[amb]

Quote:

I've read elsewhere that a 5kHz wave is also recommended....especially for tube amplifiers.  Is there a reason for this

 
Same comment applies, I don't know why there is any need for 5KHz when you have all the others already.  In fact, if you're operating a real oscilloscope, you could use just one frequency (say, 1KHz), and turn the horizontal time scale knob to "zoom" in and out of the waveform to see everything you want to see.

 

[PJPro]

 
Quote:

PPL clearly rates the HA3-5002 very highly, esp with the AD8610. Presumably Tangent supports this view...hence the PPA v1. So the HA3-5002 is a possible candidate replacement for the BUF634.

The other alternative is the LME49600.....although many appear to see this as a rebadged BUF634.

I have read that the BUF634T is the better sounding variant of the BUF634, presumably due to it maintaining its performance by keeping cooler. I had intended to go for this TO-220 version, perhaps supplemented with a small heat sink. That said, I have no idea how hot these get. They can't get that hot as it would rule out buffer stacking.

 
I need to make a decision on the buffer to use.  I've done a lot of reading (perhaps too much) but seem unable to arrive at a decision.
 
If I go for the HA3-5002, this amp will, in terms of the schematic, be essentially a clone of the PPA V1 (Tangent doesn't sell these PCBs anymore?).  As I've already mentioned above, PPL and Tangent state that these buffers have the edge over the BUF634 (even when stacked).
 
Does anyone else have experience of these two buffers?   Which would you go for?
 

 

[PJPro]

OK.  So I think I'll go for the BUF634T.  This seems to perform better than the DIP8 package and allows the use of a heaksink.