Hi.
Can I give you my story for context.

Equipment :
Project 1 X-pression with carbon arm and Ortofon 2M black.
Cambridge Audio Alva Duo
CR developments Kalypso PP EL84
FHXL / Mark Audio MAOP10

The whole system apart from the turntable is fairly new to me and I'm still getting used to it.

I'd had a 2M Bronze for about 4 or 5 years and had a feeling the stylus might be worn, hence the 2M Black. Records seemed to play ok, but were lacking a bit of sparkle. The top end definitely sounded rolled off.

Anyway, after fitting the 2M Black, I was still underwhelmed with vinyl replay..

Now, my digital source is also new to me and is a wiim pro.
I've been messing with the EQ etc simply because it's there, and found the sound I like has that "smiley face" shape on the sliders, with more emphasis on the top end. The FHXL's are quite bass heavy.

So.....

Can I do better than the Cambridge Audio phono stage?

Is it a weak link?

As always, any advice appreciated.. Further info available upon request lol..

This a new thread originated from the Haudegen thread . The initial design evolved on so many and different ways that a split was necessary to keep the overview what's cooking here 😉

Before we can dig any deeper I need to summarise all the info that is used in HtBs Oread.
Firstly some placeholders will be put in here.
Depending on the spare time - have kids they said, it will be fun they said! - the blanks are filled.

The spec goals:

• MM phono amplifier
• Gain: <xxdb>
• exp. THD <>
• discrete only
• RIAA implemented in negative feedback
• RIAA tolerance <xx%>
• economic friendly (no OOP parts included)
• proper PSU design
• more TBD!

Some general thoughts:

Any help and suggestions are more than welcome to achieve a proper enjoyable circuit for everyone.
Depending on the interest a group buy for PCBs could be initiated - but firstly we need to check the schematics/datasheets/simulation and do a nice test build with real world measurements.
I guess till end of this year we do some brain work and after the dust of xmas-warfare cleared up
we can freshly heat up our soldering irons and have some fun in the analogue world.

Hi! My name is Bartłomiej and I come from Poland in Europe.
I started here when I decided that I want have amazing speakers without that price tag that's so commonly found on them. I started by looking on open baffles, but then moved towards semi-closed designs. Right now it seems I aim to build the Anthologies II by Jim Holtz and Curt Campbell - I will most definitely have some very noob questions on them 😉 Aiming to get a lot of the design made by a CnC router so I will have to learn CAD as well.

Best regards, I look forward to speaking with you 🙂

Hi all, I'm attempting a repair of an Ayon Spark Delta. It ran for several hours without load connected and has since developed a 100Hz humm/rattle in the left channel. It's faint but noticeable and it shows up on the scope as spikes at a 100Hz interval. Besides running with no load, it also had 12AX7's instead of 12AU7's in the preamp section, causing oscillations among other unwanted audible issues (e.g. increased noise floor)

It's not an overly complex amp for the most part, but it does have some proprietary electronics for auto-bias, startup sequence, etc. It's not immediately clear what's causing the 100 Hz spikes. Power supplies are shared between channels and the right channel is clean, so... Without a schematic, it's rather hard to get my head around. Mainly because it's a 52kg beast, it takes very little to upset the auto-bias and auto-shutdown and it's a mystery to me what topology Ayon used in this amp (besides it being single ended in the output (paralleled 6C33 triodes).

All B+ and heater voltages measure fine and clean.
Switching out the tubes changes nothing.
Tested the preamp tubes to be sure on a tube tester and they check out fine.
Amp is able to auto-bias the output tubes, but in the defective channel, one 6C33 gets set to a much lower grid voltage. Also after bias settings are renewed.

Before continuing, I wondered if there's anyone out there with more info, schematics or experience? Not an amp we see everyday, so might be an interesting ride.

Hey guys,

I'm looking for some simple mid range horn plans that can be made from wood that cover about 400Hz to 4kHz. I'm curious what the DIY community here knows of and can put on my radar. Any fun ideas?

Thanks!

All work no issues just sit around going unused--- Pick up 44405 $30 each so $300 for all 10


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Been doing some poking around and measuring in my Parasound A21. Reason for this is higher odd order HD at lower load impedance (4 ohms). Mind you this amp already has low THD but odd order HD dominates. Its a fabulous sounding amp but it has some difficulty retaining its composure at high current demand peaks.

I traced much of the "problem" to the dirty vreg solution of a simple 1.5k 5W resistor feeding 15V zeners to drop 65V (!!!). Along with producing tons of heat (running at 250 degrees F !), it allows alot of garbage to modulate down into the VAS and introduce distortion. I injected external clean +/- 15V into the first input stage and it made a huge difference in sound.

Any suggestions of a better approach to regulating the +/- 15V ie. mosfet series reg or is it smarter to run separate standalone supplies instead?

Even a simple 317/337 series vreg would be way better than the dirty garbage zener approach, but there aren't any 3 terminal regs I'm aware of capable of surviving the initial B+ difference at turn on. I would like to do something like separate op amp corrected series regs for both channels.

Any suggestions?

I came across this circuit and I was wondering about its benefits, and how it could be integrated into a headphone amplifier.

But before we start, I want to clarify one thing: is a standard 4-pin cartridge a differential output device? I suppose the answer is "it depends on how you connect it". In a 3-pin dynamic microphone, you certainly have an explicit GND pin since the moving coil is center-tapped, so it provides two 180 degrees out of phase signals. But in a voice coil with two pins, such as your standard phono cart, the signals are balanced depending on how you wire it?

In the case of the circuit I posted, I understand the input is referenced to GND via R7/R8. Normally, one end would be tied to GND and the other end would be treated as a single-ended input. In the posted configuration, the differential signals are referenced to GND via the R7/R8 resistors. I suppose those resistors have to be precisely matched to avoid distortion, but if they are, the common-mode noise will be rejected better.

First question is: does this configuration provide better rejection against common mode, in comparison with the usual single-ended configuration?

Then we have the gain stage. A headphone amp chip such as the TPA6112A2 has differential inputs, and it would be straightforward to just feed this preamp, with its differential outputs, into the gain stage. This should provide a very clean signal path and lots of headroom.

so the second question is: is this assumption correct?

Finally, IMO, any preamp really needs some sort of tone control. I understand some people will prefer a "flat response" but this is an argument I don't want to go into. I'd like to have some sort of tone control. But I'm confused as for how to implement such a thing

I haven't found any differential tone control circuits. I wonder if it's even possible to implement such a thing or if i'd basically just need two controls, one for each leg of the differential path. Which i think would be a disaster. It would be impossible (or very expensive) to eq both signals exactly the same.

So the practical way to do this would be to have a single-ended opamp, which will basically render the initial circuit (balanced output) moot. Might as well just use a single-ended output opamp and keep the differential input, and everything else single-ended

final question: is there a practical way to implement a balanced (differential) tone control?

Make offer on both in this thread if interested.
1 KIT is sealed and 1 KIT is opened and missing a row of caps.

The description below seems to be similar or the same.


S-0402
Johanson Dielectrics Inc.
CAP KIT CER 1PF-0.22UF 1400PCS[/td][td]

Ceramic Capacitor Kit 1pF ~ 0.22µF 6.3 ~ 50V Surface Mount, MLCC 1400 Pieces (28 Values - 50 Each)

Hi all
In last two years I have been simulating an amplifier that I believe to be a High End equipment but I need to stop to do this in my life. So, I decided to donate my idea to DIYAUDIO community.
Any of you who find it interesting I hope you have fun.
And yes, the output of this amplifier is from the Gamut amplifier, already presented here in previous years, with some modifications made by me. As the days go by, I can respond to those who ask why each component.
I still need to design in Kicad the low noise power supplies and capacitance multipliers of this power amplifier and show here.

Regards,
Edvaldo

Hello.
My love , the Mccormack DNA-1 Power amp is bit sick..

Its drops voltage that make the speakers kind of push out when its power
on. also got extreamly hot. ( very hot.. couldnt touch).

My tecnician told me the problem in the input circuit board.
(in fact, 2 tecnicians said same..)
also got the scematics, i was told the parts in it are very hard to find and
better try get new board like this.

Steve Mccormack was amazing kind and help me, also directed me to conrad jhonson.

Conrad johnson (new owner of Mccormack) had similar board that can fit
but "sorry, out of stock.. no more :-( " .
its calld " R1 circuit board".

As im in love with that amp.. am not going to give up...
Does any body have idea of where can i get board like this ??
Any ideas ??

Thanks...
Efi

Just a noob from Germany ready to learn because of recent problems with my speakers.

My Adam A77X stopped working recently.

Both speakers are having the same issue.

They create a popping noise like a metronome. Audio ist still Pasing through them though.



I have a friend who could repair them but he told me he is helpless without schematics.



Could anyone provide schematics for this speaker? Would be highly appreciated
.



Thank you

Just got the the WONDOM ADAU1701 APM2 without the extension board so I could basically use it as a pre-amp. But I'm unfortunately unable to find a wiring diagram to connect the APM2 in a 2.1 setup without the extension board, would anybody be able to help?

Thanks!

Hi everyone,

I’d love to hear your opinions and insights about how new transistors affect the sound in vintage amplifiers. I know this is a complex topic, but after years of repairing and refurbishing old amps, and performing numerous tests, I’ve come to believe that transistors have their own sound signatures. This is especially true for transistors in the early stages of the VAS (Voltage Amplification Stage). However, there are times when I notice no difference at all. This inconsistency has been driving me a bit mad, so I wanted to share my observations and get your thoughts.

Here are a few examples from my experience:

1. Tone Control / Preamp Section:
   When I replace transistors in this part of the circuit, if I use KSC1845, the sound becomes overly bright, and the lower mids (especially vocals) seem to recede into the background. This is something I’ve noticed with most KSC-series transistors. On the other hand, when I use BC-series transistors, the sound is much more balanced, with everything sitting naturally in the soundstage.
2. VAS Stage (After the Differential Pair):
   Here’s where things get interesting. If I replace transistors in the first stage of the VAS, the effect is reversed: KSC transistors sound perfect, while BC-series transistors seem slightly off.
3. Differential Pair (Long-Tail Pair):
   When I create a matched pair of KSC transistors for the differential stage, I don’t notice any tonal difference. The sound does become cleaner and more detailed, but the tonal characteristics remain unchanged.
4. Preamp Circuit with Adjustable Voltage/Current:
   I built a preamp circuit where I could adjust the operating voltage and current to use the transistors in their most linear region. Even in this setup, the differences in sound signature persisted: KSC transistors sounded bright and less harmonic, while BC transistors were much more pleasant and musical.
5. Driver Transistors:
   The differences are even more noticeable when using these transistors as drivers for the final stage.
6. NOS NEC Transistors:
   I’ve also tested a batch of NOS (New Old Stock) NEC transistors. Most of them sounded terrible—cheap and uninspiring, with the exception of some power transistors, which were passable.
7. Output Transistors (Final Stage):
   For output transistors, I don’t notice as much of a tonal difference, but I do have a personal preference for Toshiba 2SC5200 and 2SA1943. These seem to deliver a more harmonic sound and often provide a better soundstage in many amplifiers.

My Questions for You:​

• Have you noticed similar sound differences between different transistor types?
• Do all transistors have specific sound characteristics? If so, what causes this?
• How do you choose the best transistor for a given application?
• In your experience, what are the best-sounding transistors for audio circuits?

I’d really appreciate your feedback and experiences. This topic has fascinated me for years, and I’m curious to know if others have noticed the same patterns or if my observations are more specific to certain circuit designs.

Looking forward to your thoughts!

I am trying to make a dynalo headphone amplifier, but the quiescent current of each output transistor is kinda small (around 4mA), if I change the emitter side resistors from 20ohm to smaller value like 1ohm, quiescent current rises, but the waveform shows some problem. SO what should I change in order to increase the quiescent current?

For sale ONE UNIT Accuton C79-6 (later called C90-6-079).
Although you can see 2 units, and 2 units will be shipped, one of them has been repaired and not in perfect working condition.
There is ONE unit in perfect working and good aesthetic condition if anybody needs a replacement.
asking 100€ + shipping

I have for sale a stereo set of this beautifull small amp, the LM1875 transamp. Fully build, and tested. Worrking perfectly. I have to many amps so this must to found a new home.
For free also 2 bare boards.

I am looking for 30eur + shipping, payment paypall.

Hello!
Is this power supply good for Aikido 6SN7 operating in 300v B+?

The rectifier tube would be 2 x 5R4 or 274B rather than 1 x 5AR4.

10H choke would be used

BTW, 2 x this power supply, one for each channel.

Any feedbacks??

I’m looking for some small single-cabinet options that will go a bit louder than a PM90, playing down to 80-100hz to meet a handful of TH18.

I’ve seen some people discussing coax HF (eg bms4090) and that seems great for a diy synergy/MEH, maybe with 4x LF.

Before I get too ahead of myself, are there any existing similar threads, or has anybody tried this? I’ve tried search with no luck.

Hi,



I am new to this forum and ended up here in my search for a solution for my broken DIY amplifier. The amplifier consists of two SymAsym 5.3 modules, see attached circuit. It is basically the original SymAsym design with added speaker protection and 2x 4700 uF smoothing capacitors.

Both modules functioned well for about six months. The left module then started showing problems. In the beginning I heard cracking noises and occasionally a loud pop. If I turned up the bass or volume further, the crackling went away. Some time ago the module went silent.

To investigate the problem I wanted to try out my oscilloscope with function generator, so I connected the left module to a 100W 6R. Unfortunately, R2 burned out when I placed a 1kHz sine signal on the amplifier input. I replaced R2 but it burned out again, even at low sine amplitude. So probably another component must be defective. I have desoldered all the transistors and measured them with a multimeter (diode test) and they all seem OK.

Because I have little experience with electronics, I would like to ask for your advice here. Could it be that a transistor is defective even though the diode test is successful? Or could it be other components that are causing problems?



Kind regards,



Jonas

I have a chance to listen to the vintage American speakers: ADS L980/2. I’m literally impressed them so much especially the midrange sound. They utilize two-inch dome for the midranges. I as a DIY person have a plan if I’m going to use the two-inch domes in my new projects. However, as I listened to them carefully, I found they had unique sound. Well, I have been searching for more info about this driver and I could find some info.

Material: woven soft-dome with proprietary damping
Voice coil: 50mm., wet wound, single layer
Magnet: 1.38 Tesla, 1.1 X 10^-3 Weber
Re: 6 Ohms

From provided info, has anyone ever found any modern drivers that have close specifications to them? Or, in the worst case, no longer find the units with those specifications, could it be possible to special order to nowadays driver manufacturer to make it? Is the data provided sufficient?

I have a Ka-1 amp that's new to me. Just testing with a poor speaker, I hear both channels sound different. One also warms up politely, while the other is cold. I can swap the L&R pre to main audio cables, and the sound difference follows them. So I believe the issue is within the preamp section. I need to test again to see if the other channel then warms. I presume so, but am testing for that, now I'm aware of the temperature discrepancy.

Lets have a look


I'm impressed I can post so many pics in one go. Though some have spun around, disorienting even me, and I have the thing in front of me. I hope it's not too much hard work for people.

The final image, I posted larger, is my initial thoughts. Firstly, I seem to have too many relays. I feel the Red one is outstanding, and might route everything through it, even after individual switching. It seems odd, but wishful thinking suggests an easy target. I have a phono amp in yellow. I wouldn't be surprised if the pink amp was part of it, or the two green 'Dished' caps. The green amp a buffer for the tape loop. The black one, the only one common to the couple of different inputs I have connected my CD player to, and seen the same fault. So have I narrowed it down to a very small area.. maybe. It has two dished caps I guess are on power, but shared by both channels. Then two more on the output side of things, I could swap over.
I have metered the preout, and it looked.. like I need to finally buy a scope. I see 35khz on both channels. No AC. DC of 2v and dropping. In about 30 seconds, they were down to a volt. One about 0.2v higher and I did a cold start a few times looking at this.
I guess I could now bypass the preamp completely, and inject my cd player straight into the power amp. Or bring the preamp signal out, to another amp. I have noted the main amp sits in protect if the preamp isn't connected to it. So this DC means something. I don't know. I have only an inquisitive mind. No training.

I have fancied a scope for years. Maybe 50. I have no funds or space for a desktop item, but see Ali has things from £20 now. Some are a basic multimeter at a glance, but are doing something. Has anyone messed about with these. I don't need 27mhz anymore. Just something to look at audio waves comparatively. Will anything do really? I would like to eye up a CD player I guess, but this item will live forever in it's box, and maybe never meet a real signal generator. I don't imagine I need much?

I found these but i am not sure if i like the design:

https://www.soundimports.eu/en/091-340.html

Hello
I'm a first time DIY user
We look forward to your continued support.

Hello everyone,
Does anybody know where can I buy these speaker terminals for JBL GTO1004?

Simple question:

Can a passive radiator incorporated into a subwoofer enclosure increase efficiency? Or is adding dynamic mass to the system, rather than just moving air, a reduction in efficiency but perhaps beneficial for directionality?

Is an "omnidirectional" passive enclosure -- for example, a 12" subwoofer mounted in a front baffle and housed in a framed "sealed" cubic enclosure with a compliant skin of some sort, e.g. latex or something with a relatively low modulus of elasticity, stretched taut across the five other sides worth experimenting with?

Hello to all.
I can repair most of the SD amps, including the large 35K, and i can flash the micro to the latest software version.
In some cases i might be able to buy parts for technicians, but please, do not ask me about part numbers.
Due to legal agreements i am unable to disclose any such info.

Selling my unused/open box Van Alstine ABX switch comparator.
I meant to use it, but I got locked-up in Federal Prison for avoiding to feed my goldfish.
Lol.
7 day auction.

https://www.ebay.com/itm/1969509791...FefAZ2YQ4u&var=&widget_ver=artemis&media=COPY

I'm looking for info on which jumpers enable btl on the tda7498 amp board (j1,J2,J3,J4). Also, how should the inputs and outputs be configured? My plan is to use it for a sub. Thanks!

Long time since I posted but I am seeking opinions on speaker kits . Haven't built a kit in about 20 years but had good luck when I last did it ( gr research towers going strong)
I have a large room 18ft wide by 38 ft long with high sloped ceiling( 22ft to peak) in front half where the speakers will be placed. Room has alot of hard surfaces.
Trying to decide between Neil Blanchard transmission line Towers, Troel Gravensen fatal 10 or 12-430, sb acoustics gema, or finally the css audio 2tdx or 3tdx tower kits.
From an aethetics perspective I gravitate to the classic box speaker shapes ( TG speakers, Gema) or the Neil Blanchard design.
Will be feeding with a yamaha as2100 or classe audio ca-150 ( need a new preamp for the classe)

I listen to blues, classic rock , jazz at low to moderate levels.

Neil Blanchard designs most cost effective and get good reviews . Wondering if anyone heard any of these speakers in person and might pass along their opinion.

Looking for a power amp upgrade - currently using the Toshiba 2SA1943 / 2SC5200 what's new and available that would be an easy upgrade for those parts.
I have looked at the Sanken 2SA1216 / 2SC2922 and Sanken 2SC3858 and 2SA1494 but they don't seem that available from trusted sources.
Any other recommendations that could more or less drop in and are available?

I’m out of my depth on this question, and I’m willing to learn, but I would like to assess feasibility prior to spending more time on this.

I have a Geshelli Dayzee DAC w/ 2x AK4499EX in dual mono configuration. I was corresponding with Geno from Geshelli about the PCM filter in use - in this case minimum phase sharp roll-off (number 3 of the 6 filters built into the chip). I asked whether this could be changed (I strongly prefer linear phase), and he said it would involve accessing the I2C bus, which could damage the chip if done improperly, so it would void the warranty. This started me down the rabbit hole of looking into how to access the I2C bus to modify a chip’s register, and that search kept leading me to this forum, so I made an account. This also got me thinking about other possibilities like the E70V DAC from Topping, which I’m told does not have DSD Direct enabled, and I think owners might appreciate a method to change this.

My questions:

Is it generally possible to modify the register of a chip on a commercially purchased DAC?

If yes, is special hardware required?

Any feedback is appreciated! Thanks!

As titled, for sale are these 8 inch, 8 ohm Nomex cone Peerless woofers in excellent shape. $30 each or $100 for all four, plus shipping from Madison, WI. I used them for several years in my bass bins, but I found a better driver for the sealed configuration. These probably perform best in a vented enclosure. They were never driven hard, and I believe they are in perfect condition except for some slightly dusty cones and a bit of solder on the terminals. They were manufactured with a spare pair of clean terminals on each driver if you want to use clips. I soldered (and desoldered) them with a heatsink attached to the leads, so the voice coils have never seen much heat. I have really nice boxes for each one, and a big box that perfectly holds all four, but I am willing to split them up. Will accept Paypal.

NEW LOWER PRICE! FS my complete kit to build your Raspberry based Volumio music server. It has two Raspberry processor, Version 1.2 and 1.1, one enclosure, multiple sim cards for firmware, Hifi key adapter, one IR remote, two DigiPI Digital Inputs PCB cards, all the DC adapter and even a nice HDMI Display. You can build a very nice music server with all this hardwareé Moving, kit has to go. No Docs, but there is a ton on the nets, and thread on this forum dedicated to Volumio.

Asking 100U$ (or best offer) for all + shipping + 3.5% Paypal fee

SB

FS, Four (4) 120,000uF/63V KMH Nippon Chemicon Caps (NEW). Never installed, with bracket. They are so huge they accumulate charges sitting on the shelve...

They are quite large and weights 1.1Kg each, so shipping cost will be to consider.

These Kind of large caps are almost impossible to order in small quantity these days. Thes caps are new, probably some of the best supply KMH series cap you can get.

Two will make a Keller amp power supply.

Asking 60U$ for a pair + shipping + 3.5% Paypal fee,

Or 100U$ for the 4 of them!

Let me know
Thanks
SB

Greetings! I'm here to participate in a few threads about Full Range and Dual Concentric drivers I've been using for nearly 15 years in my analog systems. My current setup based on big Tannoy System '15 DMT mk2 and you can easily scroll down my instagram for images of this setup and audiophile related stuff. As for the old system based on heavily upgraded Zu Audio Druid full range speakers you can check my gallery here and there.

Few years ago I build a custom made analog system for a new wine bar in Tel Aviv (Israel) using the latest '15 inch full range Audio Nirvana drivers in a 273 litters cabinet of my own design. Now I'm happy to learn more about DIY, so this is why I am here.

Thanks

Hello everyone. I'm from Holland and just looking for some information and hoping to find it here

Day to day I sit in front of the computer for work a lot and I really missed working with my hands. So I started my DIY journey last year to clear my head a bit. I've lurked on this forum for a while and decided just going in and doing things would probably give me most joy. Since then I've attempted designing and prototyping 3 speakers, listened to them and learned lots along the way. All tapered TL kinds of designs using Markaudio drivers. I am a kind of guy that needs to just get their hands dirty to learn, so I didn't follow a predesigned build and just hoped for the best.

Lately I've finished 2 'decent' builds, both from high density MOSO bamboo. One smaller one using the Alpair 7MS and a bigger one using the CHR120. Loved the sound, nothing near the best I've ever heard, but very enjoyable (and loved doing it in the process). I tried designing something in which the line could double as bracing and the vent at the back in the same axis as the driver, mostly to try something new and because I somehow thought that would better merge backwave and the driver (not science based whatsoever). I'll add a few pictures below, love to hear what you guys think (especially constructive critique!). My rig in this room is completely lucky second hand deals I got locally in the Netherlands. The speakers I build will eventually end up at friends/family as I live in an appartment with a very small shed.

My next project will be to design and build a 2 way WAW using an active DSP controlled crossover. Thinking about combining the MAOP-5 and the SB23MFCL45-4 in relatively compact 30L-esk box. But at the moment that's still mostly an idea, still have to dive into the possibilities.

Love being here and reading all of the expertise that's present. Good to see these kinds of strong communities are out here and I am very happy to join!

Just a question about the Pro 9028 OSF filter. The OSF can be switched off with SW2:2, in which case you need to supply your own OSF. I'm using HQPlayer to oversample everything to DSD512 using HQPlayer's own filters, so I guess I can shut off the DAC's internal OSF and just go with the HQPlayer filter.

However, the ES9028 datasheet states that the "FIR filter is bypassed" when playing DSD...does that mean the DAC is already automatically disabling its OSF whenever DSD is played? If so there would be no need to switch off the DAC's OSF manually.

A clarification on this would be greatly appreciated!

I have a multiway project that suffers in the midrange sensitivity area because of my driver selection, the Dayton RS100P, at around 86dB. In dealing with this the MTM config seems appropriate but I understand it has its flaws. In minimizing CTC I have played around with a few scenarios using an offset tweeter. The first (left) is spaced using unmodified baskets. The subsequent two are increasing degrees of butchery to the baskets in order to pack them in; tweeter offset increasing as a result.

Is this worth doing, are they all good, all bad? I don't mind trying it out but it would be nice to get as close to mark as possible. BTW, the system is active with 3k Hz and 180Hz crossover points.

Anyone has tried this? Any feedback?

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Hello, i joined the forum for some help repairing a guitar amplifier and it is a very simple one so i want to use these forums to build some repair skills for more complicated jobs.

I recently discovered this thread by Steven where he mentions his goal to design an open baffle full range speaker that’s omnidirectional and has a good low end bass. https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1704665765/17

Decware has listed this design as ZROB: https://www.decwareproducts.com/zrob I like the fact that room placement matters less in this design. But I’m not sure if it produces enough bass. Seems easy enough to try and I’m going to build a prototype in a few weeks once my Lii song silver 10 drivers arrive.

Does anyone have opinions on this design?

Hello all,

I am ordering caps to recap a 5800 and figure I might as well “upgrade” them a bit in the process since it doesn’t cost much as long as one isn’t trying to go boutique.

Is there a minimum ripple current rating I should be looking for with the four 4700uf caps?

There is plenty of chatter on the web that the Nichicon KG gold tune caps are good for power supply use, but their rc is rated at 1.7a on the 25v versions. Is this enough? I ask because I can find caps with nearly twice that.

Thanks

Hey guys this is my first post to the forum. I need help with community.

I have bought Sansui S65 speakers, (these are 4 way speaker with 12inch woofer and 1 mid and 2 tweeters) from garage sale, they are sounding really great and the drivers are in good condition but the issue was that the mdf was in bad condition. I mean the wood vinyl wrap was torn up and the actual body was damaged too die to moisture from long time.

But still sounded good.

Now call it my foolishness or i dont know what to call my self, to 1 speaker (right) which was damaged i have added 3mm mdf sheet over the original body so it dont get damaged and i dont have to make new speaker cabinet.

Now when i did test the speaker i feel like vocals are same in both but bass response from this (right speaker) is sounding Low compared to the left speaker. Now i had not done this test in past to compare bass in both speakers so dont know if this was issue or i have created an issue by adding layer of 3mm mdf sheet.

Now my question is, is it possible that bass get reduced with thickness of mdf? I feel like the left speaker has more deep base while the right one now has not so deep, not sure how to describe it.

Or this one was an original issue that i didn’t checked and its an issue with capacitors?

Even now i want to see if this was a extra panel effect or not either i have to remove the mdf sheet, which will be a huge task or add mdf sheet to the other speaker crossing finger that it will have no effect over bass response and i have to change capacitor or any other thing to left speaker.

What do you think guys please help…

Just here to say Hi 🙂

Hi everyone,
I'm reading here for years and years and finally registered. I sometimes build fun synths, EQs, effects etc, but I'm no professional 😀
I'm also into PA and DJing, that's what I do mainly in my free time. So this forum is heaven for me 🙂
Cheers
Jo

I came here to ask about DSP programming to make a digital crossover.

Hi greeting from Europe/The Netherlands!
I'm looking forward to working in this group!

Hello everybody, I'm in my fourties, my hobbies are electronics and I'm interested in building as well as repairing stuff. Long time ago I built simple amplifier from kit and more recently fixed my amplifier so my knowledge in audio electronics are very limited. I decided to join this forum as here seem to be very helpful and knowledgeable people. Looking forward to join the discussions.

Hi new member from Geneva Switzerland here. I play the guitar and I like to build / repair my suff to learn how it works. I already built a 5E3 clone from a kit and a couple of pedals. Far from being an expert I'm mostly trying to have fun and learn.

Is a typical woofer's power handling limit mechanical or thermal?
If the limit is thermal would a heatsink help? (Particularly in ported enclosures).

Hi all,

I’m entirely new to speaker builds, but I am keen to try it out.

I snagged a well working pair of Tangent Acoustics TM1 ported two-way speakers a few years back for next to nothing (300 Swedish crowns (like $27USD)).

The cabinets are not in the best cosmetic shape and I’ve been thinking about building a new set with the drivers from these, and possibly the cross-overs as well if possible/recommended.

The drivers are:

• tweeter - KEF T27-SP1032
• woofer - KEF B200-SP1014

So they are more than decent and capable but for my personal taste I’d like a smaller pair of speakers with a bit tighter bass response than now.

Where should I begin?!

DIY regulator boards, built with quality components - Positive and negative.

Asking € 40,00

Dear All,

I have a Pignose 7-100 guitar amp that has been out of operation for many years. In the past I had never really investigated the problem and just bought larger amps (not portable). Recently retired, I have more time on my hands to try and fix this thing. At this point I want to take the time to try to fix it and learn something new rather than just toss it.

I noticed corrosion in several battery terminals. I discarded the batteries and also saw one of the connectors was decrepit/cracked (from corrosion). Inspired by another post , I removed the old battery casing, snipped the red and black wires, and soldered in a new 9V battery connector and battery. The amp works but is weak and staticky. Previously i never had the power adaptor. So i bought one and tried that, and it is much louder like its supposed to be, a little noisy but I think that may be just a dirty POT.

With the power adaptor, I measured the voltage across the input and it was 9V as its supposed to be. Then with the adaptor disconnected and 9V battery in, i measured the voltage across the connecting wires (both at the solder points, as well as on the empty power cable input). It was ~9V when the guitar jack was not plugged in, but only 4-5V with the jack plugged in.

Could this be something on the board that recognizes when the jack is in and on battery (not adaptor) power? Or could it merely be the red wire from the battery side over to the other side (the red wire itself looks dark, not copper or silver like the others, but i don't know what its supposed to look like). I did notice that the conductance was the same for that wire and the black one.

If it is on the board, what component am I looking to test? I can't see anything obviously broken or burned out.

Thanks in advance for your help

Onyaw

My OCD compelled me to save these speakers from a dumpster. I've tidied them up and had a listen. I can't find anything wrong with them. The low bass is possibly amongst the best I've heard from 5" drivers. The top is crisp without being harsh. The mids are typical for a 2-way bookshelf system.
Alas, I have a ton of speakers with better badges. These are going back to the dumpster.

I joined to share my experience with 3 way active open baffle speakers I put together. The DSP Amp is from http://acoustas.com

i started my DIY audio adventure about a year ago when i received 2 subs and an off-market amp from a friend, having no clue what i was doing i was somehow able to YouTube my way through the whole install process without blowing anything up. everything was going great for a few months, besides a few minor setbacks of a loose ground wire, accidentally reverse wireing my subs etc. until about October when my Chinese knockoff amp decided to completely flatline and die. deciding i should probably get more acquainted with my audio knowledge before i dive back into fixing things ive joined this amazing page seeking golden nuggets of truth! thats my audio intro!

I would like to get the opinions of experienced builders on how they assemble and wire-up their passive crossover networks.

For instance, do you mount the components onto a board, or attach them directly to the cabinet wall? How do you attach the boards to the cabinet? Do you use mechanical disconnects in the wiring, or is everything soldered?

Do you run separate wires from the input terminals to the high-pass and low pass sections, or do you daisy chain the hot and ground wiring?

How do you test and validate your crossovers before installing them in the finished cabinet?

Thanks!



j.

I'm sure there are threads out there discussing this but I wouldn't know what to search for?

If I wanted to build a tube amp without output transformer, what tubes would be a good choice?
Lets aim for 20w or something along those lines?

I like the thought of a single ended amp so I guess that would be on my wishlist as well. But I don't know enough about designing amplifiers to really kno what I'm talking about.

I just want a place to start my reading.
So, a recomendation on suitable tubes and perhaps a topology. That'll keep me busy for a while. 😉

The idea for this project came from two separate project plans:

a) I've wanted to build battery powered, bluetooth speaker for small gatherings (less then 20 people),
b) I wanted to build my first MEH (multy entry horn).

So I almost started with two separate projects, but then I said to my self: "Hmmm, is it possible to combine both things into one project => to build relatively small, portable , battery powered MEH, so I could kill two flies with one blow?"🙂

And then, after couple of months of reading MEH threads on this forum (and outside forum), I've narrowed down my design requirements:

1.) Weight=>when completed, the whole box should be easily grabbed & lifted with one hand,
2.) Size =>the box should be around 350 x 350 x 350mm (so around 45L gross volume),
2.) Sound output =>105db/1m will be sufficient, of course the more headroom the better, but in this particular case I would rather sacrifice output for sound quality,
3.) Frequency range => from 50Hz to 20kHz,
4.) Horn type => design should be based on off-the-shelf plastic horn, with added two woofers on the side and one full range on throat flange.
5.) Lower cut-off frequency => 500 Hz should be sufficient, as it dictates portability,
6.) Loudspeaker drivers selection => initial testing will be done with my existing drivers (two 6.5" woofers & one 2" full range driver).
If the initial concept will be promising, then I will invest into new (better) drivers.
7.) Box material => most probably I will use light 10mm plywood.
8.) Amplification & DSP=> the plan is to use plate amp with DSP , but that can run on batteries (something like "Arylic Up2Stream Plate Amp 2.1").
9.) Batteries & charger => to keep things light, I plan to use Li-Ion batteries, with dedicated battery charger.

When you search MEH threads on this forum, there are plenty interesting projects, and lot of them have similar features as my project, but I couldn't find any specifically built portable MEHs.

The first thing that I wanted to define was which CD horn to choose => so I browsed through catalogues of various manufacturers and in the end I chose "SB Acoustics" H280horn:

https://www.sbaudience.com/index.php/products/horns/horn-h280/

Few reasons:
a) It has 500Hz lower cut-of frequency,
b) The size of the horn is about maximum possible to fit in desired box,
c) It has nice, large, flat areas, for mounting two woofers,
d) The distance between horn mouth and horn throat , and horn cross section allows mounting of two 8" woofers.

The ESS AMT-1 is a beast of a high frequency transducer, being able to sound great crossed as low as 800hz. I'm sure members have taken advantage of this, and the super high sensitivity as well. I'd love to know which woofers you chose to use with the AMT-1.
I would also appreciate opinions on this mid woofer, for use with an AMT-1.
Celestion CF0820BMB - 8" Low frequency
And now, a buddy just asked me why I would not choose a 12" or a 15" for better dynamics, since it is only playing up to 800hz.
Thanks for any advice.

I know that very low q drivers 0.2-0.3 have a higher group delay in a box the same or above vas. What you can do about that?
Using a smaller box?
Subwoofers with qts of 0.4-.0.45 have the group delay exactly at the "sq" limit 20ms at 30hz where the low q subs goes much more above that.
But a low q subwoofer is better for ported and should sound better. I don't get it.

Thank you

I conceived of this preamp in an effort to have an all tube audio system, which sounds amazing and (equally important)
That I can fix myself using available parts.
Early on I had collected several tube power amps, but the only tube phono stage I had was in a bogen integrated amplifier. It sounded OK, but I knew I needed to be moving towards separates, so that I could put preamplification in front of whatever power amplifiers I manage to collect. Mostly console pulls, organ pulls and that sort of cast off trash. First off I built a line stage preamp, which i really liked, but which didn't actually provide any useful function because all of my music is on the black plastic, still no phonostage....
The line stage got put on a shelf while I continued to use integrated amps, which by this point I was getting rather good at recapping. Then I got a real brain strain across my bench, a Scott 299d with uneven channel balance from the phono section. I changed virtually every component in the stage despite them all testing OK, and still had the same low volume. I looked and looked at the low volume channel and never found the issue, which turned out to be in the higher output channel, specifically the feedback PEC had gone open.
In my frustration I decided to draw a schematic of just the phono stage, with the PEC broken down into individual discreet components.
Soon after hearing this in action, the plan began brewing in my head.
Put the HH Scott feedback phonostage in front of the sRPP line stage I already built. Then I'd have a good, all tube phono preamp and line stage, which I can fix myself and which will drive whatever power amplifiers I build or find...
So I went ahead and built one, which looked OK but soon after became the sloppy copy...
My friend Alan decided that he wanted one just like it, then his friend Roger too, next Anton wanted one, then we decided that Jeremy needed one. Then Anton wanted one for his son, and so on...
Eventually I decided that I was going to build myself another one, and did a much nicer job on one for my personal system.
I gave my original to a friend when he bought a custom ST35 from me.
Here is where the project stands, I've got about 10 of them out there in the world, none of them ever break, the guys that own em, use em, and I've got what I wanted, which is a good sounding, all tube system that I can crank up, buy never blow up, and if I do ever blow it up, I have the parts and can fix it myself.

What do you think of that?
It's got 5 inputs, mm, mc, 3 line level inputs.
Relays to select them, which short unused inputs to ground through a 47k resistor for 0 bleed through.
All tube signal chain using 12ax7, and 12au7 tubes.
(If you have anything negative to parrot about the 12au7 not being linear, go start your own thread about it)
It sounds amazing, everything I put through it sounds right. If something sounds bad it's usually due to a poor recording but that is maybe 3% of the material... It's just good. If it wasn't good I would not have sold ten of em.

Hi,

I do have a UR242 and I use it for audio measurements. On the front it has 2 inputs: (1) and (2). My intention is to use input (1) as “LEFT” and input (2) as “RIGHT”.

I intend to use Visual Analyser twice (one on each screen), one with the LEFT channel and one with the RIGHT channel. I would prefer this over a single screen with both channels overlapping.

This may look like a simple question. Perhaps it is, but I’m puzzled:

a. The sensitivity of the 2 inputs is different (one is sensitive, the other is not); this is not what we need of course. We need equal inputs.
b. How do I get the inputs “connected” to the two channels? Can this be done?

Regards, Gerrit

Tek vintage museum visit:

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Hopefully the title + picture are self explanatory. I built a 4ch TPA3255 board amp to run some DML panels that need heavy EQ and a powered sub to cover the full spectrum. So I have a 4ch ADAU1701 with 2 channels going to the panels and 2 to the subs. I can't find the parametric EQ in the SigmaStudio tools. I looked through other folders but everything I see in documentation and other discussions says to look in the "Filters" folder. Any ideas?

If I want to get the driver as high as possible, can I put it at the top of the front baffle and put the port at 1/3 of the length from the bottom? Will that be generally the same as the reverse, as far as the nulling of the main peak?

On the left is the input stage that I am currently using in my SE amp. The input stage drives a MOSFET source follower that drives the grid of a transmitter triode. I get about 2.5%THD at 75Vrms with about 65dB of gain in that stage. Distortion is a very low order waterfall. The stage is simply a CCS-loaded pentode with a p-channel follower driving the cathode from a feedback divider from the output tube plate.

I'd like to see if I can maybe do a bit better with a folded cascode or shunt cascode as some here call it. I ordered some 6E5P on Ebay and I think I'll probably pick up a pair of Rod Coleman's boards to play around with. I need to get ~75Vrms out as I want to test out a 211 but I have many other output tubes that don't require that much swing. The main twist I'm adding is the p-channel drive to the cathode of the tube. I've simulated the circuit the cathode drive with common mode signal seems to add a little distortion (from the Va-k variations that the common mode swing induces) but I still want to give this a shot and breadboard it.

I'm just looking for advice on this particular circuit as I've never used it. Is this a dumb idea or will I maybe get what I'm looking for with this approach?

Hey DIYers

A while back, I ran across a pair of AD12202 on a local auction site for a very reasonable price, so I had to jump on them.
Full-range drivers always kinda impressed me, and back when I was 15, I built a pair of Cyburg Sticks with W4-655C, which sparked my interest in TQWT (back then I thought this was this "Transmission Line" thing they were all talking about) designs. On a side note, my dad is still listening to these speakers today.

Seeing this, I decided to take it upon myself to design a TQWT enclosure for the AD12202, as I couldn't find any suitable designs on here or in other forums. However, even after all these years, I still feel slightly inferior when it comes to my maths, so I would highly appreciate some feedback on my design from some of the more seasoned designers here on the board.

Here you can see a drawing of the side view, next to it the SPL graph from my simulations.



Here are the pipe parameters:
Tuning Frequency: 42 Hz
Taper Ratio: 3.333 (repeating)
Length: 2.2m
Volume: 375l
Driver Position: 75cm

Now, a few questions:

I understand the comb in the FR is inherent to the standing waves occurring inside the cabinet, and I've done my best to iron it out. How much improvement can I expect from heavily dampening the beginning/narrow end of the pipe?

Second, I couldn't really find many resources on simulating the mass loaded vent in conjunction with the pipe itself, so I essentially just ended up using a port tuned to 35Hz with the length of it fixed to the depth of the beginning of the pipe (15cm). Franky speaking, is this dumb?
In my understanding, this should on one hand further extend the pipe, but also bring its own set of implications. Is there a way to simulate the entire system, namely one that doesn't cause cluster headaches? I expect to add another few Hz on the FR, but I have no idea what other chances in phase response or especially group delay I could encounter.
I am also unsure if a port of just 5cm in height will create problems related to port noise, even though the whole cabinet is 50cm in width, creating what I would call sufficient surface area for the amount of air I expect the cone to move.

All in all, do you think this about checks out? If not, where would you start improving?

Lastly, do you even think I should go the TQWT route? I am looking for reasonable extension, but more importantly, tight upper bass, which I expect the stiff paper cone to excel at. I did, of course, think about building open baffles, but I really don't think the drivers would deliver on my bass needs, and I am spiritually against the idea of deploying a subwoofer 😀 I also thought about building a classic BR, but there I really don't want to compromise on tightness.

Anyway, thanks so far!

Hi guys.
Just found this forum and thought it might be useable for a TT dude like me.
Currently run an office setup with a Thorens TD280II and a livingroom setup with a Rega p3-24.
/ Jens N

I’m considering buying a used alpha 10 amp, but it says the remote doesn’t work. So I need to know if this is probs an easy fix (like a new remote), or if it’s a known issue with the amplifier model itself plz?

AMC CVT3030 up and running again.
Finally, aftermore than five (+) years, my repair man got another CVT 3030 in for a tube change.Also gave him an opportunity to compare and easy checking all the mods in my amp.Turned out that the trim pots for center voltage adj. (10k) was only 1k…. (Specified10k when purchased!) - Replaced and Voila! Tested the amp with E.H.el34´s. -Sounds really nice.
Now I like to re-design the amp to fit the rest of my hifi-gear. Is there anyone out there having a silver/grey front panel for sale? Regards.

Selling my beloved integrated tube amp which I modified and refurbished over the years. I am the original owner.

Very much improved from the stock version; happy to provide the list of modifications.
Comes with Sovtek EL34G tubes.

If you live in the Bay Area auditioning can be arranged.


Price is $1,300

This is to evaluate and promote interest in our latest synchronous rectifier design.
Saligny Universal is a discrete design that extend synchronous bridge capability in voltage, current and phase. Therefore high voltage, high current and 3Phase or multiphase is possible.
Another great feature is that compared with LT4320 versions, Saligny Universal support centre tapped transformer. This make possible drop-in replacement in many audio applications.
Saligny Universal will be available starting with April 2023 and price will be lower than current Standard.
Saligny Power GaN is based on a similar circuit design, but aim at very top performance in industrial&professional applications that require exceptional electrical performance.
Saligny 3Phase will follow shortly. Expect around June to be available on webstore.
Saligny Multiphase is currently on workbench and main application will be electrical vehicles.

More info on https://evotronix.eu/main/



Please indicate if you intend to use Saligny in your next project and which one.

Thank you !

We look at speaker enclosures, sharp edges cause much discussion about wave disturbance, noise issues and complaints.

Does the little sharp edge thing over the cone of this Alum - Ceramic tweeter do anything like that?

I picked this tweeter to point at because the white and black contrast is easy to visualize.

Thanks DT

I have a Dynavector 23RS low output MC cartridge with one channel broken. Is there any specialist working on anything like this? I tried contacting DV HQ but no reply yet.

Hi:

I'm getting tired of replacing the speaker terminals (16-24 AWG) in my Klipsch Promedia 2.1 speaker system. The original Klipsch terminals lasted about 12 years, but this last set I installed (found on Amazon), only lasted 3 years.

Where can I find speaker terminals for that wire gauge that will last and not break so soon. These are 4 terminal (two speaker) models.

This is my first post in around 14 years, I now have the time being retired and having all my big projects out of the way to have some fun with DIY audio.

So now to the point. I've seen a few vids on DMLs and there are big variances in the way people feel about the results, I think the concept has merit, but I expect from my past experience with Open Baffles that there is a wealth of subtle things that can be implemented to change the character of the speaker sound.

Of the top of my head, these might include: various panel types, driver placement, multiple size panels for bass and mid/treble, panels with holes in them and small tweeters in the hole, multiple drivers on single panels, various coatings, wall treatments behind the panels, wings mounted outside the panels to improve bass/mid, support options, partially textured panels, and probably a whole array of other items as well.

I haven't come across any site/vid where anyone has done fully comprehensive testing and I suspect we may be well short of what can be achieved, but then I'm just coming back so maybe there is something truly comprehensive out there.

Can anyone suggest some links? Thanks in advance.

Im trying to design my headphone amp and am at a dilemma on which output jack to implement for the balanced output.

Most headphone amps in the market seem to employ XLR output jack yet most aftermarket balanced cables seem to use 4.4mm jack.

So what is the most common type of balanced jack out there? Im rather confused about the lack of uniformity