diyAudio

savvas · 2022-03-26 11:21 pm

I'm selling my second DCG3 preamp which I've used only for testing purposes. Going balanced ain't gonna happen so here we are.

I've bought parts from Teabag but I've upgraded all resistors to better specs (but the same brand Vishay Dale military ones)
So all critical resistors (signal, feedback, filter etc) are 5-10 ppm PTF Vishay/Dale. They were quite expensive (most of them not available now from Mouser) but it's worth the investment.

Sold together with Loop Breaker (the little board) very handy if you have ground loop problems and heatsink.
Also I will provide additional resistors extra power setting (for higher current)

I've used it along with a Muse volume control and Salas I-Select which I also sell

SOLD

frequency295 · 2022-03-18 1:20 am

I've been attempting to build a DOZ amplifier using a custom board I created. First time ever creating one so if its way wrong please let me know so I can learn. Having a couple issues during my testing.

When initially trying to dial in the bias to 1.7amp I accidentally allowed it to pull through 8+ amps so its possible I killed it then and there but there was no smoke. I pulled the transistors and tested and they all test within range oddly enough. I resolved my vr2 issue and can get it to 1.7a after warming up however my output is 3.3v it says to measure and set vr1 to output to half input(24v).

Possibly just a bad design on my part or I fried something, but figured maybe someone could look at what I did and see something obvious.
The schematic should be inline with what's publicly posted. (See below)

Board design below. Did I over do the ground? 🙂

CamH · 2022-03-24 12:30 am

I have several problems to solve but I’ll start with the amp I have:

I have a HIFIDIY power amplifier A502S TPA3116D2 w/ Bluetooth and Line in https://www.aliexpress.com/item/4001194120212.html. Unfortunately it favours BT over the line-in and auto switches to it when anything is connected.

What I need is the same item but one that favours the 3.5mm aux line in. Right now if BT is connected the line in is disabled.

I’ve read here of boards that do the opposite and when line in is connected, the BT is disabled. Anyone know how I locate such a board or suggest a vendor who might help?

The one I have is perfect other then this issue, it’s powered normally from a 12v Li Ion battery 9Ah battery and BMS but can be switched to 19v PSU when more volume is required. The requirements are:

-variable voltage input 10-24v
-2 channel output
-BT input
-Aux line in input

My goal is:
- Portable battery based audio (Sony Boombox Style) (done)
- Ability to play Bluetooth music from phone (done)
- Secondary ability to add wireless microphone and mux with the bluetooth audio.

Other things I need help with
- locate a amp board that could mux (BT and line in) the two then I’d be ecstatic but I don’t think such an item exists
- locate a pre amp that could mux BT and Microphone and send to an amp (needs to operate efficiently from 10v to 19v but I can settle for one that requires a seperate PSU)

qObsession · 2022-03-27 5:55 am

Hi, all!

I realize this is a long shot, but might anyone have any information (complete T/S parameters ideal!) on these drivers (pictured). I bought these in 1996 (wow... been a while!). I've brought them out of storage and am putting them in a new install (considering making mid-bass enclosures). I've scoured the internet and NOTHING. I even contacted Soundstream and couldn't get an answer.

So... hoping that the stars align and there's an old-school car audio Soundstream aficionado who might have a clue!

Thanks in advance for your help!

bmc0 · 2022-03-23 1:45 am

Does anyone have any data (or estimates) of the DC saturation current in push-pull guitar amp output transformers? All the discussion I've managed to find on OT saturation seems to assume well matched average current across both sides of the primary, but this is not usually the case when the power amp is overdriven significantly. When a typical LTPI is overdriven, it exhibits significant bias excursion, causing duty cycle modulation of the output waveform. This means mismatched average currents in the output tubes and a DC component in the output transformer. Simulations suggest somewhere around 150mA of DC offset for a Marshall-style 50W power amp with the phase inverter driven hard.

Yoopercharged · 2022-03-26 9:49 pm

Hi. I'm looking for assistance with the proper bias setting for my B&K Sonata video 5 amp. From what I come up with, it should be 250 mA, measured across the negative voltage rail fuse. The five channels are at around 60mA now and I'm hesitant to raise it. It has two pairs of Toshiba 2SK405/2SJ115 output transistors per channel. One of the channels is also going dead after warming up for ten minutes or so. Any help would be greatly appreciated. Thanks.

cooloox · 2022-03-26 8:28 pm

Hello, sorry in advance I don't quite know which sub forum this should be posted on.

I have a older Sanyo music center and would like to mod it for it to have a sub out option.
My first thought is to take the headphone output and solder some wires there and add a new socket for the subwoofer connector (or using the headphone output itself). I already have a subwoofer amplifier and I am planning on buying a passive subwoofer from a thrift store.

Is that a realistic way that it could be done or should I trace some other place on the PCB and add the subwoofer output anywhere else with some additions?

Tom426 · 2022-03-22 10:40 pm

Hi all !! New guy here....Need some tech help on my one owner (me) Tympani 1D's...Is it Normal for all enameled Aluminum magnet VC wire to erupt with crusty, whitish oxidation & suffer with resulting numerous electrical circuit opens over time ?? My 50+ yr old 1/4 lb spool of 32 ga copper enameled mag wire Still looks factory fresh with absolutely No signs of discoloration, corrosion or continuity failure !! ...Nor have Any of the many dozens of coils I made with it....Short of marine duty or water exposure, I've just never seen any enameled mag wire corrosion damage before...Can anyone explain why never flooded or physically damaged Aluminum mag wire should "dissolve" into white dust ?? ...Thx, ...tom..

oltos · 2016-12-14 5:33 pm

Has anyone heard any of the Pure Audio Project open baffle systems? I know that these aren't DIY designs, but in terms of actual performance would they approach the SOTA?

They typically use pairs of upgraded Eminence Alpha 15 woofers per side and either Tang Band, Beyma or Heil AMT HF/MF drivers. They are ~95db and the rep told me that they give bass down to 30Hz at only 20" from the rear wall.

He uses his 2.5 watt 2A3 amp to drive his pair. He also claims that they chose the modded Alpha 15 woofers (over the otherwise excellent Acoustic Elegance woofers) y because they cross high with the driver above, and because you get full range response at low listening levels.

My other choice is very different: A pair of restored Quad 57s, raised 15" with a pair of rythmik 12" sealed servo subs.

andrew0256 · 2020-04-05 2:11 pm

Hi All. I'm new here. On lockdown and working through various projects which include attending to a pair of battered Glendales I've had for years. The problem is the paper cone tweeters are u/s. Does anyone know of any cheap direct replacements or upgrades with similar sensitivity? I've previously tried some very cheap dome tweeters and they were awful.

freddi · 2022-03-27 6:17 am

simply copying the lines and saving as a .txt file doesn't seem to work. Please explain in detail how to make it work,

noamgeller · 2022-03-12 2:24 pm

The scenario for this hypothetical question is as follows:

You want to completely eliminate Driver's back wave. What would you do?

A.
Build a speaker enclosure out of a very very long pipe and ask your neighbors to kindly leave the window open.

B.
Build a very elaborate Nautilus construction. Lawrence Dickie's style

C.
Use an overgrown DIY Gun Suppressor.

D.
Install passive Radiators behind the The Active Driver.

E. Go Planar 😉

Winston65 · 2022-03-27 5:09 pm

Hello to all, thanks for allowing to join. I'm an old age pensioner living in north Texas. I have a little experience, but always happy to find a source of knowledge beyond my own. I mainly build kits to gain skill. I'm also addicted to old Realistic speakers. I like to rebuild the crossovers to improve performance. Again, thanks for the join.

itsikhefez · 2022-03-27 3:20 am

Cardas CTFA RCA connector,
6 pairs + 1 single
New unused

$50 shipped for all ($3.85 per connector shipped)

stakkall · 2022-03-27 5:35 pm

Has anyone experienced or heard any of the InConcert cables that were manufactured or distributed under parent company Threshold at the time? It seems InConcert manufactured or distributed interconnects and speaker cables. Though familiar with InConcert's distributed WeberWire speaker cable, I searched the internet but could not find any other information on InConcert cabling -- namely interconnects -- though there is ample information on the Phantom Acoustics Shadow, which InConcert distributed. I never came across the interconnects for sale after several years of searching. It would be interesting to hear how the interconnects and speaker cables, supplementing the WeberWire line, complement Threshold amps and preamps.

6L6 · 2020-04-14 7:12 pm

I was a long-time subscriber to Listener magazine and this news coming today is sad.

Art Dudley, Rest in Peace | Stereophile.com

Art wrote a number of DIY articles over the years and recognized it as an important part of the hobby.

He will be missed. 🙁

stevef22 · 2021-12-26 12:02 am

Hi guys, can you recommend any basic audio engineering, speaker building – crossover building channels on YouTube? Or maybe a audio engineering basic class to take online?

I would like to learn the very basics of HIFI audio overall. But not get bogged down in doing calculus for hours. ( Im not very good at math anyway. )

indaco · 2022-03-26 10:01 pm

Good evening,
in order to build an OTL to drive the LCD-2 (at the specific request of a friend) I was wondering if it was possible to create a low impedance circuit for headphones with e.g. somenthing like SRPP, WCF, etc. with suitable tubes preceded by the "external" preamp stage.

That is, he would like to use a good solid state preamp he owns. He doesn't want an OT amplifier, only OTL.
Yet my doubts are 2: being the headphones at 70ohm with such a thing it will result in a mediocre damping factor, unless you introduce a decent feedback. And then they are headphones that require no low current.
Moreover, usually tube pre-amplifiers are usually preferable followed by s.s. power amplifiers (there are also examples in the opposite way, but as far as I know they are few in comparison).

All that is a good idea?

Pacific2rim · 2022-03-27 12:56 pm

Combine two E plane tees in their E arms ,explain its functioning with s matrix ? Someone please answer it.

seppoa · 2014-01-25 11:14 pm

Hello all,

I´ve got an Advance Acoustics CD player type MCD-203. It is a well built player, with an analog output with tubes, designed in France and built in China. But the digital board, with the DAC and drive electronics seem to be very cheap, of the kind in cheap DVD-players, but this board don´t have the components for the video signals equipped.

My problem is that there is a noise in the output when the mute disengages, regardless of signal when playing or in pause. The noise is maybe -40 dB, havn´t had the possibility to measure it yet.

The DAC is an AD1853, and the electronics are of the type with a buffer, so the disc is spinned faster than a normal CD-player. At the moment I´ve no access to my osciloscope, so I want to ask, if anybody may have an answer to what may cause the noise. I have reflowed the dac and main IC type MT1389QE. Maybe the buffer memory, a K4S641632H can cause this problem?

So if anybody can have a clue or answer, I´d be very grateful. I have a good knowledge of electronics, and access to all needed tools at work, but don´t want to start doing the faultfinding at my work, if you understand.

Thanks in advance,
Seppo from Sweden.

DaveFred · 2022-03-26 2:15 pm

Hello,

Looking to build a dual mono power amplifier that requires a 600va dual +/-50v PSU.

What is the difference between using two 300va toroidal transformers with dual 35v secondaries to two PSU boards vs using one 600va toroidal transformer with quad 35v secondaries to two PSU boards?

Does it make a difference?

Or do you really need two separate toroidal transformers to be true dual mono?

Thank you,

David.

NickKUK · 2022-03-27 12:01 pm

Before I go into analysis paralysis - am I barking up the wrong tree with this idea is the man aim of this post.

The TV sits in the corner and on glass corner stand at the moment. I've been eyeing up the concept of making a sound bar but combining a 1/4 wave into the mix. This would be a simple stereo TV with whatever amplification I have around. The pyramid of the corner is roughly 0.7x0.7x1m by 0.6m deep. That gives a total outside volume of 147 litres.

If the 7.2HDs are 100mm cone diameter and a 35Hz is about 2.44m long QW, then the volume is about 19.16 litres. Which, in theory, would give plenty of space within 147/2 including 18mm or double up 12mm for the walls. A QW TL could then be spiral wrapped inside the volume. I suspect that each corner would then absorb energy thus you end up with frequency peaks?

The room is not that large - about 5m by 3m, so the sound is likely to be quite unpredictable.

I have an "imposing" (read not in the house now), pair of Castle Harlechs so I'm happy with quality of extension rather than quantity.

bigino · 2017-09-30 5:15 pm

My mcd 204 still doesn't recognize discs after having changed the laser pickup today

I guess it is the board that controls the laser, as suggested by the importer's technician by phone.

Board would cost me a lot if bought from importer's warehouse, so I ask myself if there are other sources for this as it is a chinese product, or if there is something to try to repair it.

An externally hosted image should be here but it was not working when we last tested it.

jacksl520s · 2022-03-26 1:51 am

Recently, I repaired a USB DAC and encountered a damaged part,
But I don't know what it is.
Is it an optocoupler? What role does it play here

Ask for help from friends who have seen this part. Thank you

rabbitz · 2022-03-13 6:07 am

SOLD

Before I list this stuff on eBay, there may be somebody who is a Loudspeaker builder who would be interested in these items as a bulk purchase. Pick up only from the Newcastle NSW AU area.

Makita 3612 Router with selection of bits
Makita 5740NB Circular Saw with additional used blade
Jantzen Router Guide 014-0300
Progrip 50" FM-50N straight edge / fence with Router Base FM-14
Dick Smith Q-1559 LCR Meter

All items in very good condition and the Makita items are from their trade range. There may be more items that I'll throw in after I go through the workshop.

jackinnj · 2013-04-29 6:50 pm

In the second term, shouldn't it be 2kT/q?

celef · 2022-03-26 3:55 pm

I think this years cars looks stunning, and mercedes and mclaren seems to struggle, ferraris performs really well again, and the porpoising for most cars is a funny drawback, who will win this year?

crazy bill · 2022-03-11 1:37 am

Hello all, was wondering if, as the title says, there are octal equivalents.

The tubes will be triode strapped in a single ended design.

My knowledge is very minimal to non existent in this area.

Thanks in advance for any advice.

Cheers, Crazy Bill

TIC37 · 2022-03-26 12:30 pm

Wondering if both of these are correct or not and in that case why?
Question came to me since I have trouble balancing positive/negative sides and want to know if the transformer in the example HAS to be center tapped in this application or you can use a transformer with only single secondary without center tap? (picture borrowed from; https://www.circuitstoday.com/dual-adjustable-power-supply-using-lm-317-lm337 and redrawn by me)

SG should be Star Ground connected directly to main ground and do I need to connect the SG to be able to adjust positive and negative side?

sbelyo · 2022-03-25 3:49 pm

So... I have lost the components box to a set of Dayton BR-1 and have only the cabinets and the foam. I'm a speaker building newb and usually only go for headphones but I would like a pair of high efficiency monitors for a desktop setup. The amp that I will use is the Bottle head S.E.X. 2.1 I would also like to keep the crossovers external but that's not a must. I can put together a crossover but would love a PCB if possible. Can someone recommend drivers, tweeters, and a crossover?

juanito · 2022-03-26 10:11 am

Hello, I wonder if somebody here, from Germany, close to Herner Straße 4, 44787 Bochum - Bochum-Mitte, could kindly pay and collect a CD player to be shipped to Spain. Obviously, payed in advanced and no rush or hurries, at all. If it's doable, great, if not, then next...😅
I've tryed to negotiate with the german shop, via ebay kleinanzeigen, but he will not ship.
The CD player is a kenwood midi size (34 cm) and these scarce, or at least I don't find them. This particular model has digital output and seems very weel looked after.
Please send PM. Thanks very much!!

Studley · 2022-03-26 11:12 pm

Looking for a pair of these, ideally from the UK or the EU.

Julian RO · 2022-03-23 10:35 am

demetricelectronic · 2022-03-26 12:44 pm

Does anyone have schematics for this amp?

toastant · 2022-03-25 8:56 pm

Hey Guys,

I`m currently trying to repair a Teufel One S speaker.
I think i found the defective part, but can`t find something when searching for the part marking online.
The part has the marking 4202 and is 3mm on the longest side.

The same part beneath the part im searching is functional:
Pin 1 is down left.

Pin 3: 24V
Pin 4: 2.2khz
Pin 5: 6V

Also soldered to the PCB are:

40P13S MOSFET (Power Rail MOSFET i think)
TPA3118
AUDA1701
STM32

Can someone please take the time helping me find the part number?

nilsW · 2022-03-26 4:28 pm

I have complete set of woofers, tweeters and crossovers for a pair of Snell type K mk2. Picked them up at a yard sale and I want to make cabinets for them. Is there anyone who can help me with the baffle dimensions (how far from the top the tweeter sits and how far from the bottom the woofer sits)?

abacus3000 · 2022-03-24 12:15 am

Hello!
I have a question about building 4 horns.
I found picture in the web:

In this picture there are 4 separate boxes for each driver.
I was wandering what would happen to make 1 big box for 4 drivers, like this:

But to save materials not to install RED and GREEN baffles ?
It would look something like that :

And to make it rigid to use scrap narrow scrap planks just to connect bottom and top sides etc...
Will that work ?
I think it would be possible to remove GREEN part without change in response, but what about removing the RED part ?
Is there any way to model this in HornResp?
Thank you 🙂

tomst · 2022-03-18 8:30 pm

Hi all, looking for some advice on PCB layout, and improvements, it's my first attempt at a 2 layer PCB.
The following is for the IV stage and output for a Denon DCD820 2x PCM56P-L +/-1ma.
After reading the threads I have opted for the OPA861 with the LM6172 as the buffer, as it can deliver a high current if needed.
I've run the simulation in Tina and LTSpice, all looks good. C5/8 & R9/10 are there because the lm6172 requires them in unity gain mode.
I've done a fair amount of research watched quite a few video lectures including Altium and Cadence.
One of the key points was to try and get all the traces on one side and use the other for GND with a clear unbroken signal return path.
I know it may need local voltage regulators depending on where I take the power from, as this CD has a +/- 10V and +/-5V both used on the analogue circuits.
The power rails are 50mils and the signal is 24mil. I'm not happy with the top left as it is not too neet.

Thanks, Tom

MarcelvdG · 2018-04-01 7:10 am

Hi all,

Just for fun I've made a pair of very basic DSD ADCs, that is, sixth-order chaotic sigma-delta modulators that work on the DSD64 or DSD128 sample rate. It tried to construct it out of through-hole components on a double layer board, but some of the capacitors were actually 0805 SMDs because through-hole ceramic class I capacitors in E12 values are hard to get nowadays.

The dynamic range in DSD64 mode is only a mere 80 dB(A) measured with A-weighting and a steep 20 kHz low-pass. That's a consequence of keeping everything as basic as possible: the main feedback DAC is simply a 74AHCT02 gate with a series resistor. I haven't measured the dynamic range in DSD128 mode, but when I just listen to it, the noise appears to drop a few dB when switching to DSD128 mode.

I haven't built the USB interfacing part with the UM245R yet. I use the raw DSD output from U16/P3 (see the attached schematic).

Marcel

Zaphod Beeblebrox · 2022-03-10 12:06 am

I recently acquired a beautiful Panasonic VP-7721A distortion analyser to replace my ageing Sound Technology 1700B. It has had minimal repair work done, as far as I can tell. A poorly implemented PCB fuse re-repair and a new NiCd battery pack and it is as good as new. Literally. Not only are all power supply Voltages within 1% of published specs, but the oscillator meets it's published distortion specs as well. It is a complete delight to use. Very fast and, FWIW, it looks cool too.

Anyway, I was wondering if anyone has modified one of these beasts to elicit superior performance?

I'm happy to leave it alone, but, well, you know....

Rbertalotto · 2022-03-24 7:18 pm

DIY Pensil 10.2 speakers are finished! Quite a project saving the bamboo cabinets that simply didn't want to cooperate! I'll be doing a whole article on my web page soon...www.rvbprecison.com

Wayner · 2016-01-31 2:48 pm

I'm hoping someone can tell me more about a Canadian speaker manufacturer from the 1970s, Patterson Industries. Yesterday I found what appear to be a solid pair of PI 913s in a thift right shop for $30. 8 ohms 5/25. I was just about to take the dive when I decided to wait and try and and gather some info before buying. Anyone familiar? Are there particular characteristics I should be familiar with? Thanks!

Qts · 2022-03-26 4:07 pm

I have couple of Peerless 835016 10" drivers. I consider to make two way with compression driver and horn. What you think?

BasicHIFI1 · 2021-12-23 10:36 am

The mp3 file is made up the following way according to this file:

<a title="Traced by User:Stannered, original by en:User:Kim Meyrick, CC BY 2.5 <https://creativecommons.org/licenses/by/2.5>, via Wikimedia Commons" href="https://commons.wikimedia.org/wiki/File:Mp3filestructure.svg"><img width="512" alt="Mp3filestructure" src="https://upload.wikimedia.org/wikipe...estructure.svg/512px-Mp3filestructure.svg.png"></a>

Opening an mp3 file in a text editor results in the following picture. Is there a way to view the mp3 file data values, I have used Audacity, but maybe as a set of values in a text file.

Cal Weldon · 2004-01-22 1:07 am

I've been razzed on this one.

I understand the strands in the extension cord are coarser, but what's the overall effect and why shouldn't I use them?

They sure are durable, have extra shielding and are 1/4 the price of good 14 ga.

These are not used in my home!

Thanks
Cal

iqpi · 2022-02-19 6:08 am

Hello all,

I have a chance to grab a 38FD for a decent price, well not a 38FD technically but more like an unfinished CL35. What happened was one of the OTs decided to take a vacation and with the scarcity of the output tubes the owner decided to convert into a preamp instead. He had a new custom transformer made by Voller but the project was never completed. I figured there are pre-outs built into the original design so there is no need to even add those, probably just need to complete the power supply for the preamp tube section and tidy up the wiring and it'd be good to go?

Am I right in assuming that's all it'd take or am I wrong? Opinions are much appreciated.

Oh and I'm trying to match this with my Quad IIs. They are current matching with an Audiolabor Pure, although very nice but I thought the 38FD would be a better match.

Cheers,
Aaron

RS232 · 2022-03-22 6:06 pm

As per tittle
Can someone identify this amplifier ?
Is up for sale in the big auction place but it looks very dodgy to me
https://www.ebay.co.uk/itm/194847957537?hash=item2d5dd7e221:g:TssAAOSwh2liD2TO

Hogwild · 2018-03-31 8:49 pm

Hey everyone:

I picked up a couple of these amps used, but in very good condition.
Earlier, I had posted a thread requesting schematics for for the Crestron (ATI-made) CNAMPX-2X60 amps. I finally got the time to take a few pics of the internals, in case anyone is interested.

The first things that I noticed, compared with my ancient Mac 2105: The bass control is drastically better than my old McIntosh. Imaging is much better than the Mac too. The dynamics are much more lively. And the amps are very quiet. At full volume, I hear nothing through the speakers, even if I'm right beside them.

Tekjive · 2022-02-25 3:39 am

Kicker “Redline” 06 ZX750.1

All power supply mosfets literally exploded. Shielding on top inductor compromised, shielding on bottom inductor starting to flake off as well but not nearly as bad so I rewrapped both cores with 14AWG high-temp 200’c magnet wire, similar # of wraps @ 55 each, 30 on 1st layer, 25 on 2nd layer, to get near spec 135mH rating, ended up near 140mH (side note, idle current draw went from .7XXa to 1.1a after inductors rewrapped and reinstalled, I also replaced all power supply mosfets, a gate resistor on PS side and Output side, bi-polar transistors @ Q03, Q05, Q11, and Q103 and rewrapped inductors. Amp powers on out of protect and idles at 12v/1.1a with no output FETs installed.

Power Supply Mosfets
Gate: +4.25v
Drain: +12v & Square wave
Source: ~

Rectifier In
Cathode: square wave
Anode: +59v
Gate: square Wave

Rectifier Out
Cathode: square wave
Anode: -59v
Gate: square wave

High Voltage Regulator
Gate: +19v
Source: ~
Drain: +12v

Low Voltage Regulator
Gate: ~
Source: -19v
Drain: -12v

Hi Output mosfets (No FETs in board)
Gate: +50v
Drain: ~
Source: +59v

Low Side Output Mosfets (No FETs in board)
Gate: -59v
Drain: ~
Source: -59v

Updated values as of 3/18/21 with DMM checking square waves with Oscope. Perfect square waves up to LM361N before a slip on a voltage regulator caused a very audible fizzle somewhere and now squarewaves on lm361n are gone and 10 Ω resistor @ R260 looks to have a hole and measures 17ohm. Both removed and waiting on replacements.

Thank you for any and all help Perry 🖖🏼

levinson mark · 2022-03-25 6:28 pm

Please help me see what's wrong with the simulation of this output circuit in LTSpice?

santacruztv · 2017-10-09 10:04 pm

Hi everyone. I found what looks to be new, in-stock original Kenwood TA-200W IC's for a KR-9600 receiver, but am a little leery about ordering them. Does anyone have experience purchasing these from this company?

TA-200W,IGBT MODULE - CODING INTERNATIONAL CO LTD

Thanks,
Greg

lotsmorebetter · 2022-03-25 5:16 pm

In a 2 stage SE amp, both plate voltages are both coming off of one B+ source as simple split wires going into the two tubes. Given that the plate voltage for V2 is correct and comes directly out of the B+ without any problem; also given: the plate resistors are correct for both tubes and biasing for V2 is correct.
Problem: V1 needs a voltage dropping resistor and I can't seem to adjust for the correct plate voltage even with Ohms law.
Where is my mistake?
Do I also need to adjust the bias of V1?
Do I need another choke between the two tubes to "separate" their voltages?
Please advise.

hornwannabe · 2022-03-22 9:40 am

Hi! Got a DIY 600hz horn with a 2" Compression Driver (Paudio DE99) and JBL2225H 15" Woofer bi amplified and active crossover by minidsp.
Listening distance from the speakers is about 3meters away.

Looking for some crossover recommendations that would improve the "centering" of the vocals to improve the sound, and a more solid midrange.

Tried out different points and crossover slopes but I keep coming back to HP at 1200hz 6db/octave butterworth and LP at 600hz 6db/octave butterworth.

The one octave underlap between the crossovers is deliberate since that seems to sound the best for me and sounds more "live".

I may be exhibiting a bias since Im a fan of 1st order crossovers so any recommendation would help and I can immediately try it out since I have a minidsp.

Attaching pictures of the measurements and the speakers.

Priorities are dynamics and a more solid center vocal image.

Thanks in advance!

coed1992 · 2021-11-16 5:09 pm

hi, good evening I am working with a Stetsom HL 800.4 multi channel amp. which goes on protect mode after 2 minutes even without signal. I Replaced the outputs FETs of same parameters but the problem still the same. There are 4 banks in the output 2 FET each and driven each by IRS2092 , when the chips gets a little hot then it goes protect mode. Are the chips causing it to protect? I double check the FETs and the signal drive on the gates are identical only that there is difference of +or - 2 khz on the frequency readings. Rail to rail is good at +and - 38Vdc. I can't find any faults in the components I believed. Can anyone came to this problem, need help bros.

Simon1972 · 2015-11-17 9:59 pm

There were a lot more Paradise phonostage boards made than Paradise pre-reg boards, so on the basis that there must be people looking for pre-reg board kits I put the idea to start a new group buy for the psu to Benedetto.

The minimum kick off would be ten pairs of boards, any more than that and we'll run the group buy. There's a decent price break at twenty five pairs.

Benedetto is willing to handle sourcing the parts again and we think we'll be looking around Euro 250, for a pair of boards and all the caps, chokes, coil, resistors and sundry parts. No mains transformers, find your own quiet ones.

We'll know more on pricing as we move forward. If you are interested please add you name and how many sets you require. One set equals enough parts to build two channels worth of pre-regboard.

Studley · 2022-03-26 9:16 am

I’ve got an opportunity to buy a pair of 12” W7 cheaply. I’m just wondering if they would be good for a hi fi sub - possibly a Ripole sub. Any comments?

Trdat · 2022-02-21 1:27 pm

I am curious if there is a simple way to convert a crossover schematic to DSP filters? Do I still need to do the whole measurement route?

Basically, how do I figure out where on the FR(DSP) I put the capacitor and what does each electrical component represents. I know the basics that a capacitor rolls off and with a specific crossover type it gives a specific roll off but how do I know what shelf, unity or boostcut is represented on the schematic?

potstip · 2020-09-18 7:15 pm

Hello,

I am tested various emi filter on the market. And decided to design my own with trial and error method and get very good results better than commercial units.

You can find the test results unfiltered ac line vs my design filtered in the attached picture.
With my design, i got better noise figure than any commercial unit i tested and i tested more than 30 unit.
I am not an filter expert i just make lots lots of trial to find a good solution.
But after all these effort none of mine or commercial units not able to filter under 10Khz noise.

I am glad if any one know any solution or any comments.

spedge · 2021-12-12 11:46 am

I can't find the acceptable formats and sizes anymore.
has this changed ?
I used to have to convert to mp4 to upload recordings with restrictions on size.
is this the same or has it been updated ?
Steve.

PRR · 2022-03-25 8:52 pm

Puffin · 2022-03-17 7:27 am

When viewing the new posts page and clcking "more" if you view a post in "more" and click to go back it takes tyou back to the start of the new posts that you have already read and have to scroll down to the bottom and click "more" again and then find the spot you were previously looking at. Very frustrating.

Barrymidd · 2021-02-23 5:39 pm

I have a Yoshiba 50 SET amp and it has pots across the heaters on the output tubes. I am assuming these are hum buckers and my question is how to adjust them? I guess they could also be for cathode biasing, but I don't know enough to be sure.
Do you just turn them up until the valve emits hum and then turn back a bit, or is it more complicated than that?
My first real SET amp so excuse my ignorance.

demetricelectronic · 2022-03-26 2:57 am

Can anyone help with schematics for this amp

Gyulank · 2022-03-06 5:41 pm

My plan is to e.g. there is a balanced microphone and say a phantom power supply and it would be connected with a balanced cable to a standard sound card jack. So e.g. one sign would be on the left, the reverse phase would be on the right. And there would be a program that would reverse one of the phases and perform the subtraction. All this by creating an extra tool that could be selected to be used for recording and streaming.

galyons · 2022-03-26 5:31 am

I want to buy non Chinese Loktal sockets. Planning to build a line stage. I need at least 4, but could use more. Anyone have a stash that will likely to keep sitting idle?

Cheers,
Geary
Northern California

mememachine · 2015-01-15 9:34 am

Hi all,

I recently acquired a Sony SA-WMSP87 amplifier which has a mono input, and am needing a low pass filter as I currently only have a 3.5mm to rca jack as an input (homemade, joined L/R connections of the 3.5mm cable together and connected to 1 rca cable along with the ground). The subwoofer only has a mono rca input, so I'm looking for something cheap to use as a low pass filter to cut out frequencies >90-100Hz. Would something like this diy board suffice? - NE5532 LOW Pass Filter Subwoofer Process Circuit Frequency Volume FOR Amplifer | eBay

Something like this even? http://www.ebay.com.au/itm/100Hz-lo...602?pt=LH_DefaultDomain_0&hash=item1c495a3fb2

If so, how would I safely connect it to the subwoofer over RCA? The source is a HifimeDIY Sabre DAC which puts out well enough power for the sub.

I'm quite new to this stuff so sorry if I'm not being informative enough.

isaacc7 · 2022-02-23 4:27 am

Looking for E3375 tubes. Let me know what you have and the price, thanks!

Ylli · 2019-01-19 7:40 pm

Last post I see about Heathkits is dated in 2014 - time for a new one?

I've recently acquired a Heathkit AR-1500A from my brother. I actually built this thing back in February of 1971, and he has had it since. I've recently started 'collecting', so he dug it out of storage and returned it to me.

Does anyone know the whereabouts of a manual for a Heathkit AR-1500A? Of course I didn't save the one I had from 1971. Can't seem to find anything online.

This thing is *HEAVY*. I fired it up to get the dial lights so I could take a picture. Looks pretty good for a 48 year old receiver. Dusty on the top surfaces but clean on the underside. If I don't say myself, workmanship looks excellent! I'm going to be stripping this down and cleaning it the best I can, and then reassembling, testing, repairing any noted issues, and putting it in my collection.

Is there any interest in me posting more of the 'refresh'? If not I won't waste forum bandwidth.

audioguy8 · 2022-03-20 8:52 pm

I would like to sell a finished dcb1 board and an antek transformer. $100 plus shipping.
The board comes from diyaudio store,
https://diyaudiostore.com/products/mezmerize-b1-buffer?variant=5939090628

hornwannabe · 2018-04-16 3:32 am

Hi guys!

Any ideas on the smallest footprint Horn and Driver combo that can go down to 500 Hz?

Listening room is only 9ft x 9ft (hence I need something compact) so I think I can get away with crossing a compression driver (or fullranger) lower to meet a 12" woofer.

Will be using a minidsp for crossover duties and eq to tame the driver and horn.

I live in Southeast Asia and the only direct couriers we have are in the USA. I dont know if horns.pl or stereo-lab.de can ship affordably to asia. So a US supplier would be ideal.

Thanks

CharlieLaub · 2022-03-25 12:29 pm

I was trying to quote this post:
https://www.diyaudio.com/community/...ive-15-open-baffle-woofer.380714/post-6882266
The poster added several large images to their post. They take up a lot of room and are not necessary, but I would like to have the text. So I selected "reply" and attempted to delete the image links or references from the OP. They do not delete!

How to do that, apart from manually copying the text into a quoted section?

henrylrjr · 2022-03-19 6:43 pm

With the 3.3uF cap in parallel it seems the signal going through it never gets to the tweeter. If so would a low cost cap be as effective as a Mundorf Supreme?

mobyd · 2022-03-10 8:12 pm

Looking for a source of small step up mains transformers. I have suffered a recent infestation of Martin Logan Sequel ii Electrostatics with lunched polarisation transformers. The incumbents are 115+115->460v on about a 6VA core. These don't feature in any of my regular suppliers catalogs so my McGuyver solution is to use a 6VA 230v-> 9+9v to a pair of 3VA 230v->9v backwards with their primaries in series.
Will it fit ? : YES.
Will it work ? : YES.
Is it an elegant solution : NO.
Looking for a better solution that doesn't involve my Chinese winder and a lot of very fine wire.

kathe1mac · 2022-03-25 9:11 pm

Hello

I’m new to this forum but have some diy experience. I’m looking forward to learning and building new projects with the assistance of this forum.

Im excited to be part of the community and looking forward to learning and future projects.

regards,
Kathy

Miguel010192 · 2022-03-20 1:48 am

anyone have the diagram of the db drive platinum pd1200.1 series amplifier to share?

holger honda · 2007-07-30 3:59 am

Hello.
I scored a pair of Peavey 115-cx PA speakers at a yardsale.
Curious as I am I would like to make new Crossovers with new fresh caps and good aircores of my own standard....
the crossovers in the speakers now dont have any markings on caps and coils so I dont know the layout- but I do know it is crossed at 1500hz...Or so the sticker says.
Does anyone here have any information about theese speakers?
Thanks!

Spasticteapot · 2022-03-12 11:21 pm

Is the 50n25pr00 out of production? It's listed as "out of stock" but I can't find it on Tymphany's website.

Frederico Acardi · 2022-03-07 3:00 pm

Hi does a sag in the b+ add noise to the amplifier ?

Adding a sag resistor will add more noise then ?

JMJosse · 2020-05-06 5:57 pm

Hello

I've got a "dead" Audio analog Enigma all in one system and I started to repair it.
The main fuse was dead and the valve (its an hybrid valve/solid state system) was fault on one channel. The fuse and the vavle were repaired and the unit is now working like a charm.
BUT the lcd display is showing some real issues to the point of making it useless.
I've opened the beast and I'm trying to replace it by a new one.
Its' a 16x1 LCD, marked E251530 94V-01. Google gives tons of possibilities and I can't find what could be the good replacement part.
The LCD is soldered on a specific board, but soldering is not an issue for me.

Can you help?

JM

audiosteve · 2022-03-08 6:35 pm

Great quality stereo power amp. Very efficient Class D design using Bang & Olufsen 200ASC amplifier modules rated at 200 watts per channel. Very clean sound, very cool running and very compact size. I'm asking much less than the amp costs to build. BTW,the volume knob on the front does nothing, no pot is attached. This is wired as power amp. There are two modules so each channle has its own power supply. Dual mono. And, if you have a mind to you can wire this up to turn on and off based on the presence of a signal. This amp is wired to turn on and off with the power button. Please let me know if you are interested. $190 + shipping from Colorado. The modules are these: https://www.parts-express.com/ICEpo...ier-with-Power-Supply-Module-1-x-200W-326-208

Attachments

Attachments

Attachments

For Sale Cardas CTFA RCA connector, 6 pairs + 1, $50 shipped

Attachments

Attachments

WTB SLB single rail boards

Attachments

Attachments

Attachments

Attachments

Attachments

Attachments

Attachments

Attachments

Attachments

Attachments