My DIY Pre/phono Pre/Active XO/tube buffer

MillerLiteScott

Looks cool Ben. Where" the tube output from?

ben62670

MillerLiteScott wrote: »

Looks cool Ben. Where" the tube output from?

Not tubed yet

anonymouse wrote: »

any updates on how this sounds?

I am letting it burn in with the stock OpAmps, and then I will try the OPA2134's. I am not sure what to try next. I would like some 627's on a brown dog adapter, but that is $100 for 1!

As for now it is sounding pretty sweet

ben62670

My bad it is $50 from here.
http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx
I wonder if the China ones are fake?

ben62670

This was my first real DAC
http://www.polkaudio.com/forums/showthread.php?t=71222
The GV27 hooked me up with this.
http://www.polkaudio.com/forums/showthread.php?t=72911
This one is just a little better than both of those. I was pretty happy with the one that I got from Fred, but it was way too large for my single chassis solution.

ben62670

Well I have some time on my DAC now. The surprising thing to me is there wasn't a noticeable change with burnin time on this piece. It may be that it was subtle and over time, but it wasn't apparent if it was there at all. I finally got around to changing out the OpAmps. I found the BB OPA2134's in one of my parts bins. It was an easy swap with the sockets. The sound is much better all around. There is more weight to the bass, silky mids, and the imaging improved. What I would like is a sharper hit on the cybols and rim shots on the drums. I am being picky. It is there, but not as pronounced as I would like it to be. I am waiting on some OPA627's to arive and replace the 2134's. I hear the 627's are a big improvement over the 2134's, but I do have to say the 134's and the 2134's are a steal of a deal if you want improvement over what is stock in most gear. I will also say that I have no love for the AD827's. They just don't do it for me like the OPA2134's.

FTGV

You might try these in the I-V positions with your OPA627's for the output.

http://www.national.com/ds/LM/LM6172.pdf

ben62670

They are in my digikey cart right now as are the LM4562's. One thing I forgot to mention is I am not sure how much performance could be had by separating the 5v from the 12-0-12v on the PS board. The transformer is a 12-0-12 only. There is no noise as is so I am not really feeling that there would be much of an improvement there???

disneyjoe7

If 12vdc is clean, then I would think 5vdc from a regulator would be clean also if powered by the 12vdc.

FTGV

ben62670 wrote: »

One thing I forgot to mention is I am not sure how much performance could be had by separating the 5v from the 12-0-12v on the PS board. The transformer is a 12-0-12 only. There is no noise as is so I am not really feeling that there would be much of an improvement there???

You could gain some isolation with the addition of a resistor or better yet adding some inductance preceeding the regulators.That might be tricky though with the tight board real estate.

IMO upgrading the regulators would bring greater gains than would adding a separate transformer for the digital supply.Though cheap and simple to use the LM78**/LM79** series regulators are the poorest performers in regards to noise and output impedance.

Feeding those premium opamps from clean, low impedance discrete regulators like the Sulzer's,Jungs Super reg's or Burson's should prove sonically benificial.The Burson's are drop in replacements for standard 3 pin regs but they are spendy.The Sulzers and Jungs require a complete DIY effort.I have sucessfully scratch built a number of the Sulzers for use in my DAC and preamp.They were inexpensive to build but were rather tedious but well worth the effort.

FTGV

Sorry the pics are out of focus but here's a sampling of my Sulzer builds to give an idea of complexity.The single board contains both a positive and negative reg while the two separate boards contain only one polarity.

ben62670

The LDR volume control...[IMG][/img]

ben62670

My OPA627's are here!

maximillian

I know this is an old thread and that Ben is no longer around.... however, can anyone tell me if they have listened to this built gear?

The PCBs: remote pot, input selector, and tube pre are all available as kits from sellers on Ebay. I'm not interested in the DAC, just looking to possiblely make a Tube pre. However, I am not sure if in the end it will sound good compared to the money spent. The parts that Ben purchased are selling for just under $200. To that you need a good case, connectors, and a toroidal transformer. Total cost is probably over $300. I would think a decent used preamp could be purchased for only a little more than this. But I don't know how they would compare. Anyone know or care to guess?

ben62670

maximillian wrote: »

I know this is an old thread and that Ben is no longer around.... however, can anyone tell me if they have listened to this built gear?

The PCBs: remote pot, input selector, and tube pre are all available as kits from sellers on Ebay. I'm not interested in the DAC, just looking to possiblely make a Tube pre. However, I am not sure if in the end it will sound good compared to the money spent. The parts that Ben purchased are selling for just under $200. To that you need a good case, connectors, and a toroidal transformer. Total cost is probably over $300. I would think a decent used preamp could be purchased for only a little more than this. But I don't know how they would compare. Anyone know or care to guess?

Let me know if you still are interested in making a tube pre. I did the grounded grid full kit and it sounds great. I am no longer doing any electronics due to health reasons. I hope all is well.
Ben