I am lucky to have the CD.
To my best guess, the content of the CD is the document that is shipped along with the RTP3D kit.
FWIW, the SR docs in the CD is identical to the one in the cookbook.To me, the most valuable part of the
CD is the complete RTP3D schematics as my ancient version cookbook doesn't have any circuit remotely looks like the RTP3D, the FVP circuit uses 12au7!!!
To my best guess, the content of the CD is the document that is shipped along with the RTP3D kit.
FWIW, the SR docs in the CD is identical to the one in the cookbook.To me, the most valuable part of the
CD is the complete RTP3D schematics as my ancient version cookbook doesn't have any circuit remotely looks like the RTP3D, the FVP circuit uses 12au7!!!
No, I definitely wouldn't pay that much for two more SuperReg PCBs now I have two to copy (although I have to say that the quality of those supplied by VSE is very good).
I don't remember whether I already posted these to this thread, but there are some tremendous photos online of Emile Sprenger's RTP3C, which I found a huge help when I was building mine. I would think that any reasonably experienced builder armed with these photos and Allen's Preamp Cookbook would have no problem with an RTP3 .
Note that Emile's uses his own HPHV shunt regulators, rather than Allen's SuperRegs. The HPHV is a maxed-out version of the SuperReg concept which has the potential to outperform Allen's circuit, but this circuit needs top-class PCB manufacture to work reliably (unlike the ones I made), and I have a strong suspicion I damaged mine with overvoltage in the HT supply.
By the way, don't too carried away with the question of what is an RTP3C and what is an RTP3D. The differences in the signal circuits is apparently minor (apart from the reversion to PCBs in the the final production run), with the main changes being in the PSU box.
Alex
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When researching the component layout for my project I found these photos by Megan Knight an inspiration. According to Thomas this is one of the kits.
https://www.flickr.com/photos/meganknight/sets/72157633071933674/
https://www.flickr.com/photos/meganknight/sets/72157633071933674/
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Allen resisted for years, but I think the last few RTP3Ds were built on PCBs. See the photos here.
Alex
I think the RTP3D also added choke regulated supplies for the heaters, where previous versions only used chokes for the HT supply. My homebrew RTP3 only has CR for the HT, as I used separate transformers for each supply (dual mono) and had run out of room in the box...
Alex
No. Those are stiff PCB material but they are hjust used as a place to anchor the posts used to make the P-P very tidy. This layout is also very important. I have a pair of these boards assembled, if i find them i can take some pictures. I was Allen’s Mac support guy for a long time and i got paid with an RTP kit (no PS unfortunately — have the parts, just haven’t put it together).
I talked to Vacuum State after Allen’s untimely demise, so my eatlier PCB comment was postAllen. AFAIK they are still making these.
dave
I am pretty sure Allen mentioned the switch to PCB somewhere, and I have these photos that show genuine PCBs are used. The preamp is the rtp3e, which may be PCB version symbol. (that's just what I think, not necessarily true)
Attachments
dave,
Lose performance?
I respectfully disagree. PCB quality and layout are of paramount importance and can exceed PTP designs. You need to know what you are doing and have measurement equipment that can assist in that. AP 525 or better imho. I would not believe for a minute that some of the best SS designs today (ie Benchmark, Neurochrome Modulus, etc...) are done without the assistance of such measurements and tight layouts.
I am sure the RTP designs can be improved/optimized with proper effort. I remember Allen sending me spectral harmonic distortion graphs illustrating how the RTP was better than other tube preamps so it seems he was in agreement (with regards to the importance of measurements in general).
It’s all about the execution.
Best,
Anand.
Lose performance?
I respectfully disagree. PCB quality and layout are of paramount importance and can exceed PTP designs. You need to know what you are doing and have measurement equipment that can assist in that. AP 525 or better imho. I would not believe for a minute that some of the best SS designs today (ie Benchmark, Neurochrome Modulus, etc...) are done without the assistance of such measurements and tight layouts.
I am sure the RTP designs can be improved/optimized with proper effort. I remember Allen sending me spectral harmonic distortion graphs illustrating how the RTP was better than other tube preamps so it seems he was in agreement (with regards to the importance of measurements in general).
It’s all about the execution.
Best,
Anand.
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