Anyone have any experience with the interesting Stabilovolt voltage reg tubes? I think they were not allowed to be exported to the USA (it's an excellent German product) which may explain why I very seldom hear about them. ?
I see them on ebay for not so much, and they certainly look very interesting for getting several voltages out of a single bulb. I think the most common had 70V outputs, and several in series, so 70, 140, 210, and 280V outputs.
They are relatively large, but the neon ? makes for cool display.

Looking for a set of idler tires for a Marantz 5000 cassette deck. Pretty sure these may have been used in other Marantz decks as well. Can't find a source, any help you could provide would be great.
Thanks
mark

Hi All

First post, so apologies if this is a stupid question.

Here is a tweeter I like the look of but it starts dropping off at 15k: https://www.morelhifi.com/wp-content/uploads/2019/12/ST1048.pdf

At 18k its about 88db which is what I'm aiming for

Is it possible to design a passive high-pass filter that leaves 15k onwards alone and just attenuate everything below 15k? I want to cross it over at 2k.

Cheers 🙂

Ok, if we imagine we are building a single volume quarter wave for a MTM o TMM, we use the center between the two drivers as Zd.

But what about the Ariels. They have separate lines and they do not use Zd.

What are the weights of significance of using separate lines?

What if we build an MTM bipole (front + rear MTMs). What would make more sense if we have to use two separates lines overall?

Hi All,

Anyone have one I can buy/copy? I do have the SM for the 1510 and I know they are very similiar but want to be sure when troubleshooting..

Thanks,
Jim

Got myself a pair of Noratel 160w 30 volt for one of my amps and they humm way to much! Both are the same though so can't say one is off spec so to say. They got a bit better once I tightened the screw holding them down but its still more than is ok.

Reading up on it here I understand all of them do humm more or less but these are very noisy compared to my other amps/power transformers.

Question, is there a consensus on here which make of Toroid transformers that are better/best in this respect?

Alternatively is there anything I can do to minimise this (other than baking them)?

All the other amps sit on the same powerline and are "mostly quiet".

"The Crocodile" headamp

It is started a while ago, more like a joke. Attempt to show that with a pretty simplistic nested feedback loop concept and a bunch of NE5532 it is possible to achieve a 0.1ppm distortion level for 20kHz signal at 33Ohm load and couple of Vrms. I sort of achieved the goal, with an exception of a few "but". Of course one of those "but" was, as almost any early stage proto, it looked ugly as hell:

Long story short, I managed to squeezed it into a 50x50mm PCB (sorry, no imperial units allowed!) to get PCBs for cheap from the Seedstudio. So, here it is. It is green, it is still somewhat ugly, and someone called it "a crocodile", so I decided - Crocodile it is 🙂

Although I didn't stick with 5532 this time. Tried some different opamp, to see how it goes.
There are some measurement results on a 33Ohm load. In case of the 20kHz signal, the output amplitude is 4VRms (+12dBVrms), for the IMD test it is mixture of two 2Vrms (+6dBVrms) signals.
It is not hard to make something better using the same number of opamps, but the moto was "as straightforward as possible" 🙂

Hi,

I want to experiment with multiple fullrange drivers in a waveguide, is there any tool that can help me simulate it?

I know Vituixcad, it can do multiple drivers but not inside waveguide.

Thanks and Regards,
WA

At the end of summer I picked up some (FREE!) AR-90, cabinets are 5-6/10 but can be brought back to life, drivers don’t appear to be blown but need surrounds on subs and mid-woofers. The surround kit just arrived so time to get cookin They obviously need crossover work so do I...

1.) restore them to originalish or

2.) install 4 sets of binding posts and 2 passive networks (1 for mid/tweet 1 for woofer/subs) along with a bypass switch so they can be bi-amped passively or quad amped with active dsp to each driver? Or?

I’m new to Class D and getting confused with all the chip options out there. I’m looking for an amp (board or built) that will operate directly from a 12V battery (13V range).

The plan is to take the system on the road this spring in an RV. Speakers are 6 ohm Alpair 12P so looking for something less than 50W. This will be fed from a MiniDSP. P-E sells a few options but not sure about the quality of some of their products. The Allo Volt+D caught my eye but not sure it will operate on 13VDC.

Thanks.....

Wondering why the use of L78XX/L79XX with current boost(MJ2955/2N3055) is not popular as a simple linear regulator for chip amps and such?

Circuits like this (showing positive rail)



What are the reasons to shun these? Bad line/load regulation? Efficiency? For example a 15-0-15 200VA with the above configuration can make a good +/-18 V 5A power supply in theory.

I understand Opamp based finer designs with precise reference voltages have better line and load regulation. Is that the only reason?

Unused, stock (no mods) Soekris DAM1021 VERSION 1 R2R dac with 0.01% resistors. Includes USB 2 -> RS232 DB9 serial adapter/cable.


Bought and never used.

What are your comments between two different regulators for tube preamp?

T-reg HV regulator | Linear Audio NL

Hi,

Has anyone come across this before ? ( see below )

It seems very confusing !!


Andy

Good morning Guys,

Does anyone have any ideas/experience of using an AGC type circuit in the preamp stage to allow for different line input levels and thus preventing overdriving of the later stages?

What you read above. It's a very simple amp - A gain block that goes into a diode clipper followed by another gain stage, some low frequency filtering and then power output using a class B output within a unity follower feedback loop. The amplifier itself works very well without any discernible noise (this is for headphones btw, so the noise would definitely be noticeable). But when I use the only >10V supply I have (It's a pretty crappy SMPS), it induces a lot of noise into the circuit. I've tried filtering it through a CLC filter, which didn't work well. I also tried a capacitance multiplier - didn't work well either. Strangely however, if I ground myself and then touch any metallic parts on my electric guitar, the noise drops noticeably. It doesn't go away though. I'd like to know why that is, it's very interesting to me.
I'd appreciate advice on how to fix the noise as well, but the above is what I'm really here for.

Does anyone has a schematic for this amplifier? I’ve some burnt smd resistor and a missing TO92 transistor in the onboard audio drive circiut area.

Hi all,

Working on my RF T1500, seems to be an issue with the power supply card, I'm not seeing any gate drive. I've removed the card but haven't started measuring stuff yet but will start on that tomorrow. What typically goes out on these?

Does anyone have the schematic for this power board (1325-52873-06)? I have the schematic of a T1000BD that I'm referencing off of.

Also, is there a direct replacement for the LM339DG comparators? They seem to be obsolete.

Thanks

edit: after browsing around on here i've found out about quest components which have the LM339DG in stock 🙂

Is this a phenomenon? If so, is there anything that can SAFELY soften surrounds that have hardened? I went through this whole 10-page thread and came away with no real answers

https://www.diyaudio.com/forums/multi-way/71420-rubber-surrounds-hardening-age.html

The inspiring story of Chuck Surack who started in a VW Bus and has grown Sweetwater.com to over $1B in sales. Chuck is a humble man who does a lot for music education on top of being a business leader in online music instrument and equipment sales.

Founder and CEO of Sweetwater.com Chuck Surack - YouTube

I got 8 dynaudio 17w75xl woofers. Pretty sure they are all 8ohm

I've always wanted huge midrange big stage speakers. Forward sounding
Classical , string music, piano.

I found a thread where another gentleman successfully designed a 2 way Cross over for 17w75xl + d260 tweeter
1)
I wanted to see if it's possible to use the same Cross over + similar tweeter but use 4 17w75xl drivers in series + parallel (2 in series) then 2 pairs in parallel

2) wanted to see what are the issues If I position drivers in square configuration with tweeter in the center of all of them as opposed to conventional vertical array of woofers with tweeter on top.

Here is the original thread
https://www.diyaudio.com/forums/multi-way/306287-crossover-help-dynaudio-17w75xl-ohm-d260.html


Attached are the Cross overs proposed In thread above

My Sumiko S.9 subwoofer works intermittently.

It will play normally for roughly 30 minutes. Then it stops producing sound. Part of the circuit is still getting power- the led on top stays lit and so does led on the back panel. No sound or noise when it stops. It just drops out. It happens when playing at low or high volumes.

I’m guessing a relay or one of the transistors with the relay might have gone bad? When I manually turn the sub off and on, once it’s dropped out, I can’t hear the relay switch back on. The heat sink is barely warm when it drops out. It’s not overheating.

I’ve taken the amp plate off and had a look. No loose wires, bad connections or anything obvious. Let it sit for sometime or overnight and it goes back to playing normally, until it drops out again.

I can’t find a schematic on line or I would attach it. AB amp not class D.

Figured I’d ask here for thoughts first.

Thanks.

I just received a Camillus Titanium LK6 folding knife from my brother.

I send him Raisin Bread and cookies every Christmas, and he sends me a pocket knife.

Anyone else collect knives?

I have a pair of Tannoy Signature DC6T and both tweeters are broken. The unfortunate thing is that, Tannoy don't give you the chance to replace just the tweeters. Instead you have to replace the complete Dual concentric speaker, which is about 430 GBP plus delivery and customs. I have the speakers 6 years and I am a moderate listener. I am a little disappointed about the quality. Before I had a pair of canton Fonum 600 nearly 20 years with a lot of partying and they are still going.
I found some tweeters (7900 683) that are used in the DC1 and DC2 and some other speakers where they use 6,5 dual concentric drives for about 140 GBP incl. shipping. I think i take the chance.

My brother in law made a set of these and gave them to me years back and they are still the best sounding I've heard. Since then, Chris Venhaus has come up with a new silver recipe and removed this one from his website. Would anyone have happened to make these, or save the recipe?

Thanks.

Electraprint push pull output transformers

8K, 15 watt 50/50mA taps, 8 ohm with NFB

SOLD

From my hodgepodge of parts I've got

a pair of TT-119-OT 15 watt 5K SE transformers

a 550V (275-0-275) at 175mA center tapped, 6.3V at 4A and 5V at 3A transformer

and a pile of 6V6GT, 6L6GC, a couple EL34, KT66 and 6550 tubes

a 12" x 8" x 3" chassis.

What would you build with that? I've run out of room for amps so it will likely be my last build for quite some time.
It would likely go in a small room playing at fairly low levels.

I have a kegger/blueglow SE amp that I'm using now in another room running 6L6GC tubes, and I do like it but would like to try something different..

I have purchased electrolytic capacitors (Nichicon ES bipolar for decoupling in audio paths and FG Fine Gold for anything else) to recap my beloved Harman Kardon A402 from 1976 (capacitors have the date code from the same year). When I desoldered the first one (ELNA) I measured its capacitance... nominal, ESR... lower than the new ones. I tried another and another one and all the same, all of them are absolutely fine.

I tried also PSU caps ELNA 4700/50 and the same, ESR is so small that I can't measure even it, 5 mOhms or so.




So all the fun in the recap is spoiled, guys what is going on? These are 45 years old caps, they should theoretically lose their parameters after these years...

Does anyone have a pdf copy of Walt Jung's "IC array cookbook"?

ok so i am building a gainclone as poweramp and now i need a phono stage..


I've been reading around the forum, and moast pretty old threads.

dont really know if i want tube or opamp or watever..
just looking for somthing good and if possible simple.




for now i only need mm. who knows in the future 🤪


budget for parts 100-200ish

I need help to repair an electronic crossover Symmetry ACS-1
designed by John Curl.
Many IC inside but numbers erased: Secret schematic !!

If someone know the IC numbers or have a schematic.

Disclaimer: I have no idea what I am doing

Here's what I tried to do.

I have the Creative Inspire 5.1 5200 soundcard/speaker system

see specs here Creative Worldwide Support Creative Inspire 5.1 5200

I've used it for years, and for listening to MP3 music as background music, or sitting-at-my-desk normal volume, it sounds simply awesome! I'm not even using it as a 5.1 system anymore - I just run a minijack cable from my laptop headphones output, into the subwoofer/amp, and then to only 2 of the 5 speakers, cuz of course it's only putting out 2-channel stereo. And it still sounds awesome!

So, my girlfriend loves the sound I get with such small speakers, and I figured I have 5 identical speakers, I can give her a couple of the extras, try to duplicate my setup. I think, it's not the subwoofer, just need an amp, so I bought a Lepy 2020A+ which should be more than enough to drive these little speakers. But the result sounds nothing like when the Creative amp is driving it. With Creative, the bass sounds thick, dynamic, has it's own twang and dynamic, if that makes sense. With the Lepy, the bass just sounds weak and no body. Cranking up the bass with my laptop EQ and the EQ knobs on the Lepy makes no difference, just more of the same terrible sounding bass.

The difference is not the subwoofer. At the volume I listen too, the subwoofer barely makes a sound. The fact is, with my ear against the speaker, far away from the subwoofer, these little speakers sound awesome on the Creative amp and sound like laptop speakers on the Lepy. I'm thinking the Creative amp must do some DSP or have a special chip or something? What's the missing ingredient?

My EXA U2I died after 10 years. I really liked the way it sounded. I am now using a standard Amanero without isolation or reclocking. I would like to hear the opinion of those who have run the Amanero stock and with the Hermes-Cronus combo on the same system. What were the sonic differences? Which way would you run the Amanero if you were going to start over?
Thanks

Hi all!


I'm new to this world, and just inherited an Linn Akurate DS.


Now i need an amplifier for this unit (not sure if i need a preamp too, lol)


Please let me know if i'm head under heels here.


Anyways, i'm pretty good with soldering and i have basic electronic skills, but what i need now is some guidance as for what amplifier i should pair this player with?


I've read a lot on this forum on different types TK2050, TA2020, TA 3020 etc.


I'm thinking of building my own amp, not sure if i should go for mono channels or stereo, but i guess that's something i have to do some more research on.



This is some of the stuff i've been looking on:
Hifimediy-T4-mcap-TK2050-amplifier-2-x180
TPA3100D2 types of chip.
tpa3116d2


And bunch of others.



All answers are appreciated! 🙂

Do anyone here have some information on these devices? Datasheet, pinout? replacements?

I am troubleshooting an old decoder and think this integrated amplifier is not working.

thank you for your input

Hello folks,

after reading many positive reviews I decided to go for a pair of Mark Audio Alpair 7 gen 3 in a transmission line built with 5" PVC pipes

While the build process was fun and easy, the sonic results is quite disappointing, also after 100+ hours of break in

The problem is in the voice reproduction, very tinny, harsh and metallic, it resemble the 80's voice synthesizer, you can hear it well off axis, it's still present standing behind the speaker

To fight the problem I tried without success:

- 3 different amps, 2 tripath based and an Onkyo amp
- dump pipe internal volume with fibers
- zobel network

Wondering the cause could be some resonance in the cylindrical enclosure, I put the speakers in box enclosure, but same result

Then I tried a low pass filter fc 4Khz to check if the metallic timbre is caused by that nasty 10dB peak around 10 Khz, but the metallic flavour is still there while the high treble went off.

Very confused, maybe the resonance is in the mids region?

I can't see from measurement made with my behringer 8000

It seem I'm the only one in trouble with this speaker, I thought maybe it's just me, but my wife also report the same unpleasant timbre in voice, both male and female

Any suggestion will be very appreciated

Thanks

from this link: 2dac1994 what do you tjhing for this IV buffer ?


thanks

Sold: HiVi Research D5.8 mid-woofers

Sold

Been looking all over the web for a PCB Board so I can add a Bourns conductive plastic potentiometer in the bathroom. You can find them all day for Alps 16 & 27 pots, but finding nothing for the Bourns.



Here is the pot that I'll be using, although I don't think it is the right photo, as mine will be a double gang. Thanks


https://www.mouser.com/ProductDetail/Bourns/91A2A-B28-D18-D18L/?qs=1v0N1zrvLE76tP6skPZ6WA==

Hello everyone! Today I would like to ask a question about a defect of the zenon amplifiers (as in the photo) such as 3.5kw 5.0kw and probably also the larger models.

I'll explain in detail.

In the past few days, they have delivered 9 amps like the ones in the picture, all with the same defect, failed rail capacitors. Some turn on and continue to work, others instead remain in protection, 1 instead has the power supply completely failed (probably the rail capacitors have exploded and have also gone into short circuit, forcing the power supply to explode completely) but all, have the audio section intact.
The thing is very strange, 9 equal amps, all with the same defect.
So asking around I realized that it is a common defect of these amps, indeed, in the past I have happened to repair some amps that use the same audio driver board (ZNCM) which however had the significantly higher rail voltage and brand capacitors and higher values ​​(FANGZE !?).



In these great amps, I solved by changing the capacitors with some of the same value, but different brand and model (nichicon) of excellent workmanship and they no longer exploded.



While these 3.5k and 5.0k ones seem to want to explode all the capacitors I replace.

Some say there is a defect in the driver board of the psu, others say there is a defect in the driver board of the audio section, others believe that it is a problem with the feedback line (R10 on the amplifier board in the immediate vicinity driver board, 220k resistor, how can a normal 220k resistor working properly cause such a big problem?) I don't know exactly what happens, but I can share my following experience, because in the past I have repaired an amplifier similar that was entrusted to me because it was completely shorted, both audio and power supply, but the capacitors were ok:


- i installed IRFP1405 + BD439 / BD449 in the power supply using 15ohm gate resistors.



- I used FDA24N40F in audio, redone the audio driver board and replaced the drivers (buffers) with BD139 + BD140 (which worked perfectly) (some might think they are slow or not very powerful, in my case they worked without problems, maybe even better than the originals).



The result is that that amplifier is still working great everyday for the past 1 year, never exploded again, never returned, never a problem again.

Could it be a driving problem on the part of the original buffer transistors? What do you think?


i've posted here some photos of the problematic amp and
some photos of a bigger amplifier that I have repaired in the past (which used the same driver board and FANGZE rail caps) where you can see the capacitors it fitted and the ones I fitted as a replacement, never again had problems.

Since the OPA627 is prone to being a counterfeit when bought through alternative channels, I was wondering if it would be helpful to you guys if I were to maintain a list of datecodes of genuine OPA627s I come across at work from now on.

After having been confronted in the past with counterfeit OPA627s, the company I work for nowadays only orders them from a reliable (authorized) supplier. That fact together with successful tests on the instruments they're used in make it fairly certain that they are the real deal.

We use the following versions:
OPA627AP (plastic DIP);
OPA627AM (TO-99 metal);
OPA627BP (plastic DIP);
OPA627AU (SOIC).
Most of them will be the BP followed by the AU and occasionally the AM and AP versions.

We're talking of 1000-2000 OPA627s a year, bought in smaller batches, so we get to use quite some different datecodes. It's little effort for me to post them here, if you're interested.

Hi

I am looking for a the above ICs ifrom a Sony TA-8650 pre-amplifer stage a BX-270A and a BX269A.
Anyone got one or a panel with them on?

Thanks
Gary

Hello,
once again my limited knowledge leads me here hoping for enlightenment 🙂
I'm currently rebuilding a sansui 5000x based on a seemingly professional blog I found. This includes replacing small signal transistors on the eq, tone and driver boards and a few more psu related ones. I'll be using ztx694b and ksc1845fta.
I noticed the input pair of each board has a red or white dot on the top which probly indicated matched pairs so now I'm stuck with the question if I should leave those matched input transistors in place and only replace the remaining ones or not. I dont have a circuit for matching transistors I just have a peak dca55 and found pairs (ztx and ksc) which have identical hfe and vbe but I'm not sure if thats enough to call it a matched pair yet...any opinions welcome...leaving all transistors original is not an option though, the amp had popping noises which I think are related to the 458 tranaisors in the tone amp and also now that I got those relatively expensive ztx ones theres no way I wont use them...hoping for advise on the matching issue 🙂)

For sale,

Bohlender Graebener Neo8-PDR

SOLD

Hi

Just wanted to see what views there are on upgrading caps on sub amps. The current amps have 2x 10,000 uf Samwha caps in and just wondering if a pair of Nichicon KG, Mundorf mlytics or F&T would be noticeable keeping the values the same

They run up to around 70 Hz flat from 16-70 with EQ across a 2m seating area
So I’m thinking about caps that might be really good in the lower registers, dynamics etc

Constructive thoughts appreciated

WANTED: (2) genuine Burr Brown PCM63P-K DAC chips. Please pm me.

Thanks.

Rick

The new SECA KIT for the DIY is sounding very nice, PCB's for the Amp and the Dynamic PSU are now available.

I had Sam build them and he has now soldering or building experience.

Hello,
is there someone who knows this Threshold preamp?
I have never heard about it and could not find informations on Threshold Audio web page.
Thanks for your help
Fabio

I spend a lot of time modifying factory-built amps and preamps for better stability and lower distortion.

Sometimes we can drop in elements for better performance. The best example is replacing resistive current sources with "current regulating diodes." A worse example is using Darlington transistors in place of single bipolars. Darlingtons are no better than single bipolars, in terms of their parasitic Early effect and nonlinear Cob, so prepackaged Darlingtons are rarely useful in practice for modding.

Here's what I wish we could buy in a package and drop in, in place of a bipolar:

* Q1 is our "original" transistor
* J1 cascodes its base to eliminate Early effect and Cob
* R1 provides a close-to-constant bias current through Q1 so its Vbe won't vary much (high transconductance.) Any Vbe variance is nonlinear so we're happy to minimize it.
* R3 limits current gain across the whole "transistor" to a finite multiple of the hFE of Q1. That helps with stability, as does C1.

A semiconductor maker could package it up in a TO-92 and name it ("Cascopolar"?) and we could all design with it or mod existing circuits more easily. More likely: you could make a tiny PCB to assemble this on, and solder it in vertically in place of single bipolars.

Of course this presents some constraints that a single bipolar doesn't: collector current must stay above the bias current set by R1, and collector voltage must stay a few volts above the base to provide headroom for the cascode.

I'm ready to order parts for a new build. I am complete noob, just did a good amount of reading/listening on the subject, I feel like I'm ready to jump in.

I am going to follow Walton Audio's schematic and build since there is a pretty detailed guide for it.



I do have a couple of questions:

1, I am from Europe, so I am having a hard time sourcing the 3 large capacitors on the PSU. Is there maybe a modern alternative to oil capacitors that is more available works well with this? Do I really need 600V there? Would something like these work? Tube-Town Store - JJ 250 mF @ 500 V

2, I am planning to use a power transformer which has an output of 400 VAC instead of the 380 on the drawing. Is that going to be fine or I have to adjust things?

3, Since the primary of this PT has a lot of options, I wanted to double check my plan to wire this for the 230V here in Montenegro.

So for 230V, I connect the 120V BLU to the live wire, 110V BLK/RED to the neutral, cur short and tie the 0V BRN and 120V BLK together. Do I connect the SH GREY to the main earth screw?

4, This PT has pretty short heater wires, so I will definitely need to extend some of them. What's the best way to do that? I know I should twist them together very tight.


Thank you very much in advance and sorry for asking novice questions... Just want to make sure I get this right

Hello, does anybody know what is the best Vb and Fb for Hivi F6?
I'm talking about bookshelf speakers.
Thank you.
Hi-Vi, F6 - Meniscus Audio

Hello... First post on this forum.

I have a sumo nine that I love. I have an odd issue.

If I turn the amp on with no input there is a loud hum out of my right speaker. If I connect inputs, from a preamp, and turn the preamp on the hum goes away. Is this something I should be concerned with? It would seem that there is a ground issue internal to the amp and the right channel is using the ground of the preamp?

Also, both sides of the amp are within 1-2 degrees Fahrenheit of each other and it is running really cool ~92 degrees after an hour of listening. Is this normal?

Thanks for your help!

Does anyone have a sense for what it might cost to have the TDA1541 manufactured for bulk purchase?

Hi folks,

My REL Stampede seems to have an issue. When I turn it on, it will work fine for about a minute, then it might drop in volume, or go entirely silent, or maybe get way too loud and noisy. If I turn it off and back on again, it will be fine again for a minute or so, and then start misbehaving again.

I opened it up and didn't see any obvious problems. Solder all looked good. Caps read well. I did replace the 220uF/10V cap while I was in there because its ESR was a little high, but it was probably fine anyway. The new cap made no difference at all.

I've verified the connections in the wires that run from the amp to the high level Neutrik plug.

Any ideas what might be going on here?

Thanks,
Paul

I’m doing a power supply repair on a Sony car amp, original parts was K2902 mosfet 6pcs with 10ohms gate resistors, I can’t get these (in my country) I want to use subbed part, what is a simple drop in for this amp I’m already prepared to used insulators and washers for any tabbed (TO220) devices. With the 10ohms gate (I was eyeing the 3205 with the 47ohms but didn’t want to remove those resistors) could the 1010E be used with same gate resistors?

The K2902 is rated 60v @45A

The bias on the right channel starts at max level.
How can I fix that..
Does anyone got the bias schematics ? And what I can measure..
Best
Thomas

Hi,

I am building a webradio with a 20w mono speaker. My idea is use a TPA3118 or a TPA3116D2 (mono).
I don't need a lot of power,... is better to use the TPA3118 with a 12v power supply or directly go to a TPA3116 with a 24v?

SmartRadio - Esp32 analog webradio with MQTT client embedded - Hackster.io

TPA3118 works at low at 8v, so 12v would be enough.... it isn't?

Please could you give me your advice?

Thank you

Title says it all.
The word icon can too often be misapplied, but I think not on this case.

I have for sale 4x brand new boxed Volt BM220. 8 bass mid drivers for sale. Boxes have been opened to take photos but the drivers have never seen a cabinet. £150 each or very sensible offer.

Also I have 2x 15mm thick billet aluminium baffles that will take the BM220. 8 and scanspeak D2950 9700 £150

2x scanspeak D2905/97000 brand new £200

Hello~

I need to convert HDMI to I2S signal provide to TAS3251.
Does anyone know what chip can be used?
I have found a board with this functions but I don’t know what chip to use.
Are there any compatibility issues with this board?

Has anyone of you ever gotten his/her hearing measured and then equalized their system to flatten their ears' response curve? How did the outcome "feel"?


If I wanted to do that what would be the most appropriate way to measure? Get it done by an ear doctor through headphones? Would that be applicable to my hearing in a room without enclosed ears?


Thank you for your input.

Hello,



Has anyone recently been in contact with Connex Electronic?



I am currently of gathering all the parts for a Modulus-86 build from Neurochrome and the recommended PSU is from Connex.



Many thanks,
Kaden

Sale GI7BT - 50 pcs. NOS in box - for $10 ea.

I have put together a JLH1996 class A power amplifier.

It runs off +/- 15VDC and has a 8 ohm speaker.

I have set current to 500mA.

How do I work out power into speaker ?

Is it simply IIR or is it more complicated ?

Hi all, wishing you all good health at these testing times.

I have an Alpine MRV1507 on the bench, it's pulling excessive current a few seconds after applying remote power.

I've tested the power supply and although it's had a previous repair it powers up and idles fine if I disconnect the 6 pin molex which connects to the output board.

All the output transistors also test good.
Q819 has been replaced with a 2SD600 which had a loose solder pad which I have resoldered.

Initially it would power up then trip my power supply after 8-10 seconds, now it trips within a few seconds.

Any help appreciated, thanks

You may have heard that a new (6th) edition of Audio Power Amplifier Design is planned for later this year. While the basic structure of the book is fixed, the rest is not yet set in stone.

I would be glad to hear of any new topics that you think should be included, or anything else that would make it an improvement on the 5th edition.

One year ago i bought these speakers : Monitor One MKII .
First auditions were good, but they gave me the impression of too much highs & bass with laid back mids.
I opened them and changed the cheap quality bipolar caps of the crossovers with good quality MKP's at the exact same value. ( i used wima mkp10 & vishay mkp1940).
Oh my god !!! They are transformed into a high-end class speakers.
They play even better than my Sonus Faber Concertino's.
And the good thing is that they cost 150euro for a pair + overall built quality is great .
I'm not an Alesis dealer, i just want to share this info with you in case you want to buy cheap speakers & get a transformed set after a small modification !!!
Vassilis

Hi All,


I would like to remove the balance pot in my Cyrus 2 amplifier, it is a 100K potentiometer as can be seen (marked in red) in the atached drawing.
The preamp section is passive, there is only volume and balance potentiometers before the power amp stage (the phono stage is active but I'm not using it).

I would like to know please if it's better to install 2 50K resistors to replace the balance pot or would it be better to leave it without connecting any resistors?
How it will affect the signal going to the power amp stage (with 50K resistors and without)?

I also would like to know the purpose of the 150pF capacitor(marked in blue) ?


Thanks

I evaluate proposal for a pair of Lundahl 2765 shipped to Italy.

This is just to showcase a little hobby project of mine: Im working on a tube buffer for measurement purposes, to be placed between a source and a long interlink, to drive some capacitive loads.



Here is is the preliminary schematic:



Its fairly straightforward, PC86 into a PNP VAS and a 12B4 to deliver some current all with local feedback.



The FTZ560 seems at glance, a nice device for the VAS.



More to follow.

Hi folks,

This is an advanced question about playing with or the possibility of exceeding maximum g2 datasheet specs.

The problem with melting down the screen grid lies mostly in the tetrode and pentode connection in the event where the anode is at lowest voltage during maximum tube conduction.

In triode mode the screen swings together with anode, but the problem still exists a bit due to the screen being closer to the cathode. Although higher screen voltages could be applied on many tubes.

But... What is the real case with music - where we (if we got sane minds) rarely it crank up until to the point of severe clipping? If the later doesn't occur, then g2 should be pretty safe at even a bit violated datasheet voltages, no?

I don't see a problem of violation with application of UL as well, where it can be considered as a percentage of going easy on g2.

Troublesome should be of course guitar amplifiers. But we're talking about HiFi here.

Hello all


I've been given a power transformer and I know what the windings are rated at but I'm confused about the numbers on the secondary and how I should wire it up.



I have a project in the back of my mind which needs about 400VDC on the B+ so I'm wondering if this transformer will be any use to me for this.


The secondary is shown as 275-190-0 but there is a note which describes the options and that's what confuses me. It says;


0-275 winding for approx 360VDC
0-190 winding for approx 260VDC
190-275 winding for approx 115VDC


I thought 0-275 would be supplying 275VAC to the rectifier so depending on the tube I'd get a little bit less VDC out. The same principle would apply to 0-190 and 190-275 would be 85VAC to the rectifier.


Can someone please explain how this works.....

I want to build a remote-controlled volume control into my tube amp, using a motorized pot. The Alps pot is +3v for up, -3v for down... I want to build my own IR remote and my own receiver that will operate the rotary switch.

RF is really out of the question, as the tube amp is aluminum and steel and is so shielded i'm unlikely to get a signal through. The project box I found for the remote control is also aluminum.

Does anyone sell a super-simple kit that will do this? I don't want it to work with an existing remote, I want to build it myself, and the simpler the circuit the better.

Thanks!

Charles.

I have removed C44, C45, C46, C48 and CR7. I installed an LT1468 in for U1 and replaced the most of the electrolytics in the power supply and oscillator and notch filter board. I installed a 4 turn pot at r51 and r30 and replaced the output level pot. I still cannot get -100db of THD+N at 1khz, getting -98db at 1khz and -95db at 20khz. I am using a 680 ohm load on the loopback cable.


input balance and high frequency adjust have not been calibrated but the oscillator and notch filter has been.

I have a Luxman CL-38 & Luxman MA-88 KT88 monoblock set. Likely one of the best Williamson amplifiers ever made. The sound it gives is much like my McIntosh MHA150. Giving all the details with slightly less crispness and but trading it in with needed warmth.


My former el84 Luxman sq-n100 sounded very much the same with one exception. When plugging in Sennheiser 650's there was a very narrow range on the volume dial where everything would turn liquid. Not what I would consider "warmth" in any way as it became more transparent, velvety smooth, with no loss of details. Obviously artificial and musical lies but much better than the truth.


What design or tube should I be chasing more for this pleasurable lie? SET, PP, more iron in the signal path? The only time I read someone stating a similar result they turned the bias up so high it might have red plated. Most times I read of SET's it's a gooey warm of 2nd harmonics, not liquid transparency.

Hi,

What is it about SMPSs that make them unsuitable for capacitive loads.
Similarly what makes the older trafo based linear power supply more suitable for it?

Thanks and Regards,
WA