Hi all! I'm looking for a pair of these coax speaker chassis in good conditions

Anyone heard from or ordered from Classdaudio.com (Tom) lately?
I sent my damaged SDS-470 (blown input) back to Tom at his request, and it's getting close to 2 years that it's been in his hands (shipped February 2022). The last response I received was October 2022 with a "still can't find the parts" response. I am wondering if he is still in business.

Thanks!

Hi,need 4 pieces if someone have this for sale?

As tittle said I'm looking for shielded choke 10uH 10A or more OFC axial not SMD not radial.

TIA

I started designing 3D printed cases for Squeezeboxes and then tried a cheap off-the-shelf MAX9744 board, which I integrated with a microcontroller to give me IR and rotary encoder control for function, plus a small segment display. The developer of the SqueezeAMP (based on a TAS575x) liked it and asked for a design to fit the SqueezeAMP so I will soon be finishing that. I'm having so much fun I've since ordered some TPA3250 boards to pair with a valve pre-amp for the next version, but I'd like to find out what other boards are available. I know of the Infineon MA12070 board but it looks like it won't be easy to mount, and there is the JAB3+. But, I'm really just going for cheap and cheerful at the moment, when I really want to level up a bit more. Are there better boards, or should I look at conditioning the power supply, or something else entirely?

MAX9744 amp, on the right


Upcoming SqueezeAMP case - same basic design but a lot slimmer and with a jog-shuttle type dial.

I have recently received a Channel Master or (Sanyo) Model 6601 Integrated amplifier and I plan on resurrecting this nice old piece of audio gear as it is all there. It is in great shape with all the tubes installed. I have not yet powered it on but plan to on my Variac sometime into the future as well as replace any or all bad caps. I have a SAM for the unit but no owner's manual. I have searched and searched (HIFI Engine) and other sites but have not been able to locate one and was hoping that someone here may have one they would be willing to share or know where I could locate one. Thank You in advance for your help.

I've been thinking of using UPS on my Amplifiers not to power them when there's no electricity but to keep them safe from spikes short circuits , is this a good or bad idea ?

Interesting and informative article on Maria Callas who passed too early, but was the most remarkable soprano diva of the era, excerpted in part below:

https://www.nytimes.com/2023/11/29/arts/music/maria-callas-centennial.html

Her voice is the shadow that remains after shock, after anger: the sound of a woman realizing she has nothing left to live for.
It is the second act of Verdi’s opera “La Traviata.” Violetta and Alfredo, a prostitute and a wealthy young man, have fallen madly in love. But his father confronts her, demanding she drop the disreputable affair to salvage the marriage prospects of Alfredo’s sister.
For Violetta, it is an unbearable sacrifice, but she’ll do it. “Dite alla giovine,” she sings, in a broken murmur: Tell your daughter that I will abandon the one good thing I have, for her sake.
Singing that passage on May 28, 1955, at the Teatro alla Scala in Milan, the soprano Maria Callas reached the phrase about how “bella e pura” Alfredo’s sister is — how beautiful and pure — and inserted the tiniest breath before “pura.” It’s a barely noticeable silence, but within it is a black hole of resignation. Callas’s split-second pause achingly suggests Violetta knows that if she, too, were pure, her happiness would not be expendable.

Tiny details like this are how Callas — who would have turned 100 on Dec. 2 — gave opera’s over-the-top melodramas a startling sense of reality, and her characters the psychological depth and nuance of actual people. Tiny details like this, captured on hundreds of recordings, are how this most mythical of singers has stubbornly resisted drifting entirely into myth.

The defining diva of the 20th century, Callas is not so far from us in some ways; a normal life span would have brought her well into the 21st. Those many recordings — endlessly remastered, repackaged and rereleased — have kept her in our ears, the benchmark of what is possible in opera, musically and emotionally. Her dramatic art and dramatic life, often intertwined, have made her an enduring cultural touchstone: a coolly glamorous stare in Apple ads and the inspiration for plays (including a Tony Award winner), performances by Marina Abramovic (bad) and Monica Bellucci (worse), a coming film starring Angelina Jolie (we’ll see), even a hologram tour (sigh).

Yet Callas can also seem like a figure of faraway history. Her lonely death was back in 1977, when she was just 53 — and by then, her days of true performing glory were almost 20 years behind her. The number of people who saw her live, particularly in staged opera, is dwindling, and her short career was just early enough that precious little of it was filmed.

So she has been for decades, for most of us, a creation of still images and audio. We have to use those tools to conjure what her performances were like, to complete them.

There was one brief mention of this clock here on DIYA, back in 2009.
But, surprisingly, not much chatter in DIY chambers, given some of the "critical" attention PrimaLuna DACs and CDP's have received since roughly early 2008.
Not sure how Dutch company, PrimaLuna, implemented the SuperTubeClock circuit. Tho' JA does go into some detail in Stereophile write-ups:
https://www.stereophile.com/content/primaluna-prologue-eight-cd-player-upgrades-october-2008

However, subsequent correspondence with PrimaLuna engineer Marcel Crouse revealed that while the clock frequency is set by the crystal, the purity of that frequency is controlled by the noise floor of the amplifying device in the oscillator circuit. In the region of interest, 0–40kHz (a relatively narrow bandwidth because of the oscillator's very high Quality Factor, or Q), the tube actually has lower self-noise than a typical wide-bandwidth, low-noise transistor. The result, according to Crouse, is much lower phase noise on the master clock signal, which in turn results in a more precisely defined datastream.

Click to expand...

A 2020 review from hi-fi news, and more info on the STC:
https://www.hifinews.com/content/primaluna-evo-100-tube-dac-usb-tube-dac-tube-clock

According to [1], " SuperTubeClock replaces the solid state oscillator normally found in a DAC with a mini triode vacuum tube. By using a tube, we have significantly lowered the amount of jitter and noise, resulting in superior detail retrieval. .... The tube is a very rugged, long-life Russian military Triode specifically designed for oscillation purposes... "
I looked for Russian osc tubes and found some info [2]. They seem to be quite cheap on eBay, too.

PrimaLuna uses the same design in both their 2008 CD player and 2019 USB DAC products.
Including: SRC4192 asynchronous up-sampler and PCM1792 DAC . And the tube output stage and rectifier. High-slew-rate opamps (100v/us) are used in i/v.

The weirdest anomaly might not be the clock but , as PrimaLuna reports, this ....

Our USB [XMOS] input converts the jitter-filled USB digital signal to S/PDIF, dramatically improving the digital signal quality before it gets to the SuperTubeClock. This USB input is a true high-resolution digital input.

Click to expand...

============
[1]
https://www.primaluna-usa.com/primaluna-evo-100-tube-dac
[2]
https://www.radiomuseum.org/forum/russian_subminiature_tubes.html

Hi, has anyone built a DAC with this transceiver ? " LC89057 " Can it be done without a CPU/MPU , just the LC89057 with an DAC like PCM1680, etc. ?
Using coax or spdif input to LC89057 that goes into an DAC then OP-amp amp filter , output. ?.

I was reading Electronics for Vinyl (Douglas Self), and revisiting his favorite NE5534A single stage RIAA MM preamp. He mentions that the NE5534A shows a rise in distortion at low frequency due to the high closed-loop gain (meaning there's not enough open-loop gain left to keep distortion down at the device floor).

This made me revisit my RIAA design that uses separate active poles and zeros, realizing each stage only sees a max gain of 32dB or so, whereas a single stage would have about 54dB of gain at low frequency.

What's more there's no limitation on the headroom as each stage has unity gain or higher across the audio spectrum, so no stage can clip without the output clipping anyway.

The extra stage needed for correct output phase I augmented to act as a low-pass roofing filter and gain-setting stage.

A 5 pole rumble filter is available on the output if desired (why wouldn't it be?)

So why do I want to label this "blamefree"?

1) The capacitor values for each filter stage are 1nF, 10nF or 100nF, nothing awkward.
2) The nominal RIAA component values are exact - a 10nF and 31.8k make the nominal 318µs time constant for example - 31.8k can be made from two standard values in series, 30k + 1k8, and the 7.5k is already standard.
3) The input stage can benefit from the low voltage and current noise of the NE5534A without compromising on distortion by asking for too much gain
4) The 47k load resistor is synthesized to reduce its current-noise contribution - this technique is no doubt well known here, giving very good noise performance for typical MM cartridges. The aim is that no hiss is audible after a disc ends and the stylus leaves the groove - even if you've been listening at high volume (its not too difficult to be inaudible against surface noise, but once that ends I still appreciate quiet!)
5) Effective filtering of sub-20Hz noise is provided. A 5-pole Butterworth filter is not overkill here I suggest.

Here's the circuit with annotations about noise levels (in theory!).



Thoughts?

SOLD



This is a development kit for the ST ecosystem. It is designed for professional use and is not consumer friendly. It needs a programming interface that might be hard to find, and will be a little challenging to use. It is, however, almost free.

It has:
-six line level channel input
-six amplifier channel output
-5vdc power input
-DC power input, single ended, up to 50vdc (not included)
-four STA517 amplifier chips
https://www.aiema.com/part/datasheet/sta517b-fn195107197
-one STA309A multichannel DSP chip
https://www.st.com/en/audio-ics/sta309a.html

You will need a programming interface and the software that goes with it:
https://www.st.com/resource/en/appl...l-demonstration-boards-stmicroelectronics.pdf
https://www.digikey.com/en/products/detail/stmicroelectronics/STEVAL-CCA035V1/3458203

Price is free plus shipping plus gas money so ... $20?

Hazır TPA3150 kartı ile aktif hoparlör yapmayı planlıyorum. Her iki hoparlör de kablosuz olarak birbirine bağlanacaktır. Bağlantı için Bluetooth uygulamasını kullanacağım. Önerilerinize ihtiyacım olacak. Teşekkürler

Hi. I am trying to find a used solid state amp for $200 max that achieves a smooth, fatigue and grain-free sound that is also reasonably transparent, with a clean, tight but realistic low end, and a good soundstage with palpable imaging as well.

I know this is a pretty daunting challenge, but I must try.

My primary source is a Micro-Seiki BL-51/Grace 707 II/TK7e setup with a transparent clone of an EAR 834.

My preamp is a PS Audio IVH which has both active and passive mode.

My speakers are a pair of Acoustat Spectra 11's (4Ohm,83dB).

Any suggestions?

I had 30w Bluetooth soundbar battery operated 3.7v, it's amplifier borad is dead so I am trying to find a replacement borad
But unable to find the exact match.

Options left for me

1) Get a Bluetooth amplifier board with 3.7v input and output of more then 10w per channel

2) get xY-P15W amplifier board with 12v input and 15+15 output, but the catch is i need to use DC to DC step up convert 3.7v to 12v to make it run


I thought of going for option one but unable to find 3.7v input board if anyone could help with it I would be happy or else we have option 2 left

What do you guys suggest




Below attached pics of old amplifier

When giving amp 0 volts to around 9 volts the power led comes on and is solid. But when I apply more voltage it starts flashing along with the clipping and protection led. Does anyone know what is going on with it.

Hello
A few ,months back i opened my SL-6 box, to check on the driver as it was rubbing, anyway to my shock there was a lot of fuzz white stuff around , initially thought it was the box stuffing as its white and dusty. I cleaned them up and boxed the drivers, and the tweeter magnets were the same.

They dont look as bad today, however i see some rusts spots ( as per photos). I hear of products like CorrosionX etc. I thought a clean up and paint would be enough? I have no idea. Some anti paints out there, or plain non water based.

Upon removing the copper domes, i was shocked there was corrosion there, up to the tweeter itself. I was afraid to mess with the cotton pad or whatever it is. I clean it up the best i could.

I have oil based paints, and water based on hand at home right now., as i said early, not sure if that would help in the long run. Very humid here in summer and there is no a/c,, and thinking the celestion were a close speaker system it would be immune to such a problem. Part of the old gaskets for the drivers has worn in places and its possible the cabinet might have some leak, i am thinking to use some desiccant to keep it in there?


woofer - was worse than fhis the first time i saw it



This is how the woofer and tweeter backs looked but worse, when first saw them, this is the front of the tweeter

scraping it off, and a protective cup over tweeter.

I'm currently thinking about modifying my speaker cabinets and thought of a design that could have a wider distribution angle.

So I started with this one, which is a push-push (bipole), with three speakers, each pointing in a different direction (front, top, rear).
The back is the same as the front, except it has the terminal to place the wires.

A box with the tweeter will be on top of the bass box, with a small space that will appear to be an omnidirectional design.

G'day Guys,

I picked up a faulty Sony STR-DA80ES for $5.

This thing is built like a tank. I have never seen a big brand, mainstream brand amp built like this before.
I grab all the faulty amps I can to salvage what I can and this thing is just different.
It is assembled different to normal, much more complex, more brackets, more rigid, thicker steel etc.

The power transformer is "380w" but is twice the size one would expect. It weights 6kg. I salvaged a 360w pioneer recently with a power transformer that weighed a measly 4kg.



These caps are 50mm wide by 70mm tall.

These wacky 5 pin chips are what really baffle me.

Does a sealed enclosure have laminar (linear) flow or turbulent flow?

If it is not linear, what would be the disadvantages and advantages of it?

.How do you delete a thread?

hello every one
I have a bit of an issue here. I'm either going insane and having " auditory hallucinations" that seem to be angry and only threatens me. Or a psychopath stalker is really knowledgeable with audio equipment, and is only playing around.
Their ability to emit audio at an un recordable level. And to threaten my family and I with death and insanity. Plus it's years of this audio attacks. Kids have fallen victims to this. The police either think I'm joking and don't help, every time. I still make reports.
Also, I recently was away from home and didn't have this. "audio hallucinations". so I'm 100 percent sure I'm not crazy. I need solid proof.
What I can be assured of is that a group of audio terrorists have gotten audio equipment and project their voice in a modulated audio, with small wave lengths . Even tho one can slightly hear it, yet a device to record audio won't pick it up. As if the audio isn't loud enough to move the mics pick up .
Their audio is not projected in a normal way like regular sound normally works. as most know.
What is strange is that their audio is loud enough to be heard even when I play music at a high volume, yet is not loud enough to be clearly heard when recorded. Like regular conversation would be, or like when just trying to record ambient noise and can hear what's near and far.
What's also abnormal is that this sound is emitted as if it's coming from your head.
They threaten and talk insults , all the bad things you can say they do. without the care for children. they live here too and can hear them !!!!
I need to record these terrorists asap .
I tried recording them, using live listen with my iPhones, Tascam recording device. my Acer pc, and nothing has been successfully. I even tried the wood box with just a small opening and the iPhone docks on top. an inflatable pool thing and cut a whole enough to put my phone in, sealed it and inflated it . or a horn with the wood box at the small end. aimed it at to where I can hear their location, and or sound source. and nothing legit to be considered proof.
How can I record this group of Terrorists?
please help as soon as possible.!

I'm sorry if this has been posted already; I did a bit of research and haven't found anything related to my issue. I have some vintage Fisher stv-648 3-way speakers that need new caps. (I think). Anyway, I have included some pictures of the existing crossover. I want to rebuild it, but I don't know where to start to find the parts I need. Any suggestions or direction would be greatly appreciated.

Thank you

Help me find Ecler XPA11000 power amplifier schematic.

Hi guys. It's about Ecler's XPA-11000 audio amplifier. Does someone have a schematic ? I wrote to Ecler but they answered very politely
that they don't give schematics (confidential stuff). There is nothing besides the specs on the web but looking at some available pictures,
it looks like its a class H, 3 step power amplifier. Probably the output devices are Hexfets, IRF640/IRF9640. I'll appreciate any information.

Cheers. 🙂

Here is the service manual for the other XPA models. The XPA-11000 specs are there but no schematic. Strange. ->
http://www.audiowerk.at/downloads/temp/Ecler_XPA_Service_Manual.pdf

Hello all,

First time poster. Fairly new to the game, have tried to do some research on this but definitely have not done anything exhaustive. I'm currently building my own phono preamp setup which will include a separate linear power supply in its own case (everything being built by me). I'm far from an electrical engineer and I have a very healthy respect for electricity, so I'm trying to do my due diligence here, and I appreciate your time and any help/advice/input you can provide. Whenever I post in forums, I try to be exhaustive with my details (sometimes to an excessive degree) to be as clear-cut as possible with my questions and in the hopes that the answers will be more easily provided, however this inevitably leads to very long posts, so this will be no exception. Without further adieu, here we go:

The primary concern here is making sure this system is SAFE and will not be hazardous to anyone in my family, under normal operation or in the event of a failure/short within the system. Based on my research, I believe I already know the answers to most of my questions, but I'm coming here for confirmation/expert opinion. Secondary is the potential to preemptively appropriately ground the system in terms of feedback/loops/hum, etc., as I'm obviously going through these efforts to create something I'm hoping is bordering audiophile level, and inherent in that is minimizing/"eliminating" any hum.

The basics of the system are as follows:
Power Supply:
Metal case from eBay (second image is basically the same item with a similar layout to what mine will look like)


R-core transformer from eBay (15v-0-15v)

Sigma22 board from eBay

Silkscreen/Circuit sides of board, for reference




Phono preamp:
Akitika preamp board (https://www.akitika.com/PhonoPreamp.html)

Case from eBay



My Primary Questions (Safety related):
1. The R-core transformers have a built in GWG (mains ground) wire, I plan on obviously connecting this to the GWG pin of the IEC connector (per the example power supply image), however should I also ground the power supply chassis to the same IEC ground? My thought/plan is: YES
2. Because of the above, and because of the example image above, am I able to bolt the transformer directly to the chassis, or should I use either standoffs (at least for increased airflow around it for heat dissipation) or possibly even insulate it using nylon bolts/washers? My thought/plan is: BOLT DIRECTLY TO CHASSIS
3. The Sigma22 board - should I ground the DC 0v side to GWG, as well? My thought/plan is: NO
4. The Sigma22 board - can I use standard metal standoffs for this or should I try to use nylon hardware for isolation purposes? My thought/plan is: USE METAL STANDOFFS
5. The female 3-pin connector on both the PS and the preamp chassis, should these be insulated from connecting the chassis metal or do I want them contacting the chassis metal for grounding purposes (or does it not matter)? My thought/plan is: DO NOT INSULATE THEM FROM CHASSIS
6. For safety purposes ONLY (both shock hazard and risk to damaging either/both boards - not talking about feedback loops, etc., yet): should any part of the preamp chassis and/or Akitika board be also grounded in some way (obviously the 0v DC ground will be connected to the Sigma22 board)? My thought/plan is: NO, outside of whatever is decided subsequently about potential feedback loop grounding

My Secondary Questions:
7. My turntable has a ground wire (I installed, it originally didn't) that I will be connecting to a knurled nut grounding post on the back of the preamp chassis. I'm having a difficult time discerning how best to ground this from this point based on all the different things I've read (including from Akitika as their board is "meant" to be included in their larger amplifier setup in the same chassis and, ultimately, is grounded to its chassis which is obviously GWG).

I know hum/"ground loop" grounding is a hard concept for most to grasp (outside of those with vast electrical knowledge/experience, of which I am absolutely not) and can be a rabbit hole at times, so I don't necessarily expect an answer on this but curious in case someone has an obvious and (hopefully straightforward) answer. I've read through this article (https://diyaudioprojects.com/Technical/Grounding-Shielding/) and assume something like this would work, however I don't fully grasp what he's talking about and therefore how to implement it (I am entirely a visual person, if this were drawn out I'm sure I'd follow but just reading through text is hard for me to understand exactly what's going on, especially being inexperienced with the nuances of electrical engineering terminology).

8. One final, dumb question - the PSU case I bought has a LCD voltage readout screen that I'm hoping I can hook up. My questions are: since this is just a 2-wire DC unit, do I hook it up to the Sigma22 +15V and 0V, or the -15V and 0V, or does it not matter? And, subsequently, and this might not be obvious without knowing the part, but can it handle/read the ~15V, assuming it's usually used for 12V?

Anyway, as I mentioned previously, I absolutely appreciate any and all help with this, and thank you for taking the time to read this if you've gotten to this point, and even more so if you decide to respond. Please feel free to completely rebut any of my "thought/plans" above, etc., in your responses and just generally tell me where I'm wrong (or right) and any general concerns/red flags you might see with any of the above.

Cheers

Hi all

This week I bought this beauty, a Grundig Konzertschrank Rossini 8:

However, the audio sounds pretty horrible. It has a build in amplifier, a record player, a tape recorder and two build in speakers:

The cabinets left and right have a different size (because of the different devices on top) and the backsides of the cabinet are closed with very thin loose perforated wood. Inside are old Grundig oval speakers. 30cm x 18cm type 7048-036
This is the speaker:


So I am planning on upgrading the audio of this beauty, while leaving the whole structure intact. I already have a small digital amp that meets most of my requirements, so it is mainly the speakers i am worried about. How should I go about this?

Difficulties:
1. The speaker cabinets themselves in the Rossini will be pretty difficult to seal (especially the right one, where the top of the cabinet is the turntable on top, I mean, the turntable is basically build on the topside of the speaker cabinet, sticking through).
Closing the backside of the cabinets will be easy enough, but the cabinets will be a different size. The left one is basically half the grill's height, the left one about 4/5 of the grill's height. The one on the left can be sealed completely, the right one not.

It will also be difficult to have a different opening in the front than the current oval whole for the Grundig oval speaker (the beautiful speaker grill seems to be glued to the piece of wood with the opening for the speaker in it, high risk of damaging the grill if i was to enlarge or remove this piece).

What I have done now is place small bookshelf speakers i made with Audience A3 drivers in the cabinets.



It sounds a lot better, but still lacks a lot of bass. So I could work with a build in small sub, or an external small sub.

But I am curious if you guys have any other ideas? I cant seem to find a replacement for the old Grundig speakers....

Any tips or ideas very much appreciated!

I wondered if someone can explain a bit benefits of the push-push design, each woofer placed on one side of the speaker.
For example MBL uses them in their 116. 120 and 126 models.
I understand it helps radiate sound as an omni source and as they shot in opposite directions the forces get cancelled out.
Sound wise, is this approach similar to Open baffle design?
Does it help to reduce room impact to the overall bass sound?

Used 5 minutes only to test they work perfectly. Those are between the best of the best. They have the diamond on bottom of course.
Readings on boxer picture
175 Eur+ shipping

Hi as the title I'm gonna build a pair of
Speakers. Using 4 Dayton audio esoteric 7inchers and seas dxt tweeters.
Using the thing in the pictures and mdf for boxes easy to work with they will be sand filled. The problem is i need help with what size to cut the tubes in to get right volume.

I recently did some minor repairs to a fine condition Spectral DMC-12, but have been unable to find a service manual, schematic, or even a user manual.

There are trim pots for gain, and others which are for bias of the output MOSFETs, I assume. There are also dip switches for all of the inputs except the phono section, which appears to have solder pads for loading resistors.

Does anyone have a schematic or manual for the DMC-12, or have knowledge of how to adjust these units?

Thanks!

Hello all,

I traded an Bel Canto integrated amp for this ST70 Project with a member here a few years back. I managed to get most of the hard work done in the first couple weeks, and then there it sat for the past three years as you see it, when work and life got a bit crazy.

Has custom wound transformers for ST70, and the Triode Electronics Input and power supply boards fully populated. Base is a beautiful Mahogany.

The boards need to be wired up, Bias circuit needs to be added (for pairs or individual tubes), and Choke (Triad C-24X) needs to be installed inside base (not the exact C-354 choke, but should be close). Includes all you see - but no tubes....

I have all the schematics, wiring diagrams and directions. Should include all info needed to complete the build...

Just need to offload some projects I will likely never get to - including refurbing Apogee Scintillas, two pairs of Acoustats, Hammond AO tube amp Monoblocks, etc).

How's $650 + ship? Or pick up is west sub of Chicago?

Hi guys,

I started my HiFi hobby in about 1978 with a pair of Realistic Optimus 5B speakers I bought with money from delivering newspapers. I soon sold those for Bose 601s, I was inexperienced. I became interested in DIY in the early 80s and sold the Bose to finance a Dynaudio build around 21W54 woofers and D28 tweeters. A nice improvement. Lately I started looking for the 5Bs to see just how far I progressed or just how much time and money I wasted. Today I started that re-evaluation with a $40.00 pair from facebook marketplace.

I hooked them up to the Onkyo 886 preamp and Ashly amp and sat and listened for a while. First impressions was "not bad". I put the mid and tweeter levels at the lowest setting. I attached a screen shot of the response with distortion. Bass and vocals sound open and smooth but highs sound like someone banging on a pie tin. tonal balance is bright and that's easy to see why. This is despite the measurements showing distortion on the highs to be very surprising low. I'm measuring mid and high distortion well under 1% at the given level. This is on par with my best tweeters but mostly 3rd order where the others are mostly 2nd.

Bass distortion is about as expected at above 1% rising to 6-7% about peaking at 10 times my favorite woofers.

I would put the frequency response at 38-18khz. Sens at 84db with the mids and highs at 89ish db. Not terrible for era, devices, cost and design.

Sound stage and imaging fall short of any other system in the house.

The plan is to give them a fair listen, dissect the crossover, match the levels and decide after that.

Background: Had done some work on my Audio Research D70, and was getting some odd results, so I started testing and measuring with my Scarlett Solo. I had the output of the Scarlett connected to the input of the amp, and the output from the amp was connected to my speakers, and I had clips on the + and - terminals going to the input on my Scarlett. I was making connections and checking my software, when I smelled the blue smoke smell, and observed that my Scarlett seemed to be on fire. After opening it up, I saw serious black burned/melted PCB around one of the ground pins on the output jack I was using.

I wasn't running a signal into the amp during this time. The output voltage from the amp at idle was nominally zero. I didn't observe any weird voltages coming from the input jack.

I have been messing around with the output wiring in the power amp, and at least once got my signal/ground pair mixed up. That led me to wonder if improper grounding could have caused this failure? I don't fully understand why the output jack would fry like that.

Hi,

I am looking for a DIY project based on LM3886 which could deliever 100W @8 ohm per channel.
There are some projects out there (for example: https://electronics-diy.com/100w-lm3886-power-amplifier.php), but they refer to 4 Ohm and 100W.

Is it even possibe to use LM3886 in some configuration which would be able to deliever requested output?
Apologies if this was already discussed here. I checked, but didn't find it.

Thanks in advance!

Best regards,

Mario.

I am planning to connect my Ares Ii DAC via differential (balanced) connection to my home-build power amplifier (which is based on a TPA-3251 board from 3e Audio).
As the differential output of the DAC is rather high @ 2.4KOhm, I was thinking to use a 100KOhm 4-gang potentiometer (Alps RK27). My reasoning: a 100K pot delivers worst case a minimum of 25% of it's rated resistance (at 12 o'clock setting a 100K pot has a resistance of 2x 50K in parallel = 25K. And 25K is a little over 10 times the output impedance DAC, so the DAC's output doesn't experience voltage drops due to excessive loading of its output. So far so good, I guess.

Because the input impedance of the power amplifier (balanced input) is 20KOhm, I thought it would be wise to place a buffer between the 100K pot and the 20K input of the power amplifier.
However, the buffers for balanced signals I came across had rather low input impedances themselves: the one with highest input impedance was 48K, which is about half of the 100K potentiometer that is on the buffer's input side.

Finally my question: is this a problem and does this defy the sole purpose of the buffer, or does this combination still make sense?
Should I take a 50K pot instead, or 20K even? What would be the best trade-off?

I recently bought an old PA amp (a Champion) and it came with some valves I had not encountered before, EL12 and EF12. They use the Y8A base, which is apparently quite common on older European electrical equipment.

EL12's can be bought NOS for quite reasonable money, especially on the German version of a certain auction site, but the only reference I could find for them here was a big thumbs up when used in a guitar amp.

Does anyone have any experience of their use in hifi?

Hi there,

I am trying to fix an old Marantz PM250. There is no amplified sound, although there is a very quiet, distorted sound from both channels. As both cannels behave in the same way, I suspected common circuity to be at fault, e.g. power supply. I used oscilloscope to check the signal at the input of the Volume module PG00 - looked great and the output - the waveform is distorted. The output is connected to the input of pre-amp stage, so I suspected that the power supply for pre-amp was faulty. Sure enough, the emitter of Q812 that supposed to be -11.4V shows approx 1V positive. I immediately suspected burned Zener Q805 or regulator transistor Q812, however both of them, as well as the capacitor C804, were fine. More to it, when I disconnected emitter of Q812 from the PCB it shows -11.4V as it should. It points to the issue somewhere else.

The question I was going to ask - are there any obvious candidates to be checked? I could start cutting PCB tracks trying to find a culprit, but before that wanted to ask if there is a better approach...

Thanks in advance,

Sold sold sold sold. Please remove. Here's the opening paragraph for the owner's manual of the Simaudio W10 amps:

"The MOON W-10 was a fully balanced differential mono-block amplifier that produced 750 watts into 8 ohms, 1400 watts into 4 ohms and was capable of driving virtually any loudspeaker. Employing our "Advanced Renaissance" technology featuring a "no overall feedback" circuit and bipolar output devices, the W-10 produced a warm, grain free sound common to some of the very best tube amplifiers, but had the reliability of solid state designs. With respect to external cosmetics, the MOON W-10 was similar to the W-5, the main exception being the rear panel connections."

(You can find the entire manual here: https://simaudio.com/en/guides/w-10/ )

Here's the sad story on this pair. I bought them on ebay from an idiot who knew everything...including how to pack a pair of amplifiers that each weigh 70 pounds... NOT! He did a crappy job of packing the amps and several of the front faceplate corners got dinged up. And one of the amps doesn't work.

THese amps cost $12,000 in 2001.

The other one works fine.. Amps look OK, put they are far from perfect.

I think the problem could be a speaker relay, BUT I AM NOT A TECH. Far from it.

I'm going to attempt to attach files, including two short videos of the non-working amp but if that doesn't work, shot me an email to kolle1@comcast.net and I will send the pix and vids. As you can hopefully see in the vids, the inoperable amps plays music very briefly when turned on then LCD1 illuminates and the amp shuts down. At the same time, the relay clicks off.

BONUS: When you pick up the amps in Bethel, CT and pay my asking price I'll give you a Simaudio Eclipse CD player and power supply. This unit cost $5295 in 2001. I bought it from the aforementioned idiot who packed the amps. I told him that before shipping the CD player transport locking screws had to be installed. Of course he said he knew all about that too. But he didn't put in transport screws and the CD player arrived broken. It weighs about 50 pounds. No remote.

Please bring help to load this beasts. I had a heart attack two months ago and it my cardiologist knew I'd lifted one of these amps up onto a bench to take photos, she'd pitch a fit.

$1000 cash at pick up.

Thank you.

Jefferson Kolle

****
****
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I understand that idealy we want all of our grounds wired to one spot or star ground...

In my build every terminal strip has a tab thats supposed to be at ground, and is always the same lug connected to the mounting tab for obvious reasons...

Aree we supposed to lift that terminal strips mounting tab with associated nuts and bolts off thr metal chassis or is running a hookup wire from that ground tan to the main star ground enough?

The web is full of mentoring for victims of so called narcissists. Did they replace micro aggressors and I haven't noticed ?

Hi guys, long time lurker first time poster. This is a little hobby project I am doing. I am basically wanting to hook this CSR 8675 BT transceiver board variant up to this SA9227 USB interface. I have got sort of halfway into researching everything I need to make it happen but am now feeling a little lost. I figured you guys will likely be able to figure it out in minutes what is taking me days to make sense of.

The SA9227 Interface seems to have SPDIF in and out. As well as I2c. The driver that installs gives me "Speakers" and "Line in" I assume this is related to the SPDIF in and out at the front of the board.

The CSR 8675 based BT transceiver board is actually quite a nicely done bit of kit with the major drawback of having no USB functionality apart from an SPI interface and potentially the ability to use it as a BT module. What I am hoping to do is to get it to talk to my PC as an audio interface. I do not think that doing that is possible without adding an interface chip such as the SA9227 (please correct me if I am wrong + the SA9227 was not specially selected so much as what I had laying about).

I guess my question is, is there any obvious way for me to patch the SPDIF or I2C on the SA9227 into this CSR board so I can use it as a playback and recording interface from my PC? Or is there perhaps an easier way to get the CSR board to function as an USB sound card that I have not thought of?
I am really hoping to take advantage of the OPT and AUX connectors and the DAC/ADC/DSP in the CSR chip.

Hi everyone! My project is a Pinnacle Classic Gold Tower upgrade which uses two 8 inch woofers with the lower woofer using a 1st order coil at 150Hz. Crossover point for top woofer and new tweeter is no higher that 2K. I will be building new crossovers to meet the needs of the new tweeter. If this was your project, what tweeter would you consider. My budget is <$70. I have had good experience with HiVi and Peerless dome tweeters in the $20-$30 range but would like to consider a tweeter considered a step up.

I'm attempting to covert my speakers' crossovers from passive two-pole Butterworth to active four-pole Linkwitz-Riley characteristics. I've successfully calculated the corner frequencies with the aid of VituixCAD2 software. However, there's a problem to decide whether the polarity of either driver should be inverted or not, after converting them to active.

Here are the FR and Phase of the original passive crossovers.


FR and Phase of active crossovers WITHOUT reversing polarity.


FR and Phase of active crossovers WITH reversing polarity.


Finally, the comparison


Please advice which way between inverting and non-inverting gives the closet behavior to the passive crossovers.

Selling following pairs of PCBs surplus to requirement:

SMD LT4320 a pair for 2eur
THT LT4320 a pair for 4eur
LT4320+CRC a pair for 14eur
CRCRC PSU a pair for 18 eur

selling in pairs, payment via paypal f&f, shipping at cost from Italy

Hi.

I have a Node 2 that have been working very well, but my unit stopped working completely and while measuring on the connecter between the built-in power supply and the main board, it is completely dead. So this is something more then just the standard issue with the two 1000uF caps.

Is there by any chance someone here that knows what supply voltages that the mainboard expects? My thinking is to build something in line with the upgrade PSU that I have seen some companies sell, but I of course needs to know the voltages. A fair assumption is that there is +/-5V and maybe also 3.3V? Unfortunate needier the mina board or the power supply board gives any clues.

Best regards,
Johan Christensson

Using DACT Type SMD Stepped Attenuators I am repairing a NAD 3500 volume control. The control has dual concentric stereo stages, the front one is a 20K audio taper with a loudness tap at 5200. The balance is a 50K MN control. The following is what I have done.

1) I had to make a MN control, so I took a 21 step SMD attenuator and removed the SMD resistors, and soldered in 4.7K SMDs up to the mid points and shorted the remaining contacts. Make sure to do the right sides (these are NOT mirror images for stereo).

2) The 20K audio taper stepped attenuator is easy to get. I took it apart, and filed the side of the case so the center tap can come out. I used twisted wire-wrap wire to make the tap at the 5.2K step. Strain relief with some super glue.

========
To get the concentric control to work, I need to file the front wiper to accept the outer control shaft. Tolerances are a bit close, but not to hard to do.

The only issue is I don't have detents on the unit, since the concentric shaft is too large for the detent part of the control..

To solder the surface mount parts I used low temp solder paste. I placed the part in a cast iron pan and heated it on an induction stove until the solder reflowed. A little solder paste goes a long way, and the parts will self align if you get them close to being in position.

Fun!!

Let me know if you need more details.

So I'm Buying a this mic as i need to make frequently response of 2 woofers that I'm going to use for a 3 way build I'm doing.

So i need a 1watt output of i think pink noise at a distance of 1 meter.
Can the Dayton audio DATS do this as i have one on the way. ( the 12in woofers I'm using don't have a spec sheet anywhere as there from 2001)

what is the proper way of measuring frequently response. is it the same 1 meter away at 1 watt?

and how do i import that data into a software like Xsim (every video i watched kinda just skips past it).

and what programs you you guys recommend for box and crossover calculation.

and here is the link to the other post on the speakers that I'm building (HERE)

just a short list of what im going to use
Vifa d27, peerless SDS-P830657 6½ and 2x Vifa M30wo-15 (and ovs x2 as that's just one speaker)

idk what the sensitivity is for the Vifa M30wo-15 the closest spec sheet said 93DB

Any help would be largely appreciated.

Are these adjusted to take into account woofer response?:

Says 90bd - 96db - 102 dB , but is this throughout the frequency range or at a specific point?
https://www.dibirama.altervista.org...k-26w-8534g00-woofer-10-8-ohm-150-wmax-2.html

Some other tests:
https://hificompass.com/en/speakers/measurements?page=2
http://zaphaudio.com/8test/

This guy I can understand; he has relative measurements:
https://feleppa.com.au/speakermeasmid.html

Having trouble figuring out which driver(s) has the lowest bass distortion.
Trying to "eyeball it", but doesn't seem that easy. And I don't know where the SPL is referenced from or if they might be relative?

Hello,

I am planning to build a DIY grounding box. I am planning to connect my DAC and Integrated amp to this grounding box by connectig the unused RCA input terminals on the both. For this I need to create two cables with Banana at one end and RCA at the other end so that I can connect them via speaker binding post on grounding box.
I need help with how & where to attach (solder) the cable on RCA socket.

I also need help in understanding if I can connect both L & R RCA input sockets on same amp to same grounding box (assuming I am going to solder the wire on the shell/-ve part of RCA connector)? Also Can I similarly connect all unused inputs on DAC/Amp to grounding box.

I understand attaching multiple inputs to grounding box is not going to amplify the effect & I just want to do it for protection of those input terminals.
Regards,

audio_phool

Hello
I'm just trying this new player but I can't make it work.
I'm using one RPI4 with ES9038 hat and one USB flash drive with 300 DFF files.
After configuration and reboot, the configuring window is frozen, the library shows radio stations but I can't see anywhere my music folders.
Where is the error ?
Until now, I was using Volumio and it' works great with one exception : there is a random POP when changing track.
So I wanted to give Moode a try.

Jhofland has designed a very slick solid state relay (SSR) headphone DC protection module that has no mechanical relay to wear out and uses ultra low Rdson MOSFETs that do not alter the signal in any way (as previously shown via measurements on the RTR SSR DC protection board for speakers). This unit however uses comparators to check for the DC offset, which is set at +/-500mV. A CRC filter is used prevent audio transients from inadvertantly triggering the relay. The comparators then trigger an optoisolator which then activates the gates of a pair of back-to-back MOSFETs as the SSR. The module is also stereo, so only a single board is needed for a headphone amplifier. It needs a +/- voltage power supply from the amp's rails with at least +/-8vdc and less than +/-30vdc. This is regulated down to +/-5vdc for the comparators to function. The MOSFETs are rated to 30v presently and are 10mOhm RDson units SQ4282EY)

Unit is very compact: 45mm x 37.5mm and uses 8-pin Molex KK connector for all connections.

Works great for DC coupled preamps as well to avoid turn on / turn-off thump. Delay for turn on is 2.5 seconds, turn off depends on how quickly PSU caps bleed off upon power off. But generally turn off thump is not as bad as turn on thump.

Schematic:


Build topside:


Build bottom side:


Test with parallel 8x OPA1622 headphone amplifer:


FFT showing harmionic distortion spectrum and THD without the SSR DC protection in place for 2Vpp into 51ohm load (9.2ppm THD):


FFT showing same with the SSR DC protection module in place (still 9.2ppm THD):


The unit works reliably and quickly and will protect your headphones from a DC offset error that could blow them up.

These are available as bare PCBs in my shop:
SSR Headphone Protection PCBs | Etsy

A stalled project, now at a bargain price!



This is the "Square Basket" version of SB Acoustics' 4-inch coaxial driver.

BUT WAIT, THERE'S MORE! It comes with two separate (tweeter and woofer) fully assembled Madisound crossover boards, made to the SB Acoustics factory schematic. This project started out with "Fair Hopes," and I love working with coaxials. But when the shipment arrived and I saw that Madisound had not combined both crossover circuits on one PCB, that made packaging more of an issue and I put the project aside. The driver, crossover boards, and shipping cost me $136. You can buy these parts, buy or make a small cabinet, test it out, and see if you want to build the other of the pair.

My asking price is $60 plus the actual cost of shipping.

john

Just picked up a pair of old "Fried" - Bud Fried - Signature A/6 speakers.
Both speakers work, but the left one has a slightly muffled sound. What gives?
So, have tested out by exchanging the wires – I.e by switching L&R wires on the Amplifier. Making one speaker the L, which was earlier R, and vice versa.
One speaker , speaker X, is definitely voicing EVERYTHING with lesser volume and strength as compared to the other speaker in the Pair. Tweeter is working, but plays fainter. Midwoofer is working, but again fainter. Thus both the tweeter and midwoofer of speaker X are playing fainting as compared to the other of the Pair

Do note that the M.A.R.S system cable is NOT present :

FYI:

The m.a.r.s.® technology requires a two-conductor interconnect between the two loudspeakers. In order to maintain proper polarity Fried has supplied you with a twenty (20) foot cable for this purpose. The two-bladed plug on each end of the cable can only be inserted one way. If you wish to use a different cable, it is necessary to solder the plugs on the two ends so that the conductors are, in effect, crossed. In other words, one conductor should be wired to the larger blade on one end and the smaller blade on the other, and vice versa with the other conductor.

NON-m.a.r.s.® OPERATION:
Your A/6 loudspeakers may also be used in a non-m.a.r.s.® mode. Included with each loudspeaker is a short jumper cable that should be attached from the m.a.r.s.® socket to the negative (black) binding post to operate in the non-m.a.r.s.® mode. One may completely remove the knurled cap of the black binding post and place the ring connector of the jumper on the post. After replacing the cap, you are ready to conveniently switch between m.a.r.s.® and non-m.a.r.s.® modes by either using the m.a.r.s.® cable or the non-m.a.r.s.® jumpers.

Opened up the Crossover and found the below - it's supposed to be a SERIES Crossover (not parallel)
These are 23-24 year old speakers.

Can someone help me with finding best crossover details for AIWA HIFI SPEAKER MODEL : NSX-V900

I'm a massively huge fan of vintage analog synthesizers, effects and musical instruments having grown up in the 70s and 80s. I have a soft spot for the music of that era, specifically British pop, old school hip hop and RnB (the REAL kind WITHOUT AUTOTUNE). My son and I frequently try to quiz each other which synths, drum machines and samples were used in various music back in the day.

I'm not a regular YT watcher, but I needed to share this video I came across, which is beyond excellent and incredibly well done. I hope you enjoy it as much as I did.

Login to view embedded media

Want to buy a pair of Focal, Sonus Faber or Scan-Speak 6.5 inch bass woofers, 8 Ohm impedance.

Thanks.

I am trying to replicate the Revel M105 copy project from ASR, but with a different tweeter. I built the cabinets, the waveguide, mounted the speakers and am ready for the next step (crossover design). I have taken horizontal measurements of both the tweeter and woofer while mounted in the enclosure (driving each one separately).
In the case of the woofer I have collected near field measurements and the same for the port. Microphone placement was about 0.2" from the cone center, and in the case of the port, the microphone was pretty much inside. I used REW, a UMIK-1 to collect measurements all driven from a yamaha amp without changing the output volume (near field measurements were at a lower volume due to clipping).
I combined the port and woofer near field measurements and adjusted the port SPL using the appropriate formula (20Log(portdia/woofereffectivedia). I then adjusted the near field for the baffle diffraction. Once I had a cleaned/combined/adjusted near field I blended with the far field 0deg measurements to get the response shown below.

The woofer is a Scanspeak 15W/8530K00 and the tweeter is a Morel ST1108 supreme.

I have a few questions and am looking for some expert advice.

1. How do I determine what the port tuning frequency is at right now? (Jeff bagby paper references a drop in SPL, which should occur at the tuning of the enclosure, but I don't really see it). I am targeting about 40hz for enclosure tuning and cut the port length appropriately (2" diameter port).
2. What is going on with the scanspeak at the 250-3550hz range. Why is SPL dumping out? Should I be concerned? Where should I be looking to try to address this?

The enclosure is made from 1" MDF walls (2 pieces of 1/2" glued) and the front is 1.5"MDF (3 pieces of 1/2" glued). The internal is braced and I glued some melamine foam to the interior.

Here are some pictures. I appreciate any help you can provide.







Here is my attempt at a crossover.

I've built almost any kind of exotic loadspeaker: planars, ribbon, Rubanoid and of course AMTs.

My last endeavour will start with four of these:


This will be a real time adventure as usual, so there will for sure be bumps on the trip.

First I got rid the net and its fasteners:


More later...

Hello diyAudio forum,

I'm a first time owner of an amplifier, as I've just bought two passive speakers. I wish to connect it all to both a record player, and my TV.

I'm having issues with the NAD T743, and I apologize if I can't explain it well, because I'm really not technically gifted.

The speakers are connected to the right places with the wires.
The red/white cables are put into the "CD" input on the back.
I turn it on and put it on CD, and connect my phone. But I can only hear a VERY low sound of the music playing, and that's while the amplifier and phone is at maximum.

I've pressed all the buttons and I don't know what to do. I've tried to factory reset, but it doesn't work per the guides I found online, and I don't understand what the user manual describes. I have a remote, and it can turn the amplifier ON, but it can't do anything else than that. All the buttons just light up red when you click them.

I hope someone wants to help. I was really hoping to have this set up by now, but I've spent 4 hours playing with it and have no results.

Thank you.
Best regards,
Anders

4 channel amp not powering on
I checked voltages on mosfets
Drive voltage and 12v are present at left and middle leg but led of power or protection not glowing
I suspect pwn ic as faulty
Can anyone tell me all voltages of kia494ap at each pin and how to verify that it is serviceable
In my case voltages are
1 nil
2 5v
3 500mv
4 220mv
5 2v
6 1.7v
7 gnd
8 12v
9 4.7v
10 4.7v
11 12v
13 5v
14 5v
15 2.5v
16 0.2v
Kindly assist to clear fault
Thx in advance

I've just registered on this forum so please forgive any errors in procedure in my request for help.
I have a CD880 and a good while ago it seemed to require some time from switching on to read a disc. I thought that perhaps a deteriorating component needed some warm-up time. The problem got so bad that I decided to leave the machine switched on all the time. Eventually, this approach failed and it ceased to read a disc at all. Somewhere, I have seen a reference to replacing the 33uF capacitor on the pcb on the underside of the disc mechanism as being a possible solution. I have gained access to that capacitor and would like advice on the specification of any suitable replacement; 33uF, yes, but what else should I be aware of - voltage rating or build type, for example?
Grateful for any advice to keep this vintage device alive, which can include other possible solutions to the problem in case the capacitor change fails to do the trick.

Hello, I have consulted this in another forum specialized in Sansui, but I did not receive answers, maybe someone here can help me, thank you.

"Hello everyoneI have this tuner that has some drift in the FM tuning, it is not much, but it is annoying, when the tuning changes, listening in stereo it activates the mute, you have to correct a little to hear well again, the power supply is correct and it lacks ripple, I even tried changing it and the tuning does not change when doing this, I replaced the TC3 trimmer, the C8 capacitor of type NP0 and Q6, and the problem persists. Use a freezing spray but its influence is very powerful, I'm not sure the temperature is the problem either. Any opinion or suggestion is welcome."

Czy ktoś budował taką konstrukcję? Dwa głośniki Acoustic Elegant TD10S w zamkniętej obudowie. Dodatkowo Bliesma 34b, Audax po modernizacji. Wiele osób dodaje oddzielne wzmacniacze dsp. Mam monobloki o mocy 250 W/8 omów. Pokój 20 m2
Czy ktoś ma doświadczenie w budowie głośników 3-drożnych z głośnikami TD10s?
Mam problem z dokonaniem wyboru. Czy powinienem wybrać 2x 8-calowy grafen Seas Excel czy AE td10s. Wiem, że te dwie mniejsze są szybsze, ale nic nie brzmi tak dobrze, jak duża membrana. Pozdrowienia.

---

I have 2 new SMPS boards from the DENON PMA60

These boards are well made and have multiple voltages available

Dual rail set for +27v 0 -27v at 5A

Also +12v -12v rails to power opamp circuit.

220~240V supply

Voltages available on board:

+5V 1A

+12V 0,35A

-12V 0,3A

+19V 0,05A

+27V 0 -27v 5A

size is 16,5 x 9 x 5 cm
Postage Australia Only
$40 ea. + postage

How is this for an excuse for applying brakes to a few thousand dollars of new audio gear, boards, components and drivers?


Hello all, please allow me to introduce Randhir Jagawar Lal, two and a half months old now











So, how are your projects progressing. Any interesting excuses? 🙂

Hello everyone, I am getting into the world of electronics applied to the field of music. I have built a pre-amplifier circuit for an electret microphone controlled by a PTT that closes with GND, and I am facing the following problems:

• I have to get the microphone too close to my mouth for it to work.
• Without pressing the PTT, when I speak excessively loud with the microphone close to my mouth, it can be heard through the speakers.
• We have tested to change R99 to 1k and R96 to 100k but it doesn't work.

The model of the headphones is as follows: Sennheiser GSP 302.

Attached is my schematic, thank you very much.

One of my power transformers developed a short - firsthand knowledge of how important is a good ground!
Since I had a bit of mechanical hum from the old ones, I want to mount them on a rubber pad. I installed grommets in the mounting holes and was planning on using some rubber washers under the bolts to help with eliminating the hum. The hum is purely mechanical and the transformers have a history of this. As a matter of fact, the company sells a rubber sheet specifically for this purpose.
So how can I safely rubber mount these transformers while insuring a safe electrical ground? I was thinking of running a wire from one of the mounting bolts to the chassis. Does that fulfill safety requirements? The end-bells bolts are insulated with plastic shoulder washers and cardboard sleeves so electrically seem isolated from each other. Should I use one wire from each end-bell mounting bolt to the chassis?
Thanks for any help
Dave

SOLD

Happy Holidays All!

Over winter break I plan to build a pair of B&C Sub 15s I'm going to slightly modify the design to incorporate an extension around the enclosure about 40mm to countersink a flush grill. I want the vents covered also as these will live in my garage when not in use and I live rural so rodents are a real thing. Given that the enclosure is on the smaller side and the vent is fairly sizeable, small differences in length seems to make big differences in tuning. The flange will extend the vent on 3 sides, since it is only 3 sides, how do I account for/calculate the amount if vent I have to leave off internally?

Thanks!

Chad

Just finished building my Aleph J and when adjusting the bias and offset, I got some possibly concerning results. Once powered on, I set the bias to 0.35V for both sides, then let it sit for 30 minutes. I then adjusted to 0.40V. I started measuring the DC offset and got 0.011v for the left channel and .021v for the right channel. I put the top cover on let it cook for another 30 minutes. After 30 minutes with the top on, the bias voltage on both sides dropped a little bit under .40V. so I boosted them back up to spec. The DC offset then rose back up to the aforementioned values.

I cannot seem to get a lower DC offset voltage while having the bias set to 0.40v. Is 0.011v and 0.021v okay for both channels? I did some research and it seems it will be, but I wanted to get some opinions from people much more experienced than me. 🙂

Thanks!

I can post pictures if needed

Finally a Bluetooth speaker worth buying!
Coming soon to a listening room near you (Free shipping and free returns (at least here in Australia))

Buzzword compliant - AirPlay, BT, wifi streaming via Chromecast, Spotify and Roon ready etc





Teeny tiny skinny floorstanding cabinets your born in 21C partner / children would like.

for the DIY audio nerds- it’s an
active 3 way with a 5” wide baffle with 4” coaxial midrange/tweeter closely surrounded by four 5.25” woofers crammed into only 12.5L of cabinet volume.

500/100/100 Watts (4ohm) for LF/MF/HF
Uses DSP for baffle step compensation, delays, crossover, equalisation and +/- phase correction, and limiters for woofer protection.
The coaxial is part of KEF’s recently released ranges, albeit smaller, with acoustically tuned damper for the tweeter.

Each pair of midwoofers share a common magnet (!) , but optimised for low rubber surround radiation distortion: the white paper suggests a very flat and symmetrical Kms(x) & BL(x) curves.

The woofers also use voice coil current negative feedback for reduced bass distortion, which is advantageous when using small woofers in small boxes.

Here is the White Paper with the details:
https://us.kef.com/pub/media/ls60-content/LS60W_WP.pdf

Now, I know what you’re thinking. Big deal.
And they’re €7K/US$7K/AU$10K a pair.
Let's forget about the price for a moment, or whether you can afford them, and even if you could, are you in the market for one.

I'm glad that not all wireless speakers are $100 BT speakers... I'm looking at you Apple, Google with more resources for R&D than anybody else. This is a problem that Sean Olive commented on- how do you get people to be interested in acoustic excellence; there’s not much captured in the specs or reviews that indicate why a large high performance speaker (the size and weight of a person and the cost of a small automobile) is better than a $100 speaker with essentially the same frequency response? Of course; that is, without having to sell them a piece of (audio) furniture?

Come on, let’s make an easy-to-use wireless speaker that the kids and spouse can use with their voice / phone, but us audio nuts might also enjoy listening to...

K E F
Make Speakers Great Again

@Galu
@AllenB
@newvirus2008 u
@Andrew Eckhardt
Good evening guys here I am then, this new thread is true because the project has changed, I will use 2 lower frequencies (5khz) to be able to overcome the impedance. Their interference will produce a 10khz wave, which is not ultrasound, but I'll start from there. However, for now I believe that the important question is the mathematical formulas, such as how does the frequency and amplitude vary based on the materials they pass through? I hope to make it with your help

For those who aren't aware, HiVi sells completed speakers, and I just wanted to make a post saying that they're pretty good! At least the ones I bought.

HiVi-Swans OS-10 HiFi Stereo Speakers, Bluetooth 5.0 Active Computer Bookshelf Speakers - 4'' Dynamic Woofer, Powered Desk Speakers 62w RMS with Touch Control for PC/Phone/TV https://a.co/d/cMzKvAA

These are on sale right now, so I bought a pair for a friend in need, and I'm quite impressed with them. Seems to be the T20 tweeter and B4N midwoofer? And they are powered with RCA, coax, optical and Bluetooth inputs. All of the cables you might need are included with the speakers, and they even come with a remote (and batteries!) I don't have any of my equipment to take any measurements, but subjectively the sound is very full bodied for their size, with impressive bass and a very calm (almost subdued) top end that does not call attention to itself. I think this laid back sound signature fits these speakers quite well, as most speakers I've heard in this size range have sounded shouty and anemic.

Anyways, if any of y'all are in the mood for gift giving, or just need a set of TV speakers or something, check these out! I think you'll be pleasantly surprised

Given how common Zoom is today, I'd thought it would be fun to have occasional Zoom meetings to chat about audio. Whenever someone wants to host a meeting, post a link here. I'll go first: https://us05web.zoom.us/j/88169974953?pwd=izSjEbvblrglQ4jSs5CjyZ7ev8LdhK.1

Any experience with Tang Band W8-1808 in sealed box?

Massive NAD surround receiver for parts. I don't have the time to fix it, but transformer and heatsinks appear to be in good condition. Xform is approx 2x45V loaded. Guessing 400-600VA. Weight 20kg.

I think local pickup or shipping in Dk is the only realistic option.

300DkKr?

Hi. I am trying to figure out the best impedance match between a passive attenuator, and a unique old amp.

The amp in question is an Onkyo M-505. It has an input impedance of 100k. There was a matching preamp (P-303) with an output impedance of 600 Ohms.

The designer says that this is to ensure for the least amount of voltage loss.

I am not aware of any quality 1K audio pots, and I am not sure that one could build a stepped attenuator that could achieve or maintain this value.

I thought about trying a 10K pot, but this may skew the sound of this special amp.

https://audio-database.com/ONKYO/amp/integram-505-e.html

Where can I buy the "Power & Shorts" Lamp/lights for the B&K 747B

I have single ended triode and pentode amps and push pull pentodes, so got to thinking about building a push pull triode amplifier.
Target output: 15 - 20 watts no feedback.
Ideally something just a little bit more exotic than trioded el34, 84 6L6 etc.... and got plans for PL36s EL500/4/9 already so not them. UK based which seems to limit the (cheap) availability of a lot of American triode sweep tubes that would be suitable. 🙁
Don't want to spend much money if possible.
Seems the days of super cheap tubes are gone, initial thoughts, in an ideal world, would be something like a 2A3 amp, but even 6B4G quite expensive nowadays.
Initially the 6P21s seems like it could provide some DHT goodness, but I hear reservations about the longevity of the filament. It is a "relatively normal" tube though? so if that was a problem it would not be a total loss to redesign the amp with say a 6L6 type of valve. I could use a fairly normal 6k ish A-A output transformer.
I also have some 12E1 tubes. I get the impression they are not the happiest in triode mode though, but they are more powerful than I need so some room for flexibility, but seems moving towards lower voltage lower Z transformer.
And then there are the (Russian) regulator triodes, and 6080s. On reflection I could imagine paralleled 6080s (2) into a carefully chosen toroidal mains transformer, although not aesthetically what I am after, could have the potential to deliver the kind of sound I think I would like, clean and tight...
any thoughts.

I want to know where to allocate funds when specifying transformers for a tube amp build (read: what corners to cut).

At the risk of oversimplifying things... From what I understand the output transformers make the most difference sonically; however, I know that amps are the sum of their parts and each typology would stress different aspects of each component. To get the best OPT possible, would you go with a slightly lesser quality choke or power transformer? I'm leaning toward cutting corners on the choke but I would like to get a second opinion.

When I imagine cutting corners, it would not be on choke specification... more on overall quality (I guess???)... for example, forgoing the Hashimoto choke for an Edcor or Hammond. Obviously, there will be a difference...

I'm heading to Japan next month and specifically wondering if I should get some nice big ISO OPTs and General Transformer (formerly Noguchi Transformer) chokes or get slightly lesser ISO OPTs and ISO chokes. Am I overthinking this?