B1 Buffer Preamp

Dear sq225917,

Well finally got mine finished today, even though some parts are on back order,Aura Teflons for the 1uf and a 25k goldpoint pot. Mine uses a single Teddyreg between rectifier board and input to give a lovely clean 24v. I started the build considering a Wallwart so my choice of 10k uf Mundorfs for C1 and C2 is now looking a little silly./QUOTE]

At last somebody is using Teddyregs as I recommended months ago.
Jleaman, do you use them also?
I am starting to use cheap NOS military spec Russian PETP caps for coupling which sound softer and more "organic" than 10uF Epcos MKT for example (my previous choice for price/performance). I could try parallel 0u1 Teflons with the PETP. What do you think?

Cheers,
M
 
Hi Fran,

Do you mean C2? I did not get an answer about the importance of that one and I choose a 10%value: 1500uF Rubycon ZL. Sounds good to me.
As C1, I have around 6000uF on Rubycons.
All I say is that if you are going to use regulated supply I recommend using a good regulator, be it Teddyreg or other, instead of monolythic regs...

Hi sq225917,

Glad to hear.
Do you use Powerregs for power amps too? I am using them everywhere, as time allows.
I also use -ECdesigns'- "charge-transfer" supply on the B1. It comes in two flavors: conventional and floating. Floating would be OK for stock B1, though I installed the conventional before the other one was created...

To tell the truth, I use no pre on my "main system number two", now. :cool:

Regards,
M
 
Hi Fran,

Do you mean C2? I did not get an answer about the importance of that one and I choose a 10%value: 1500uF Rubycon ZL. Sounds good to me.
As C1, I have around 6000uF on Rubycons.
All I say is that if you are going to use regulated supply I recommend using a good regulator, be it Teddyreg or other, instead of monolythic regs...

Hi sq225917,

Glad to hear.
Do you use Powerregs for power amps too? I am using them everywhere, as time allows.
I also use -ECdesigns'- "charge-transfer" supply on the B1. It comes in two flavors: conventional and floating. Floating would be OK for stock B1, though I installed the conventional before the other one was created...

To tell the truth, I use no pre on my "main system number two", now. :cool:

Regards,
M

I use a passive pot, thats about it between the amplifier and cd player.
 
Sorry for OT:

I use -ECdesigns'- M1 NOS DAC (galvanicaly isolated USB) with a pot (paralleled with a low noise R) as variable load resistor for the TDA1543DAC output. This way the output V of the DAC is chosen and the DAC and amp are connected directly. Theoretically noisier but sound is very satisfying. DAC's output variation is at most +/-6dB, so the load resistance is tailored to suit the amps sensitivity... :cool:

Try the Teddyreg plus the charge transfer supply ;)

Cheers,
M
 
DAC with B1 Buffer

Hi,

I am hoping to include a DAC in my B1 buffer project. The DAC needs to support USB interface as well as the usual digital inputs. The idea is that the two-way B1 input switch will select between digital sources (from the output of the DAC) and the analog inputs coming via the phono connectors.

Does anyone out there have experience of a DAC with the B1 buffer, or can recommend a DIY DAC for use in my project?

Thanks for the help

George
 
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Joined 2008
Paid Member
Hi,

I am hoping to include a DAC in my B1 buffer project. The DAC needs to support USB interface as well as the usual digital inputs. The idea is that the two-way B1 input switch will select between digital sources (from the output of the DAC) and the analog inputs coming via the phono connectors.

Does anyone out there have experience of a DAC with the B1 buffer, or can recommend a DIY DAC for use in my project?

Thanks for the help

George

Hi George,

I am using a diy B1 buffer preamp with a diy DAC at present, although not on the same box as you are proposing, and am pretty pleased with the result. The B1 is the standard circuit, not the symmetrical PSU one. The DAC is a PCM2707 receiving the USB signal configured to output I2S, and the DAC chip is a PCM1793. The datasheet for the PCM2707 has pretty much evrything you need to know to use it; I also used information from the Opus DAC information from Twisted Pear, and from

ecp.cc

I used the PCM2707 self-powered rather than bus-powered, which is why I had to mix the two. (The circuit from the Opus DAC is bus-powered.)

The PCM1793 part was from a circuit for a "MINI PCM1793 DAC" that I found somewhere online, but I'm afraid I can't find it again to post a link. In any event, the only part of the circuit I used was for the PCM1793 itself, since I didn't do any inputs other than USB. (Next project will maybe be a PCM1794 DAC with more of these bells and whistles...) So I'm afraid I can't help you much with other inputs, except to point out the following thread:

http://www.diyaudio.com/forums/digital-source/133597-micro-dir9001-pcm1794a-dac.html

which may be of help, if you haven't seen it. If you'd like to see more details about the PCM1793 stuff I did, you can find it at

http://www.diyaudio.com/forums/digital-line-level/151650-few-questions-pcm1793-based-usb-dac.html

Cheers

Nigel
 
Hi Nigel,

thanks for that information... this is turning into a research project. I guess what I was looking to do was modify an off-the-shelf kit or somesuch.... I have not (yet) got into board making. Your approach is interesting and it seems that I have some reading to do before I decide on my next steps. Anyone else with thoughts on DAC with B1?

Not me, Sony CDP > B1 Aleph's.

Simple, clean easy GOOD SOUND!
 
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Joined 2008
Paid Member
Hi Nigel,

thanks for that information... this is turning into a research project. I guess what I was looking to do was modify an off-the-shelf kit or somesuch.... I have not (yet) got into board making. Your approach is interesting and it seems that I have some reading to do before I decide on my next steps. Anyone else with thoughts on DAC with B1?

Hi George,

Well, you don't need to make a board for this - I didn't, as you can see on the thread I posted. (Although I am planning to do so next time, for reasons that have little to do with sound quality). Another thing you might want to look at is an Alien DAC kit. I bought one a while ago from Glass Jar audio, and it works very well. I'm not sure how much it can be modified to hook up inputs other than USB - although I'm sure there's info somewhere on the net about it - but at least it would be a small, convenient board to fit into a preamp. (I must say my PCM1793 effort sounds better, though...)

Cheers

Nigel