Quote: Originally Posted by S_Dedalus Ray Samuels has already explained that the topology of the SR-71 is a very simple opamp gain stage, buffer ouput stage amplifier, this is used in almost every headphone amp I've seen, and has very little to do with the overall sound or quality of a...

Hey, watch it Gsferrari! I see you have over 3,000 posts here. Dude, you need to get a girlfriend.

Uh, whatever you say chummy. Yours and gsferrari's posts prove my point that no one is going to clone the SR-71 build quality so there is no reason to keep the opamp and buffer a secret. Unless, as I said before, it is an obvious choice. If that is the case, then people would question paying...

Quote: Originally Posted by Ray Samuels Gain head... If you are the same person in the headwise called "PURE", & accusing me of what you tried in that thread, all I can say is you are a real sick person, you are mad at me becuase you wanted information on how the SR-71 was built & how...

Quote: Originally Posted by gsferrari Why cant you get creative and come up with your own designs anyway? I'm not trying to copy his design, I was just pointing out to the earlier statement that the opamps/buffers in the SR-71 are known. I think RS painted over them because it is...

Quote: Originally Posted by gsferrari No - thats what that dude "thinks" he knows. RS had an opportunity to deny the claim and he did not, so that is a fairly good indicator that the AD8610/BUF634 combination is correct. Other factors also indicate this combination is correct...

Quote: Originally Posted by gaboo Trouble is we don't know what op amps SR-71 uses, except for the red nail polish. Oh, wait, that is coloring the sound Yes, we do. It is the AD8610 and BUF634. See here: http://headwize.com/ubb/showpage.php?fnum=3&tid=5276

Quote: Originally Posted by Puddleglum I've heard great things, and I believe the vast majority of them to be true. But I really want a home amp of the same quality/price ratio as the SR-71. The quality to price ratio of the SR-71 is not very good. See here...

If you need an amp, buy a Mint instead of the SR-71. It is apparently the same thing: http://headwize.com/ubb/showpage.php?fnum=3&tid=5276.

Quote: Originally Posted by Tuberoller This post is on-topic and relavant. Your earlier post was just a link to another thread,which linked to two others, made no point and attempted to make no point. You're saying basically the same thing here and that's fine. O.K. - Sorry for...

Quote: Originally Posted by Tuberoller Start a thread specific to your issue and you can discuss A,B and C. My response was basically to point out, as Sygyzy explained, that most designs are similar or the same to other well-known designs, using the SR-71 as an example. This was...

Tuberoller, so what your saying is that no one can ever mention B when discussing A, even if B is relevant to A? This does not make sense.

Quote: Originally Posted by 00940 It has already been done. The old thread with all the furious answers against this poor little opamp alone in its big box is still somewhere on headwize. I know - it was a rhetorical statement. But a good example of why this thread is veering into...

Quote: Originally Posted by Wodgy Mikhail could do us all a favor by coming clean about this very question. It would be best to hear it from the horse's mouth. Barring that, we'll have to wait for someone to trace the circuit of their amp (and be willing to come forward about it) or...

I threw in C1 and it helps but does not eliminate the offset which is now 0.265-0.267 V on each side. I am getting these measurements with no source connected and no headphones connected. This opamp is f#@* pissing me off! Edit: Actually the offset is now 0.066V on each side.

I just found this post here http://www4.head-fi.org/forums/showt...3&highlight=r2 where Jamont describes that taking out C1 caused his DC offset problem. This is another difference between my new layout and the old - I took out C1. I did not think this was relevant to my question above though. I...

You left out the new Panasonic FM.

I found some text by Jan Meier over at Headwize stating that he was successful with the LM6171 using R4 = 300k, R3 = 56k and R2 = 47.5k. I modified my board layout and will try my same values (R2 = 100k, R3 = 127k and R4 = 464k), as well as Jan's and report back.

I don't think you can get 4 AAA into that battery holder though. But with the DN2, I have used the available extended metal end panel and created a battery door just like that on the SR-71. I use two 4 AAA batery holders inside for 12V.

The Lansing DN2 enclosure will just fit a 4 AAA battery holder and comes in 3, 4 or 5 inch lengths.

The only values I am coming up with that are lower and still keep R2 at 50k is R3 and R4 = 100k so a gain of 2. Any thoughts from the audience? Tangent, you have had success with the values posted on your website. Perhaps you would be willing to post a photo of your layout?

Earwax, 100ohm should do the trick. It did on my previous prototype.

Well, I think I am going to play around with some alternative resistor values, such as for R5, and see if I can get this thing working. If you look at the PCB for Meier's Porta Corda II, you can see that layout is not very critical (no offense to Jan).

My resistor values are R2 = 100k, R3 = 127k and R4 = 464k. I'm measuring the offset with no source connected and no load. What I cannot fathom is why these values work fine with my earlier layout and not with this new layout. The decoupling caps and power traces are identical and the signal...

I have been working on an implementation of the LM6171 for a headphone amplifier. The schematic is similar to that shown in Tangent's website (http://tangentsoft.net/audio/hs-opamp.html) and the LM6171 datasheet (http://cache.national.com/ds/LM/LM6171.pdf). My first prototypes yielded DC offsets...