TAS1020>AKM4584>LM722 http://snipurl.com/j48m There is more inside than what you think. BTW: AKM chips don't have bad specs at all

If you are looking for a more transparent sound why don't you try that: http://www6.head-fi.org/forums/showp...&postcount=653 I tried (with PPA v1.0, intersil buffers and HD580) and liked a lot. You have discrete buffers so it makes even more sense. It requires modding the amp but it's easy.

Thank you for your very interesting impressions. As I built a PPA 1.0 (with intersil's integrated buffers and now with ad744 bypassed output) and recently an M3 (more or less standard parts) I am also trying to discern sonical differences. I still haven't realized well but it seems to me that...

Yes, even with low impedence cans (MDR-V6) at full volume I can barely hear just a distant "somenthing" (thermal noise?). I though about lowering R1 (the att. is 10k) but with the actual performance I guess it is useless 'cause source noise is predominant anyway.

I cased the amp. No more buzz or hum. It's so silent I though it was broken I'd like to post pictures but I have no digital camera. It is a standard M3 anyway. The minor differences are the fixed BB, crossfed (Tangent board) with rotary switch in the back along with stepped att. and shaft...

I still listen to my PPA (my first DIY) and modding it. Recently installed AD744 with bypassed output and even with intersil buffers is a clear improvement. It's a great project and has a lot of options and "add-ons" to settle with an amp that fits your preferences. I finished an M3 yesterday...

Quote: Originally Posted by 00940 it depends of your model. Ladder, serie or shunt. Mine is a ladder but from this point of view it doesn't differ from a series. As I said it seems to me that the only thing that would occur is interrupting the signal from the source and I don't...

Quote: Originally Posted by ooheadsoo Basically, they say if it wasn't make before break, you'd be blowing your preamp up about now. I don't understand the point. Break before make, if I got it right, means that before making the next contact the switch interrupt the previous...

No, it is easy to turn and the knob has a good grip (and it is really massive). I am just complaining the clicking noise in the amp. I guess they use the wrong switch (bbm). Quote: Originally Posted by phobus You're talking about clicking noise in the amp right? I was just commenting...

I bought one of those but already done. It is noisy, it clicks when switching levels. I have tested it with clips (I am thinking of returning it) but I doubt the casing will solve the problem.

I retested the board and now the amp is working. No more problems with the ground channel (don't ask me why). I still have a little buzz, volume dependent, that magically disapper at full volume (no attenuation) but I guess casing and grounding the pot case will fix it. Just few minutes of...

Quote: Originally Posted by amb I recommend 33pF for the ground channel. You might not hear any anomaly with a smaller value cap, but the 33pF value was chosen with extensive testing and is optimized for best stability and bandwidth. Ops Now I realize i made the same mistake

Thank you Morsel for your suggestions. RMAA could fail but I hope my ears don't Building the PPA I had the same experience, casing the PCB the noise disappeared. This time is really huge. No wonder there is somenthig wrong in the grounding with all those clip wires I am using hanging...

DC specs. The "BP" is selected for better offset.

I have completed my M3 board and now I am testing it but something strange is happening. First, I hear a steady noise even with 300ohm cans, only with 600 ohm k240 is not clearly audible. RMAA tells me is a huge 50hz hum. I know that this sort of problems usually disappear with casing and proper...

I really like this project. I was waiting for a DIY hi-end DAC using 1704. I second 00940 suggestions, specially discrete I/V, jitter control, USB isolation and regulation (why not a jung-like reg. implemented on the board?). I do not have any skill to help you in the design but I will be in...

Quote: Originally Posted by Squeek Hi All, I was hoping someone could shed some light on these to opamps. I have SuperMacro on the way, and I'll be expiramenting with these two as well as OPA627AP. What are the characteristics of all of these? The "BP" selection has better...

I didn't understand if it is advisable to try the 744 with the output stage bypassed in a PPA with Intersil buffers. I don't plan to go the discrete buffer way for the moment (I am working on M3) but I'd like to try that 744 stuff. BTW Do the trick apply to the ground channel too?

Something like that?

I have some OPA2604 in the drawer and I am thinking: can I use them to build a Pimeta-like circuit using one half for buffer? The idea crossed my mind seeing Levallois-cmoy amp and 2604 datasheet

Thank you AMB and Morsel. I am looking forward to listen to your work (still collecting parts)

A question 'bout part selection. Is it important that the bass boost pot has an overall impedence of 50K? I understand it is used just as a variable resitor so the resistence "seen" from the input circuit is variable too anyway. Can I go for a cheaper pot? I don't plan to use the bass boost...

Thanks everybody for the replies. The guy promise a refund if the att. is not noiseless but acually he use the same switches shown in the diyaudio thread. The "James" switches can be seen here http://www.octave-electronics.com/Parts/switches.shtml The clicking noise between switches can...

Quote: Originally Posted by hubcaps There's a thread on this over at diyaudio.com. Which forum? Thank you

Does anybody tried this att. sold on ebay? http://cgi.ebay.it/ws/eBayISAPI.dll?...tem=5762004799 The guy has a good feedback and uses Dale resistors. It looks like the one sold by Octave Audio. Only 10K and 100k. I am thinking 'bout a 10k for my M³. BTW: 10k is too low an input...