Need some help and advice. Im having a DC offset problem with my D2.0 (I have both DAC boards , the CS and the AD one). I have the caps by-passed and blackgate mod. What im getting is a high DC offset on the right channel 3.2V !! and about 50mv on the left with with the AD DAC board. Changes a little with the CS board 4.5V (right) !! on the left I only get 5mv.
I have tried swapping in the dy2000 in center and the 2604 on the sides opamps with basically the same voltage readings. The LM4562s in all three positions that I have been useing for months also give the same readings. Any ideas what the problem could be or what I should test next ?
Should look into some decent blackgates for the caps that are by-passed if this is not cureable ? which ones as far as series and size would be most helpfull.
I really want to get the zapfilter but my budget is just not up to it at the moment , that would cure this for sure right ?
Originally Posted by joe_cool /img/forum/go_quote.gif Measure the four DC voltages at the inputs to the analog stages (where the caps are bypassed) and you should have a useful indicator.
That's a good diagnostic step. Make sure you measure on the nodes inside the PCB (towards the opamps).
Since the behavior is the same with different opamps and DAC boards, the likely scenario is that you have missed one wire or it was a marginal solder joint and now it's loose. If that's the case then you'll hear a 3 dB lower (i.e. half) output from the faulty (right) channel.
Thanks much guys , I will check this as soon as I get the chance. Been busy building a Mini3. I have a feeling your right about the wonky soldering since at the time I only jumpered them and did not remove the caps totally , meaning to at a later date. Again thanks.
I took the caps out for good tonight and used some scrap 26gauge silver solid core wire I had left over for the LOD I made for my ipod (Mini3 sounds fantastic btw). Im now getting 53mv on the right channel and still about 50mv on the left with the AD board , is that passable ? Im thinking I should switch the LMs around to see if it lowers things or is the AD board prone to higher offset (havent tried the CS one as of yet) will as soon as I get the time though to test everything a bit more. Thanks , seems to have solved the problem.
Damn forgot to measure at the nodes inside , getting old sucks LOL. I took these readings at the RCA outs. Will do it the right way.
Originally Posted by keyid /img/forum/go_quote.gif I got an used Zaholu 2.5c with 2604 opamps, I did the caps bypass and I could not stand the sibilance in the highs. Tried burning it in hoping it would go away but still the same, what was weird is that my silver plated coaxial made it worst, the cccc's and ssss's was unbearable all the highs are too electronic sounding.
When I used an optical it tamed the highs alittle more organic sounding.
Question I have is would 2107 or LM4562 tame the highs even more. I do really like sound with the bypass but I need a more natural high
This is with almost any cd with women's voices singing, I cant listen to eva cassidy anymore... My amp is a Pimeta with 627/637.
Originally Posted by d-cee /img/forum/go_quote.gif no, thankfully they use DIP-8 sockets where the opamps are so you can remove the existing opamp and "roll" in new ones relatively quickly and easily
My situation is similar to above poster's in that I'm a Newbie and want to do some Op Amp rolling. I've gone to Nat'l Semiconductor's site, but I don't think I can buy just the few LM4562s that I need. Is is two (2) op amps that I need to fit a DIP8 socket? Is there a precise product code I will need....and just how fast and easy is the install? Who can I call or what site can I visit to buy these? Thanks!
Originally Posted by audiohound /img/forum/go_quote.gif My situation is similar to above poster's in that I'm a Newbie and want to do some Op Amp rolling. I've gone to Nat'l Semiconductor's site, but I don't think I can buy just the few LM4562s that I need. Is is two (2) op amps that I need to fit a DIP8 socket? Is there a precise product code I will need....and just how fast and easy is the install? Who can I call or what site can I visit to buy these? Thanks!
You can order them from www.digikey.com. I just ordered a pair from them about 3 weeks ago and they had them in stock. Other sources for op amps and electronic parts are Mouser Electronics and Newark Electronics.
I just ordered a Zhaolu D2.5C with optional discrete amplifier module upgrade from Audiomagus. I have no idea how this unit is going to sound and was wondering if anyone else here has heard it or compared it to the stock and/or Ori modded headphone amp module? I think I am going DAC/amp crazt as in the past couple of weeks I bought 3 DAC/amps... an iBasso D1, a ZERO 24/192 (Zhaolu clone?) and now a Zhaolu D2.5C with discrete headphone amp. I only have the ZERO 24/192 DAC/amp in hand now and amp burning it in. I did try some op amp rolling on it initially and I think I liked the OPA627 op amps in place of the OPA2604 DAC amp that came with it. For now, I am running it with all of its original op amps to give it a chance to smooth out/burn in. Can't wait to get my other DAC/amps to compare them.