AudioSector-chip amp kits, dacs, chassis

[Peter Daniel]

I listen mostly to alternative rock, heavy rock, progressive metal, house and some trance. I appreciate well defined base with punch and dynamic highs over smooth tubey sound. I like my mids clear with as much detail as possible (i love hearing new things in my recordings).

You see with that material, and your listening preferences, the snubber may indeed be a very good choice. I also listen a lot to trance and house, as well industrial music, and this is where I first tried snubber and felt substantial improvement. As this music is already synthesized (and one of my initial advisors told me that he felt like snubber produces synthesized character to the sound) you shouldn't noticed any drawbacks, and gains in dynamic, vocal presence, and distinct highs. It's only when you go into more acoustic presentation, when snubber may become undesirable.

I tried those 10,000u Elnas that Brian should still have, and they were pretty good comparing to Jensens and Nichicons KG. They were increasing sibilances slightly, but not to big degree. If you don't want to spend too much go for Panasonic FC, my friends reported them similar in character as BG N (although not that refined). If you want to spend more, you might try BG STD.

Panasonic FC and BG STD are still my first choices for 1000u cap values.

 

[pinkmouse]

Well, Peter will disagree,( ) but if you're using the 3875, I would go for 2x1000uf Rubycon ZL per rail to start, to give you a litttle bass definition. If you find the mids and highs a little lacking, then just lose 1000uf per side. That will be lighter, but clearer. The extra caps should only cost you a buck or so, and you can always use them for something else later.

 

[Peter Daniel]

Oh no now u really got me scared. I have an old technics amp with that button, and its only pressed in when listening to very electronic and basey music at lower levels (when base is a must), any other time, i cannot stand it for a second.

I was joking a bit, the snubber does not increase lows and and highs in a way that loudness does. But the coloration itself (without altering frequency) may be similar .

 

[pinkmouse]

See!

But the Panasonics are a good bet.

 

[Peter Daniel]

Well, Peter will disagree,( ) but if you're using the 3875, I would go for 2x1000uf Rubycon ZL per rail to start, to give you a litttle bass definition. If you find the mids and highs a little lacking, then just lose 1000uf per side. That will be lighter, but clearer. The extra caps should only cost you a buck or so, and you can always use them for something else later.

Actually I could sell you those, as I bought them from Reference Audio Mods, and still have some unused pieces. They were $3 ea.

And I agree that they may be very good, if your system matches them. They are very clean, detailed with well defined bass. Somebody told me they are not a good match when Caddocks and Rikens are used.

 

[homer09]

I tried those 10,000u Elnas that Brian should still have, and they were pretty good comparing to Jensens and Nichicons KG. They were increasing sibilances slightly, but not to big degree. If you don't want to spend too much go for Panasonic FC, my friends reported them similar in character as BG N (although not that refined). If you want to spend more, you might try BG STD.

Panasonic FC and BG STD are still my first choices for 1000u cap values.

That's good to hear, i had chosen the Elna's over the Panasonics for 10000u setup already (i could source them cheaper from www.solen.ca at the same price as the panasonics from digikey). I also have a set of Pan FC 1500u which is somewhat of a compromise between Peter's recommendation and Pinkmouse's. And finally the snubber calls for 100u at the chip anyway, so ill have those to try also.

With a little creative planning, i could experiment without blowing the bank, ill order the Elna's from solen if im unsatisfied listening to my house/trance

Edit: Oh and the BG's will be a future upgrade if i like low cap setup

Thanks for the advice Peter and Pinkmouse, greatly appreciated as always!

 

[pinkmouse]

I think the best bet is to just go for the basic kit to start, and see how you get on. The great thing about these projects is that they are so easy to mod, as the whim takes you. For instance, in a spare half hour today I swapped all the diodes on the LM4780 boards for MBR10100s. There is a difference, but I'm not sure if I can pin down exactly what it is yet, and listening to a live Greatful Dead concert on DAB isn't the best auditioning material anyway...

 

[Peter Daniel]

Somebody asked me today if I'll be offering Snubberized Non Inverting LM3875 rev3 Dual Mono Kit in Premium version. The answer is that the current Premium version can be made with a snubber as well, as the boards are ready for those extra components, see pictures here:
http://www.diyaudio.com/forums/showthread.php?postid=584429#post584429

Snuber cap and resistor (1ohm and 100n) are available free of charge, but you have to ask for them when ordering. The 10,000 Panasonics can be added on special request (by e-mail) and additional charges would apply (Digi Key prices).

 

[Hanzwillem]

I found my transformers are pretty useless, so I am in for a full premium DAC kit!

Just that you know, Peter

 

[StalfoS]

Hey.. I allways wondered what the deal was with those 'loudness' buttons and the answer was revealed to my in my univerity studies of acoutics. Turns out the human ear responds most sensitively to frequencies ~3kHz but is otherwise relatively flat---when the sound pressure is significantly lound ( around 60-80 db). At quieter SPL's (0-60db), the human ear tapers off quite dramatically below ~1kHz and above about ~4kHz. Hence the 'loundness' button should theoretically be usefull at lower volumes.

Of course some people just like to make the stereos sound like those cheap sub-sat computer speakers with no midrange...

Anyways Peter, I sent you an email regarding a lm3875 kit, and have not recieved a reply.. it's cool if you are swamped with orders or whatnot, but im begining to feel like i have been left hanging here.

Thanks,
Nate

 

[Peter Daniel]

Nobody is ever left hanging here. I usually don't confirm payments, unless somebody ask me for that specifically. I noticed your e-mail today, and was going to answer it, but it's good you reminded me. I'm still waiting for regular (3875) boards to be fabricated (I only have premium boards presently). It's probably another week before I will receive them.

All orders placed before March 1st has been sent out (except for one from Italy, without shipping being paid yet). Next batch of orders will be sent before the week's end. I usually send them out on Friday, and they arrive on Wendsday to most European destinations. Canada may take 2 days.

 

[Peter Daniel]

I'm slowly running out of LM4780 boards, and i was considering a revision, with updated layout, accomodating all 3 options: parallel, balanced and stereo.

If balanced would be to implemented, the board does not use inverted method (like per AL-1192 notes), but both halves are non inverting and additional circuit is required.

I will be comming with balanced active line stage, so that could be used there, or I might include a small board, implementing LM6172 for buffering and phase splitting.

Below is the proposed layout I was working on yesterday. As you see, the signal traces lengths are substantially reduced, there is more separation (in layout) between both sections and the chip can be also used in stereo mode, providing same funsctionality as two LM3886 chips.

If stereo or balanced operation is looked for, the balast resistors are not required and output is taken directly before those output resistors. In case of parallel operation, resistors should be in place and there is one output only.

The signal grounding is very symetrical for both channels and also simplified.

I plan to do mirrored boards (2 amp board per one main board, as usually). So if someone uses boards for balanced operation, they can be put back to back with PS connections aligned for paralleling. A multiple number of such parallel modules could be connected in parallel (with bus wires for supply) providing simple power distribution scheme and high power.

The accompanying PS board will feature all presently popular options (large caps and snubbers)

As usually, all comments and suggestions are welcome. It will be at least a month before those boards become available.

 

[jleaman]

Peter i notice on all your boards so far that your lines are not neat and tidy there in difrent ways and if not rout there squiggly ? How come ?

 

[Peter Daniel]

What do you mean exactly?

 

[jleaman]

The ones i put x's on are the ones im talking about. : O )

 

[Peter Daniel]

Those are probably bugs in a program, or maybe it depends how it's opened. But when I print it, it looks fine. Besides, it's still work in progress, so I'm not concerned with those small imperfections.

 

[jleaman]

Thats what i thought.. : O ) Good job though..

 

[pinkmouse]

How about an option for T0220 output resistors? We can't get Mills that easily over here, but the Vishay thick film are very good and an excellent substitution.

 

[Peter Daniel]

What is the price on those Vishay TO-220 resistors, any links?

If it's a standard TO-220 package, there shouldn't be a problem to implement it.

 

[pinkmouse]

Go to RS components, and search for "Film Resistors 20W Type RTO 20". The site is session based, so I can't give you a direct link, sorry.