Just received some new parts as follows. I have 2 of each (for monoblocks) and thus am able to swap to see if a specific part is the issue.


The filament transformer (4V for an Aa tube) + 2A LC filament supply works as designed. spot on. no problems.

However, filament transformer (20V for GM 70 tube) + 3A LC filament supply produces a significant mechanical hum/vibration from the filament transformer. The GM70 tube is drawing 2.88A current (spec is 3A). The GM70 is measuring 19Vdc (spec is 19-20Vdc). So, I swapped transformers. Still same issue. I swapped LC filament supply. Still same issue. I swapped tubes. Same issue.

Then, instead of using the 3A LC, I tried a Coleman V9 regulator. This worked fine. Just a slight mechanical hum from the filament transformers, but nothing worth discussing. So, it appears that the LC is causing the filament transformer to hum, yet the transformer is rated for 3A. Any thoughts on this?

Here is the LC design:


FYI: Once I get the filament transformer mechanical hum problem fixed, I will be adding another choke. This will give a nicely supplied LCL. I am comparing the LCL to the LC + Coleman solution. Should be fun once the mechanical hum is fixed.

For sale are two LCD screen modules, 6€ each, or 10€ both, plus shipping.
These are 16x2 characters big. One is white characters on black background, the other is black on white/green.

Please see pictures below.

SOLD the white on black display.
6€ for the other one still available, plus shipping.

I have extras to sell of the Electrodyne/Quad Eight ACN 3B's. Tested and working. Vintage summing modules, 21 input combined into one balanced output. Input can be either 600 ohm or 10k unbalanced.

Hi I am looking for a well built pass pearl ii. Thank you
Located in USA

Hey guys, I am trying to upgrade my transformers and came across NP Acoustics as a potential choice. Corresponding with them has been great and the gentleman running the company is very prompt with his responses.

I need 1 pair of OPTs for my GM70 monoblocks, 1 pair of interstage transformers for 2A3 tube driving the GM70 and 1 Pair of ITs for 4p1L preamp (the IT gets used as an OPT there).

I am good in having finalised the specifications of all 3 pairs of these transformers. However, what concerns me now are the hundreds of user impressions about the amorphous cores sounding bright, brittle, sharp in trebles and light on bass. I really can't do with this sort of sound/tone. What is paramount for me is to get a detailed yet sweet tone and not utterly bright and unnatural sound, if that makes any sense.

I understand NP Acoustics has few great feedbacks recorded online and since they perhaps use large core sizes, hence folks may not have observed any loss of bass. However, I wanted to open this thread so that those of you who have experience using these transformers could let me know if this company and moreover amorphous core trafos will indeed be the right choice considering my tastes as mentioned above. Does it make sense to only go for the ITs as amorphous and the OPT as something else?

Thanks in advance

Kartick

Attempting a Quad 606 clone using Chinese PCBs as shown. Working well on headphone (390R resistor in series with load) but massive distortion on speaker - which increases as heat sink area increased.

Hi all. Total REW noob here. I'm planning on running REW on a Windows 10 laptop initially. Is there a particular mic, stand, other parts, etc... you would recommend starting off with? Would I be better off with the UMIK-1 or -2 or something completely different? Any particular mic stand that would be good to start with? Any special tools needed other than a laptop, software, mic, mic stand, etc.. to get started? I'm assuming most just order from miniDSP directly?

I'll be starting out doing some room tuning but want to eventually build a high-end set of mains for 2 channel listening w/ multiple subs (true 3 or 4 way active setup). I'll also be playing around with my current HT setup to experiment with multiple subs. For reference, I'm currently running a 5.2 setup with active subs using a Denon AVR-X4400H w/ 11ch pre out capability. I have a separate Adcom GFA-555 I've been using on my mains but will probably DIY separate amps when going for the active mains build.

I don't currently have any miniDSP hardware. I wanted to get the room measured and treated as my first step, but does it make more sense to buy a hardware and mic bundle if I'm planning to go down that path?

Sorry for all the questions, but there are a lot of options on the miniDSP website. I figure some of you have already been down this path before. Any recommendations about a good starting point would be appreciated.

Thanks,
Bill

Good day guys, have an Hifonics amplifier that goes into limited protect (momentarily mute) when playing a deeper note and more often when it’s powering two speakers, I’ve already replace rail caps and even the output filter cap which was swollen.
The customer described to me that the relay disengage when it’s momentarily in protection, I don’t know if the PWM power supply card wants recap if it’s a case where the relay is opening due to low voltage/current to feeding it, and also if there’s any applicable mod to let it play lower Ohms without muting (as like some of the JBL BP series amp).

Hi there, I bought an old transformer to built a guitar amplifier for personal use. When it arrived I took a no load test to see if it was working. The voltages on the HT reads 450v -0 -450v. The transformer is very heavy as it came out of a 100w amp running 4 x EL34s. My idea was to use it on a 50w build but I dont want to use it with that high voltages as I am planning to use solid state rectifiers. That would bring me into the 630 range and feel that is going to load the tubes too much. The circuit I have in mind is a Hiwatt clone. Would voltage dropping resistors work to bring the voltage down to a reasonable 450v dc or should I look at another transformer. Where should I put them? before or after the rectifier. Any help would be great Thanx.

Hello DIY folks.

As we all know, acoustic measurements can be extremely beneficial in designing loudspeakers. As far as budget hardware is concerned, the miniDSP Umik-1 is a very popular solution.

The Umik-1 comes with SPL & frequency calibration. However, it doesn't fulfill any standards, and since there is also no public review in which its performance / accuracy has ever been tested, it basically has been up to guesswork if this piece of hardware provides reliable data.

To try to bring some light into the darkness, here's my comparison vs. reference (IEC 61672 Class 1) measurement hardware:

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Regards
Stoneeh

I'm trying to measure the phase and amplitude of four 1KHz audio pulses from four separate
QSD's. The 1khz tone upstream is from one source. I'm told that the output Z of these is low enough to use balanced mic inputs in a audio a to d, (~300 ohm input should be fine). I'm looking intially at a cheap 4 channel interfaces like a MOTU M4 4x4, (115db dynamic range, 60db gain). I don't know if this would do the job. Two things I need in hardware as well as software. I need to have phase correct sine display and if possible to resolve 1uV. So I'm looking for software that can give me in phase the fours sources. I'm also told the 115db dynamic range should be good at least for the start. So I'm looking for thoughts on hardware and software recomendations.
Thank you for checking out, Michael

I was thinking about building a relatively cheap portable system using an SMSL SA1000 amp (50w). The reason why I was thinking of using this amp is because I don't need a 80W-100W+ amp and it has Bluetooth 5.0. I wanted to keep the power requirements as minimum as I could while still providing some decent level of power. The only issue is I am still having a tough time finding a batter pack/bank that isn't $250-400 to power it. The SMSL SA100's power supply is listed at 19V 6.73A.

The speakers i'm driving are Dayton Audio B652 6-1/2"
6 ohm
Sensitivity: 87 dB 1W/1m
40 watts RMS/75 watts max

Would anyone know of a way to power the SMSL for under $200? (wanted to keep this system fairly cheap)

Hello everyone, I'm new here, so I hope you will be forgiving of any initial Pecaillo's.

I just got back from the 2015 California Audio Show in San Francisco. That in itself isn't that interesting for DIY'ers, but I discovered that Mundorf is now selling a speaker kit. It comes with a completely Mundorf parts crossover, Mundorf AMT tweeter and Accuton mid-woofer. According to Mr. Mundorf, they needed to be around 40 cm from the back walls, but I'm not sure if that is needed with a sub.

Sadly, the room or the electronics really sucked and I did not hear much I liked there.

I'm wondering if anyone else has experience with the Mundorf AMT tweeters in general? What I am looking for most of all is an endless decay. I'm not sure if this is ever a tweeter's job, but systems that I most like tend to have the ability to show an instrument's or a voice's decay seem limitless. In most systems I hear there's a point where it just gets cut off. This is by comparison, so for all I know there's just a post-signal rigning, but I like it.

This is the main reason I chose an ARC DAC-8 over others in it's price range and above. The end of a plucked string, or the decay in Emilou Harris's voice just seemed to trail off forever. Otherwise, it's like you reach a diode, and bam, off. Sorry for the bad descriptions.

The second thing I need is it has to maintain clarity in a small space. I have Focal's now, but going to a San Francisco apartment I've lost a lot of the clarity they had in my previous apartment, so I think what I want is something with relatively narrow dispersion.

I've also been thinking about a kit from Selah audio, the Verity.

Thanks for your thoughts in advance!

Erik

Hi Everyone,

I haven't been here in a while but a recent built by Troels Gravesen has made me think about building a new, 3-way active center. Mostly I'm intrigued by the Illuminator 12MU he used.

Here's my question. Assuming I go fully active with a similar design, is there any benefit to digitally delaying the tweeter or tweeter/mid to co-locate the acoustic plane for all 3 sets of drivers?? In simulations I've tried before using 2-way speakers it seemed the only real benefit was smoother off-axis response. Assuming I went with a 3-way active amp/crossover is it going to be worthwhile to attempt to simulate this using digital delays?

Thank you!

Erik

hi guys

any of you know if this is a cap? (red arrow) and if so what type ?

its my mates and he says it has a bit of a hum. I thought transformer hum, but he seems to think it is this component

cheers 👍

In Jean Hiragas Book "LED AUDIO Initiation aux amplis a tubes".
Page 98. Output transformers for push pull amps.
Freq. range. I think that freq. range for Tango, Lux and Tamura is measured at 1 W output, and for Millerioux at full output !
Does anybody know the core size for some of the 28 output transformers ?

Going where few (in this forum) had dare go before.
Pick your favorite diode, which one 'sounds' best?😉

Hello,
I brought 2 used PA cabs Sr-4733x for cheap would like to build 2 ways x-over. The CD is not original. The woofer is from JBL don't know if it's original . I don't trust my measurements as it doesn't sound dull i.e. missing the high . I did the individual drivers in DAT. I eventually will try to get the accurate measurements in REW.

Hi guys - selling a large quantity of my valves. Prices can be negotiated to some extent for multiple numbers. Please contact me with any questions or if you want more details about particular valves.

I would draw your attention to the European radio triodes - these are rare and collectible and have a gain (mu) of 30 or over. They sound very good and make excellent driver tubes for amplifiers.

Hi,

Thank you for reading my question.

I'm interested in upgrading/modding the amp in an old Yamaha receiver and wondering if it is feasible to do it with one of Pass designs that are available in the store.

I am a newcomer to working with electronics and don't know enough yet to be able to think my way through the project.

The heat sink is approximately 8cm by 16cm. It is 20 watts per channel into 8 ohm

I've attached 4 pictures of the inside of the case.

The model is a Yamaha CR-240.

I tried to paste a link to the hifiengine info page, but the forum would not allow me to post a website link.

Any advice would be appreciated.

Thanks in advance.

Hello,

Does it make sense to build a woofer in such a way that it has a relatively high mms in order to get a very low frequency response? Especially when you build a multway system and the woofer is only responsible for the really low frequencies. or would you advise me against it?

As new Ortofon AS212S tonearm with box €.1050

I have a problem that I have not solved successfully after many hours of staring at the German manual (PE 3046) of my Turntable (I don't understand German and use Google translate for pieces of it), and the English manual of the similar Dual 1224/1225 turntables.

So there is a black lever underneath the platter that is actuated by a cam that both raises and lowers the tonearm, and pushes it off of the tonearm rest onto the record and returns it from the record to the tonearm rest. I got a new rubber steuerpimpel for it, and it is working much better, but not perfectly. The steuerpimpel (a little rubber button) is placed over a steel pin which the black lever presses on to move the tonearm inwards towards the center of the record and outwards towards the tonearm rest.

When the record ends, it seems to work fine, with the tonearm being lifted and pulled outwards and placed on the tonearm rest by the black lever mechanism being actuated by the cam. However, when I start a record, a thing happens that I can not figure out. The tonearm is lifted and moved towards the center of the record. However, it is always moved back off the record before it is lowered down and so misses the record. From watching videos on Youtube, it's not supposed to pull the tonearm backwards towards the rest when starting a record, it's only supposed to go outwards and then drop onto the edge of the record.

There's an eccentric nut that one can adjust by switching the speed lever from the 33 to 45 rpm position, which adjusts the position of the tonearm before it is dropped onto the record. This works, and it changes the position that the tonearm is moved inwards to, but it is always moved outwards again and drops the tonearm off the edge of the record.

I also played with the anti-skating control to make sure it wasn't being pulled too strongly outwards. Even at the zero anti-staking control position, it still moves the tonearm outwards after moving it inwards.

Anyways if anyone has encountered a similar problem on Dual or PE turntables that would be helpful. It does play beautifully if I set the tonearm on the edge of the record manually. Thanks!

Dan

Hey Guys,

I decided to stop working on the expensive STEG K2.02 and start working on a cheaper one, because these are my first Car Amp repairs.

Ok so now to my patient.

First i recognized prior repair attempts. As you can see on the picture.
What will help me a lot, would be a service manual or a schematic of this board.
I thermal imaged the PCB when power on the amp.

IC50 (HIP4080AIPZ) is getting hot and ZD10 and the 2 330 Ohms Resistors.
Also theres a prior attempt with the white jumper wire.

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Where to start?

Imagine a simple circuit. Just a lamp a power supply and a switch connected so that when you throw the switch, the light goes on.

Question: Now imagine this circuit to have the size of the visible universe, with all the 3 components as far away as possible. If you throw the switch when does the light go on?

I have for sale a mint pair mid-woofer Beyma 12nd80 V2. Price €.400

​

*Wasn't sure where else to put this but since some of you liked my previous discussion with Rene Christenson, I thought I'd share this chat with Beth. This was one of my favorite chats so far. Be sure to leave a “thanks” to Beth for sharing her time to talk about her research and AES publications.

(Note: My “interviews” are not monetized)

The Steely Dan thing is a joke that makes sense if you watch the video.

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I'm really no good at circuits, so need help to choose simpel buffer. I have some TPA3118 and pascal spro2 that need buffers. I have found some but need advice. Noise must be very low, easy to implement, volume nice to have but not really needed. Strong enough to drive my spro2 modules, single ended, I don't need balanced input

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#Aliexpress US $9.79 14%OFF | Aiyima TPA6120 Headphone Amplifier Board Amplificador TPA6120A2 Mini Double Channel Headphone Amplifier Diy
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WTB:

Twisted Pear: Legato v3.1 PCB or a working one fully populated 🙂

I can pay with Paypal.

Thanks in advance!

Hi all, I've got projects coming up that require adding additional opamp stages to existing equipment. Thus I am on the hunt for a good pre-made PCB breadboard that can hold one or two 8-pin dual opamps & the usual supporting parts.

I haven't bought any of these since Radio Shack led the way lol. Who makes decent ones these days? Many thanks...

my current system is using an macbook usb output to 3x MiniDSP HD to run a 6 way speaker system (each with their own amp).

I would like to upgrade to a DSP with analogue outs or a DSP and a multichannel DAC because I am worried about timing jitter between 3 different DSPs/DACs.

Does anyone know of a DSP or DAC combo that can take a digital input and output 12 (or more) channels? I am thinking this would be pro audio gear?

Hello.
If I use an ecc83, I want it to amplify less than mu, I can't load it too much because it will skew the waveform.
I can't also limit the mA because it will cold bias it, and shift the waveform too.

so what can I do if I don't need all the gain (noise) ?

Thank you.

Anyone have a clue on where to obtain the Via VT1731 chip, and a data sheet? I’m interested to see what it will take to get together a dac with that chip!

Peerless by Tymphany SDS-160F25PR01-08 6-1/2" Paper Cone Woofer Speaker

Anyone used these recently or ?

I was thinking:

4 of these as two small subs in a office/small shop? With a pair of ‘MtM mains’ (hivi m4n or dayton rs100 and tweeters.

Or as a W in a pair of WMtMW?

Or 4 seperates as TMW?

Im Kind of a 2 channel and subwoofer listener but that isn't really important... rs100s/hivi/peerless parts in hand(currently in other speakers.

I’m just posting to see if anyone here would be interested in a beogram 8000. I have one that I would like to sell. It doesn’t have a working cartridge unfortunately ,the Mmc 20cl is with it but appears to be broken. The turntable runs and changes from 33-45. The arm runs back and forth smoothly. It doesn’t have the cable with it, it only has the power cable. It will need some work but it is in nice shape generally. I’ve looked at other examples on eBay etc and I’m asking $475 which I think is very fair. I would like this to go to a good home as this was owned by my aunt and run in a system with Macintosh amps. If no one wants it, can someone recommend a good place to list it as I’m not a fan of eBay.

I have a transformer from an NAD C370. There are no specs/values written on it and I haven't been able to find any on the web. I'd like to use it for another project but have no idea what the VA rating is. Is there a way to measure it?

I have studied ohms law and Kirchoffs law but hadn't come across the equi-potential theory before.
https://www.eevblog.com/2022/05/09/eevblog-1472-resistor-cube-problem-solved/

So I was giving my surrounds a renewal on a very old set of woofers and I noticed that one of the spiders was pretty concave down while the other was flat. I'm wondering which one these woofers is the "correct" one and which might be problematic? Is there any way to fix it that doesn't require replacing the spider?

From an educational perspective I'm also wondering what effects the out of place spider would have on the sound.

Thanks!

Woofer #1


Woofer #2

Hello!
Between MDF, HDF and Bamboo plywood, which one is more suitable for building the cabinet of dipole subwoofer?

Thanks!

Hi;

I am looking for proper pcb layout for my 20x 2200uF cap bank smooting pcb for my Class-AB amplifier.

There are 3 main design i saw on the samples;
A) 2 LAYER PCB - Power plane over Ground plane.
B) 2 LAYER PCB - Power taces over ground plane.
C) 1 LAYER PCB - Seperatred power and ground traces and they do not overlap each other.

I am glad if you can explain which one is the right way to go? And Why?

Hi All,
I fancy a dig around in my little dot MK2 headphone amp. I'm pretty new to this but think the obvious place to start a bit of modding may be the coupling caps.
According this schematic I found, it seems to be a 220ufd bypassed by a 0.68ufd - both electrolytics.
What type of caps would be suitable as a replacement do you think? Space is at a premium in there so massive Russian cans aren't an option.

Thanks in advance

Hi🙂
I want to buy DAC chip Ad1865

Any advantage to gain using Non-Magnetic over metal film Resistors on next amplifier project.

I am looking for some recommendations as to what kind and brand of caps to use in a tube phono-stage's RIAA circuit. I've had recommendations from REL-TFTs to Charcroft's Silver/Mica to Copper foil and propylene. Looking for help in selecting these.

Thanks in advance

Soekris dam1121-01 R2R DAC module, the highest quality 0.01% version. New €365 including VAT, bought from Soekris on January 14, 2021. Asking price €295 275 excluding shipping from The Netherlands.

As good as new and with the latest stock firmware and filters, at the moment configured for the soft filter and easily changeable using a TTL serial connection.





It comes with two "helping headers" that are stackable on the 2 mm headers. These helping headers make it effortless to connect I2S using jumper wires and audio out with signal cables. I got too close to one of the Molex-terminals, but that's cosmetic only and working fine.



Besides these helping headers, I'm also including an unfinished PCB for easy connection to a Twisted Pear Cronus reclocker or Amanero USB-to-I2S module.



I have enormously enjoyed this module, but got DAC fever and bought a Denafrips, and this module is much to good to sit on the shelves unused.

There are a lot of custom filters available too on this very forum (or you can build them yourself) to experiment to your hearts desire. For me, it were the quasi-NOS filters that really brought this module to life. Others swear by the linear filters. Your choice!

Manual: http://www.soekris.dk/download/dam1121/dam1121_manual.pdf

hi guys,

since a few of you already know; I am working on my ATC SCM100 clone
(SCM100ASL Pro | ATC Loudspeakers)

It uses a 12" ATC bass in a ~100L cabinet and a 10cm dia port tuned to 30Hz.
Now I am wondering about the cabinets damping.

I have some Basotect over laying around and was wondering if thats a suitable material for damping a cabinet?
I know it's brilliant for acoustic treatment in rooms but not sure about cabinet and speaker design?

Any experience and/or suggestions?

Hi, Tube folks,

Currently there are 2 major flavors of audio output transformers (both SE and PP) - with silicon steel and amorphous cores.

Amorphous cores are ferromagnetic alloys based on iron (73.5%), silicon (13.5%), boron (9%), niobium (3%) and copper (1%)). Depending on the type of heat treatment after quenching they may have a rectangular (Br/Bs = 0,2-0,9), linear or circular hysteresis loop. They allow to build smaller transformers with given power rating with lower losses, high saturation flux (up to 1.56 Tesla), etc.

The question is - which one would you suggest? Different people state different things - some say only silicon steel (because of higher distortions of amorphous cores - IMHO a somewhat unproven statement), other say "I DON’T EVER WANT TO GO BACK to silicon steel".

Any suggestion(s) are greatly appreciated.

Hi , bought an A100 spares & repair from ebay. It switched on fan run and power light was on but no sound. With lid off i found R1 & R2 OC and one channel op transistors short and a dj on the volume pot. It was clear it had been worked on before as the op tranny's were MJ15003/4 types and the smoothing caps and a few other components had been changed.
I changed R1 & R2 0.47 ohm 2w and the pair of shorted transistors checked around the circuit for other obvious stuff and switched on. I now have +- 35v at R13/14 R113 / R114 on the 35v rail side. But i have anywhere between 12.5v -13v on the Zener side The voltage gradually ramps up, i switch off before letting it go any further. This is the same for all the 12 v Zener rails +ve -ve. I am not sure exactly what's going on here but would assume whatever is wrong is common to all the 12v rails? I am assuming the zener's hold the rails at bang on 12v? I have also noticed that voltages around pin 11 and 4 on IC1 also ramp and are not a the voltages suggested by the cct diagram on Mark Hennessey web site. ZD3 does not reach 5.2v either. I have checked most resistors and diodes in the power amp circuit and i also changed 12v Zener just to check. The diode that came out was fine and the new one i fitted exhibited the same fault condition. Any thoughts /help welcome. I have read the Hennessey website and most of the threads on here and find nothing relevant to this so far. Oh one more thing for interest my board is marked A100 ver5 .
For background , i was a TV & Radio service engineer back when these were new but left that side of engineering a long time ago. More than a bit rusty now in more ways than one.

SOLD

Hello, I would first like to thank all of the contributors to this forum. Without you I wouldn't have gotten this far into the design process whatsoever.

So I'm building some compact-ish bookshelf speakers and some input on my crossover design would be very much appreciated.

I get a deep null but there is phase overlap only on one side. Would that be a problem? Is there any way to fix this and make the phase responses match better? I've played around with the components, changing values, adding or removing parts, but nothing so far has fixed it. Am I overlooking something?

Speaker drivers that I'm using:
Dayton Audio AMT Mini-8
Dayton Audio DS135-8 5"

Hey All,

Here I am again, looking for a schematic for a piece of vintage audio gear...

Seems I keep coming up with old stuff that I can't find info on with a simple internet search.

Now, I'm looking for a schematic for a 80's/90's vintage DOD 1642 XLR II, 16 channel rackmount mixer.

Digitech/DOD did not freely distribute schematics, unless you were an authorized repair center.
Now, they are pretty much defunct...
So, I'm hoping someone here has this archived...

Can anyone out there help?

Regards,
JohnR

Hello People, I am repairing a Crown model CSL800 power amplifier, it uses a 100Vdc power supply with floating ground. I can't get data on the original output transistors (4 per rail), although I saw on some forums that they have used MJ15025 and MJ15025 as replacements. Unfortunately, in my country, it is very difficult to obtain original transistors, I decided to buy some and when I received them, visually they already seemed like bad copies. I measured the breaking Vce and they barely reach 140V. My query is as follows, I have a sufficient quantity of MJ15003 and 15004, of good and proven origin, and although these are 140V against the 200V of the 15024/25, as I see it, in the SOA curves it could work well, what's more, the 15003/4 looks a bit better. If I consider an increase in VCC of 20%, I still have a safety margin. Any suggestion, much appreciated.

I'm unloading most of my driver stock. All drivers are in excellent condition and used very little. All drivers have their original packaging unless noted. Local pick up in Southeast Michigan or can ship at buyers expense. Paypal add 3%.

(Driver Description, Quantity, Asking Price (Ea), Available)

Dayton RS225 8in woofer 2 $40 SOLD
Peerless DA32TX00 1.25” conundrum tweeter 3 $40 SOLD
SB Acoust SB29BAC-C00-4 29mm Be tweeter 2 $200 SOLD
Eton 5-312/C8/25 Hex 5.25” midwoofer 4 $50 SOLD
Audax HM130Z0 5.25” Aerogel midwoofer 2 $40 Sold
Eton 5-212/C8/25 Hex 5.25” midwoofer 1 $50 Yes
Morel MDM55 2-1/8in soft dome mid 4 $35 SOLD
Fountek NeoCd3.5h (missing original packaging) 2.5” horn ribbon 2 $50 SOLD
Tymphany NE315W-08 12in woofer 4 $100 SOLD
Aurum Cantus G3Si Ribbon tweeters 3 $90 2-SOLD, 1-Available
Dayton RSS315HFA-8 12in woofer 1 $100 Yes

Anyone has built a dipole subwoofer with Acoustic Elegance Dipole 18?

Any comments??

Hi everyone and regards from Paris (misleading pseudonym I know). Long time lurker here whom never bothered to register as I didn't feel I had anything to contribute, especially being an audio newbie that found a sudden interest (or rather, urge) to come in possession of a good sounding mic (for work), then excellent headphones and finally drifted into vintage amps due to an obsessive nature for anything unknown and intellectually arousing. This tendancy to propel myself head first into any rabbit hole I come across has previously led me to build a DIY joystick from a hacked Xbox pad and Japanase hardware (Sanwa stick! Seimitsu buttons!), a mechanical keyboard with an obscure 72% PCB produced by a Korean amateur with some vintage-looking double-shot keycaps ordered as part of a group buy that took 18 months to produce (R5 anyone?) and an oak-tanned bull leather belt among other things. I am also bad with punctuation with an obnoxious tendancy to write unnecessarily long sentences, which I was repeatedly told was mentally exhausting. Coming to think of it this would probably my defining characteristic and should any mod venture this deep into my intro thread please feel free to rename my profile to "ExhaustingPhil".

Anyway I still don't have anything to contribute, but having recently purchased my first vintage amp (yay!) that has experienced a rather critical capacitor failure (booo) I come to thee in dire need of help 'cause I don't have the faintest idea of what I'm doing.
I'm already thinking about making an amp and obviously the lure of DIY resonates strongly within this one, but since I have found the one in a thousand WAF-compliant amp I'd like to fix what I have first, plus I figure it'll be good practice.

TL;DR: French dude, happy to be here.

I bought this for parts from ebay.

Like seller told me, it damaged by opposite power polarity or by power polarity bridge, probably.

After power on, nothing is happening!
Because we have not any circuit diagram, I am looking with the continuity of multimeter the paths after power switch.

It is a searching in blind, sure! Maybe the best solution is to find the appropriate flex connector for working with the both parts open, not closed like now.

After that, I found some electronics to have a relation with the power paths. At the attachment photo I have mark some of these.
I have changed 2 of these (by yellow circles) and now lights on the green led (power on led) above headphone level, but no any other led.

1) Any suggestions?
2) Can someone find to me the appropriate code (farnell, mouser) for extra flex connector? I want to work, with both sides open.

i read on ebay: https://www.ebay.it/itm/22444294322...3220.N36.S1.typeWATCH_ITEM_ENDING_SOON.R1.TR5
"KSA50 and KSA80 are praised as beautiful Krell power amplifiers by all walks of life. Among them, KSA50 is a Krell power amplifier, and it is also its own work (in terms of timbre). To this day, Nelson Pass, the designer of the American audio PASS and the founder of another audio Threshold, also said that the KSA50 circuit is better than the current 95% HI-END amplifier!"
I'd like to know if Nelson Pass really said that, thank you.

I needed some AD9201ARSZ a2d converters for a scope project which I have used before.
Out of interest looked around usual vendors for a price. Prices ranged from around £10 upwards.
I looked on Ali Express and they were 52p each !
The last batch I got a couple of years back from Ali and they worked fine.

Looked for some 4700uf 35v caps on RS and they were £2 + VAT.
Looked on ebay and they were 60p each including p+p

I have some crossover parts from a Lampizator p17 build as I've decided to use active crossovers with bi or tri amping due to a change of drivers. I'm not sure how to price these so please tell me if I'm asking for too much...

I have the following available - item, quantity, price per item:

Mundorf MCap MKP Classic 82uF, 250V / 2 / £20
Mundorf L200 Air core 2mm 0.39mH / 4 / £15
4.7mH Jantzen C-Coil 0.07 ohm / 2 / £40

Based in Bristol, UK but can post.

Heya. I am taking some time to peek inside the driver efficiency and implications of that. While here and on AVS, there is lots of knowledgeable people, this topic is still not general knowledge. Firstly, high efficiency means low Qts, which is big no-no for oldschool people and hi-fi people. Then there are other compromises to be made, and then, there are details of speaker manufacturers approach to this, that I would like to know.

This graph below is just a starter, work in progress, and will show 1Watt SPL output (kind of efficiency in decibels)of some known drivers, which I will add. Just from seeing the outcome, a lot of implications were understood immediately. Compromise is being made by setting the reference box volume and a port. I will try to add closed box comparison of the same driver to see, what that one does to the system efficiency. Looking at ported graphs, it looks like the port doesn't do a thing.

https://ibb.co/DfXXnG3

I wonder why high end driver manufacturers decide to use stiffer suspension, to lose on both sensitivity and efficiency, especially in the upper range of bass. Any ideas?
Yes, high end high excursion drivers with narrow magnetic gap prolly need to solve rocking modes, but is that it, or there is more to it?

OK...first of all let me say this....


For years before I was even considering DIY audio, I bought a pair of ACI (Audio Concepts Inc) Sapphire III's from my little brother.

Probably the most impressive thing about these speakers were the cabinets, they were made from 1 inch HDF! (High Density Fiber board.) The knock test on these makes everything else seem amateur!

To make a long story short when I decided to build my own speakers, naturally I wanted HDF! But we had huge problems there.

The problem wasn't just not being able to find it, nobody even knows what it is!!!! But with a diligent internet search and a LOT of CREATIVITY I found the hands down solution to building speaker cabinets with HDF !!! No JOKE!


Let me clarify right here I am working out some details but my first test seems like it will work WITHOUT improving anything from my first trial.


Okay so here goes.


I am currently building the popular Elsinores project. And in one post Joe mentioned one of the biggest improvements you could make to the cabinet was to build just the front panel out of HDF!

"But the thing that I believe would improve the box most is the most simple (and yet difficult at the same time), take a look at the newer Dynaudio designs, that baffle of theirs made of high density fibre board. I have heard a pair of Lenehan ML-1 speakers in both standard and 'Signature' versions and this was the only difference. Make the front part of the box structure out of this material and I believe the improvement would be greater than anything I have covered so far, no kidding!" (http://www.diyaudio.com/forums/multi-way/97043-elsinore-project-thread-15.html)

So I have spent the last several weeks...not to mention several years trying to source HDF! But it wasn't happening! You can get it but you have to buy a few thousand dollars worth of inventory!


But I did find something called "hardboard". And as it turns out it is the same thing as HDF, but it's just come is thin sheets.


So I got the idea of laminating several sheets together to make the thickness needed to build a cabinet!


So I bought a sheet of it, ripped the sizes I needed and this afternoon laminated them together...and all I can say is WOW!


WOW, WOW, WOW!!!!

On a single 9" X 4' panel the knock test hurts your knuckles! I am not kidding! It is like concrete, without any bracing of even a structure! For speaker building I think it was the smartest move I've made!


I used 7 total 1"x 4"s with braces behind them and my test piece is not as straight as I'd like. Which I am sure once even thing is put together would not be a problem, but tomorrow I'm going to get a half sheet (4' x 4') of 1/2" hardwood plywood and make a "former" to keep the rest of the laminations straighter!



I'll update when I have more to tell...and pictures.

I got another Cyrus Two that blows mains fuse. I suspect that the transformer is fried because the copper leads to the preamp rectifier are melted away and diodes are shorted. Most likely the secondary has some melts as well.
I consider my options:
1. get similar new transformer - 2x30V 300W = expensive
2. get two 30V 10.5A transformers, wire these in series and keep these outside in a box = 4 times cheaper
3. get smaller(less than 100W and maybe 2x12-15V - I don't think it has to be 30V - preamp needs 18V DC) transformer just for the preamp and build PSX with these 300W trannies(total 600W?) for the main amp

For me the third option sounds the most interesting since the original PSX(not the PSX-R) seems to be very simple device.
What do you think and what is the best way doing it(what parts to use and what improvements I could include)?

Interesting article about a new analogue physical music format. Claimed to be the pinnacle of sound.
https://www.whathifi.com/news/there...ound?msclkid=bc92236ed0ff11ecacd9588a99097e37

What are the changes of survival? For starters the name of the format (Ionic Original) does not stir me. Looks like these Ionic Original discs can be played on a DVD player. This part confuses me a bit – playing an analogue format on a digital disc player. The disc looks rather pie shaped on the photo. Are DVD players still available?

Anyway, it certainly sounds amazing, and I hope it survives longer and is more successful than Neil Young’s attempt a few years back.
https://www.noise11.com/news/r-i-p-...0423?msclkid=a21bc70dd0fe11eca0abc9b5d7da8044

Looking for wireless HDMI transmitter/receivers relatively affordable (<$200) unless a little more gets a lot more performance.
The distance between the receiver/transmitter would only be around 20ft and would be mostly without obstruction other than a bedroom door. Also would need it to be remote/IR capable.
Thanks for any direct recommendations as the reviews for the ones I’ve seen are all over the place unless you get into systems in the big money category.

Sansui BA-F1 schematic

Would anyone happen to have this diagram?

Much obliged.

/Hugo

Hello,
I want to build full range stereo loudspeakers with Visaton BG20 speaker. Can you help me please what will be the good volume for the sealed cabinets?
I saw that it was given as 1,06 ft3 and 1,66 ft3 and i am confused.
Thanks a lot for your help
Noyan

https://www.visaton.de/sites/default/files/dd_product/BG 20.pdf
https://www.visaton.de/en/products/drivers/fullrange-systems/bg-20-8-ohm
https://www.visaton.de/en/products/drivers/fullrange-systems/bg-20-8-ohm
https://www.parts-express.com/Visaton-BG20-8-8-Full-Range-Speaker-with-Whizzer-Cone-292-548

1x Morel MSW144 New - $75 shipped
1x Morel CAW538 New - $110 shipped
CSS powered MTM bookshelf monitors with Aurum Cantus ribbons, WR125 mids and Parts Express active 2-channel plate amps Used/Good - $350 shipped
Anthem MRX-500 w/remote Used/Good - $425 shipped
Rotel RDV-1045 w/remote Used/Good - $125 shipped

Looking to identify the center IC on this YEUM1007A output driver card. Card is from a Sundown SAX-125.4 but the same card is common on many of the class D 4-ch zenon board amplifiers.

So I salvaged two large Peavey CS800 power amps. They are old school class A/B quasi complimentary output with a 50lb power transformer.
I kept blowing transistors until I realized the speaker protection crowbar triac had gone dead short permanently.
This is the second time this triac has gone short circuit. I think what happens is it get's triggered on power up because one power rail rises quicker than the other.
As usual, like any semiconductor, it's failure mode is short circuit.
I really question the value of a crowbar. I guess the philosophy is save the speakers by sacrificing the amp.
One thing I noticed is the filter circuit for firing the triac has a capacitor half the value of what is listed on the schematic. I speculate I could easily triple or quadrupole that value as listed on the schematic and still save speakers.
Maybe I'll just nix the crowbar.
Thoughts?

If I measured my own drive units with REW and then used Xsim to model a crossover, how close would the finished speaker be to the model?

Hi all!
I found a nice older Shure 545 (Series 2 - "pistol grip") microphone that needed some work, at a garage sale.
One of the challenges is that I would like to find one of the adapters that Switchcraft used to make (#L3MN), that would adapt the 4 pin 'Amphenol' connector on the mic base to the now more standard 3 pin 'XLR'.
It looks like Switchcraft doesn't make that L3MN adapter anymore, but I just thought I'd put out feelers to see if any of you have seen anything like that or may know of a good alternative?

Thanks for your help and leads,
Buck

Hi all, wasn't sure where to post this.

Have done a bit of googling but was hoping on some direct opinions and advice....

I bought a job lot of 6 JBL 2226s, second hand, for a decent price. The guy seemed honest, was doing me a deal on a bunch of stuff, said he had tested them etc. Consumer advice not neccesary, Im aware I did take a minor leap of faith.

They then sat around for a while in my (nice and dry) workshop waiting for some cabs to go in, which I have finally built a couple of. And now I have a job for two of them, so i loaded one into each cab, and was excited to hear.... nothing. Spent ages troubleshooting the amp and cables, but turns out the drivers show an open circuit on the multimeter. Tested the rest and 4 out of 6 are showing open circuit! Cones all move freely and without crunch, terminals all look ok and generally they are in decent enough shape. So, whats likely to be going on here? Broken connections to the voice coil? What can I check and repair?

Apologies if its a basic question but im hoping they can be salvaged
Many thanks!
Fen

Hi looking to buy one of these to replace one I have that has gone faulty in a specific physical configuration (so I am not able to use later versions). It has to be a III version and not the IIIse. If you have one for sale can you send me a reply or PM. I am located in the UK but happy to pay worldwide shipping. Thanks.

Hi there,

I'm looking at an alternative EU source (Other than Farnell, RS, Mouser, digikey) for 'medium' quantities of passive components, let's say typically quantities of 1000 resistors or caps.
Usually I find low quantities at a very high price or all-in on 100.000 at the price I can afford. I understand this is how it works but I wonder if some of you have found the resistor heaven. Also curious about every source I'm not aware of. I remember 10 years ago buying 100 pcs from farnell very cheap, this is not the case anymore and I need to address it.

I can buy as private or company, around 90% through hole, website with datasheets only.

Direct from manufacturer with low moq and an online store or reactive support would be perfect.

Tried the search function as I'm pretty sure this has been posted before but got no luck. Do not hesitate to link other recent threads.

Thanks!

Trying to sort out production dates for some Hitachi 2SJ49 MOSFETs... marked 5C1, but no luck so far..

This is an offshoot from the Alpha Nirvana amp thread here:

https://www.diyaudio.com/community/...8ohm-class-a-amp.344540/page-110#post-6949783
@minek123 adapted @AKSA ’s 39W Class A amp to use a JFET input opamp as the input stage.

This has several advantages as explained by Minek including lower distortion, etc usual things opamps offer.



I wanted to move the discussion to a new thread as it really is a different and new amp. This will keep discussion of the original Alpha Nirvana amp less confusing for those looking for info on the base amp.

Thank you to Hugh Dean for the original Alpha Nirvana and to Minek for the new modern opamp variant.

Every year I try to do something a little crazy. Last year I built two 15" guitar cabs based on my own design which apparently had a lot in common with the old Forte 3D guitar cabs. They turned out fantastic, so looking to build something crazier now. The 15" cabs turned out great, but there wasn't a lot of trial-n-error. I guess I just happened to guess well on dimensions and such. Looking to be a bit more scientific in this next build.

So what I'm looking to do this year is build another guitar cab. This one would have an 18" driver in a spherical enclosure with a 12" driver in a teardrop shaped enclosure. See attached pic below (not to scale obviously).

Can anyone school me on what I need to know to get the dimensions for this design right?

A few things to note:

The "cone" shaped thing behind the drivers is for rear deflection from the driver. For the 12" cab, this will be screwed into the backside of the cab. For the 15" cab, I will likely need to suspend it inside the cab so it is centered behind the driver. This should add a little bracing and will be closer to the center of the sphere (scale way off on that one).

I was planning to make the walls 1" thick but can be thicker or thinner based on advice here. How thick should the walls be?

I live in South America and wood species are different here. I don't have access to Baltic Birch ply here believe it or not. I used some local pine for my last cabs and it was fine. I will likely veneer these cabs, so I don't care what the wood looks like. But I do need to know what qualities of wood to look for here as any specific wood species suggestion isn't gonna be helpful unless you know how the wood strength/density varies by species here. I know most folks say to look for voidless marine grade wood. Anything else?

My plan is for the 18" cab to be sealed. How can I calculate the cab resonance pre-build to see if I will likely need to add a tuned port?

In my 15" cabs, I spent a bunch of time focused on eliminating standing waves in the cab. Other than the rear cone deflector, I also cut grooves all over the interior of the cab.

For these spherical and teardrop shaped cabs, do I want the inside surfaces to be silky smooth or should I add a bunch of half-dome wood dimples of various sizes inside to create more diffusion?

For the 18" cab, is a sphere going to be better than say slightly stretching the design out into more of an oval?

Any guidance on how to design the curves & proportions of the 12" cab?

For the 12" cab, my idea was to have the piece at the rear with the rear deflector attached have openings to vent from the backside, so this is kinda open back. Any advantage to cutting some slits at the skinny part of the cab to make it even more open or is venting out that backside all I need?

Here was one of the final designs for my 15" cab. I didn't end up doing the rear or side deflectors and used a wood dome rear reflector instead. Design also doesn't show all the details of what I did inside the cab, but you get the idea.

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Hi all,

Anyone have schematics for a Dynacord L2400 that includes the output
pc board ? The copy I have does not include the output board.

Thanks so much 🙂

I have several DP3T (ON-ON-ON) switches. Instructions indicate "jumper needed to achieve triple throw", but no drawing of this on the datasheet.
Can anyone explain or show me how this would be achieved?

Hi! I know that this one has been asked before (even on other forums).

I am currently servicing a Tapco 4400 for a friend of mine and have the following issues:

1. Sticky Faders which have improved after cleaning with alcohol
2. Channel 1 reverb randomly drops out sometimes and takes a while to start working again
   1. Perhaps there is a cold joint?
3. Channel 2 Reverb/EQ has a very low output - perhaps a bad op-amp or capacitor?

Thanks! I look forward to hearing your suggestions. I'm obviously going to have a look at the service manual to identify the signal paths.