Hey diyAudio Friends.

I am designing and building my first set of desktop speakers. Casting them from concrete! See below.
Here are some specifications:

Internal Volume 3.1 L
Woofer: Dayton Audio TCP-115 8Ohm
Tweeter: Dayton Audio PTMini-6 Planar Tweeter 6 Ohm

I am currently designing the crossover. I am using VituixCAD to do the modelling, but I am a total newbie.
Could anyone give some input. I am especially confused about the power supply settings.


Any input is appreciated!

Thank

Sam

I just got a Denon DRA-550 receiver from the thrift store. looking for ways to upgrade it
I notice that there is a 4558 OP AMP but not sure if it is even in the audio path. it looks like it might be a switch. can someone smarter than me tell me the purpose of this 4558

thanks !

Are there currently any SIT transistors that can be implemented like those in First Watt SIT-1 that aren't unobtainium or extremely expensive (sony vfets)?

Do they have any industrial uses so that we may see them exist in future?

Hello everyone, after a long time I return to the forum.
I am struggling with a Denon dvd 2930 that unfortunately has no audio, neither Cd nor Dvd at the analog outputs. The Cd works in HDMI but not the Dvd. The video is great, very stable, does not lose a frame. Excluding optical pickup problems, in Test Mode I noticed that in the firmware check I get BE 8283-B MAKE DAY 802 DSP 00.00.
In the service manual indicates that when the DSP is 00.00 means that first of all you have to insert the firmware in the FLASH ROM, if there are no other hardware problems.
I'm searching everywhere on the net but the links where to download the firmware do not make download anymore, the same in the official support page of Denon.
I was asking if you have the firmware for the 2930 (European version) mentioned above.
I really need your help.

My amp, Usher R1.5, consumes around 50 watts when plugged even when it is off as a circuit is active to keep the amp warmed up, to save on electricity I disconnect the power cord. To make it convenient, I installed a power strip with an on/off switch and leave the power amp in the On position and just power on/off using the power strip. Would there be any ill effects using the power strip as main switch for the power amp?

Hey

I am looking for some EL84 tubes, or any other type that is compatible.

What tubes do you like and why?

I am not too fond of overly warm sounding tubes and neither with very bright treble.

Can you recommend something or just share your experiences?

Telefunken, Russian 6P14P-EV, Sylvanias Black Plates have peaked my interest so far.


Cheers

I see Tung-Sol have a KT170. I guess PP you could get 250W out. They just keep getting bigger and bigger.

Hello dear fellas,

do any of you have experience with this shop here:
AUDIO-HI.FI, Loudspeaker shop

they always have the very cheapest prices available so I got sceptic if they are trustworthy or if that site is just a scam?

thank you

Hello,

I was wondering what I loose/gain by building these smaller cabinets ( see attached photo ) compared to bigger cabinets based on original Tannoy plans.

Ref ( comparison ) : http://www.44bx.com/tannoy/images/Lancaster3.gif

TNT ( comparison ) : [DIY project] DIY Tannoy 12" Dual Concentric Horn

INFO:
This IIILZ cabinet will be my speaker cabinet in my second hifi system.
It is needed to be a smaller cabinet, posting because of thoughts of cabinets for the future... and info from other builders that understand cabinets better than myself...

- Is it the bass frequency I will loose compared to Lancaster? This I can live with , but if there are other things I loose I would greatly appreciate an informative answer.

PS: I have already started building the IIILZ cabinets 🙂 - will post pictures when finished !

hi everyone, i was interested in making a 12v trigger x turn on my power amp. perhaps complete with soft start. do you have schemes to suggest to me? thank you

Hi,

I was looking for IPS, which would nicely suite push-pull VAS, and came up with an idea to rotate half of differential input (IPS-A). First simulations seems interesting but I couldn't find any info. There is no point in reinventing the wheel, so any indication/name of such IPS/comments would be very helpful. Thanks.

Stanislaw


Schematics and FFTs attached (initial idea validation):

• 2nd harmonic is higher but it doesn't require additional circuitry to move signal to opposite rail (IPS-A vs. IPS-C),
• part of it is probably generated by Beta differences (not optimal transistors),

Some amps have input like this. While the input is RCA (not balanced), the receiver is configured to sense differential between + and - (like balance input receiver).

Both the + and - are passed via capacitor (E001-E002-E003-E004). The - (shield) is not connected directly to ground, but by capacitors (C021-C022)

What is the merit of doing this? Better sound? Breaking ground loop?

Why not just connect the shield of the RCA directly to ground?

I got Cyrus Two (issue 06) with problems. The previous owner said that only one channel works. I tested with headphones and both channels work however one is significantly lower in volume. And there is some distortion.
When I look at the PCB it is clear that some parts have been overheating. First test of Power Supply goes fine until voltage regulators VR1 and VR2. Both put out (+-)17,8V. However these VRs are overheating fast.
I remember reading that these VRs are not very good and could be replaced with better contemporary ones.
The problem is further down the line somewhere. I wonder if there is a obvious place to check first before I start to to follow the signal path step by step?

Hello, I'm new here, but not to audio. I would like to get opinions on PI speakers.; whether on kits or completed units. They strike me as quite unique & would appreciate honest opinions please from those who hwve lived with them.
Thanks,
Tony

Hi,

I'm new to amplifier repair and I need some advice here. I received some times ago a Musical Fidelity E11 to repair from a friend of mine which did not power up. The fuses where broken so, I quickly tested parts and found that all the right channel power transistor were shorted. So, I replaced every one of these 4 TIP35C as well as the TIP31 which was on the heatsink. I also checked what seem as the previous stage of power and noticed for every ZTX753 and ZTX653, once desoldered and tested on my multimeter gave a way too small Hfe value. So I replaced them as well. As every component around seemed ok, I powered the amplifier and everything working fine, gave it back to my friend.

He uses his amplifier for some month without any problem but now, he gave it back to me saying there was a faulty channel. What is strange and why I post here is that it's again the right channel which is broken. But, this time, there is no short on the power transistor but I measure about 46/48V DC on the right speaker connector. So, before I desolder anything to test (as none of the transistor seems shorted or broken with a simple diode mode test) I'd like to know if this new problem may come from the previous one or my repair which may have not been properly done. I noticed a trim pot but did not touch it. I search and found this post which suggest it's a current biais but I cannot find any information on how to adjust it correctly (if a transisor replacement need any reajustment)...

Anyway, could any of you suggest a better way to find what is the problem? Maybe someone has the service manual or the schematic for it which would eased my research?

Thanks for your help and advices,
Simon

Hi. I have a Mesa Nomad 55 amp that's giving me trouble, and I was wondering if anyone here would be willing to help me track down the problem.

I recorded a video that shows what's happening, but I'll try to explain here, as I don't know how to share the video.

All 3 channels work. Master volumes and gain controls work. Lights come on, and the voicing switch on each channel works.

However, none of the tone controls works. On channel 1, if I rotate the treble control down to around 8:00, the amp suddenly gets loud. One other control does a similar thing at around 3:00. I think it's the mid on channel 2.

Anyway, I'd like to get these tone controls working. I'm thinking that since all 3 channels are affected, it's something in the circuit where everything's combined, and maybe the whole tone stack is open or grounded, but I can't find the problem. The board shows no signs of overheating, nor do any components, and there is no evidence of abuse. While I see what look like many "cold" solder joints from the factory, I can't find any cracked or loose connections.

Wondering if anyone can give me some clues on where to test.

There is a plethora of 6J1 valve pre-amps on ebay from china/hong kong.

Photo of a typical example is below.

I would like somebody to confirm the circuit diagram is the correct one. I've buzzed 3 resistors (not the ones in the voltage multiplier) and they match so I am reasonably sure it is correct.

But I would like to know how to convert the circuit to unity gain (i.e. to behave as a buffer). The potentiometer is to be removed and resistors to control the gain changed - but so that there is not clipping and frequency response is unchanged - hopefully that is possible.

My guess gain is set by (R13 / R14) = 470 k / 200 or by comparing to another circuit I have, is it (R16 / R150 = 100 k / 4.7 k ?

Hi All,

I would really like a dedicated DAP to replace my phone, however I use a Subsonic-API music streamer (Navidrome) primarily. I have used the various iOS apps, but none really work well particularly regarding sync and shuffle play.

I have built my own desktop player using the Subsonic API in Swift, and have had the crazy idea of building a DAP based on this software running Linux. I could use something like the Pimoroni Pirate Audio board, but would rather have everything in a single board with a 4-5" display and larger battery.

I have made some initial research, and have asked an electronic engineer to create a prototype PCB based on the ESS ES9218 DAC/Amp and an ARM Cortex processor. An SD card slot or WiFi could be used to load the OS/music, and a 3.5" output would be included. If a WiFi/BT chip is included, there is no reason BT streaming to/from the device could not be included also, or USB audio out etc... The sky is the limit when a general-purpose OS is running and the hardware is open.

Has anyone done anything like this or would be interested in such a device? Any thoughts on the DAC/Amp combo? The ESS chip is relatively expensive, but does have a Linux driver as released by LG. There are obviously other separate chip DAC and amps that could be used.

https://beebom.com/developer-built-diy-winamp-mp3-player/

https://shop.pimoroni.com/products/pirate-audio-headphone-amp

https://opensource.lge.com/osSch/list?types=NAME&search=lgmv300s

https://evanhailey.com/2021/09/20/spot-box/

I read somewhere in this forum that to bias a Class A amp, Nelson Pass recommended that the heatsinks needs to operate at 50 degrees C. Wouldn't the heatsink temp be dependent on the size of the heat sink? meaning a larger heatsink would require more idle current to heat the heatsinks to 50 degrees C, so if two identical 50 watt class A amplifiers circuits are made with one having a larger heat sink, the one with the smaller heatsink would have less Class A watts vs the one with a larger heatsinks, is this correct?

Hello.
Amplifier Cyrus Smartpower.
R258 & R259 blown.
All fuses are Ok.
Protect mode.
No service manual.
Thank you.

what do you think? i intend to run them 48volts and 100mA drain currents, gain of 5...

I built one of Shannon Parks' diytube ST35s on a Hammond chassis 20 years ago. It still sounds great, and even better with the new JJ tubes I scored right before everything shut down. But I've always regretted not buying one of the nice Triode chassis when they were readily available. So if you've been sitting on one, let me know. I'd also be interested in a complete unassembled kit should anyone have one of those.
Larry Fisher
Port Townsend Washington

hi i am Rob. i hail from the UK. if there is anyone on here who knows someone selling a pair of Minimus 21 speakers. they must be the ones with the two speakers and aluminium
floating tweeter. someone on here had bought a pair and someone else said they were only made for the Aussie market but i bought a pair back in the 80s from Tandy store in Hull in the UK. please get in touch on my email.
thanks everyone.

Hello -
I've added photos of my finished projects to the Gallery. How do I add a link to the personal album to my signature?

I am seeing posts by parties that I have on my ignore list. Interestingly enough,
when the ignored parties are quoted by someone else, that quote is now blanked out,
which was not the case in the old site, and which is very welcome.

Just when I was about convinced I was going to drain my bank account and buy a pair of TAD 1601A, I discovered that Augspurger is now replacing the 15" TAD TL-160x woofers with the Augspurger GA15X-8 that they had designed to provide the same performance as the Pioneer.

Does anyone have any first hand experience with the new Augspurger 15 inchers? Do they really perform identically to the TL-1601a for example? They are ~$200 less per woof than new 1601A TADs.

2-47uF/160 volt Obbligato film caps.
$15.00 each and $5.00 ship in US.

Which resistor is better for a home audio application? I’m sure they sound the same, but one of them is probably constructed better. The green one is a few cents more but that could simply be because they’re less common. Tolerance is good enough for either.

I have had the white ceramic ones crack off pieces from the corners, and the leads are short. Green ones have longer leads and no ceramic to crack. But does the ceramic dissipate heat better? I can’t tell what the green coating is. Little worried it is like a paper wrapping that will start flaking apart in 10 years.

A First Watt B1 preamp is for sale now on Swap Meet ...

So, what started out as a quick little writeup about crossovers...turned into a bit more...about 60 pages more.

The DIYRM-A is a Do-It-Yourself Reference Monitor....much along the lines of an LS3/5a. Can be used a bit more broadly and works better with modern music.

The writeup can be found at:

goo.gl/XboqRW



The document covers:

Introduction
Design Goals
Driver Selection
Enclosure Design and Construction
Design Measurements
Crossover Design
Listening Notes
Crossover Power Handling Testing
Conclusion

They are excellent for a variety of applications from near-field monitoring, two channel stereo where space is a concern and surround sound applications, again where space prevents the use of larger designs.

I hope you enjoy.

Scott "SpeakerScott" Hinson

Hi everyone.... what is the safe dc spike level for speakers? I'm getting 2v dc spike at the output when i turn on the amp.

Hello all,

I'm trying to make a DIY DJ audio mixer and am wondering what is the reasoning behind using VCA for channels on some mixers, while others use resistance-based audio level control via potentiometers?

I understand that if I use a stereo potentiometer, and run stereo sound through it, it will not come out exactly as it should, as they have a tolerance of around 20% it seems (Alps RK27 for example) between the L and R channels. The VCA seems to overcome this issue, as it would only run a certain voltage through one of the potentiometer's channels instead of both, so the L/R tolerance of the potentiometer becomes irrelevant.

But is this all there is to it, or am I missing something? Because for me at the moment, it seems VCA is superior?

I have a one-man one-van PA system of about 450kg, heaviest piece 40kg. As a 60-year old at 6'1" and 220lbs I had no problem until my back went out recently. Afeared of a repeat of level 10 pain, I would be most grateful of any ideas with regard to shifting this lot around in my 1974 VW panel van to keep Prog Rock alive!

Thanks folks.

There are so many designs out there, I need some help picking a bread and butter design to build. Someone recommended the Hinson Neman horn, wich looks pretty awesome, but looking for something with a little more manageable size wise. is the 1850 cab the standard? or is there a more efficent horn design out there?

-Single folded horn ( not W )
-a design that can be reproduced without much copyright infringement
-fairly flat from 40Hz-100Hz
-doesnt require a specialized or super expensive driver
-efficient cabinet design (not overly large)

Hello to all from Essex, UK,
I have been a member here for several years, but never had the courage to post. I am a builder rather than a designer and stand in awe at the knowledge people have here. I spent many years as a domestic TV repair technician with an interest in Hi-Fi. Now as I pass retirement I'm still working as a touchscreen engineer keeping the cogs turning.
My current Hi-Fi consists of a Classe CA 2300 power amp, Sansui C2301 pre with Marantz CD10 player and an Alphason Sonata turntable with the HR-100S arm. Speakers are home built Statements II from the Speaker Design website. Hopefully the Sansui will be replaced soon with a Classe CP-700 preamp.
One of the reasons I finally plucked up the courage to post is the matching power amp to the Sansui pre (B2301) has an odd issue I will be asking for help with. Other plans for the coming months are to build a music server and possibly a decent MC phono stage (the Classe CP-700 does not have one).

Best Regards to all.
Alan.

I have for sale a premium ACA with cap mult, powered by a 24V smps. The amp, is finished in a nice enclosure, top plate need to be sanded (for a premium look), top and bottom plate are laser cut from 3mm Alu. Amplifier is in perfect condition, basicaly new. It is for sale because I need to make some place.

250EUR + shipping.

I'm in the early stages of planning a guitar amp build for my living room. The design is art deco inspired and I'll do all the cab construction. But need to decide which amp circuit I'd like to base the first run on.

I'd really like to optimize this amp for playing in the 80-90 dB range. Of course I want it to sound great at lower and higher output. But I really want an amp that feels incredibly alive in that 80-90 dB range.

This isn't meant to be a "practice" amp per se. I'd probably rather have an amp with a good master volume for the circuit.

I play mostly clean, but it would be ideal if this circuit could get great OD + Distortion from the amp itself. I'd probably want an fx loop or onboard spring reverb if possible.

Any suggestions on tried and true circuits that meet my main criteria?

What would you want to see in an ideal living room / studio amp?

Hi,

I'm currently working on modelling an 18inch sub driver from scratch. I have guideline T&S parameters I'm aiming for but they're flexible as the design process continues.

Currently using FEMM to analyse magnetic flux for the magnet coil system. Flux density diagram can be seen below. As well as corresponding Bl(x) curve.





My main question is. Is it okay to have the pole higher than the backplate like i have here? This is to correctly for symmetry in the BL(x) curve, if it's at the same height then the forward and backwards displacement gives differing BL. I don't see why it wouldn't be okay but all the models I've seen have the pole at the same height as the backplate.

The coil is hard to pic out in the image but it's overhung, 28cm winding depth.

Are you able to give me the general function of these two schematics?

This Christmas and around the New Years eve I was left completly alone with a friend's cat that i had to feed and I could take my time measuring about a hundred germanium transistors, mainly ac 180, ac181 , ac187 and ac 188 .Then I started some simulations for some buffers, but I had to use silicon models.In the beginning I considered a simple op amp driving a diamond buffer.I've both included the buffer inside the op amp loop and then excluded the buffer out of the loop, but I wanted to hear what germanium transistors have to say outside the loop.Then a very simple buffer idea stroke me when finding that a diamond buffer topology can't properly compensate germanium transistors due to the natural leakage and hfe differences between npn and pnp gèrmañium transistors. Moreover the new buffer proved to be 20...30db more linear than a diamond buffer in simulations just around -100 db THD in all audio range up to 20 khz using silicon trz models so I considered the global feedback useless and I was right.
The listening tests with the buffer outside the op-amp loop...as linear as can possibly be , no " germanium compression"...It sounded like the best tpa6120 headphones amp to my ears right from the begining and the transistors were completly cold.Although i did plenty of simulations for 32 ohms loads with very good results too i could only test my 250 ohms headphones.
Anyone willing to sort germanium transistors will find this simple schematic rewarding for all the efforts.Some inductors might be useful here and there.
Of course you can try a rail bootstraped version for higher output powers too..
I have to thank to Sergiu, a good friend of mine who got me into this crazy idea that germanium can sing, to Molly for inspiration and to Franzm for Hartsuiker's design idea.
What I really didn't expect was to measure less than 10mv output dc offset to real ground...
I used first njm4556 , then lm4562 as they work reasonably well at +-3V DC.I'll try lm6152 next as it works at even lower voltages and I have some around, but I'm really open for rro low voltage op-amps suggestions .
Unfortunately due to some problems I have with my computer i can't post the simulations.

Heyo

I was wondering if anyone has done a DIY similar to the Tekton Lore which uses a 10" Eminence Legend woofer and a gold Audax tweeter with a simple crossover. I'd like to learn more about this design.

Cheers~

My tarantula trx4880 has no power ,. I notice r512 is open, can someone tell me the value.... What mite b other causes why this amp have no power

First time poster.

I bought two Australian Monitor AMISPre-1 Mic amplifiers today.
I opened them up and discovered that they use one JRC4558 Op - Amp and two A733 PNP Amplifier Transistors, which are common parts, and because the circuit is quite simple, I believe I should be able to upgrade some components in the signal path to lower-noise components.

I have a couple of OPA2134 and 2N3906, and I'm thinking about soldering in some sockets and experimenting with different opamp/transistor combinations to see if I can lower the noise floor a little.
Do you think I should focus on the active components or the capacitors in the signal path to help reduce noise?

Any advice is appreciated!

This is starting to annoy me.
Last week, and again today, I got a "Vogue" woman's fashion magazine delivered in my home mailbox.
It has my name and correct address on the front mailing label, but I did not ask for this magazine, nor do I want it to continue showing up in my mailbox.
I called the 800 number for Vogue, went through the annoying voice prompts, etc, and was told by madam robot that I had to call another 800 number for deleting/cancelling the subscription.
Calling THAT number, I get another recording "sorry, no one is available to assist you".
Geez!
I guess they don't work on Saturdays, I'll try on monday.

But why.... WHY would I be targeted for a woman's magazine subscription, I'm a guy, and I don't wear dresses or need makeup.

I just got some some kappa pro 15-lfs. And I am wanting to design an enclosure for them. I see that they are designed for ported enclosures, but will they work in a sealed? I am running a sub below them.

Hello, I am new to the DIY community and wanting help with building a Bluetooth speaker.

Speakers:

https://www.parts-express.com/Tang-Band-T1-1828SD-Speaker-Module-4-Ohm-264-935

https://www.parts-express.com/HiVi-TN25-Fabric-Dome-Tweeter-297-408

I used a speaker crossover calculator and came up with below. Cam someone check this out and tell me if it will work for a small Bluetooth speaker?

2nd order link-witz Riley. Crossover showed that those two speaker should be crossed between 6600 to 6700 I think.


The Component Values are:
C1 = 2.4121 µF
C2 = 3.0151 µF
L1 = 0.2411 mH
L2 = 0.1929 mH

https://goodcalculators.com/crossover-calculator/
© 2015-2022 goodcalculators.com

I am selling my pair of Lowther DX4 speakers (16924 and 18718). I purchased a pair directly from Lowther, but one had to be replaced by them due to faulty coils therefore the serial numbers are not matching, but despite this they play wonderfully. There's no scrubbing of the coils, cones and suspension (foam surround) are in perfect condition. I am selling them as they are not my primary speakers and I would like to try other wideband speakers. All in all they've been played around 150 hours.

Foam surrounds on both are original.

Version: 8 ohm silver

They are in their original boxes and I will put them into a bigger box (box in box with proper padding) to ensure safe shipping.
Units are located in Budapest (Hungary), but I am happy to ship them anywhere in the World.

Asking price for the pair: EUR 1.000 including shipping within Europe (outside of Europe for a small extra)

The homepage for me suddenly looks like this instead of newest topics showing up as just listings. How can i revert to it if possible?

And id like to add that, if this change was a conscious choice, its really too much too soon. The old forum was a classic that stood the test of time for a good reason and the new design did not need to deviate from it as much as it has

Why is the standard FM and TV antenna called "Yagi"? Mr Hideisugu Yagi is why.
https://en.wikipedia.org/wiki/Hidetsugu_Yagi

After not quite finishing my previous preamp project I decided to change some of the goals and build a new one. This is what I want in my new preamp:
- Compact
- Volume control
- A few inputs
- Start-up mute
- Good performance
- Remote control of input selection, volume and mute
- Quality, high resolution rotary encoder
- Nice design
- Something I can actually finish and use!

In this thread I'll pull together a few separate modules I've made and include build details, pictures, BOMs, measurements etc.

I'll also post full Eagle PCB schematics and layouts so people can use or change my designs. All PCBs were made by OSHPark. If anyone wants PCBs, I may have 1 or 2 spare (as the OSHPark minimum order is 3) or just download the Eagle files, upload them to OSHPark and order them yourself 🙂

I'm working on an amp project using op-amps feeding into BD139/140.

I'm at the measurement stage and have noticed noise on one of the channels that I'm unsure of the origin.

Looking at the following, we have noise at 50Hz, which is a given, but then the left channel has spikes at 100Hz intervals:



Any pointers on what might cause such a pattern of spikes?

Hi Fella's I have a pair of DIY speakers with Raal 70-10, Accuton C50 mids and Scanspeak 18wU/4747T00 illuminator woofers.

Have been enjoying the speakers for around 2ish years now but have noticed in the last day or 2 a buzzing/rattling noise come from one of the scanspeak drivers in one of the speakers.
The driver in question also makes a weird sort of scratching noise when I gently press on it.

I have found that by pressing firmly on the rubber surround on the right side of the driver it makes the buzzing/rattle go away, though it comes back sometimes requiring me to do this again.
Also when I gently press on the right side of the driver it self it doesn't make a weird noise.

Is this driver toast? and can it be fixed?
I live in Australia and these drivers are like $500aud to replace.

Woofer sound - Google Drive

The first recording is me playing a 70hz tone with the left speaker making the rattling/buzzing noise
The second is of me gently pushing against the driver and it making a weird noise, completely different to the other scan speak driver in the other speaker.

For sale 4 drivers for B&W 80x Nautilus speakers part number ZZ10669. They are perfectlly refoamed with original rubber. It can be used also for DIY speaker therefore Alu cast is painted black for better looking. I have measured all 4 drivers so i can give you TS parameters for all4. (Fs - 38hz, Qt-0,43, Vas-19l app.) . Price 69€ per piece. You can get all 4 drivers for a price of 1. https://www.ebay.com/itm/334031919745
Prefer shipping to EU.

Hello All,

after completing my gu46 amp I am about to embark on a new (and life threatening) adventure. My boss asked for a nice, medium powered (<30W) amplifier with a consistent "aesthetic" factor to it.

Well, I came up with a gu48 (833A) amplifier.

I have everything I need except the opts.

These are the specs:

gu48 @ 1500v and 100ma + bias current / 5k load

driver: 6sn7 input feeding 307A in triode mode CCS loaded with a mosfet follower (fet to be determined in due course)

The power transformer is a universal 1000VA unit I designed some time ago which features multiple secondaries and generous power ratings on all rails.

I have a big issue with OPTS. I used the 1628SEA units from Hammond loading the gu46 tubes of my other amps @ 1500v and 100mA idle current. The result is good in terms of sound quality and power output but with the gu48 I would like to investigate other options.

So.... are there alternatives to the hammond 1628SEA opts with greater idle current capability and in the same price range?

Any and all suggestions concerning the project are welcome of course.

Cheers,

Hey guys this TPA3124d2 chip amp has 2 caps on pin 22 and 15 (the yellow and red arrows) I reckon they are ceramic caps, one has corroded off due to the glue they use over the cap and coil.
So looking at the diagram they are .22uf BUT doesn't that symbol indicate a polarized cap? So are they electrolytic or something? I think they used the wrong symbol OR the manufacturer changed the design of the circuit slightly and used ceramic instead of electrolytic.

Any help would be greatly appreciated.
Cheers

Dear forum members,
since Thule Audio has gone out of business and I need to repair my preamp, I am looking for the service manual for he Thule PR-250B preamp processor.

Cheers!,
Abraham

Looking for warmer sounding diy bookshelf kit. Budget $2k including cabinets.

So far been reading about GR research, parts express, madisound, creative sound solutions. Not sure which I should choose. Ideally something as high sensitivity as possible that would work with a 10-20 watt+ tube amp.

Thanks!

I'm a new member from Sydney Australia. I've spent the last couple of years slowly building, upgrading...and then upgrading some more.
My current hifi system includes from top to bottom:
-Small Jaycar kit amplifier currently not being used
-Preamp - Input/output switching and the volume attenuator both AMB labs (delta1 and delta2 controlled by the LCDuino) but the power supplies and actual preamp are Rod Elliot designs (p05 and p88)
-Active analogue 4 way crossover - Rod Elliot P125
-6 channel (3x stereo) Rod Elliot P3A amplifiers
-Separate power supply box that houses all of the power supplies for the preamp, active crossover and 6 amp.
-Not shown are Jim Holtz's Finalist speakers that are 3 way tri-amped with all the above gear.

I am overwhelmed by the number of designs, variants of said designs and how involved and complicated they can get. reading all I have, my imagination is spinning with all sorts of crazy ideas and dreams that I know aren't realistic, so I've decided to ask all the wise and experienced here for some direction to help an ignorant but willing neophyte.

my current gear is the Kanto YU6 and SUB8. are there beginner friendly full range bookshelf speakers that will outperform them? what options would be good to consider if I had $500, $750 or $1000 CAD to budget? for just the speakers, not including the sub.

I have this amp in, which likely had an over-voltage failure. Owner runs 16v in his vehicle, and noticed all that appears to be wrong in this particular amp is the UCC27324 PS driver IC; which is shorted across half its legs. PS Fets are IRF1404 and appear to have survived.

UCC27324 SOIC8 is only rated for 15v max, and so I guess it failed at 16v supply.

Is there another low side driver IC that may work (such as UCC27289) which will operate at +16v?

Thanks in advance.

Hi all,

I want to build copy of Dynaco ST-70 amp. I have pair of OPTs from Edgar TP101 power amp which use EL34 PP. Specification might be Raa 4k, 40-50W, output 4 and 8R, UL connection possible.
So I went through posts on this forum and on internet at all, and find some issues.
I want to preserve former pentode-triode driver, but as you know, 7199 is quite hard to find (and not cheap). So, I read, that I can use another types of similar tubes for this purpose. I have several type, like 6f1p, 6f12p, ECF82,ECF803.
My question is, may I use ECF82 with former values of parts please? Or do you have any experience, which need to change some parts? Or, is it possible to do with 6f1p or 6f12p the same way? What about ECF803?

I found on this phorum that:
"The 7199's variability in the ST70 often caused quite asymmetric swing on the driver outputs. The only simple fix was a variable screen resistance.
I used a 499k in series with a 1M cermet pot. As it turned out, the best adjustment was for about 110VDC on the pentode plate/triode grid." rayma 8th April 2015, 01:06 AM
What do you think about? Is it about resistor 1.5M connected on pin 3 of pentode section?

As output tubes I want tu use Tesla EL34, and I want to try Toshiba 6GB8 also. If I found good information, value of Ub+ is around 410V, is this value right? Bias is around 1,56V on cathode resistor (15.6R), so around 50mA for each tube. Is this ok also?
I thinking about switching power tubes between UL and penthode connection too. And maybe triode?

For power supply I use for beginning simple power transformer with SS rectifier. Later maybe I edit it to vacuum rectifier (probably with 5c4s or 5c3s), with other power transformer of course.

I attached schematic of ST70, which I want to use.

Thanks for your help.

Bought these for a project that I never completed. Unused/as-new. $225/pair + actual cost CONUS.

Hi community, I am a newcomer to building kits but have successfully put together two ACA amps and the Kork Nutube preamp. My latest project the SS HP amp and pre amp however has a problem. I use it as a pre amp. It sounds fantastic but when it heats up (about 15 min after it’s turned on) one channel, mostly the right, goes quiet. The headphone output still works though, and when I tested that I found out that inserting the headphone plug half way in fixes the pre amp channel issue. I have to leave the plug inserted 1/2 way in to continue listening on both channels. Is this a problem anybody has experienced? Is it possibly the headphone input that needs to be replaced? Any advice is greatly appreciated.

I just replaced two flaky bias trimmers in a JVC VR-5660 receiver. Problem is, the settings of the originals are an unreliable reference for what the new ones should be set to, and I don't have a copy of the service manual. Assuming I'm measuring across the emitter resistors between X3 and X7 and then X4 and X8, what's a safe voltage to shoot for?

I have a Thorens TD320 Mk ii that I picked up recently. TP90 tonearm, TP95 headshell. I was trying to mount a Grace F9 with a SoundSmith stylus on it. I am using a Dennessen Soundtractor for alignment (bought in the '80s/'90s) and am running into a problem where I can't get the cartridge back quite far enough. It is very close. I believe I am using M2.5 mounting hardware and was considering switching to M2 hardware, which might get me about 0.25mm more travel. I'd prefer not having to file out the slots slightly, but I guess if that is what it takes, so be it.

Any ideas or thoughts? Thanks!

Hello. I just snapped one of my tone arm wires on a Rega RB600. Can anyone recomend a reasonable priced wire to use to re wire with please? I`ve seen the comercial cables and they seem a bit expensive for a DIY`er like myself.


Thanks

Chris

This is my first pair of maggies I notice they are slightly concave rather than straight. Is this a design element or is it the fact that they are quite old? any advice would be appreciatedd. Also Ive been reading that some people recommend putting more ridgid hardwood enclosures on them etc-any thoughts?

Wanted to share an interesting experiment I've been testing. Using a 5.1 AVR for a 2.1 channel active system. Not the usual way using pre-outs, but instead using the multiple channels built into the AVR.

For one 2 way speaker I'm using the left main channel and the left surround channel. Woofer on main, CD on surround. Woofer and Cd both set to small. Woofer high pass set to whatever you like for your sub situation. CD set to the highest setting available which is 250hz. AVR set to multichannel stereo.

When using multichannel stereo the AVR does not send any of the bass from the surround channels to the sub, it only uses the L&R main channels. Bass from the surrounds is tossed out, so the high pass for the surround only protects the CD (a little). The CD also has a cap on it to protect it from accidents.

Next up is level matching, which is simply done via the channel trim adjustments in the AVR. You can also adjust distance/delay but the steps are large, so only slightly useful.

Then I'm using manual eq. I have +6 to -20db of adjustment for 7 bands. I set the out-of-bandwidth ranges to -20db to act as a high/low pass filter.

Between the level trims and the manual eq, you can get quite a bit of adjustment range, add in the 250hz HPF and you can get enough filtering for the CD.

I looked around and couldn't find any other threads about this, but I can't see why this wouldn't be a viable option for a simple active 2 way with or without sub. You can find a 5.1 AVR for next to nothing. Could even use a 7.1 and still keep your surround channels working. You won't be able to use the auto room eq though.

Thoughts?

Dear all,
I made some mods to 3 2910s, only Stereo R/L channels (the most ellaborated in the analog channels) and ended with 3 serious competitos that having different "flavors" beated top models (SACD players, CD players, so on) from NAD, ARCAM, LEXICON ($3.500!!!!!!!), not said by me but from the actual owners.
Very simple, OPs changed to LM4562 I/V (way more warmth and detail at the same time!), output buffers changed to LM4562, LM49723 and OPA1642 in each player, muting transistors taken away, Output Condensers taken away, and shunted one of two output resistors, leaving 150 ohm in series.
All players in general are seriously impaired in the analog output stage (low cost parts), I know they can't leave a product without an output condenser, for instance, but as single mod it is to shunt it, im not aware of a bigger and cheapest mod.
One of the kings I sold to a customer wich has Lexicons, Arcams, Proceeds, beeing his 1st player, forcing Him to play more CDs than other formats is a 1989 SL-P999 Technics... with the same mods described, LM49723 output OPs.... that´s it.
For one of my Denons it started the common issue of non reading CDs, I'm going to ask for a couple of HOP1200R/S pickups, but they don`t will be here till next 2 weeks, so I will ask I someone could tell me wich of the 2 presets at the base of the pickup is for the CD laser??? to see if I can do something in the meantime... (THANKS in advance for this little help!)
As for the Flavors of the output buffers...
LM4562 - Very lineal, everything is at the same level, strong dynamics (a little on the more than enough side), but in this case sound stage is short of right. Voicing is extremely precise with very high definition.
OPA1642 - More Hifish presentation, more bass and highs than mids, very high definition sensation could be highs in the 10k over to be some dB up.
Laid back vocals. And high contrast dynamics.
LM49723 - Somewhere in the middle, but above, other dimension...
you are there Sound Stage, natural crispness of transients, natural voices weight, bass is deeper and makes all blend toguether without loose definition and being overweighted... I can talk of a similitude to my analog old Pioneer RT-2022 open reel here...
Cheers
Marcelo

I am thinking of building some speakers to place next to my tv.

I listen to metal and hard rock, also a lot of live concerts from blu-rays.

I have an ACA camp amp (class a, 8wpc) hooked up directly to my media pc.

The options i am considering are:

https://celestion.com/blog/build-this-compact-12-two-way-pa-cabinet-design/

Or

https://kjfaudio.com/product/frugel-horn-xl-flat-pack-speaker-kit/


I don't really listen at super loud levels maybe 85db max give or take.

Which one would be a better fit do you think? Any other designs I should consider?

I've built a small pocket headphone amp. For my volume pot I chose a Bourns 50k pot. A great pot, however I find that the volume goes from silent to very loud quickly. Can I switch to a 100k pot to get something a little smoother? Bourns or Alps is ok with me. I am a green amateur so any suggestions would be greatly appreciated. Thanks to all.

After reading several reviews this could be one of the most interesting wireless speaker.
Who have heard this 2 years old wireless powered speaker model ?
Are there anywhere measurement results like usual in the magazine "Stereophile" ?
Thanks for comments.

https://buchardtaudio.com/products/a500
https://gearspace.com/board/reviews/1322565-buchardt-audio-a500.html
https://6moons.com/audioreview_articles/buchardt4/
https://darko.audio/2020/09/a-long-film-about-the-buchardt-audio-a500/
https://www.audiosciencereview.com/forum/index.php?threads/buchardt-a500-diy.20479/
https://www.audiosciencereview.com/...uchardt-will-release-an-active-speaker.10832/
https://www.modernhifi.de/buchardt-audio-a500-test/
https://www.lowbeats.de/die-daenische-kultmarke-goes-aktiv-buchardt-audio-a700/
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So I've decided to try making a portable speaker. The Dayton KABD series of amplifiers looks good to me. I feel like a small setup needs to be able to implement a high-pass and compression to get the most out of it. I've picked up a KABD-250 that I've been experimenting with. And I've been wanting to play with Sigma Studio.

But what transducer? I'm inclined to go full range, but would consider a wide-range woofer with tweeter support if it could be implemented with a simple enough filter. I think 3-3.5" is probably the compromise to make between output level / bass and dispersion. I'd like to keep the price under $30 per channel, and the size near 1/4 cu ft or less (per ch). Note that with DSP I can work with sub-optimal box alignments. I expect to port it. It'll go into a portable unit, so I hope to find something rugged. Metal or PP preferred over paper, and prefer to avoid a phase plug that leaves an opening down to the gap.

I'm leaning toward the Aura NS3 / Dayton ND90. They have lots of excursion (for the class) but some reviews complain about distortion. I've personally heard the NS3 and the Tymphany TC9FD18 solo in vented boxes. While the TC9 sounds better at low volume, it became confused sounding at louder volumes. I put this down to available Xmax. The NS3 starts out a little rougher, but can keep going to higher output levels. Reviews complain about the distortion in the NS3, though, so maybe there is a better option I'm not aware of? Also, does anyone know the relationship between Dayton and Aura regarding the NS3 / ND90? PE doesn't have the NS3 any more, but Madisound still lists them. If the NS90 is antagonistic to Aura, I could reach for the OG.

Visaton FR 10-8 (or FR 10-4?) looks like it models nicely and claims good Xmax, but I start to worry about dispersion. It's got a whizzer, maybe it would be ok? I haven't heard it.

Tectonic TEBM65C20F-4 seems like an interesting option. PE details page says 5 mm xmax on the 8 ohm version, but you look on the spec sheet they link and they call 10 mm P-P xmech instead, so I'm unsure of actual xmax. It's got an ugly FR null around 1.7k, but could maybe help it with EQ.

Timothy Feleppa's page (https://feleppa.com.au/speakermeasmid.html) doesn't like the Aura and seems to think the Dynavox LY302F is the cool choice but Xmax at 1.55 mm seems like it would run out of steam before you could get to musically satisfying output levels.

If there was a 4" that had the kind of damped HF response that would play nice with a single tweeter+cap or possibly piezo then that might be a cool option also, but I haven't stumbled across a solution like that yet.

So whadya think? Got any winners I'm unaware of? Experience comparing FR10 / TEBM65 / LY302F directly to the NS3?

This is a bit of a confusing amp given the crossover modules and jumpers, and a 37 page manual which tries to explain things.

Amp came in and was able to power up, but power terminals were loose to PCB. All but CH5-6 were able to work but Im not sure if those channels were tied to inputs other than CH5&6. Someone had played around with jumpers, wires, and settings and none of it made sense and didn't follow the manual's suggestions so I pulled all settings and modules out. After repairing the power block, I tried following the manual for 1-to-1 jumper settings but there is none; so I went with the factory default settings on the first page (Page 7 w/0 AC502). Amp now goes straight into protect. I pulled ALL jumpers and modules out and still straight into protect. I dont know if the problem is in the pre-amp, configurations, or something else.

Manual I've been following here: V:\ADS manuals\M860 manual.tif - DirectedDealers.comhttp://www.directeddealers.com › ads-mobile › ad...

For an extremely brief moment I can see drive signal FLASH on pins 9&10 of the TL.

TL494
1. 0
2. 3.510
3. 3.510
4. 0.006
5. 1.461
6. 3.369
7. 0
8. 14.40
9. 0.054
10. 0.054
11. 14.40
12. 14.42
13. 4.95
14. 4.95
15. 3.510
16. 3.510

I've noticed that when referring to the data sheets of drivers, the value for Xmax seems to contradict dimensions that it can be worked out from, for example, taken from the data sheer for the PD1850

Xmax = 11.05 mm

but

Magnet Gap Depth = 12 mm / 0.47"
Voice Coil Winding Depth = 28 mm / 1.1"

I was under the impression that Xmax corresponded to: (coil length - magnet gap)/2

So that would mean an Xmax of +/- 8

Where is the other value coming from?

Thanks

Hi there!

I just got a CD2 from someone, and it has a faulty laser (probably). Do you guys think it`s worth the effort to put in a replacement laser?

I know it has the CDM2 mechanism, and 4 * TDA1541 DACs, but that`s about it...

Kind regards,

Berend

Dear all!

After my mixed experiences with round traxtrix horns the question came to my mind how the radiation could be more focused to the horizintal plane. As I was always fascinated of the orginal Klangfilm publications and the math behind it I thought some time how to change the design to an elliptical one. Now, I think that I have fond a solution and would like to share this but only for diy use! For any commercial use, please conatct me! A lot of work was put into this calculator!

The round horns produce considerable beaming - too much for my taste... On the other hand such horns does not have any diffrations zones and therefore many point out the natural sound character. This smooth transition without any sudden diffrations zones should be retained.

What I do not want are discussions that other horn designs are better!

Maybe not all you are aware that the original Klangfilm profile is closed. Nealry all real desings terminate the profile near the mouth. Therefore, the constraint must be that any existing stretch factor must be zero at beginning and at end of the determing x-coordinate. It took a long time until I found a quite good working sinus dependend transformation from round to elliptical.

It was already a hard to work to implement the original round formulas in Excel VBA. The 3D to 2D projections were taken from the web. There exist several examples how to do that. I wanted to have the horn profile visible and rotable for my eyes.

The original design assumes the wave front to be a spherical surface cap. The math to calculate this surface is quite simple. If we transform this to elliptical the math is not simple anymore. So far as I found there do not exist any natural expressions to solve the integral of the surface of an tri-axial ellipsoidal surface cap. The only way is a numerical integration what I have implemented and I think it works quite nicely now.

How does it work? At eny point along the horn axis, first the original round values are calculated. Then the dependend stretch factor is calculated which is max at the maximum rollback of the horn profile. Two possibilities exist to stretch the xy coordinates multiply or divide. I choosed to devide one of the coordinates of the ellipse which gives better looking profiles. This is easy to understand if you look at how to invest some money into shares (stock exchange). You can loose normally only 100% of your capital but can gain more than 100% of your capital 😀

At every point, after calculating the stretch or compression factor for one elliptical coordinate the other is numerically optimized by a Newton optimizaton to yield the same ellipsoidal cap surface as for the round horn by numerically calculate the first derivative with respect to the change of the other elliptical coordinate. As starting point the 2D surfaces are assumed to be equal which is not the case for 3D but already numerically very near to the real value. Perfect for the Newton iteration.

The stretch factor should be greater than 1. The sheet produces a complete set of xyz coordinates on Sheet2 for the resulting horn. I hope to receive some feedback how to transform these xyz coordinates to an 3D printable format or input format.

Sadly, I assume that this sheet only works with Micorsoft Excel VBA.

Hi there.

As per title, do horns become more sensitive (louder) the harder you drive them (more input power to the driver)?

I’ve been wondering about this for a while. I think it might be the case that there is a minimum amount of excursion in some designs before the horn starts to load significantly.

Specifically, I’m thinking about differences in response between Tapped horns, back loaded horns and transmission lines (and perhaps super planars for that matter).

Thanks

Ok, something very general regarding vinyls... I have a very good set, my third one turntable 7kg platter, doze, tube RIAA classical, I am building tube amps by myself electronic engineer, lot of vinyl..
Vinyl sounds very natural - wide and deep scene, I even cannot compare with a CD, very very levels above, .. but last tracks are sounds distorted. I bought my favourite GnR album and Pink Floyd The Wall non remastered old edition, last tracks I got crazy to listen. How I should trust on this format?

For the cartridge "Blue Oasis" there are a special made MC pre amplifier from the brand
Sao Zaw Win (Win Research Group, Inc.)
formerly: Win Labs
7320 Hollister Avenue, Goleta, CA93117
Voice: (805) 968-5213. Fax: (805) 685-2781
information from 14 PDF- URL
http://www.theaudiocritic.com/back_issues/The_Audio_Critic_17_r.pdf

For this device I need schematic and the IC "SL459" (SL 459) itself.

This IC is in use by the input stage (brand: Plessey). Datasheet unfortunately not online, but I have a original databook. Below you see a clone of the internal circuit (pdf schematic)

Perhaps one of the members know more about the currently brand name, additional about a delivery source for the "hard to find" part "SL-459".

Please note, only the outline of the SL459 is like a OP AMP (i. e. DIP-8) but not the internal topology.

A modification to the "easy to find" AD797 delivers not the sweet sonic performance than the SL-459.

Thank you for your advices.