years old, but have been in storage the last 5 years. Solderwork could have been a little neater, but everything functions perfectly. R24 and R14 of the board look a little dark. This is because I changed from at AT7 input tube to a 12BH4, and didn't upgrade the resistor for increased current draw until a a few months later. Nothing falied, and I doubled the wattage of the resistor once I realized.
If you're worried about it, you can just jump the board with a wire.

Only $25 for the board! Fully populated with sockets and all parts. I have QTY 2

Also for sale are 2 output transformers. Edcor GXPP10-8-8k These are PP types, and NOT SE types usually used for the Tubelab SSE. I actually used 2 SSE boards in a differential arrangement to make a PP amp. Transformers are in excellent condition.

$40 for both transformers.

Hi all,

I've built both a "small" (40x120 cm) and big (68x178 cm) electrostatic loudspeaker. Currently I use the big panels as they go lower in frequency, although the small panels still perform quite good given theire relative small size.

I will post some near-field and far-field frequency repsonse measurements, but it turns out there is a very steep high (Q) resonance at 25 Hz on both panels. I used small rectangular spacers, two vertical rows, similar to silocone dots, so I guess the membrane have multiple resonance frequencies, but at 25 Hz there is a very clear resonance. Fortunately, only in very specific recordings this is audible - the membrane starts to rattle.

I used the esl_seg_ui software by Edo Huzlebos to simulate and design the ladder segmentation. I have 9 wire groups of different widths - the middle is about 1 cm width and the groups get wider towards the sides of the panel.

I have a few questions about frequency response, especially about low frequency repsonse.

My first question: does the esl_seg_ui software take into account dipole acoustic cancellation?

My second question: at what frequency starts acoustic cancellation? At Wikipedia (link) I read:

"The bass rolloff 3db point occurs when the narrowest panel dimension equals a quarter wavelength of the radiated frequency for dipole radiators, so for a Quad ESL-63, which is 0.66 meters wide, this occurs at around 129 Hz, comparable to many box speakers (calculated with the speed of sound taken as 343 m/s)."

Bass rolloff of my 68 cm wide panels would then start at 343 / (0.68 * 4) = 126 Hz at 6 dB/oct.

hi all
Amp going into cycle of on and off while playing music. Without input stays on all the time. While playing music it goes into cycle. The output of test tone is very clean.
Image upload is giving trouble.

20200914-094547 — ImgBB

Well I’ve broke my own heart. My wife and have decided to move our household to Europe and now I have to sell off my favorite toys. In this case my pair of JBL cinema cabinets with IWATA 300 fiberglass waveguides from Auto Tech in Poland. The compression drivers are JBL commercial cinema loaded with TrueExtent berryllium diaphragms. I tell you the sound is truly magical! I got four UREI 6250 amplifiers that used to power that I amthrowing into package. Their condition is absolutely pristine. You will never hear a better stereo. The last time that I measured them, they were quite flat from 40Hz to 18kHz and had no trouble reproducing authentic theater sound tracks. Unfortunately I cannot ship these. The buyer will have to come to my home and pickup. To offset the hassle I am offering the whole package for $2,500 total. How is that for a deal?

I also have two JBL commercial cinema subwoofers. They feature 18 inch drivers in a cabinet 4 cubic feet. They are very clean to 40Hz in most rooms. I will sell these two cabinets deep discounted. They work

very well with the described loudspeaker pair.

Should anyone have an interest, Please let me know

Hi,

I'm building my first audio amplifier and I have everything I need... except a cabinet. I cannot find something affordable, even in China, the shipping cost is 2 times the price of the box...

Any ideas?

PS I'm in Europe

Thanks on advance!

Alex

Hi.
I've been playing with wm8805 chip lately and i really love the sound of that chip but i cant get it to lock on anything higher than 16/44.
If i play higher res.like 24/96 Files the sound gets hiccups and if i play 24/192 than i get no sound and lots of crackles.
Im using spdif input with cap in series and 75ohm to ground. ...the chip is connected to wm8741 dac (i2s).
The chip is setup in hardware mode and it suppose to support all data up to 192.
...i cant figure out what im doing wrong.
But it sound amazing with 16/44 files.
Has anyone experience similar problem with wm8805?, if you have any suggestions please let me know.
K.

Simple question but, I'm not sure about that:


Bass speaker crossover; there is serial inductor and paralel capasitor&resistance (6,8uf&3,3ohm-series). Speaker is 3,8-4ohm and 0,06mh.

So, question is this series capasitor&resistance(c3, r4) are Zobel network?

Hi Folks,

Great to be here, and this is my first post!

My company Pangolin manufactures laser equipment, including servo drivers and laser scanners.

We use LM3886 as a part of our servo driver. Our servo driver is like an audio amplifier, and our scanner (motor) is like a speaker. Our laser scanners have impedance properties similar to a speaker, so the LM3886 works well for this application.

The LM3886 is incorporated into a digital servo driver. This servo driver has a multi-channel A/D, and with a high sample rate, we digitize both the voltage coming from the LM3886 output, and also the current flowing through the scanner's coil (current that is ultimately provided by the transistors in the LM3886).

Digitizing the voltage and current provides great insight towards our servo system operation. I can graph these over time, and create oscilloscope waveforms of various quantities, including this voltage and current. We can also perform "math" on these, and graph related quantities.

For example, we calculate the average power dissipated (heat generated) by our scanner (like the speaker in an audio system). To accomplish this, we simply do RMS Current squared, multiplied by the coil resistance. (One way to get Average Power is I^2R.) Since we digitize the current, it's easy to do an RMS computation on the samples and obtain that quantity.

We'd also like to calculate the actual power dissipation (i.e. heat generated) on the part of the LM3886. In other words, I'd like to calculate the average power. But for the power amplifier, I'm having trouble wrapping my head around how to do that. It seems a bit more tricky.

The question is about calculating power dissipation (watts) in real time based on data samples.

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

As I mentioned, our servo driver has digitizes both the voltage that is output from the power transistors to the motor coil (we call this "Instantaneous voltage") and also the current flowing through the motor's coil (we call this "Instantaneous current"). We sample these quantities very often, so at all times the servo driver is aware of the instantaneous voltage and current.

I'd like to calculate the heat generated by the power transistors while they are supplying current to the coil.

Presently my way of calculating this is shown below.

if(InstantaneousCurrent >= 0)
{ //Current is positive -- must be coming from the positive transistor
InstantaneousTransistorVoltage = (PositiveRailVoltage - InstantaneousVoltage); //For example, 24 - 21 = 3V
InstantaneousTransistorPower = InstantaneousTransistorVoltage * InstantaneousCurrent; //For example: 3V * 3A = 9W (Power = Voltage * Current)
}
else
{ //Current is negative -- must be coming from the negative transistor
InstantaneousTransistorVoltage = (NegativeRailVoltage - InstantaneousVoltage); //In this case transistor voltage will be negative (-24V - -21V = -3V
InstantaneousTransistorPower = InstantaneousTransistorVoltage * InstantaneousCurrent; //For example: -3V * -3A = 9W (Power = Voltage * Current)
}
AverageTransistorPower += CurrentFilterConstant * (InstantaneousTransistorPower - AverageTransistorPower);


So, in other words, for each sample, I take the instantaneous voltage through either the upper transistor or lower transistor as applicable, and multiply it by the instantaneous current to obtain an "InstantaneousTransistorPower", and then average that over time.

Alternatively I could calculate the heat in the upper transistor if(InstantaneousCurrent >= 0), or heat in the lower transistor, and then sum the two together.

Either of these techniques make intuitive sense to me.

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

But then, just today, while searching for "calculating average power", I see "Average power = VRMS * IRMS". So, they're multiplying the RMS of each.

My code presented above above makes intuitive sense, but it deals only with the average. So it would be like "Average Power = Average Voltage * Average Current". For sure Average isn't the same as RMS.

So here's the question for all of you folks on DIY Audio: Should I be calculating the RMS voltage that appears across each transistors, and multiplying that by the RMS current flowing through each transistor (and then summing the upper and lower transistors)?

Note that sometimes the current flows through the positive transistors, and sometimes through the negative transistor. In the case of the LM3886, both are in the same physical package so I don't care too much, and it's all about the heat that is being generated, and thus must be dissipated by the user.

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

Best regards,


William Benner

I have 6 new in the box nc400 modules for sale. Would like to sell them all but will consider sales of even numbers. All 6 for $1700. Buyer pays shipping. Thanks.

I have already had some help from members in the past for which I am grateful, however I am still stuck 🙁.

After resoldering the power supply and NEON power supply, and measuring the voltages, Q701 (2SC1431) doesn't have the right values (resp. B=36v, E=53v, C=240v). According tot the service manual it should be 155v, 157v, 220v. I suppose that's the reason Q413 doesn't measure right either.

Does anyone have an idea what might be wrong? 😱