AudioSector-chip amp kits, dacs, chassis

[tangen]

Here is the schematic of VSPS based phono stage using Allen Wright's modified curve, with the additional zero at 3.2 µS.

Post #1553

Dear Peter.

Are you aware of that your phono amp gives your DAC some serious competition? I ordered two Cinemag CMQEE-3440A transformers and hook them up before your phono amp. This combo really plays music! I haven't tried the S&B transformers you use. But they have to be really good if they shall defend their price tag.

But the sound is of course first of all determinded by your phono amp. You have to produce this commercially! The music lovers deserve it! I have not played music on the cd player/dac combo for a week.

Thanks again for your offer and giving me this opportunity to have this gem of a phono amp.

Best wishes
Jan Ove

PS If you come of with other products that offer this musical quality, you have to tell me ;-)

[Peter Daniel]

Hi Jan,

I'm glad you like that phono amp. For anybody intersted, the circuit was described here: http://www.diyaudio.com/forums/showt...20#post1123520 (RIAA section based on VSPS)

It was actually the first phono stage that I've built recently and the one that I still have the biggest sentiment for. I later tried phono cube clone (the real one) and Pass Ono, but none of those played that good without the need for extensive mods and tuning. In fact, none of that is completed yet.

Below picture of my original setup.

[Peter Daniel]

Originally posted by arild
I have to decide on what amp to start with, i was set on the LM3875 but should i go for the LM4780? heck maybe i will just order both and find out for myself, as long as i can use the same power supply looks like the LM4780 are quite flexible to supply voltage http://www.national.com/cat/?i=289. Do you have a preference between the two amp's

I have a preferrence for LM3875 and that's what I use in all my commercial amps. Parallel LM4780 is mostly recommended for low impedance loads, where higher power is desired.

I still use LM4780 in bridged configuration in one of my systems and it performs well. Probably the easiest way to get balanced signal from unbalanced source is to use matching transformers. Here's the affordable solution that performed really well (I tried it): http://www.edcorusa.com/products/tra...sm10k-10k.html

[Peter Daniel]

Originally posted by luvdunhill
I saw a recent post of your linking to where you describe some mods to the Meitner bidat. I currently own one and love it. Given this, do you have a recommendation for a NOS DAC kit, and how does it compare to the Meitner? Any kits that use the TDA1547 that have a similar flavor (or better!) than the bidat?

According to some, a modified Bidat is one of the best DACs available, at any price. Well, I have one and I think it may be true

I described some of my mods here: http://www.diyaudio.com/forums/showt...594#post901594 I later did a bit more, which I did not described.

I bought that unit more than a year ago and it's been in my system ever since. Initially, it didn't sound to me as good as the modified NOS DAC, although I could detect some hidden potential. After the mods, I would say it's some 10-20% better than NOS DAC, it has more refinement, when NOS can be still a bit rough on the edges or a bit colored. NOS DAC on the other hand offers probably more raw energy.

For best results, Bidat needs to be modified, otherwise it sounds veiled and a bit boring.

[Peter Daniel]

Originally posted by richyrich212t
Peter,

what are "cz" and "Rz" used for on the lm4780 kit ??

Those parts are described in the schematic that is supplied with a kit, or can be found on my website:

http://audiosector.com/lm4780%20amp.pdf
http://audiosector.com/lm4780%20psu.pdf

Cz and Rz are optional Zobel parts. I don't use them with the kits as they affect the sound in a way that should be avoided.

[Peter Daniel]

Originally posted by rickmcinnis
I have heard some interesting rumblings about these things and thought MAYBE you had some ideas for implementation.

What is responsible for your hesitation in using these? If there is anything more to it than time?

It seems like the next step from the LM3875.

For me a next step from the LM3875 would be F3 or F4.

Somehow, I don't feel tempted to add output devices to the chips; it's either chip by itself or completely discreet circuit.

[ttan98]

Peter,

what happen to your DAC, last time I visited I could find any on sale?

[Peter Daniel]

As I mentioned few times already, I don't advertise my DACs, they are being sold through a word of mouth from satisfied customers. You can find info on DACs among those links:

Battery charger for DAC:

http://www.diyaudio.com/forums/showt...967#post803967

DAC polarity fix:

http://www.diyaudio.com/forums/showt...138#post764138

GC ground arrangement:

http://www.diyaudio.com/forums/showt...773#post787773

buffer info:

http://www.diyaudio.com/forums/showt...978#post805978

300pf cap:

LM3886 very prone to mains noise

Wiring CT transformer:

http://www.diyaudio.com/forums/showt...382#post548382

Wiring LM3875 kit:

http://www.diyaudio.com/forums/showt...20#post1108820

Modyfying dual bridges into single bridges:

http://www.diyaudio.com/forums/showt...83#post1196283

GC clipping:

http://www.diyaudio.com/forums/showt...53#post1262953

Integrated Amp chassis:

Chassis for a group order of non-inverted GC kit?

Oscillator in USB DAC:

http://www.diyaudio.com/forums/showt...13#post1212713

Phono stage:

http://www.diyaudio.com/forums/showt...20#post1123520


GC upgrades:

http://www.diyaudio.com/forums/showt...32#post1231532

NOS DAC:

http://www.diyaudio.com/forums/showt...36#post1170936

USB DAC:

http://www.diyaudio.com/forums/showt...46#post1195246

Universal PS board:

http://www.diyaudio.com/forums/showt...60#post1237660

F4 boards:

http://www.diyaudio.com/forums/showt...98#post1230598

Remote volume attenuator circuit:

http://www.diyaudio.com/forums/showt...38#post1175938

LM3875 as a headphone amp:

LM3875 as a headphone amp (another try)

Capacitors evaluation:

http://www.diyaudio.com/forums/showt...431#post574431

http://www.diyaudio.com/forums/showt...230#post581230

Most advanced Gainclone:

The most advanced GainClone amp yet

[ttan98]

all links are upgrades and fixes, if i am interested in BUYING one should i talk to directly?

since you are here, questions incl.:

1. Price
2. options
3. technical specs.

many more, that is why you should put info on yr site rather than repeating yourself.

[Peter Daniel]

BTW, recently a customer who bought one of the DACs some years ago asked to have it modified into balanced version.

Here's how it came out ( I added another DAC board, the circuit reversing DATA phase is glued to receiver chip).