I'm considering upgrading my digital source from a rather obsolete board that doesn't work with Raspberry Pi 4s to a setup based on Ian Canada's boards. Currently I use a single stereo DAC feeding a board that splits the signal into 2.1 in hardware, with a fixed crossover frequency. This isn't very flexible and as the latest version of moodeaudio integrates DSP software that should be able to do the splitting in software I'd like to know if it's possible to use 2 of Ian's DAC boards to obtain up to 4 audio channels output (I only really need 3 but the boards are stereo so...) That way I could get rid of the hardware 2.1 board. Has anyone done anything like this?

Hey people,


I'm thinking about buying a pair of new tweeters for my 2.5-way active speakers. Last year I've damaged the plastic at a mounting hole of one of my Monacor DTM-104/8 tweeters ( https://www.monacor.de/produkte/components/lautsprechertechnik/hi-fi-hochtoener/dtm-104-8/?r=pdf ), and since then, there is always the thought of replace/ slightly upgrade them.
Crossover frequency should be around 2,5kHz, the diameter is 104mm, price not more than 100€ a pair.
Any suggestions?


best regards

technically I'm not a newbie here. years I follow this site with interesting in all the PaPa's amp designing and till now I DIY my AM/AJ/F6/M2 with great joy. but something wrong with my last account which cannot summit any valid post. when I knew that PaPa will do a lottery to give some VFET with rare NOS devices, I can't help to register a new one to try my luck.😛

So, just wait and see🙄

Very good condition. I would not recommend these for music listening*, but for DJ, studio use they are ideal: comfortable, well isolated, and durable.

With Shure detachable, coiled cable nominal 2m length. 3.5mm with screw in 1/4" adapter.

44 ohm, 102 dB/mW

80$ US including shipping

* By design they are balanced for high volume playback, a low listening volume there is not enough bass energy to support the forward upper midrange.

DS-DAC-10 - 1BIT USB-DAC | KORG (Japan)

Cirrus Logic CS4398
2.8224MHz/5.6448 1bit PCM
44.1kHz/48kHz/88,2kHz/96kHz/176.4kHz/192kHz 16bit/24bit（S/PDIF）PCM
USB powered, you need a USB cable, and you'll need to download and install the Korg drivers to enable the high bitrate modes.

$150 US including shipping

Hi there,

Newbie from Belgium overhere.

Guitar player and gear lover. Mostly building and repairing guitar pedals and amps as a side job, next to my job as a music and science teacher. Sometimes some hifi stuff and other things too. Seems like this is the place to be for the hifi part.

Cheers,
Erik

Hi, due to a cancellation of my project I am selling the phono tube pre amp kit offered by another member on the thread below:

https://www.diyaudio.com/forums/swap-meet/348332-kit-mm-tube-phono-stage-2.html

The kit is untouched and still in the original packaging. I am asking for 90 EUR + EU shipping costs.

I also have an enclosure from Aliexpress I bought for the project. This can also be offered at a good price.

Non-oversampling DACs and bass

Hi Gents,

I was curious. How does the TDA1543 create a lot of low end grunt when compared to regular DACs ? Due to the output impedance ? Or is it missing high frequency bits ?

Thanks.

Hey all,

Restoring a pair of Tympani T-1D. These required a total rewire - not just a reglue. Previous owner really buggered these up.

All rewired, but cannot find the info on start - stop of the voice coil - got a 50-50 chance on guessing, but not feeling very luck (yeah yeah, just do the opposite?)

Trying to confirm following on the T-ID:

Serial xxxxxx-1 is Right Speaker
Serial xxxxxx-2 is Left Speaker
Resistance of Treble/mid Panel (10.2 ohm or 5.1 ohm)
Pole plate is to listener (front) on T-Id
Looking down at the voice-coil, start entry (Hot speaker RED) is to right
Looking down at the voice-coil exit (Return speaker BLACK) is to left (actually center as it completes a double pass)
Woofer panel (no button) is in middle, pole plate out

Thanks in Advance!!

I know this is about as original as breathing or eating, but I've found all the similar threads useful in building up the motivation to get started, so I thought I'd add another example to the library! 🙂

My SSE board is currently winging its way from the US to the UK, and I have a shiny new Hammond 374BX sat waiting.

I'm in the process of buying up all the small components (passives etc), but am looking for tips on where to buy things like valve sockets, and any advice on the apparently allways used motor run cap for UK buyers.

I'm also interested to know what peoples thoughts are on SS vs tube rectification - my view was always that SS was better unless you want sag (guitar amps etc), but I mostly seem to see valve rectification on kits. Am I missing something? I didn't think that most audio valves cared too much about soft start, but my experience is limited. I do know that the 6L6GT in my 5F1 champ clone has lived a loooong time with a SS rectifier, and my Bottlehead Crack is SS too.

Excited to get started! 🙂

I’ve rebuilt most of this amp but can’t get anything out of the left channel.

During rebuild, some of the muting circuitry needed to be replaced as both of the 8099s and the 8599 transistors were bad. Replaced with same part numbers. Also several resistors especially r170, r171 , and r185 were burned up and now replaced.

New outputs across both channels. I’m not getting left audio on the base of the mpsa14. I tried swapping driver boards and same. Both driver cards work in the right channel.

All switches in this amp have been replaced. They are testing 100% functional with my dvm.

Tracing through, I observed both L and R audio up until the muting circuitry. This ones getting me scratching my head.

Is there perhaps a problem with the new r170,r185, and Q56? Where else can I look. Anything I might be obviously missing?

This one is going to give me problem. If I didn't LOVE SS amps this one would have gone to parts. Very bad off. This is one that I now own and so its kind of an experiment to see if I can get working. Where to start...

First I cleaned the board with simple green and water. It was SO bad, I didn't even want to touch it without gloves. It had mice droppings on it lol. Simple green worked well. I dried the board with a hair drier after it's bath also. The good news is, mostly the PCB looks actually fine but keep reading.

The PS FETs AND output darlingtons were all flip-flopped around randomly and some were installed on the component side of the board. I removed everything I absolutely could as I've been in so many SS amps recently, this one was like a joke how someone took a fat-iron and mounted stuff all over the place.

Now its starting to look like a SS amp...

Amongst all these fantastic modifications, an owner literally 'ripped' the SG3524 out of the board. I'm thinking someone pried it off with a screw driver. All 16x Vias pulled straight out of the board and are GONE. No connectivity at all. Some of the traces were curled up into tiny balls. I cleaned up all loose traces and then HARD-WIRED in a new SG3524. Each of the pins are now connected after a time-consuming affair.

Rectifiers and PS FETs are out of circuit.

I didn't expect this one to work, and of course it didn't, so here comes the fun!

I set my PS to 12.25v, and 0.12A to keep things as calm as possible. The amp barely accepts this tiny amount of power like this.

While testing voltages, the SG3524 gets warm to the touch I powered down the amp twice during testing to let the SG cool off. I probably smoked this new SG by now due to a hard-wiring mis-haps I probably messed up.

SG3524
1: 12.23
2: 5.71
3: 2.141
4: 0
5: 0
6: 9.21
7: 0.580
8: 0
9: 0.033
10: 0.020
11: 0
12: 12.23
13: 12.23
14: 0
15: 11.64
16: 10.18

I stumbled across the following phono amp from the 30s, prior to the RIAA standard which was written in the 50s. When there was no standard for compression it was apparently desirable to be able to adjust expansion.

http://www.one-electron.com/Archive... 6L7 as a Volume Expander for Phonographs.pdf

I thought that when one is being social and the music is in the background it would be desirable to reduce expansion so that soft passages could be heard over conversation without the loud passages preventing conversation.

Do any of you have experience with variable expansion and have any recommendations or alternative circuits?

Hi

Does anyone know where to get genuine replacement parts? Can I replace those Sankens with another part that has similar specifications? Last resort will be to order a pair from ebay, possibly not as good as originals, but are the fakes still acceptable to use?

Thanks

I’m getting a big dip I my response in my 3 way center.
The two 8ohm woofers ran in parallel are using one 8mh iron core inductor for the crossover and I’m thinking the polarity might be better flipped.
How do you flip the polarity on two drivers ran in parallel with an inductor on the positive leads coming out?
All of the speakers are ran out to the same red/black in this 3 way.
Do I just run the positive coming off the inductor into the whole system’s negative and negative into the whole systems positive?
The big dip is in the 200-700 range so I’m assuming these woofers are inverse of the midrange?

I have a couple of these from a shop that used to sell Melos back in the day - they had found two of these SHA GOLDs in storage room - holding one one for myself...

6299 based preamp that has Single Ended and Balanced out (true balanced out too). This apparently was the best headphone amp on the planet a few years back.

All working perfectly - all original. Comes with pair of 6n23 tubes. Unit does not have a phonostage. Comes with non original programmable remote (not one shown).

$850 + ship. Ship or pickup in west sub of Chicago.

Hello all,

I have an amp I want to add a VU meter to. In the interest of keeping my sound as clean as possible I decided I needed a buffer circuit, I have come across this circuit but I need some help understanding how it works. The design I had originally came up with on my own did not have 90% of what this design has, and I am curious why.

Thanks,
JD

upgrade from Surface 1 , but still with only 2 power tubes.
6v6 amp - YouTube

I got this today and i was told that it is not s real tube preamplifier (edited). There are transistors doing the job, tubes are just for decoration. Is this true? It is powered by a 12V AC transformer.

Also he told me there is no way a 12v AC transformer could power those tubes. They need voltages like 120V or something.

How true are these statements?

My Parasound a23 2 channel stereo power amp comes with a three prong plug. when using that type plug, I get speaker hum with Dish receiver hooked up feeding audio to preamp but not when it's not hooked up it, also has a three prong plug. I've been using two prong with power amp to defeat the speaker hum. I don't like using the two prong and loosing the grounding prong. I've been told on another forum that it was a common problem with Dish receiver use through stereo. Also, they mentioned the use of a ground loop isolator would solve the hum problem so I could use the factory 3 pronged plug that came with the power amp. Anyone familiar with the ground loop isolator they speak of? Through unhooking things, I for sure isolated the problem to be because of the Dish receiver which, was stated to be a common problem. I'd sure appreciate all input and, maybe some links to the type ground loop isolator others were referring to. Thank You! 🙂

I've had this item for around 5 years now, and today it powered on, tubes lit up, then suddenly the tubes went dark. Tried again to bring it back on, and the same thing. Now the power light is on, but the tubes remain dark after several attempts and nothing pumping to the speakers.

By the way.. I looked through the threads on here and couldn't find anything with this particular issue. So I apologize if I missed something.

I have new tubes on order, but I need to make sure if that's what I'm looking at.

Any advice would be helpful.🙂

The picture attachment is when it was working.. just fyi..

Thanks. -DLNorton

Right now I have a Systemdek IIX with a Profile II tonearm that runs a Nagaoka MP-200 MM cartridge.

I quite enjoy my setup but alas I'm always looking for the "next best thing". My MP200 also is getting up there in terms of hours and could use a replacement.


I am thinking of getting in to the world of MC cartridges. Any recommendations for a MC cartridge? I would say budget is about $600 USD.

I think I'd prefer HOMC but I guess it doesn't really matter. I am going to build a new phono stage to go with whatever cartridge I choose.

Can someone please direct me to a forum thread or spot reference the above thread Title.

Looking for someone that can QC goods and possible do lite assembly work

Please contact me via PM or text/call 303.594.7586

Pay averages about $25 per hour. This is a Part Time Gig - maybe 40 to 50 hours per month.

The business asking me for help with this is in business for over 22 years and very good track record.

Thanks

Mark

PS - If I'm in the wrong area - my apologies

Hello everyone here.
I would want to know if it is possible to duplicate a part of a schematic already tested in LT Spice IV, changing the part(s) number(s), obviously, in the same window.

Kind Regards.
Salu2 para to2.

$75 plus shipping

Tested not used. Some additional connectors. Has not had the power supply upgrade.

I won’t get around to this.

$80 shipped continental US

I am building a very simple amp, or so I thought.

It only consists of 5AR4 -> LC -> LC -> KT88 single ended output stage (cathode biased)

The input stage is to be built on a separate chassis.

I turned on the amp without tubeI started with 630mA fuse, which blew. I increased the fuse size progressively till 1.25A, which still blew.

I checked for shorts from B+ to ground, or anywhere else to ground. None that I could find.

I got fed up and used a 10A fuse, then the power transformer smoked. Bad idea in retrospect. At the time I concluded that I had a bad power transformer.

So I replaced the power transformer. Powered it up, it worked, sort of. B+ is between 350-380V, I don’t remember exactly, transformer secondary is 420V, so seems good. One of the tube achieved 36.6V bias, seems good. The other tube wasn’t conducting, due to a loose connection.

I rectified the loose connection, and powered it up. I watched the tube bias rises to 50+V, which is very strange, and then the fuse blew.

I checked everywhere for short, but none that I could find.

I removed the tubes, fuse still blew.

Then I realised, the OPT is unloaded after I replaced the power transformer. I thought I might have fried the OPT.

I disconnected the OPT, fuse still blew.

I disconnected the second stage LC, fuse still blew.

I removed the rectifier tube, fuse did not blow. So I guess, at least the power transformer is fine.

So, there is something wrong between the 5AR4 and the first LC? The choke seems fine, no short to ground. The capacitor seems fine to me too, correct capacitance reading, no short to ground.

How else can I check if a choke is faulty?

Would faulty rectifier tube blow fuse? It lights up fine, and seems to pass current fine.

I don’t know what else to check for.

For sale tda1541 D3 Dac. Geniue tda1541 included. Dac was tested with ak4118 input board and battery power supply and it is working perfectly. As you see assembley is perfectly done. Upgrade Pps foil capacitors instead ceramics.
For sale
Symultanious input board + dac board+ Tda1541
GIFT: UFL cables
Price 150eur

Just when you think you know everything.....Does this solder rally make a difference in kit building?

Let's suppose you have a diode bridge in your amplifier's power supply. What are the symptoms that call for a snubber? I mean if you consider the amplifier a black box (you have no access to the internals), what signal degradation or unwanted signal do you see at its output?
In general, how do you tell whether a precisely selected series RC parallel to each diode is necessary or just a C of 10nF value is sufficient?

I bought these to try in a project and decided against them, so they are nearly new (a couple hours on them).

$75 plus shipping (US only).

I just received my order of 10 Jantzen air coils from Nonsolospeakers
Take a look on the picture, theses Jantzen coils seems definitely not in pure copper as they should be... but in aluminum wire...

I contacted Jantzen Audio which confirm: No, we do not manufacture aluminum wire or foil induction coils, as they are usually only for industrial applications, not audio.

We have not sold any coils directly to Nonsolospeakers, but that does not mean that they did not buy our coils via one of our official channels (distributors).

The answer of Nonsolospeakers is: the product is original the coil is covered with tin to avoid oxidation and to facilitate welding.
Our official channel (Jantzen distribution) is contacting Mr. Michael Dahl, you will receyved soon confirm from Jantzen
Regards

Where is the mistake ? 😡

I want to design and build a multi driver setup to control directivity, but not finding any software that fully allows me to do what I am wanting.

Design would be like a Kii 3 or Beolab 90, achieving directionality by using multiple drivers. Not going to make it adjustable, just one fixed setting, so certainly a lot simpler than a Beolab 90, but I do want directivity across a broader range than the Kii3 achieves.


The typical array software or calculators that I am finding are to constrained.


What software can design and model a multi driver directional setup?

Does someone have the specs or a digikey number for the blue screw terminal that is not in the parts kit for the B1 preamp but is recommended in the build guide?

I know where to buy parts buI don't know enough yet to distinguish this particular one -- that will work with the PCB board for the potentiometer -- from the the many options out there and need to buy it per the spec or the number.

Bonesthrower

Hi, I have a solid state Marshall 3315 head that I'm attempting to get back up and also use as a learning experience. One day years ago I turned it on and it just didn't work.

I replaced the 10amp pico fuses but they burnt right up. Should have known better. I then checked the diode bridge and saw that the negative and positive rails were shorted so I took it out of the circuit but it didn't help as the short was still on the pcb at the same point. I did notice if I disconnected either of the emitter leads of the power transistors MJ11015/MJ11016 that the resistance between the power supply rail goes to 10k.



what should I try next? I am mostly a tube guy so I lack any real experience in dealing with solid state power amps. any help is greatly appreciated.

Any body can point me to someone on here diyaudio site for proven plans, my budget with components and crossover is $700 except BB ply for a 3 way home stereo sounding pair of speakers for small PA use? I just finished a few months ago a pair of diy 3 way fully horn loaded and neo drivers from another well known site and sounds ok but it just sounds too PA if you know what I mean. I spent $1200 for the build total. I know I could've spent that on a JBL or QSC powered but I like to build and hope with great success. I have used this for 4 dj use and birthday parties not really what I am looking for and will probably just use it as a back up speakers for future gigs. Thanks🙂😕

Or designs that are DIY friendly? I just built some nifty bookshelf speakers but I am interested in some planer or ESL as a future project.

Hi all,

I was about to order a couple of Eminence Kappa 15C to put in my Peavey FH-1 bass horns. I do know that the Kappa 15C works really well in the FH-1 enclosure, having seen measurements and testimonials.

But I stumbled across an ad of a guy selling a few B&C 15NDL76 woofers, mint, a price slightly cheaper than brand new Kappa 15C; so now I'm hesitating.
Looking at the specs, the B&C seems perfect for a horn with a QTS of 0,22; it also has strong Neodymium magnet and cast frame vs ferrite and stamped steel.
It also has 7mm Xmax vs 2,5mm for the Kappa 15C.

I would be using it on the 70 to 400Hz range, in a tri-amped audiophile system, with low power class D amplifiers.

But I would like to model the response but I cannot do it; my computer is a Mac and Hornrespons can't be used on it.

If someone looking at the specs could tell me if it is a good choice, or possibly model it for me?... :-/ Klipsch Lascala / Belle model could work as well, as the horn is very similar. Currently using Klipsch K33E woofers but I would like more definition and output in the 150-400 range, which the Kappa 15C does.

Thanks in advance!

here are the specs:

B&C Speakers

Volume control module PGA2310 with Rotary Encoder - Audiophonics

Is this volume control IC any good compared to a classic stepped attenuator / passive volume control?

I have been rebuilding a Dynaco ST35 amp. I am thinking of doing a new power supply External larger transformer and DC heater circuit. Has anyone tried this?

The little amp before in its original state run very hot. I have seen some threads that say the one thing about this amp is the power supply was never sufficient and is taxed.

Scott.

Hi

I'm at the stage where I have my two speakers built. They are 3-way with two woofers for 4 drivers altogether (perhaps regretting that bit but I'm all in now).

I've been doing some measurements and trying to design a crossover. I have roughly the response I want, I've got impedance in check (I think) but I can't make head nor tail of what i should be looking for in the phase department.

Here's what I have, can someone tell me what's wrong or right about the phase graph?

NOW SOLD Mono 8-Ohm 50W Type AT-50H L-pad
2x for l and r channels

sold by Grieder Bauteile
see:
Speaker L-Pad Mono 8-Ohm 50W Type AT-50H or AT-52H, Grieder Elektronik Bauteile AG

Possibly made in Taiwan ! and not CH.

PAIR
Touch-turn is more than smooth; these are high quality, in
vgc (been used and tested briefly)

these are 29CAD$ + tx new (at SOLEN) -
pair for 22$ is v. reasonable

all Canada postage is 18$ by tracked box.
Prefer EMT Interac (Paypal add 4%)

Hi All.


I'd like to have on hand electrical cable of various colors for Loudspeaker internals. I'd like to minimize cost while catering for both 4.8mm & 2.8mm spades, for most circuit boards, as well as most power requirements I might encounter in domestic HiFi?
Is there a one size fits all AWG which I can use?


cheers Cliff

Hallo ich bin auf der Suche nach jemand der mir helfen kann ich habe vor kurzem einen sansui seven gekauft und jetzt auf einmal keinen FM Stereo mehr auch der Signal vu schlägt nicht mehr aus.
Die Mono Taste scheint ebenfalls nicht das zu tun was sie soll ich denke aber es hängt alles miteinander zusammen weil direkt nachdem ich ihn gekauft habe hat es funktioniert.
Ich bin für jede Hilfe dankbar eventuell auch jemand aus der Umgebung rendsburg mit dem ich das Gerät zusammen durchgehen kann weil ich würde auch gerne etwas lernen .

Freue mich über Nachrichten

viele Grüße Karin

Hi, I have some of these tubes, I would like to know what your opinions are on on this version also in general.... and with which polarization they perform best.
I would like to start using one in a follower cathode of a preamp.

Is a voltage of 270v, grid at -3 / 3.5 and current of 5 / 6mA suitable?

Or is it advisable to have a higher current and a grid .. type at -2?

Thanks 🙂

Hi all,

Has anyone tried to make a home brew Spex card for this amp to bypass the contour preset into the individual cards supplied with the unit? I’m using it successfully with a standalone passive sub, but obviously it would be better if it was simply a straight power amplifier without preset response curves. I’m thinking a bypass should not be too difficult?

Thanks
Mat

12" Radian Coaxes w/ 450sp $230 shipped USA

One pair of vintage Radian 5012 coaxial speaker drivers, including the woofers and high frequency compression drivers.
From the 1990s.
All 4 drivers are in good working condition.
The woofer foams are good and strong.
The cones are good, no tears or rips.
The woofers actually measure 13" across the frame, they're huge.
I had them mounted in some test enclosures and they sounded great.
The compression drivers are Radian 450sp 8 ohms (sp for spade, rather than pb for push button connectors).
Same compression drivers as are used in many other Radian coaxes including the 8", 10" and some 12" newer versions.
Please ask any questions before buying.
The picture with the 10" Eminence woofers is for size comparison only. The Eminence woofers are not included.
No crossovers or enclosures are included.

EDIT: PRICE DROP
$230 shipped within lower 48, paypal f&f or add 3%

No returns, no refunds, sold as is.
These drivers will be expertly packed!!
Shipping via UPS Ground with tracking and insurance.
Thank you for looking.

Hi, I'm building this line preamp to srpp + output buffer.



I have, for the heaters, a toroidal with two 6A 0-8V secondaries.
The tubes I use are 6n23p (instead of ecc88).
The B + is 180v.

For the SRPP stage I would like to use 4x 6n23p tubes, instead of two.
Of each valve I have two options.

First option:
Use only one triode and leave the other unused (if not used they advised me to put the grid on gnd).

Second option:
Put the two triodes of each tube in parallel ... just so as not to leave the second triode disconnected.

Which solution is the best?

The purpose of using 4 separate tubes is to be able to lift the heaters of the high triodes separately from the low ones and, at the same time, not to pass the "left and right" signal in the same tube (even if it has the screen).

With triodes in parallel I would have half the output impedance.
I don't care, I have a 15mA polarized CF for the output.

Thanks!

I built a 4-way tube crossover for a friend. He’s experiencing noise like frying eggs and bacon when playing SACDs at a similar level to the music. The noise is present during quiet passages too. A large collection of SACDs is unlistenable.

There’s no noise when playing standard CDs.

Below is a block diagram of the system.

When playing SACDs there’s no noise when:

• The tube crossover is replaced with an Accuphase digital crossover

• The SACD/CD player is connected directly to the tube crossover.

I’ve read that SACD/DSD produces “an enormous amount of ultrasonic noise (created by the noise-shaping technique used to achieve a respectable dynamic range in the audible part of the band) that can affect amplifiers and cause intermodulation problems in a largely unpredictable way”. I’m doing more research on that.

Is that what we’re hearing?

If the output of the SACD/CD player is causing audio band problems in the Absolare tube preamp:

• how does the Accuphase digital crossover then get rid of those artefacts in the audio band?

• why doesn’t it do the same to the tube crossover which has the same architecture (grounded cathode amplifier stage followed by cathode followers)?

The predecessor to the K1X SACD/CD player had the same problem, and as you’d expect, with DSD fed to its DACs, but the manufacturer installed a brick-wall filter that eliminated it. This time, the manufacturer either can’t or won’t provide such a fix.

Can anyone explain what the problem is and what we might do to fix it please?

I know the ECL86 (in triode mode) is a good sounding tube for making a simple SET mini amp with. Just curious if an ECL85 would do even better? Any experiences soundwise?

Finished a new FEA18RCZ build using the specs provided in the Seas Application Note exactly. Great sound except for the extremely bright top end. Not really listenable at higher volumes. Seas recommends to install an inductor/resistor circuit, and recommends using 1.2mH and 18 Ohms. I had a 15 Ohm, so I used it instead. Now the highs are severely attenuated, and not really listenable. Almost as if you removed the tweeter from a typical 2-way system. Do you think that using a 15 Ohm instead of the 18 Ohm made much of a difference? I wouldn't think so, and if anything it would have attenuated the higher frequencies less than an 18 Ohm resistor. Seas states that this design "offers the listener a loudspeaker system with a precise, coherent and engaging listening experience using this high quality driver." I attached a picture of the assembly I put together for testing. Thanks for the help!

Can somebody please explain to me if lossless digital volume control can be implemented on a Mac?

In practical terms all my sources are on my Mac Pro:
- YouTube and other online sites
- TV channels (I watch Freeview channels on my computer, no TV)
- iTunes (all my music is on an external hard disc)

My tube system is designed to have only the amplification I need, nothing more. So normal listening level is around 80% of maximum volume at a guess. If -6db means losing 1 bit, I'm probably not losing that much.

I'm interested in the idea of lossless digital volume controls, but I have no idea how to implement this on my computer since my mouse does all the volume control on whatever website or software I'm using.

Do you have any thoughts about changing factory binding posts?


In this case to pure copper or mostly copper, upper 90%.

Besides the new potential parts I chose looking way nicer, the original parts contain mostly brass in them. Maybe I opened a proverbial can of worms upgrading all of my stereo wire and spades to parts containing a high percentage of copper and silver. If there is an inferior link in my speaker connection chain it would be the factory posts.

Fortunately I'm not utilizing all 4 posts, the WTB or Cardas aren't exactly inexpensive.

Hi,

I have good basic electrical engineering knowledge but little experience. I now have a problem is out out my league, so if any of you can give me a a head-start I would be very grateful.

I got a NAD-amplifier from the dump, that I try to repair. Except from starting up, it did not "do" anything and the first fix seemed simple enough. BR101 looked bad, so I replaced it. That made the LED on the board work again, but the amp still did not work. Then I noticed how R167, R154 and R156 got smoking hot (I saw smoke) within a minute. I then switch off the amp.

So the left channel and the right channel have resistors that carry way too much current. Notice that the resistor R167 has a different function than R156 and R154.

Then some measurements: R154 and R156 had a voltage of 15V (and rapidly rising) R167 measured 90V

In simpler amplifier diagrams I can calculate the expected current running through stages. Here my lack of experience is showing. In this schematic I did not see how current sources set the circuit.

Then I registered on this forum hoping that posting my question here teaches me how to go about with this one.

The service manual is attached to this posting

Somewhat tube related, was wondering if anyone had a copy for the ART Tube MP schematic.
Tube MP – The Original – ART Pro Audio

Thanks in advance.

Up for sale are new never used pcb boards to build a no compromise class AB power amp.
Power 400+ W @ 4ohms

Boards:
1x Amp control board ver. 6
1x NS modular input supply board ( for the drivers stage psu)
2x NS modular supply board ( PSU boards)
2x NS modular X4 input board (a driver stage)
2x NS OPS double power board (output power amp boards, they are huge!!!)
2x Thermal sensor boards (for monitoring temperature)
1x Protection board (Speakers protection board)

The boards are the newest revision! I can provide all the manuals I got. Or more info here: Virtual Zero Audio Store





Price: Feel free to make me an offer...
Shipping worldwide.

SOLD!!!

Up for sale is a nice balanced gain stage board using the 12AU7 tubes. The original circuit is from Andrea on his page:
Hi-End DAC tube output stage
As you see on the pictures there are no pcb sockets installed as I used chassis mounting but I guess this is no problem to solder
a 9-pin ceramic or better belton pcb socket on the board.
The CCS for the tubes is 2sk170BL this way it sounds uncolored! The original CCS had a glare like sound and this is not my cup of tea. But If you want it
back to original schematic then I guess its only two Jfets and 4x resistors to change.
On the board are very good parts, also the 2.2uF russian MKP new production very good sounding.

For sale are also mains transformer EI core and a special wide band 20H choke.
If you want the populated board only the price is 150 EUR (icluded a nice pair of GE 12AU7 tubes)
Mains transformer (P: 230V S:230V @ 300mA + 15V @ 4A) and 20H 170mA choke= 100 EUR

I am shipping worldwide!

Hello girls and boys...
Need an advice or "how to"...
I have a pair of P Audio BM-8CXA drivers.
Would like to remove the back of the tweeter for mounting into an open baffle project i am working on currently.
Can someone tell me what to expect under the cap of the backside of the tweeter?

I know i have 4 screws to remove but what is holding the tweeter coil with the dome there and how to secure it when i remove the backside of the tweeter part of the driver....

Would love to know what i have to be careful on before going into this ..
thank you

Hi,

I’m quite new on analogue electronics. I found this schematic for a audio line mixer, but I can’t understand something... maybe someone could help me:

1) Why audio signal pass on drain level on t1-t2-t3 but on source level on t4?
2) Why is not present another capacitor to filter dc - ac on output line after t4?
3) why r1 is after t4 and the resistor on the source of t4 has a different value respect the other resistors?


Thank you for your help... I’m try to learning but eletroninc is not so easy...

Someone said why our forum have no any FPGA-based DAC. So It’s here now. I hope someone will interested in and discuss
This DAC will be compatible with Raspberry Pi and any I2S signal.

About DAC:
+ Auto detect sampling rate upto 768khz and bitdepth upto 32bit
+ Asynchronous I2S FIFO with 2 clocks for 2 sampling rate families (x44.1 and x48)
+ Upsampling or Resampling
+ FPGA-based Delta-sigma DAC with digital filter and noise shapping.
Board Detail:
+ Intel/Altera Cyclone IV FPGA
+ 2 clocks with precision power supply (ADM7150)
+ Power supply 5V or all individual voltage for Diyer upgrade (1.2V, 2.5V, 3.3V)

I have a two way set of speakers that need 5db attenuation to balance the speakers.
8ohms
50w
Tweeter = 95db
Woofer = 90db
According to the online line calculator I have been using here L-Pad (Driver Attenuation Circuit) Designer / Calculator
Then I get R1=3.5 ohms @ 21.88watts
R2 =10.28 ohms @ 10.28 watts.
5w & 10w resistors are available from a limited source, but the question here is what would be the best way to approach the contruction for this Lpad.
Do we really need more than a 10watt resistor or can we use a combination.Bear with me here as I'm still a noob when it comes to design and build for crossovers.

Amp cam in with blown outputs and the output filter inductor broken off the board .

Fixed the inductor and replaced all outputs with matching date codes .

Amp will power up and idle fine .

Problem is the amp has very distorted output .

Any ideas on where to start ?

Hello. Many years ago i was given this subwoofer, the speaker box without the servo amplifier. I purchased a couple of used Velodyne servos online but the system did not work. Later on a learned that the servo had to be calibrated to the specific driver and that there was a built in accelerometer on the driver to do the feedback required to reduce distortion. I still have the box, i would love to make it work. Amplifier technology has improved, before spending money and time, i would like to ask if the sub is worthy of it. I could buy a decent sub for a bit more than $1k but I rather no put this thing in the trash can if possible. The driver box and foam surround are in good condition. I was thinking of a hypex based plate amp with built in servo circuit. What do you think? Advice appreciated.

I see that the MCHStreamer and USB Streamer support 10 channels in via USB and 8 channels out via I2S plus another 2 via existing SPDIF - for a total of 10

I'd like to somehow take the 8 I2S channel outputs, convert them to SPDIF and send them along to 4 Khadas ToneBoards ... to support active speakers (DSP functions applied in the source PC) with mostly 44k & 48k signals ie. CD and Video standard audio

In theory its easy. ToneBoards accept I2S input (in theory) and I2S can be converted to SPDIF
BUT

How to do this,

• sending over distance > 25cm (my understanding is that signal I2S integrity suffers over these distances)
• sharing one clock from I2S so all DACs are synchronised
• sending "correct" voltages etc
• I'd prefer to avoid debuging I2S - I2S unless both ends are known to be compatible across all proposed use cases

Is there an add-on board that will plug-n-play. Does anyone have schematics or advice on how to do this (or how not to do it)?

I'm aware that the UDIO-8 and nanoDigi offer this kind of functionality but both are limited to 8 channels out and the nanoDigi only offers 2 channels in

grateful for any advice 😀

Hi everyone. I need help in measuring my Mezzo Utopias with new focal drivers to adjust the crossover.
I decided to biamp them. So I bought a Crown 1502 to use for the bass and I will use my Aethetix Atas for the mid-tweeter sections.
The current status is that I have new Woofers, the ones used in their latest Utopia Scala speakers, and replacement midrange drivers from the Mezzo era but the ones used in the Grand Utopia then, and I have had my tweeter replaced by focal, with a titanium I think, since they had no spares for my tweeters.
This is the state of the drivers. I also purchased both Parts Express DATS and Omnimic V2 measuring systes, so that I can take proper measurements and be more sure about what I am doing. So the expert measuring system is at hand, I just need the brains(which I do not claim to possess...).
As I am using a Metric Halo Lio-8 3D as both pre-amp and DAC, and since it has the capability to act as anything soundwise really, including a crossover, I was thinking of using it for this task.
Initially I was thinking of connecting the drivers on the cabinet but without any crossover and to test them in place (including the effect of the box), using the DATS and the Omnimic, to have all the right parameters. I could change the parameters of one speaker using three of the four channels availiable in my amplifiers, until I get the right curve, so that I can know the best cutoff points between the three drivers. I will then keep the crossover for the bass and the output for it and make a crossover for the mid and tweeter without the need to cut the low for the mid, since I will be cutting it using a the Lio-8. In this way I can build a crossover with minimum components and exact to my speakers.
Since I have no experience in this, I would very much appreciate it if you can give me some guidance as to what to do. If you can help I can send you the characteristics and you could perhaps help me with the design of the crossover.
Initially I read various articles on measuring the speaker response and I have a couple of questions:
1. Do I take near field measurements of all, the bass(and port), the mid and the tweeter, to reduce the effect of room interaction, or do I use the transient response curve for the mid/tweeter to identify room interaction and separate the useful part of the frequency response of each driver and add it up to get the real response of it?
2. In near field measurements, do I measure in the same distance from the center of the drivers for all drivers(so I am limited by the woofer distance which is the largest), or each one within 0.11 times its' diameter which will remove outside interference?
3. If I take measurements at ear level and 1m from the speaker, should I activate one at a time or all together and measure the resulting curve?
Should I also take measurements around this area, moving the mic higher/lower to the right/left?
I am not sure about all this. I have Xsim to input the data of the measurements for the drivers, and I can perhaps then design a crossover. I can perhaps use the crossover that in them as a guide.
If there is another simpler way that I can follow, please tell me. I do feel a bit lost....

We are constantly told how bad our SE tube amplifier are when it comes to Damping Factor, some people don't realise or choose to ignore the fact that the actual speakers DC resistance tends to be dominant in most cases.

Hi, I have noticed in many schemes the presence of a diode between the grid and the cathode.
I would like to have, if possible, all the information about it, if it is useful and when, if there is a degradation of sound ... etc ..
I also notice that there are those who implement it with a resistor ..
What is resistance needed?
What value should it be put on?

Thanks! I attach some pictures ...

Hi Guys,

After some advice please? Hope this is ok to post here but please move if this is in the wrong place. I've recently built the 8600SVK but have an intermittent issue with the right channel.

Powered up and there was a crackle/pop on the right channel and then silence.🙁 Followed the troubleshooting guide, swapped the 300b and the right channel started working again so assumed it was a faulty tube.🙂

• Received a replacement 300b, installed, and worked a dream listening to music all day.🙂
  
• Following morning powered up and a crackle/pop and the right channel is out again.🙁
  
• Took voltage reading's to diagnose where the issue may be and tested again with music on the off chance and both channels working again!🙂
  
• Following morning tried again and the same crackle/pop on the right and it's out of action again.🙁

Before I tear it all apart and review all the soldering is there anywhere I should be focussing on first?

Readings below: TP3 & TP4 seem to be whack so i'm not sure if this help's diagnose where the issue may be.

Any comments/thoughts gratefully received.

TP1 0.8 0.84
TP2 0.8 0.82
TP3 110 98
TP4 110 103
TP5 0 0
TP6 0 0
TP7 8.7 8.7
TP8 8.7 8.7
TP9 175 167
TP10 175 168
TP11 235 223
TP12 235 226
TP13 330 335
TP14 330 339
TP15 -70 -72
TP16 -70 -72
TP17 -70 -72
TP18 -70 -72
TP19 360 364
TP20 360 366
TP21 5 5
TP22 5 5
TP23 365 370
TP24 365 371
TP25 2.7 2.7
TP26 2.7 2.7
TP27 16-22 15.4
TP28 16-22 15
TP29 385 390
TP30 385 390
TP31 -98 -98
TP32 160 159
TP33 12.6 12.6
TP34 60 59.5
TP35 6.5 6
TP36 6.5 6
TP37 12.6 12.2
TP38 300 296

Hey there,

I'm stuck with a Beyerdynamic A1 clone kit I'm building: 2015 Latest Headphone Amplifier kit reference to Beyer dynamic A amp | eBay

The board is fully populated, and I've applied power:

+/-16vac has been applied to the board from a 30VA centre tapped transformer.

Both LEDs near the driver transistors come on, but the relay does not engage and the front LED does not come on.

If I apply signal and turn up the potentiometer, the heatsinks start getting a bit warm, but no where near hot.

I've attached photos.

If anyone could help me with troubleshooting steps that would be appreciated!

Thanks,
Chris

Never used, can’t even recall what they cost. I think they are about 9.3k output impedance.

How about $60 plus shipping for the pair?

Discount if bought with the toroidal power transformer separately listed.

My offer are ultra low distortion amplifier DiY kits at a non-profit price until further notice, sold through Ebay, payed with Paypal.
Condition for resorting to the non-profit price: send me photos of the completed amp that I can post on my homepage within 6 months of purchase.

All kind of distortions are surely much lower than what can be sensed by human hearing (e.g. 1kHz THD<0.001%). 6 prototypes were built and all function perfectly. ABX blind tests and nulltest prove no "sound of its own", neutral and transparent. Can be used as reference amplifier or loudspeaker measurement amplifier, too.

LDA MIN: 2x80 Watts stereo with turn-on thump muting via a mechanical relay (the mechanical relay may somewhat degrade distortion), no protections. 75 EUR + shipping.
LDA DM1: 2x120 Watts dual mono with full protections via ultra low distortion solid state relays. 140 EUR + shipping.
LDA DM2: 2x200 Watts dual mono with full protections via ultra low distortion solid state relays. 178 EUR + shipping.
LDA MON: 1x200 Watts mono with full protections via an ultra low distortion solid state relay. 90 EUR + shipping.

Outside of Europe shipping costs may be prohibitive. The above non-profit prices include packaging fee, Ebay commission, and Paypal commission. Currently on Ebay in the UK, Germany, France, Spain, Italy. If you're interested and the kit is not listed on the Ebay of your country, please write me a private message. If there is no Ebay in your country or you don't have Paypal, then you can't buy safely from me.

All components are from reliable source. Critical components are from renowned manufacturers.

More information: DiY loudspeaker and amplifier design
LDA home
Please check what is included in the kits and what is not.

Hello,

I would like to build my first pp; a 6as7 circuit to suit the tubes and opts I already have (opts are from vintage Philips el84 parallel PP recording studio amps, 4k to 8ohms). I have been looking around for schematics and found a few candidates but each poses a problem to my limited technical know-how:

http://www.diyparadiso.com/sk6as7pp1.htm

--> looks promising; my plan would be to leave out the PS and desing one using PSUDII to suit my old stock power trafo; is the part of the circuit on the top right meant to delay B+ for the 6as7's? Additional problem would be to achieve the high 550V B- (my trafo is about 375V@ 200mA, I never designed a PS with B+ and B- rails) + the circuit is not so simple for a beginner like me

http://www.triodeguy.com/6as7_pp.htm

--> Biggest downside is the class A operation (to suit the toroids I guess); I would prefer the 10watts output of class A/B. However, amending this circuit with simple class a/b output stage cathode bias would, if the preceding stages can drive it, seem like an easy 'beginners'-circuit. I'ld also design a different PS with the additional filtering these amendments would necessitate

http://www.dissident-audio.com/PP_6AS7/Schema.gif

--> I can't identify the phase-splitter used, looks weird to me + the output stage and PS have a few elements I don't understand (the connection starting from the power trafo's centre tap)..


I would be very happy if some of the members with more technical luggage could comment on these circuits or do some propositions; for now the second schematic with new output stage and PS looks like the best option...

Thanks a lot!!

Simon 😀

Hi All
I'm looking for reliable and competent Accuphase P-300 (Kensonic) repairs on east coast, Recommendations north of NYC are ok but not further south of Baltimore, MD.

Anyone have experience with repair shops? please keep discussions limited to experiences of actual Accuphase repairs done please.

Thanks
Rob

Went to Madisound and sb acoustic to check mw19p paper driver spec. Even at the same impedance driver both site are listing different specification. Did satori made some update on their satori paper drivers ? The fs showed in an accoustic site are rated lower.

This has probably already been discussed many times but the forum search engine refuses to search for sag :-(


I'm working on an experimental guitar amp for a friend, and I plan to do this in stages, i.e. first build a pre-amp and then start work on the power stage. As a result I will need a power supply for the pre-amp before I even know what the final B+ will be for the whole, so for a while at least I will be working with a power supply which is only designed to drive the pre. And that leads me indirectly to some speculations ...



One of the things I plan to play in this amp with is controlled power sag, and this leads me to ask: when sag occurs, does this primarily affect the power amp or is there also also a sonic effect on the earlier stages? My guess is that all stages are affected, so for example a pre-amp stage might go into clipping earlier when the plate voltage falls. Is this so, and is the result more likely to be "interesting", or just crappy?

I am working on a passive crossover of a 3-way. There is an active crossover in my preamp, dividing the bass and higher frequencies.
Then, there is a passive crossover between my mid and tweeter. This is the crossover I am working on.

What I have noticed is that, while trying different alterations of my crossover, the performance of the bass varies considerably.

I know that the bass unit (which has seen no changes) can play very very well, with deep and very dynamic accurate bass. However, with some iterations my xo the bass becomes thick and slow. I have looked, but cannot find anything that might explain what I hear. I looked at phase integration between the hf-drivers and the bass. I have looked at timing differences (time domain). But what I hear seems uncorrelated with anything I can analyze.

I am sure that experienced designers must be familiar with this, and I hope that in general terms I could get some pointers to look at.

What am I missing?

Should the electrolytics (esp. the big filter caps) in a 20 year old low bias class AB amp be OK? By low bias I mean runs pretty cool, not a lot of heat in the chassis interior to accelerate aging. I found an amp I've always wanted but it is 20 years old and not cheap ...

I bought a pair of Chinese KT88 SE circuit boards with the intention of using one per channel for a pair of KT120s and one 6SL7 per board as the voltage amplifier. (Gain of about 30-40 required and will be fixed biased)



The pcbs are quite decent and the KT88 sockets are on snap off pcb sections.


However I am struggling to decide the input stage topology.



According to the Tubecad app it seems to be a cross between a self biased totem pole and a current sourced plate follower.



The totem pole gives higher gain, better psrr and lower output impedance but needs a grid resistor on V1b and R2 would need to be reduced to the same value (~ 4.7k) and both cathode resistors being the same.


Any comments or suggestions?

Hello there

I'm in need of some advice to sort out a speaker problem.

I have a pair of old B&W P4 floorstanders and just recently I noticed that only the tweeter was firing on one of the pair, the mid driver was silent.

So, I pulled out the mid driver and tried it on the other speaker - works ok so the driver itself appears to be fine. Next I tried the driver from the good speaker on the bad one, no sound. So at this point I'm assuming the crossover is the root cause.

I pulled out the crossover - at least as far as I could and notice there are 2 caps on there and not much else.


So, I'm assuming that one or both of these caps needs replacing but I'm totally new to this kind of thing so I've no idea how to properly identity these caps or source replacements. Alternatively, I could keep an eye on ebay for a entire crossover - though I assume the failure is age related and so any of these units will be liable to fail at any point given the age of them (25 years-ish).

Any help / guidance would be very much appreciated.

Thanks!

Never used, but was hooked up and powered on briefly so wires twisted.

See photo for outputs.

Can’t recall what it cost new.

$125 plus shipping

Discount if purchased with the OPTs separately listed.