Gentlemen, my living-room amplifier (Audio Agile Step AMP, the company "Audio Agile" does no longer exist and I have not been able
to source the amplifiers schematic for repair) passed away 2 month ago, and I need a replacement for it.

I do not like to use my SYMASYM as replacement.
The SYMASYM has been the "working-horse" for all of my projects and works perfectly with them.

Nor do I want and use any of Mr. Nelson Pass' amplifiers.
His amplifiers (I have built his A40, F5, ACA) are too weak (may I therefore call them "CORONA amplifiers" - without being put into the bin?)
to ventilate my speakers (f.e.: KAPPA Infinity 600).

I have remembered Prof. Nelson Pass' amplifier (Release 4.5) to sound very well and have done a layout of my own.
Image1 shows the schematic; Image2 shows the layout.

I have the needed MPSA06, MPSA56, 2N3439 and 2N5416 at hand for 5 pairs of the Leach_AMP PCBs.

I will use NJL0281DG / NJL0302DG with integrated thermal diodes as output transistors.
MOUSER does not currently offer the NJL. But ARROW does!

I have not yet ordered anything from ARROW. Is it a trustworthy company?
If so: I will order 25 pcs. of NJL0281DG/NJL0302DG each and match them (as well as the MPSA transistors) for you.

The PCB size is 228 x 79 mm.
The price for 1 PCB, 6xMPSA06, 5xMPSA56, 2x2N3439 and 2x2N5416 is 15€. A pair of PCBs will then cost 30€ (shipping cost not included).
2 pairs of the Leach AMP PCBs are already spoken for.

Are there any 3 (even more?) of you, who want to build this amplifier?
Give me a PM then.

Best regards - Rudi_Ratlos

Hi Guys, am looking for one of these, does anyone know of one please?

SOLD --- SOLD --- SOLD

My_Ref amps have been sold, so no longer available!

It’s time for a clear out! So, for sale are the following items, fully assembled and completed, and sounding great! Built by me as I progressed through my DIY audiophile journey, now surplus to my needs.

My_Ref Fremen Edition power amplifier, version 1.8 pcb’s
Built exactly as per official build guide as 2 x mono-blocks, with cost being no object. All ‘best’ components installed, including all recommended audiophile upgrades completed:
I/C’s: LM318 Op Amp, LM3886 Main Amp
Caps: Nichicon, Elna Cerafine, Mundorf MCap Supreme, Amtrans
Resistors: Vishay Dale, Charcroft Z-Foils, Mundorf MResist Ultra
Transformers: 2 x 240vac, 25vdc, 225VA
Enclosures: 2 x Galaxy Maggiorato GX288 (230 x 280), black with silver front panels
RCA + Speaker Posts: Hifi Collective gold plated
Front LED indicator

… and the result is a terrific sounding little amplifier! Total build cost was in the region of £700, but I would be happy with any sensible offers - say £300?

Some images attached, reasonable offers considered!

If you'd like any more info, please drop me a PM.

(Note - LM3886 Gainclone power amplifier is sold, so I've edited this post to remove the details as no longer relevant)

Cambridge Audio CXN V2 network player in perfect condition, in original box. Free shipping to continental US.

Asking $500.

VG

I am attempting to determine whether some JFETS I have on hand are behaving properly.
I breadboarded this circuit (I reversed battery polarity for P-channel JFETs):

And got these results (horizontal axis is volts and vertical axis is milliamps):

One P channel device is most certainly dead: 1-2 and 1-1 isn't linear.
But are the others alright?

Selling my fostex 208 NS drivers that were originally in my kirishima cabinets.

£300 collection only, sorry no packaging.
Selling / sold off my complete system.

Let me know if you want anymore pics etc.

Cheers all.

Here is some information on an MFB speaker I worked on and eventually made a couple of samples of for my own use back in the early 80s. At some point I hope to analyze it a bit with newer tools and share that information. Hopefully it will be of interest to at least a few. Frankly, I don't think that this will provide any new information for those here who are technically inclined and have experimented with the technology. There are certainly people here with a much better handle on electronics and control theory than I have. But it provides another example of an acceleration feedback system to read about. 🙂

I haven't worked on this sort of thing since that time but I find myself interested in giving it another go. But I have a lot to learn about the tools being used today for this sort of development. I may need some guidance on that.

But anyways, first a bit of history. Back around 1979, I had what I thought was the brand new, never-before tried and supremely brilliant idea of fixing the non-linearities of a low frequency loudspeaker with some sort of negative feedback. I constructed a very simple op amp adder feedback circuit (pushing the limit of my technical knowledge to the extreme) and fed back a position signal derived from a lamp, LDR and light blocking card attached to the back of the speaker cone to the preamp signal. Well, it worked right away and was stable. What's so hard about this! For a moment, I thought I had solved all the world's problems with accurate low frequency reproduction.

Then reality set in.

I knew it was working because I could push hard on the cone with my fingers and the amplifier was pushing back. If I pushed hard enough, the over-current protection on the amplifier would trip. But I soon discovered it only worked at very low frequencies. And as I rationalized later, it probably was only stable due to an extremely limited bandwidth of the sensor.

So after some trips to the University library, I realized there were already successful implementations of motion feedback using both velocity-sensing coil and accelerometer feedback methods. I discovered the 1968 Philips paper by Klaassen and Koning and discovered an MFB speaker had already been produced in Canada by PSB Speakers. This was the Beta II which employed a Philips MFB driver and, if memory serves, it had been in production since the mid 70's. In pursuit of a B.Eng.Sc. degree I needed a 4th year project so this became the "Motional Feedback Speaker" where I would try to develop a version on my own. Fortunately, I had access to lab equipment and a very good lab technician who frankly ran rings around me on the electronics side of things. And Paul Barton graciously forwarded additional technical articles that were not in the library. Without these, I seriously doubt a good result would have been possible.

I don't have any pictures of the original prototype, but attached is a pic taken recently of one of the two speakers that were built for my own use back in 1982 along with the MFB control box for a stereo pair. Note the drivers are P/N AD80671/MFB which were round versions of the original octagonal driver P/N AD8067/MFB. I think these were available in the later years the MFB drivers were produced. You could just order these drivers and 12" versions directly from a Philips distributor at the time.

Hi
So long time owner of the Marantz MM-8003 multi channel power amp. Had it from new and even if I have since purchased other amps I still use it to drive my rear channels in bi-amp mode. Now the issue is that I have had a re-occurring fault that have forced me to send it in for repair 3 times - every time with the same protection fault error.
Guess what - have now happened again. I have the service manual but honestly no direct clues except for measuring the whole amp.
I am guessing this is due to a component that should be replaced with a better version so that the error would not happen again. But, no clue available from the previous places that have repaired in the past and I honestly are getting a bit tired of paying for this.
So, does anyone have a clue to where this error is located? The amp will start but stop in protection mode with a fast blinking LED.
Would really appreciate if someone could give me a clue.. I know how to solder but not really equipped to do a complete fault finding (Yes, have measuring tools, multi meters etc. but still...)
THX

Hi, I need help in troubleshhooting my Magnepans 1.7i!

They emmit a kazoo like sound, when playing Trumpets or womens Voices.
It sounds distorted and only affects a small high frequency range.
It's not so much dependent on volume, even at low volumes it's recognizable.
Visualy the foils look ok. The alu-traces are OK and completly glued to the foil.
There are three dots in the middle of the membran, to spread resonances.
I suspect, there's a rubber between the discs that has hardened over time.

The speakers are 6 years old.

Did somebody experience a similar problem?
I ruled out the other components in the chain.
It's definitly the speaker.

What's your opinion?

Thanks
Olaf

Hi all,

I am in a process of rebuilding some old gear, namely a TAG Mclaren processor with new capacitors as the current ones are reaching the 15y old mark. This is done for quite a lot of folks and apparently is sufficient to fix some error codes / glitches that the processor exhibits in a device of this age.

Meanwhile, i was wondering if it would be sensible to "recap" the AKSA power amps after 2 decades of good old service too ? My eldest amps from Hugh are the AKSA 100N, dont remember the exact date but probably getting to 20 years now.....that is a lot ....wow...time flies.

Does it make sense to touch it, if no problem seem to be happening ?
Is there a % reduction in say power supply reservoir capacity with a 20 year old psu ? TAG fans seem to refer that a 10 year old amp, probably is at 70% capacity and this can be noticed in "midrange and bass". Does this make any sense ?

I honestly cant say if anything sounds different from 20y ago...as my memory is not THAT good. 😀

Food for thought and discussion 🙂
SAF

I am selling my trusted Audio Precision System One. Everything is working, and the device has been used less than 50 hours since last check. Good condition.

Old school top of the line dedicated audio measuring system.

The AP comes with:

• Rack mounts Currently not mounted in the AP (See picture).
• AES17 measurement filter PCB. Currently not mounted in the AP (See picture). Only used approx 20 hours. Cost is approx 200 USD.
• USB adapter for AP System One/Two. This makes it possible to run the AP from a modern computer without the parallel port. Only used for approx 50 hours. Cost 290 USD. https://www.s1usb.com/

Make me an offer 🙂

I stumbled over a decription to build a hybrid amp "br398 mostube" from brinck in denmark.

in the decription there is a dual triode "EV21" but i cannot find any infor about this tube.
Any hints

Can anyone recommend a repairer for Revox tuner? It is a B160.

Many thanks,

Brian

EDIT:

Also for TEAC T1 Transport!!!

I have tried everything, google, ai assistant and diy audio but I am not able to find answers to my question.

My questions,
first
in image 1 output transistor q4 is tied to r6 resistance which is part of constant current with q2.
but
in image 2 two out transistor is directly connected to rails.
what are the pro and cons of each approach.
why to chose one over another ?

second
in image one no constant current source is used with q1 while it is used in image two with q4.
what are the pro and cons of each approach.
why to chose one over another ?

third
i am looking for good resources so that i can learn how to properly bias the transistors and select optimum resistance values.
could someone put towards right direction or guide me how to calculate the current and resistance values for chosen transistors and operating voltage.

any assistance would be appreciated.
thanks and regards.

I have a 60" TV in my above garage man cave/bar that is mounted on the wall, here's a pic.




The Center channel that's in there now is a Klipsch, I think maybe a G-28 or something. Doesn't really matter as it's not very good. It's thin and fits in the space perfectly, but it sound terrible, sort of like a 1970s mini transistor radio.

So the space is almost 7" from the bottom of the TV to the top of the built in area where the electronics are, and it's 4' wide or so. I can probably get away with 3-4" deep and I can't cut back into the wall because there is a stud behind the center of the area. That stud is actually part of a truss for the structure, so I can't cut into that.

I'm thinking about trying to design a center channel speaker that would replace that klipsch. To prevent comb filtering I am considering just using a single speaker module. The idea would be to build a box in similar shape to the Klipsch so maybe 3" deep, 7" tall, and the length could be anything less than about 40" to accommodate the box volume needed. Could be a sealed box, or if we could get away with it, a ported box maybe with two ports on each side of the center speaker.

For driver choice, I might be able to get away with a 6" driver but it depends on the actual frame size and a few other factors, certainly can do a 5" or 4". I don't think there is anything below 4" that would perform better than the 4" and above drivers. For center channel, maybe there are some 4" offerings that work as well as the larger ones and that would be much easier to construct a box for. Since there is only one driver, power handling is a concern.

Since I will only buy one driver, cost is not an overriding concern but I would like to keep it below $200, although if there was something that was far superior to the rest, maybe I could be convinced. Thus far, I have looked at the following potential driver candidates.
Markaudio - chr90, alpair 10.3, pluvia 11, Pluvia 7HD - The Pluvia 11 looks nice, but it would be a very tight fit, so not sure it would work.
Foxtex - FW108HS, FF165WK, FF125WK, FF105WK. The FF165Wk would also be a very tight fit.
Scanspeak - 10F/8414G-10
Seas - Prestige FU10RB H1600

So, a few questions.

1. Is this just a stupid idea? Maybe I cannot do any better than the Klipsch "70s transistor radio" sound! I sure hope that's not the case.
2. Any opinions on driver selection? Not limited to the ones I have looked at, I'm totally open to any driver.
3. Any opinions on Sealed vs Ported design?
4. Has this idea already been done? I've searched diyaudio but I couldn't find anything. I would have thought this to be a common issue and was surprised I didn't find any other threads, maybe I'm just not good at searching.

Thanks.

Hello, maybe someone have a controller schematic and .hex file for PCM1792A software control?
I am interesting a PCM/DSD switch function.
Ready to buy it.

Hello to all diyAudio users!
Selling my Hi-End CD-Tuner Alpine F1 Status CDA-7990J, for Japanese domestic market. It is brand new, complete factory set with box. Tested to make sure it works. It has not been used or installed. It was purchased by me from Japan at the time. But never had a chance to install it. Stored carefully, in a box. These are rare nowadays.

I'll give it to you for 2000$.
Experience in shipments is available, so I will send around the world.
Sending from Latvia, as I live here.
+37125973099 whatsapp

Hi All

Just picked up a pair of Celestion Ditton 551 (1979)and managed to repair a tweeter and replace both blown 500mA
fuses. I have listened to them a bit using my Sansui 250 which is not a very high power tube amp. (10-15W a side?)
They sound great turned up about 1/2 way, but the bass response is not as powerful as I would imagine.
I have no previous experience with these speakers and wonder if it's just a characteristic of them
when not driven very hard or the crossovers need recapping for optimum bass?
I visually checked 1 cross-over and it looked original with no swelling caps and resistors measured almost within tolerance.
I really wanted to avoid recapping at this stage as:
They sound pretty good to my ears except bass a little underwhelming.
I am refinishing cabs and grille cloth (hands are full)
It's a real pain to pop out the woofers to get at crossovers and risk damaging something else.





So I was hoping some people who are familiar with these speakers may shed some light.
Would be much appreciated.
Thanks Rich

By this I mean for less than ideal speakers. Due to WAF factor, my MTMs of about 91dB are less than ideal but results are good.
I'm currently discussing making speakers for SETs, seems equally valid to discuss making SETs for normal speakers here, they are intimately linked.
I will cover the principles here, if anyone wants the amp design I can look it up and post it; the principles should apply to any SET.

A critical friend (I liken him to Craig Revel Horwood, he is fair but harsh for my own good) is highly into dynamics, with a powerful active Naim setup.
He has said of my present amp/speaker system that it has fast clean leading edges, and that at last I have some dynamics. Funnily , this is the least powerful amp I have even had; I've had EL34 PP and 2 300B SETs.
This amp is 45 parallel SET, 6C8G/E83F mu stage driver. Yes, I know parallel 45 is much like a 2A3, but I heard a 45 and wanted 45's, did it, right or wrong. I was thinking of 45 PP but a friend, expert, who knows me well said Mike, you're a SET guy, go parallel.

For dynamics, my principles were:
It's all in the PSU (well, very very nearly all).
I tend to think this; compare say a 3watt amp with 300 watt PSU, vs a 30 watt amp with 30 watt PSU; we know which will measure more powerful but I'm sure I know which will sound more powerful in the real world driving speakers.

Big mains TX, over rated by about 3 times.
Use a separate PSU for the driver stage. I learnt this from Naim, who split PSUs by stage rather than by channel; it prevents the sag from a drop in output stage PSU from getting to the driver stage; definitely recommended.
I use a GZ34 for the driver stage, but for the output stage a pair of 6CJ3 damper diodes in a full wave (CT transformer); very low voltage drop.
Both PSUs are 2 pi; low DCR chokes in the output stage PSU. Film caps including motor run oil caps, medium values; I forget exactly but of the order of 5uF, 20uF, 40uF.
In particular, the output stage was tuned in PSUD for fast clean transient response, using the PSUD step load function. Search in Audio Asylum. Tube DIY Asylum to learn how to do this; it really works, hence the fast clean leading edges, good 'speed' to the sound generally; nothing slow or lazy to this amp.
This is my approach, other ways are equally valid and may well be better.

For good dynamics to drive real speakers, a good driver stage is vital. To get real power and dynamics I like to be able to swing almost twice the bias voltage each way from a low impedance source. Many ways to do this; I chose a mu stage as I've had good results.
6SL7 does not have enough current; 6SN7 does not quite have enough gain; I needed a 6SM7 but there never was one.
6C8G is the 6SM7 that never was! Mid way between L7 and N7. Runs well at 5mA, and the E83F pentode runs at 12mA total current and is a sweet sounding pentode, I use it a lot as active load.
To run these valves at good operating points, giving say 90V swing both ways, needs a lot of B+, well over 400V if I remember; another reason for the separate PSU for the driver.
Anyway, with a low Zout, this driver will be able to drive the triodes well, giving a lot of current when it's called for.

Which leads to the next issue. Driving the triodes hard (over driving them?) will lead to grid current, which can be a problem. The fix is to use a grid choke, highly recommended.

The result of all this is a decent ability to drive speakers; even at half the power of my 300B amp, it drives them much better.

I'm not saying these things are the only way! You experts will have found good ways to do similar. But I can recommend these principles; in particular, PSUD step response modelling.

Could use two of these.

I already saw myself splurging on cars and women after "fixing " the player but damn clamp motor keep stalling or the bearings are seizing. I gave it a squirt of alcohol and applied a drop of synthetic oil to upper and lower bushings and it worked fine for a day and stalled. Once I give it a gentle push it works fine for some time but inevitably stops. I dont have much experience with those drivers and lubrication. Don't want to mess it up with an experimental treatment. The player was not played since 2005. Any proven solution to the problem ?

Does anyone have the FTD & ZMA files for the Scan-Speak Discovery 10F/4424G00?

I am using it in a two-way with an SB Acoustics tweeter, and just want to quickly model the upper freq area in this online crossover tool that allows FRD and ZMA files, so I can pick values for my first go-around with the crossover. Right now, planning an easy first order crossover.

Just the published response. I don't yet have a calibrated mic. I am planning to order one for my FocusRite audio interface. (Also, what software should i look at for the mic?)

Hi folks,

I've got a pair of Truth 2030A monitors and one of them has what I believe to be a bad transformer (keeps blowing fuses). I've swapped in the transformer from the other monitor and that seems to work fine, so I don't believe it's a fault with the board.

There are no specifications on the transformer itself regarding VA rating etc, but I believe it's 24V secondaries with a center tap.

I'd appreciate if anyone could steer me in the right direction - given a board requirement of ±15v (after rectification, which is handled by 4 discrete diodes), and that the Truth 2030A provides 110w (75w+35w), would a 160VA toroid with 25V secondaries with centre tap be sufficient?

Cheers

I have just constructed a precisely 40dB (1/100) attenuation circuit – in order to help me accurately set the gain of some phono products I build.

I set up a simple resistive bridge circuit in LTspice and, playing with different numbers, found that a 7K7 resistor sitting on top of a 38R9 resistor - with the signal output taken from the top of the 38R9 resistor - produced 5mV out, from 500mV in.

After I'd built it - using my CRO to measure the result - I expected to find 80mV out (on the CRO screen) from 8v in. However, in the real world – I measured only about 40mV out!!??

After a bit of experimenting, I was able to achieve 80mV out … by putting 2x 12k resistors in parallel with the 7K7 value (which was actually 2x 15K resistors in parallel).

Although I've achieved my aim of building a 1/100 attenuator, I'm wondering why the LTspice circuit gave me the wrong result! Any suggestions?

The Open Source DHT Estat Headphone Amp (OSDEHA) needs a power supply!

The main thread about the OSDEHA development is in the Headphone Systems section (see here), but I don't think the power supply gurus will notice it over there. The purpose of this post here in the PSU section is to get feedback for the PSU design draft described here. I also attached the PSU and main amplifier schematics to this post, together with my breakdown of the PSU design notes.

Please shoot with comments and thoughts!

Breakdown of the different PSU sections (starting at the bottom of the schematic):

• The DC supply for the heaters of the input-stage tubes is nothing fancy. Just a full-wave rectifier followed by an LM1085 to get 6.3 VDC for the heaters. The heaters of the 6E5P tubes take up to 0.65 A each. There are two 6E5P per channel (four for stereo), so we need about 2.6 A in total. The Coleman filament regulators for the DHT filaments are on separate boards, so they are not shown here.
• On top of the heaters DC rides a delay circuit that turns on the B+ and B- supplies a few seconds after the heaters are up. The circuit is inspired by the delay used in the High-Amp AC amplifiere (see here). It's 555 timer with 1MΩ + 22uF RC element controls a relay that turn on the transformer secondaries of the B+ and B- supplies.
• The high-voltage supplies (see separate drawing) for the B+, B-, and buffers/grid-bias are inspired by a circuit shown by @mogliaa (see here). It is a relatively simple concept using a CCS for a stable voltage reference (2 x LND-150 cascode). The voltage drop across the "RSET" resistor is buffered by ZTX560 BJT and applied to the STF5NK100Z FET that outputs a smooth DC. There are many other schematics/concepts for HV PSUs out there, but they usually rely on a feedback mechanism for regulation of the output voltage. This may provide excellent measured performance, but a PSU without feedback regulation tends to provide better sound in my experience.
• The bias voltage for the headphone stator is inspired by the Golden Reference HV PSU (see here). It's basically a "charge pump" from the transformer secondary AC riding on the B+ DC output. When the AC swings negative and falls below the DC voltage derived from the B+, the B+ supply charges the capacitor connected to the AC secondary. Once the AC starts swinging positive again, the capacitor charge is pumped through the 10M90S and into the tail of the circuit, where the voltage is limited to 580 VDC by the Zener string.

Hi all. I've posted a few times here before regarding a few different ideas for a WAW. I have been going back and forth on different ideas for what I want for months now, and now I've decided what I finally want and would appreciate any help. I've been reading for hours every day trying to find answers to questions, but I still need some advice so I thought it would be best to ask here. Don't be scared off by the wall of text that's about to follow.

My design goals are this:

- Sealed midwoofers crossed over to Alpair 7ms (these are the drivers I have and I'd like to stick with for now)
- Tight bass with good dynamics, hoping for some really quick transients
- Shallow depth (Max 200mm, less the better, I have been inspired by these - HTS11 On-Wall Loudspeaker | ATC Loudspeakers - which are ATCs monitors but turned into a wall mountable edition). I also like the idea of minimising baffle step loss and the delay in reflections from the back wall
- F6 50hz or less
- Listening distance will be 1m most of the time, will likely be used for PC use only. At most, probably 3m if they are to be moved
- Mostly listen at moderate volumes, about 85db-90db. I do like to rock out from time to time though, so maybe 95db+ volume. Never actually measured my listening volume

- Digital XO around 200hz

So I have a few questions. Firstly, midwoofer wise I was looking at the Dayton Audio RS225 (inspired by XRK). It looks great, measures well and comes in at a good price. My only issue is that putting this driver in a shallow enclosure around 24 litres results in something rather big. Once the alpair enclosure is on top, it'd be around 600mm tall or wide, depending on what way round the enclosure is orientated. I was wondering if anyone knows of similar quality woofers that can live in a smaller enclosure whilst still retaining reasonable extension. I have seen the SB Acoustics SB17CAC35-8 but haven't modelled this in winisd yet.

I would appreciate some advice around the XO. The 7ms seems to have a rising bass response which I assume is to compensate for baffle losses. I was hoping to use a 6db per octave xover but this basically counteracts that if crossing around 200hz. If I were to still use a 6db slope, would this result in the woofers and alpairs summing and creating esentially a bass heavy speaker, or would this have other adverse effects? I generally prefer my speakers with a bit of extra bass. Here is a link to the freq response of the 7ms - https://www.markaudio.com/wp-content/uploads/2019/06/Alpair-7MS-spec-final.pdf

My third question is how shallow can you really go before this having a negative effect on the cabinet reflections. I read somewhere with long bass waves, this isn't so much of an issue and it just ends up as pressure in the cabinet rather than a reflecting wave, but I am not sure.

I think my final question for now is would it be okay to leave the 7ms ported. I ask this because I wonder if the sound will be effected by any group delay. When I'm simluating it sealed, I can't really think of how I can create a 6db per octave slope. I also feel like I would need to create a sealed box and actually measure it to see how it behaves in real life as the rolloff on winisd doesn't seem to match up to the datasheet (as in it starts rolling off earlier in winisd).

I do have a measurement mic and am willing to put time into this project, but what I don't want to do is spend a year on this and then realise I'm not very happy with the sound.

Any help would be appreciated

I am selling an assembled Bottlehead Quicksand. There are Vishay Dale resistors and Nichicon audio grade capacitors. These parts have high tolerances and can be used with a 24V battery. The amplifier works well. No case is included, just the assembled board.

There’s a bunch of optional extras: new TPA3122 chip (a backup), (2) Powerizer 24V 4.5Ah NiMH batteries, NiMH smart charger, and a volt meter. I also have a TPA3125 chip… supposedly it’s a higher end chip, but there’s a subtle variation in the circuit—so using the TPA3125 would be a risk. Everything is in great condition, including the batteries.

If interested, let me know.

Hi, I was looking at the very attractive 47 labs amps recently and trying to learn about the whole concept of gaincards/gainclones (yes, very late to the party). While the original seems to be built around a specific chip, the subsequent gainclones seem to use a wide array of different ones, seemingly with comparable or better results.

Putting on an altruistic hat for a moment, can somebody describe the whole concept and its evolution over the years in short? Are these still relevant in 2024?

I remembered than, I have one "such" (minimalist) chip amp in Vista Audio Spark 2. I only use HE speakers and i used it most with ls3/5a chinese clones (11ohm). Prefered it to NAD integrateds for sure. Clean and smooth sounding.

Here are some pics of it. Single LM1876tf inside, 20w per channel. Is this related to the gainclones? How does it rank? Is it worth keeping, improving?

I realise these questions are very generalistic, so general insight is appreciated🙂

Pair of brand-new, unused,boxed, neat SXT tweeters as used in motive and momentum. SX range. Brand-new and perfect for a DIY loudspeaker project or a speaker upgrade.
£95 with free postage to UK buyers.

Now reduced to £70 with free uk delivery.

Hello Everyone -


Curious as to what the benefits would be to having 1 amplifier per driver vs. having 1 amplifier driving a group of drivers?
(Ex: In an MTM setup, having 1 amp driving each midrange vs having 1 amp to drive both midranges)

Wondering if there would be reasonable performance benefits compared to added cost of having extra amps?

Hi all,

I'm interested for

10 x Ohmite AG 0R22 5W
2 x Ohmite AG 1R 5W
2 x Ohmite AG 4R7 5W

If anyone have them please let me know 😊

But speakers are closer to 8 Ohm on average (Probably even lower) . That leaves me with a reflected load of say 1250 since the winding ratio is 12.5:1

What would be a tube that would be suitable? Since 2a3 needs around 2,5k. 2a3 *2 would be too much right? For a 3Watt output transformer.

Any creative ideas to make this OT suitable for the usual suspects?

Greetings, Friends. I've built a Champ clone or 2, sticking close to the original 5F1 or 5F2A schematics, and I want to access the sweet, OD tones without all of the ear-bleeding.

I see PartsExpress has a range of L-Pad Attenuators from 100 watt down to this little 15w beauty

LME49811 diy hi end amplifier for sale 88€
LME49811 amplifier PCB with matched NPN and PNP Thoshiba output stage,diodes heatsink and connectors are included.
With the supplied output BJT's powers up to 300 watt are easily achieved.
If you require power supply pcb I can supply, reach me or check by, soon displayed in another listing.
Tracked shipment to European union
Skematics sended together with articles.
If you enjoy this kind of stuff check my stuff related:
https://www.ebay.de/usr/dialedinmusic?_trksid=p4429486.m3561.l2559

Just saw this up for sale…

Is it worth it?!

I also saw what was supposedly Curt’s distortion box somewhere recently also.

https://www.ebay.com/itm/2651640211...jZM2ndFzNMEePe+9djrlcT7A==|tkp:Bk9SR5LW6ZG3Yw

I own a pair of YG acoustic’s Kipod II speakers I bought used. I love them but have had some issues.

I recently noticed (not sure if they were always this way) that one speaker is significantly quieter than the other (some rough spl measurement looks like 10-15db quieter or more. I haven’t tried to isolate it, but I believe this applies to both tweeter and woofer.

I did some trouble shooting, swapping amps, wires, and even drive units and the one speaker is still a lot quieter in all scenarios.

I’m not a technician, but logic is pointing me to the crossover. Problem is, I didn’t think a crossover fault could only affect volume. But the fact remains, something g has happened to one of the crossovers (could be the loud one of the soft one).

Has anyone heard of an issue like this? Are there any tests or measurements I can do to verify the issue?

Thanks in advance for your help and advice.

here are some tubes .
if interested ask for info and pics

I'm selling 6 pairs of genuine Toshiba 2SK1529 & 2SJ200 (NOS condition).

Asking for SOLD

PM me if interested



Thanks for looking

Good morning....
I've been reading and following any all threads trying to gather as much information as possible in regards to speaker setups using the ARC D250.
Recently came across Brian Beck's post regarding using TWO of these amplifiers in a bi-amp setup. I will also be applying the THUMP delete schematic that was posted here I believe 2 years ago at next tube change.
Question/ dilemma is the speaker output terminals are setup different.
For 8ohm speakers you are required to use the 4ohm terminal for neg.
Current speakers:
1 pair Klipschorns
1 pair Klipsch Belle's
1 non-powered sub
I've been doing the occasional switching of speakers whenever I'm feeling energetic. But now I just want the Khorns for my front stage and the Belle's rear stage and the sub box in it's optimum spot. All the Klipsch's are rated @100w. and at 30w would run you out of the room. So I have plenty power to go around but what device can be put together to run this system? I've attached a picture of rear of the amp inputs & outputs. Unlike a audio/video style amp it doesn't allow independent zone outputs. If say for instance, if right front & right rear speakers was both install into the right 8ohm terminal... that will change impedance load. Also.... regarding the subwoofer, it does not have a designated out on the D250 amp like standard A/V amps to be installed. Without adding any additional devices that may add noise in the audio chain.... any known wiring schematics for this type setup. THANKS.
If these were $200-300 components and speakers I wouldn't be as cautious but one indecent proposal and POP GOES THE WEASEL!!!

Hi, the Aavik I-800 use "tesla coils" in there amplifier. They say two coils that wounded in each direction.

Something we diyers can make / use?

Frank

Hi folk´s ( don´t know if this is the ringt forum)

A few years back i bought a paket of things from a collecter here in Sweden, inclueding this Pioneer D-23 2/3/4-way crossover in originalbox stored for 30 years.

https://audio-database.com/PIONEER-EXCLUSIVE/etc/d-23-e.html

Its from the "golden age" and from Japan who make good things & have quality
But im a little afraid to start it up, as I want to be careful about it and definitely don't want to make a big bang and smell something burnt.

Is there any way to prevent these risks?
Lock at some components inside, mesaure any particular component ?

I haven´t got the possibility to make a "slowstart" with lower voltage, and slowly raise the voltage.
Sweden has 240 Volt 50 hz.

A few mesaurements from a guy in France, you can use Google translate.

https://www.audiovintage.fr/2022/12/02/pioneer-d-23/

Best regards John

My CD player was skipping tracks so I cleaned the lens and wiped and lubricated the rails.

It read the index and while playing track one it skipped ahead by a minute. I was able to skip to each track and it seemed to work fine. When I returned to track one the disc just spins and won’t play.

I’ve confirmed the laser moves up and down centers itself as it should after closing the tray. The STA341M does get very hot.

Any ideas?

In US preferably .

Electra-print AC8037 chokes for sale. I have four of these that are unused with minor surface corrosion on the exterior. These are 70H plate chokes for tubes running up to 20mA of plate current. I'd like $150 shipped CONUS for these.

I find myself having to work on a speaker, and to test it at maximum volume at home I am limited to pushing it to the maximum for a few seconds without disturbing the neighbors. This is limiting.

I would like to build an isolating case to attenuate the audio power as much as possible inside it and be able to listen for any distortions present at maximum volume, in a simple and DIY way.

I was thinking of lining a polystyrene box and mounting the speaker inside it, but would it be effective as an attenuator? Has anyone faced a similar problem or have a better idea? I know it's not ideal for evaluating audio quality and it could worsen it, but I could add a hole in this theoretical isolating box to bring the ear closer for a more realistic listening experience. In any case, it must be something temporary, not high engineering.

some more tubes ask for info and pics if any interest.
ps i would concider a generous discount for a whole sale..

here are some audio tubes for sale..
ask for pics if interested

Our house was built in 1906. At some point electricity and indoor plumbing along with central heat was added. The original wiring was tube and knob style. Much of it has been redone and there is a proper 200 amp service. The old wiring with a wandering neutral was not always connected to properly when making updates so there is some AC on the neutral and ground bus bars. This has always worried me thinking it could damage electronics.

Was thinking I could run a new hifi circuit with it's own earth ground to work around this issue. What do you all think?

Looking for a manufacturer who sells big ribbons. Is there anyone or only DIY?

On my desk at my work I'm using a 2.1 PC speakers F&D A510.


The set consists of 6.5" subwoofer and 2 satellites which are 4" full range drivers in a plastic shell. I don't know if this can be called speaker enclosure. It is just shell.
According to the specs the woofer is rated 20-120Hz and the satellites are rated as 4ohm 16W 120Hz-20KHz.
In fact the woofer kinda drops at 140Hz and the satellites start to pickup at around 230-240Hz.
There is huge dip in sound level between 150 and 230Hz. It is effectively missing around 180Hz.

I would like to upgrade the satellites with some DIY project for a reasonable price.
I am searching for a driver and enclosure plan which is easy for execution and the goal is to build a speakers which can go down to 120Hz or even 100Hz.
As the title suggests this is used on my desk so space or at least the footprint is somewhat limited. I suspect that sealed box will not do the job.

I'm placing the topic in the FR section for several reasons:
1. I'm fan of FR speakers
2. I expect the budget for 2 FR drivers to be less than 2 woofers + 2 tweeters and 2 crossovers.
3. I can't hear a s**t over 14KHz because of my age and hearing

Currently my number one candidate for the job is MA CHN-50 4ohm. It is reasonably cheap (17EUR/pc + shipping) and there are plans available from MA web site.
The designs that fit in my space are Fenlon 50 simple vented box and Markaudio CHN-50 Slot Vent Box

Do I have any better options?
Maybe some of the variants of Visaton FR10 4ohm at 12.5EUR/pc + shipping
Or Faital Pro 3FE25 4ohm at 14.4EUR/pc + shipping
Or Visaton FRS8 or FRS8M at 12.7EUR+shipping
And what would be suitable enclosure for them?

see multilangiage subtitles
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Class AB 100 watt amp.

I have the two PCBs for Balanced Zen Line Stage -- power supply and preamp boards. Papa calls for two 30VA 30v+30v transformers for the power supply. Will two 25VA 30v + 30V work?

https://www.antekinc.com/an-0230-25va-30v-transformer/

Posted in the Pearl 3 thread but got no response. Bob Graham has a simple Azimuth adjustment tool, that in a nut shell ties l/r plus, 1 channel inverted phase. Then using a monaural recording with limited high frequency response you can adjust Azimuth to get the least amount of music coming through. The question centers around how to make one, the 1 that I have in the store worked a while ago but more recently when I went to use it I got a lot of hum.

I would like to make a working version and anyone getting seriously into vinyl might want to as well. So if someone can give a quick explanation on the correct way to do this it would be appreciated.

Hi guys, does anyone have experience with equalizing networks on Lowther? I read Nelson Pass's article "Current Source Amplifiers and Sensitive Full Range Drivers".

I would love to get some feedback and advice.

Good music!

Yet another "large" coax build Celestion FTX1225 (ongoing, advice needed)

So my obsession with 12" coax drivers and classic monitor designs continues.
I'm slow though, I bought the drivers and material in June and I'm still assembling, and as of mid September there is quite a bit work left before testing.

Learning from previous mistakes Ive started building my speakers with removable front and rear using double baffle assembly. Meaning I can play around with driver selection and sealed vs ported designs. I decided on a 60l box cabinet inspired by Tannoy Little Red/Gold, Klipsch Heresy and JBL 4312/19 designs but with my own take on the golden ratio and available material locally. My plan is to build a few more pairs if its a success but with other drivers. This time I landed on the Celestion FTX1225 as it looks both rugged and flexible. I do not aim for the deepest bass or the clearest highs or mids but fun live and dynamic sound for reasonably large rooms. I might compliment with a sub 15 or 18" as well. I decided on a mix of MDF and oak to see if I could make it look good but still keep the price and amount of work to minimum. Stained oak should be easy to make look OK. The MDF will hardly be visible as I plan to have a full front grill.

As I usual I don't plan enough and as thing progress I start to get some questions in my head and I'm also losing my patience and start to take shortcuts. I thought I share some design specs and pics, and then list my questions in next post. I currently have no strategy for passports nor crossover, I thoughts I assemble the box first, get it connected, burn it in with some old crossovers and then perhaps try to measurements as input to crossover design. My original idea was to have it sealed but I'm getting second thoughts about that. The openings you see in the pics will be covered by the removable front and rear baffles, these cutouts are primarily to have access as the bracing makes it a bit difficult.


Some specs for the system.

Cabinet specs:
Outer dimensions: 62x40x40
Inner dimensions: 58x36x30
Aprox Volume: 60l
Front/rear: double 58x36cm 19mm MDF (outer removable, not shown in pics yet)
Sides: 58x40cm 18mm oak
Top/bottorm: 40x40cm 18mm oak

Drivers specs:
Nominal Diameter 305mm/12in
Nominal Power Rating 300W
Sensitivity 97dB
Rated Impedance 8Ω
Frequency Range 50Hz-4000Hz
Voice coil diameter 2.5in
Chassis Type Cast Aluminium
Magnet Type Ferrite
Magnet Weight 2.3kg/81oz
Cone material Kevlar loaded paper
Surround Material Cloth-sealed
Xmax 4mm

Additional HF Specifications:
Power Rating 60W
Nominal Impedance 8Ω
Sensitivity 104dB
Frequency Range 1000Hz-20,000Hz
Recommended Min. Crossover 12dB/oct 2000Hz
Voice Coil Diameter 1.75in
Diaphragm and Surround Material Polyimide


Some pics on the driver and the ongoing build attached.

To be continued.

Every time I try to enhance the lm3886, the sound gets cleaner but goes back stage, as if the recorder microphone is placed far from the subject. I made a composite MOSFET +LM3886 to get single ended triode type sound
Post in thread 'Chip amp + MOSFET composite' https://www.diyaudio.com/community/threads/chip-amp-mosfet-composite.403832/post-7539252
The sound is very nice but far back staged.
I can workout to make this character adjustable as I know guitar accompany players do need to go background to let the voice of the singer to be on front stage by using probably reverb.
I need to know if such amp can be useful for instruments?

I'm going to design two-way speakers. My initial rough design goal is a front 100cm tall by 50cm wide.










It will include the design of a trumpet with an exponential exit area approximated to a tractrix but rectangular in shape, built in wood.
The out of the TAD is 2 inches. 49 mm.










The area of the circle:
A=PI * R^2 will be divided into 5 equal parts.
A/5= (PI* R^2)/5
A=(R^2)/2 * [angle- sin(angle)]

It's one of the rarest models on the market. Anybody got a user manual ? It's based on Philips drive and belongs to a friend. Kind of temperental player. Supposedly studio version and very expensive back in a day. I borrowed it to try and it sounds absolutely average. Never heard Micromega player before but the brand had strong following and this was one of their more ambitious designs. I will open it up tomorrow to see if there is something fishy inside.

So this may seem very random, but I am an artist who is trying to capture the scent of electronics, new motherboards, old burnt out hardware, nostalgic e-materials -- think hot dust, ozone, phenolic resin, burnt plastic and metal, etc. To do this is fairly simple, I'm just absorbing the aroma molecules of discarded electronics using fat, but I want to make sure I'm not actually doing anything that would be harmful to inhale. I am a bit out of my depth with my knowledge of the dangers of these scent materials - does anyone know if inhaling these electronic smells is generally bad? Is there anything I should definitely avoid capturing, older electronics or specific materials for example? At the moment I''m concerned about VOC (volatile organic compounds) because those will likely be picked up the most. Thanks in advance!

Had this in for repair from a guy at work, real mess.

managed to do the repair but ive nver seen the rear terminal melt like this

any ideas?

It took out the reglated pair of transitors and most of the components around them

a short perhaps???

Hi,
I want to modify my CD-player Pioneer PD-S703 with a new clock. I fond the CD clock design by Ray (G.Tent and E. Kwak) on internet (see attached file) and decided to built one of this. In the attached files you can find my own PCB design and loyout. the problem is that I can't get it to work. I've tried it for several days on my PCB and on the breadboard but I can't get the right signal on my oscilloscope . Can you please take a look on this and help me. I run the test whit an external 12VDC power supply.
thank you!

Hi all..
Im looking for a working cd lens/board please....

Greetings folks - long time lurker looking for recommendations or guidance on a planned 2-way project. This is a music only system.

Design brief is for a 2-way system using a ported/vented enclosure up to 500-600hz. 4" TAD or JBL 2426 (w/True Extent beryllium diaphragms) will cover 500-15k+ on a suitable TBD horn - most likely Iwata 300, JMLC or Yuichi Arai.

A three way with a suitable hifi section from 6k-20k could be contemplated later. I would likely use the Gauss HF4000 for MF in this scenario. First, I need to get the LF section sorted.

I know many will find fault (for valid sonic reasons), but this design will be entirely passive: no dsp, eq or subs/separate LF reinforcement.

High efficiency from the 15" is required, as the system will be powered primarily by tube amplification from low power SET to 70watt tube designs.

The enclosures for this project are already built: ~6.8 cu ft Altec Iconic/612 replicas, with removable/replaceable front baffle, so any front vent/port arrangement can be accommodated.

I'm writing today to collect your recommendations for 15" drivers - present or past (as long as they can be acquired).

I would like to achieve the absolute best accuracy, texture and timbral realism possible up to 500hz, as well as best possible LF extension to 40hz or lower. Is 35hz possible? Cost is not a factor.

Drivers I'm currently considering include JBL 2225, 2234, 2235, 2226, Altec 416 (ideally 416-8b), AE T15X, AE T15M, TAD 1601a/b, TAD 1603. What am I missing?

I have most "ear time" with the Altec 416-8b in large enclosures. It has great performance. The Altec 515 would be wasted on a design crossing so low, plus, anemic LF performance (I know it's technically good, so let's say anemic LF/midbass impact/punch).

Has anyone compared any of the JBL/TAD/Altec designs and be willing to offer thoughts/data on best performance for this application?

Are there any drivers out there that have significantly 'better' sonically than the Altec 416, with better LF impact, and which also have comparable efficiency? I hope so.... while the 416 is a wonderful driver, I would love to hear something that matches its timbral realism but adds more LF authority/midbass punch. That would be my ideal driver from a sonic perspective.

If there is no such driver, and I were to drop the requirement for super-high efficiency/good LF performance with <10 watts - making minimum power closer to 20-30 watts - would this put other drivers in the running? Which ones? High power solid state amplification is not an option.

I am fully aware of the compromises involved with foregoing dsp - no real need to rub salt in the wound or discuss the why's of that aspect of the design.

Thanks in advance for your assistance!

I am adding a Receiver PI Pro to the below IanCanada stack to connect additional inputs from other sources - coax spdif, Toslink optical. Does the IanCanada stack with add any sonic benefit (eg rechecking) to these inputs or is it more of a pass through?

1. FifoPi Q7II
2. PurePi II ultra capacitor/battery power supply(no batteries)
3. MonitorPi Pro display/Controller/analyzer
4. TransportPi AES

Thanks.
John

Hi All.

Could someone please help me with regards to modding my dac to run in NOS.

I have been researching on here but nothing really detailed or specific on how to do it.

If anyone has done this mod could you possibly send me links or perhaps a thread that can assist me.

Many thanks

Can anyone recommend any books about designing the tape path on a tape recorder? specifically looking for things like scrap flutter, head wrap. etc etc. I want to learn more about the dos and don't when designing a reel to reel tape recorder playback device.

Finally, my first SB Acoustics setup, MW16P-8 + SB26ADC.

Months ago, I was browsing through this forum looking for a budget tweeter, and I couldn't help but noticed SB26ADC's good reputation. I already bought MW16P-8, which is a low distortion mid-woofer, and an idea came to my mind: how about building a low distortion system? So, after some further investigation, I found a website called HiFicompass, they've done some incredible work, and they provide a whole bunch of key measurement data. Comparing the SB26ADC Measurement to almost every tweeter I ever know, even SBA's Satori Beryllium tweeters, and on paper, SB26ADC can outperform most of them: exceptionally low distortion, linear frequency response up to 40KHz, good transient response, all in all, looks promising. So, I bought it.

Conclusion:

Considering the price, it's perfect! After some measuring and tunning, crossed at ~2200Hz, it sounds so good. I wouldn't describe it as "silky smooth", well it's not a "silk" dome, but transparent and low distorting while keeping the harshness to its minimum. Linear frequency response and low Fs make it easy to work with. Only 3 components were used in the LR2 filter, a 3.3ohm resistor, a 6.8uF capacitor, and a 0.3mH inductor. I know, it's not perfect, but these are the components on hand, so, not bad.

I listen to lots of Celine Dion and The Carpenters, close your eyes, it felt like you can discern almost every detail in her sound. I was surprised about how resolving this tweeter can be.

Watching movies? I'm a fan of Bourne movies, and after enjoying them for 4 hours, I found there's a little "imperfection" to this setup: it's too calm. That low distortion characteristics of tweeter and mid-woofer make the sound a little bit too transparent and resolving which doesn't help much when it comes to the atmosphere.

I would recommend those who are looking for a value tweeter to try it out.

Happy Saturday, all.

I'm at the assembly portion of my DIY 2-Way build - and am currently utilizing a Dayton Audio DSP-408 as an active crossover. This will change - but is super convenient for now.

The system is a 22" Oris Circular Horn w/ Celestion AxI2050 Compression driver, and midbass / bass is handled by an 18" Acoustic Elegance TD18H+ Apollo driver.

I have not finished the cabinet, and it is just bare MDF on the inside - even the external curved baffle isn't installed yet to the facia. It's not even glued together at this point - just clamped together for some driver measurements. The cabinet was custom cut as a mid bass module by GSGAudio specifically tuned for this driver, it's a 5.75cf cabinet with a slot port tuned to 27hz, which is also where I have the high pass filter set on the driver.

That said - I'm hoping someone can help me make sense of the various REW screens - all measurements taken at MLP, Audessy off.

Thanks so much.

Kind of wondering where I go from here - still left to do is proper damping of the cabinet, proper crossover build, etc.

I'm very interested in the waterfall and distortion measurements...

AND if I'm even doing the testing correctly. Thanks so much!

And as before - I'm pretty new to this - but enjoying the journey so far and definitely open to constructive criticism and suggestions / ideas.

The attached images show the device, that is in question. No sticker on rear and no naming on the front regarding the model (only the brand name is to read on front).
The amplifier was purchased between 1981 and 1983 in brandnew condition. On rear panel is to find only a white sticker with the number 8646 - the serial number - so I think (in the same kind as to see on the forth and fifth image from attachment, but without the blue stickers).

Maybe with help of the serial-No 8646 (which is also to find on a second sticker on the bottom plate) and the year of purchase in not used condition it is possible to say from any member, what is the associated model naming. Thank you very much in advance.

As you can see on the images from follow URLs there are five different models without model naming on the front and rear panel. Only later manufactured power amp devices from the models "AW-65" and "AW-100" show the model naming below the brand name on the front panel and from AW-II and AW-IIa on the rear panel.

URLs from AW-1
https://www.ricardo.ch/de/a/xxx-rare-electrocompaniet-'ampliwire'-1138733358/
https://megazakaz.com/ebay/product/154520059918
URLs from AW-II
https://www.diyaudio.com/community/threads/fs-electrocompaniet-amp-preamp.386118/
https://sorscha.org/Content/html/Specials/AW-II-html/html/AW-II.html
https://www.aussieaudiomart.com/det...-ampliwire-ii-power-amplifier/images/1396055/
https://www.ukaudiomart.com/details...-ampliwire-ii-power-amplifier/images/1396051/
https://www.dba.dk/effektforstaerker/id-1104299504/
URLs from AW-IIa
http://www.audiotecnico.it/riparazi...liwire_IIa/Electrocompaniet_Ampliwire_IIa.htm
https://www.audiocircle.com/index.php?topic=185472.0
URLs from AW-65
https://www.classicaudio.fi/product/electrocompaniet-aw65-ec-1-paate-ja-etuvahvistin/
https://www.hifiengine.com/manual_library/electrocompaniet/aw-65.shtml
https://www.usaudiomart.com/details...paniet-ampliwire-65-amplifier/images/2818978/
URLs from AW-100
https://allegrolokalnie.pl/oferta/electrocompaniet-aw-100
https://www.kleinanzeigen.de/s-anze...MI7qHhmvbigwMV5pSDBx03Zg9-EAQYASABEgLCCPD_BwE

Hello , I will be building an enclosure of internal dimension of 6.25X7.375X32 inches. Based on Vikash calculator, the first standing waves are at 214, 1009, 917Hz.
The speaker will be crossed around 750Hz, so the most problematic standing wave is 214, 427...
The walls of the enclosure are made of 5/8mdf + 1/2 Birch plywood glued together. See pictures.
It is a Passive radiator tuned box. 1 Single P-R.
The internal dimensions are rather small so how can i brace and stuff tis enclosure to eliminate the room modes. There is not much room to add damping material.
My second concern is the vibration of the P-R, i purposely put it near the floor to maximize the coupling and reduce vibrations. Based on your experience, would the vibration be sufficiently large to affect the sound. I can add a second P-R on the other side.
I am trying to avoid trial and errors as much as possible.
Your suggestions would be most welcome.
Thank you

Hi

I have a pair of Carlsbro Deta 12 full range 300w RMS speakers.

One of the compression drivers has failed.

I have emailed Carlsbro and no response as trying to find out what size / RMS power I need to replace the driver with.

It’s a bolt on unit.

Thanks for any help

Hello,

In a scenario where a darlington pair is built using a high-current low-beta device driven by a signal high-beta transistor, what is the recommendation for placement of the driver, close to the output device's heatsink or on the contrary farther away so it doesn't pick up heat from the high-current pass transistor? Logically the driver should thermally track the output device, since in a monolithic Darlington they are on the same die no? I also have observed that the darlington input drivers tend to be next to their output transistors in power amplifiers. Thermal issues causes and effects are still a bit fuzzy to me, I would appreciate an explanation of the thermal effects at play in such a situation.

Below is a tentative pcb layout where I put the driver (Q1, TO-92) inside the output's transistor (Q2) heatsink fins, the output device being on the other side of that heatsink. Note that this circuit is high voltage (200-400V).



As always, thanks for any insights. Regards,
- Joris

Once upon the dawn of car audio, there were 1/3 octave and parametric EQs, and a few rare time-based things. What options do I have today?
And, as a bonus question, can I get away with a stereo unit for EQing the fronts* only, and use lowpass and gain and maybe Punch EQ to adjust the bass?

There's a 2017 VW Alltrack I'm driving frequently now, want to up the system around the factory radio. The current ideas:
- Replace the fronts with a component set (Crutchfield shows both 5" and 6" models supposedly fit...?!?). Probably a high end Focal since we have their home speakers, and a friend's swap in a CR-V sounds really clear.

• Gonna have made a box to fit in the rear footwell right behind the driver's seat. Currently thinking a pair of Rockford** 8" in an opposed configuration for force canceling. Fb around 60, Q below 0.7, should sound tight.
• Some 4-channel Rockford** amp to power the fronts and the sub. The fader will thus control the sub level.

OK all beautiful hopefully. BUT surely I will not be so lucky as to achieve perfectly flat response, hence the question above...


*Disconnect the rear speakers, I don't listen to rear stereo at home, screw this.
**why RF? My old business partner can get me all this free.

So I’m confused, and hoping someone can help enlighten me over what I can find on line.

Everywhere I look I get people saying if I’m building speakers, to only use a single woofer and a single tweeter… otherwise you get comb filtering.

Yet, every where I look- even super high end $100k speakers… there are multiple same size woofers in the floor standing cabinets.

So why?

How have they solved the issue?

:frustrated:

Thanks all

(2) CDT500/64k Renkus Heinz. Pulled from the CT5/64k speaker pair, same combo as what fits in the CDT-1 without bracket and rear weather protection cup (drivers are sealed anyway, so the same performance). If you want point source from a HUGE 24" x 24" horn exit! 103db Pattern Control down to 500hz. Reminds me of the original Lambda Unity or Danley Synergy. Too large for my application, which is why I am selling. Sound great!

$500 per horn w/driver and crossover included or $900 for the pair (w/drivers and both crossovers). Buyer pays actual shipping cost (24x24x24 box, 30lbs per drive - I may be able to fit everything into one box)

Photos show the actual horns, no cracks and output show they both pass rub&buzz test on Dayton DATS3 woofer tester (horn disconnected during test).

Shipped from Nashville, TN area. My Ebay name is "daus300b". PayPal. PM me if interested.




More info: https://www.renkus-heinz.com/product_detail/cdt500/

CDT500 series horns feature Complex Conic waveguide technology
and the unique Renkus-Heinz CDT-1L CoEntrant mid/high frequency
driver. They offer smooth pattern control down to 500 Hz along with
tonal quality unattainable with conventional high frequency drivers.


CoEntrant Topology (U.S. Pat. 5,526,456)
Integrates a midrange cone and HF compression driver into a true point source with inherent time-alignment.

Complex Conic: The Next Step in Horn Evolution
Complex Conic horns provide superior pattern control and more natural sound; may be rotated 90º.

High-Frequency Compression Driver
Provides crystal clear highs from 1800 Hz to18 kHz.

Eight-Inch Mid-Range Cone Transducer
Easily extends response down to 350 Hz with low distortion.

Weather Resistant Design
Sealed driver enclosure and weather resistant cone offer maximum protection from the elements.

Choice of Coverage Patterns
Choose between 90º by 40º, 60º by 40º , 60º by 60º and long throw 40º by 40º designs

Choice of Models
The CDT500-64K is a medium throw horn with a 60º by 40º coverage pattern.
The CDT500-94K is a medium throw horn with a 90º by 40º coverage pattern.
The CDT500-44K features long throw 40º by 40º dispersion.
The CDT500-66K features 60º by 60º coverage, ideal for overhead distributed systems used in large high ceiling areas.

All four models provide tight pattern control down to 500 Hz and below. They come complete with a built-in crossover and a weather resistant housing for the driver/crossover network.

Hello I have a DVC subwoofer that has 2.6ohm coils and have been searching for some cheap chip amps that could power it. I'm not looking to spend a lot on it because it's just an extra sub for my garage. It it were a dual 4 ohm sub it would make life much easier but I'm trying to work with what I have. Would it be possible to use an amp like the Aiyima A07 and hook 1 voice coil to each channel? I know it's below the recommended ohms but would it work if I used a lower voltage power supply with more amps? I have a SMPS that is adjustable from 1v-48v with 10amps.

After using a 90’s vintage Yamaha power amp (MX630) with my Chinese DAC (SMSL D300) for a spell, I got to thinking maybe I should upgrade to a new modern amplifier. I took home a demo unit from a local audio store. The amp was a Hegel H190. Retails for around $4500 Canadian. I used an optical cable splitter and fed it with the same signal as my SMSL DAC connected to the old Yamaha. The digital source was a WiiM pro streaming CD quality from TIDAL. I also had a three way amp/speaker switch so I could switch amps on the fly. I adjusted volume to the same level in both using an dB meter on my iPhone.
After extensive listening and switching back and forth, neither I, my wife nor my 24 year old son could hear any difference. If I wanted to guess, the Hegel may have been a bit fuller in the upper bass, but if it was it was marginal. Soundstage and imaging were indistinguishable.
For speakers I was using my DIY Seas Idunn two way bass reflex bookshelves. I have listened to these side by side with Focals and Martin Logan’s and they hold their own.
My amp system cost $600. $500 for the DAC, $100 for the used amp. Far cry from $4500. Needless to say I will not be keeping the Hegel.
Goes to show you they knew how to make excellent sounding amps back in the day, and the Chinese DACs that are flooding the market can be pretty good. In fact the best sound I got from the Hegel was when I fed the SMSL DAC into its analog input.
Cheers.

Hello. I am a new diyAudio member and have just registered now. I own a pair of Beveridge 2SW-1 speakers which I bought back in '79 as store demos which was the only way I could afford them, barely, and that was a sacrifice to do so. I got a real good deal on them. Back then Harold Bev came to the store where I bought the spkrs, gave a talk and demo on his system and I met him then( and much later on called him to ask what a good dummy spkr load would be). I am still listening to these going on 45yrs. For the first 20 yrs I owned them they were 'on' almost as much as my refrigerator. I have a lot of info I can share with fellow 2SW-1 owners in future posts regarding failures, tubes to use, etc., but right now I am extremely eager to get my left channel amp back up and running. I have read the posts from cvanc, kcin, and others regarding these amps and it looks like I'm in good company.

I have attached the newer redrawn amp schematic for referencing for my question(s).
The failure mode (there were other failure types in the distant past which I permanently fixed) I have from time to time is that any of three resistors in the screen/cathode circuit of the 36KD6's partially burn up which blow the fuse. They are R201, 203 and 205 which are 10K, 22K and 10K, respectively, half watt, carbon film type. In this case, R201 failed. I replaced it and powered up the amp again and I could only hear very low level lower frequency sound from the spkrs. I hooked up the other good amp to these spkrs and played fine with no issue. I opened up the bad amp and traced a 1kHz signal through the driver board to find there was no signal at the collector of Q110. There was signal at collector of Q111. So the stators (electrodes as Rick Bev calls them) were getting no audio signal and the diaphrams were. So I replaced Q110 with a suitable equivalent (BD140) which did not fix the problem. If I remember correctly, there was signal at Q106/107 collectors. So after doing some more probing with my scope the amp started to blow fuses when I would turn it on and V204 tube arc'd bigtime in the base area of the tube. Q111 collector (which has signal) is tied to grid of V204 through the 1K (910ohm in my amps) resistor. The dilemma I am having in trying to continue probing is that in order to see the signal at the Q110/111 xistors, the HV has to be connected so there is feedback present through R1 and R3 at the bases of Q108/109. I confirmed this by disconnecting the HV on the good amp and seeing there was no signal at the collectors of these xistors when HV is disabled Back in the mid 90's I bought and built the softstart circuit boards which Ron Welborne (Welborne Labs) sold and installed them right over the main pwr xformers using 3 nylon stand-offs. They still work and are preserving the main xformers. Something I will try tomorow is to bring the mains voltage up very slowly with my variac and see if V204 will live and not blow a fuse so I can continue to check for signal at Q110/111 collectors. Measuring input and output voltages on the driver bd, up to the Q110/111 collectors, I calculated 28dB voltage gain.

If anyone has any suggestions/ideas to try please pass them on. Thanks much!