I recently built a Nelson Pass Firstwatt amp and am on the home stretch with a more in depth project from Rod Elliot. I also built a few kit preamps that have worked just fine.
I also just bought the boards for the monoblock amp discussed here. I filled most of the BOM last night and ordered the cases.
I want to ask for some advice on how to get a better foundational understanding of what I'm doing with tube amps. So far I'm really just painting by numbers. The discussions here, I can tell, would be great with a better fundamental understanding. Learning on your own is great, but you can end up going along for quite a while with some major misconceptions. Some of the terminology, while I recognize it, is lost on me. Are there any books that someone can recommend that start from the beginning. I know this can be a tough question because many of you probably don't realize how much you actually know. Having spent, in many cases, a lifetime in electronics it probably is second nature. For instance the 6HJ5 tubes seem a little scarce for my monoblock build. I see substitutions mentioned, but I have no idea how to judge candidates for a substitutions or how I'd re-pin the wiring.
Hopefully my request is clear. Anything you could do to point me in a direction would be appreciated.
Thank you
John
I also just bought the boards for the monoblock amp discussed here. I filled most of the BOM last night and ordered the cases.
I want to ask for some advice on how to get a better foundational understanding of what I'm doing with tube amps. So far I'm really just painting by numbers. The discussions here, I can tell, would be great with a better fundamental understanding. Learning on your own is great, but you can end up going along for quite a while with some major misconceptions. Some of the terminology, while I recognize it, is lost on me. Are there any books that someone can recommend that start from the beginning. I know this can be a tough question because many of you probably don't realize how much you actually know. Having spent, in many cases, a lifetime in electronics it probably is second nature. For instance the 6HJ5 tubes seem a little scarce for my monoblock build. I see substitutions mentioned, but I have no idea how to judge candidates for a substitutions or how I'd re-pin the wiring.
Hopefully my request is clear. Anything you could do to point me in a direction would be appreciated.
Thank you
John
iplayforme,
I'm very much a novice but these helped me a little bit:
The "RCA Tube Receiving Manual" has a section on tube theory toward the beginning:
http://www.tubebooks.org/tubedata/rc30.pdf
Uncle Doug's youtube channel also has a good basic explanation on how tube amps work. Parts 1 and 2:
I'm very much a novice but these helped me a little bit:
The "RCA Tube Receiving Manual" has a section on tube theory toward the beginning:
http://www.tubebooks.org/tubedata/rc30.pdf
Uncle Doug's youtube channel also has a good basic explanation on how tube amps work. Parts 1 and 2:
When I built my amps, vacuumtubes.net had the 6HJ5 at reasonable prices. Don't support the guy on eBay that's trying to get $80 a pair for them.
Yes, I saw that by now and it certainly seems crazy. This is the price that's paid for something becoming trendy. He's probably sold more than a few pairs.
I got the tubes at "Vacuum Tubes division of Radio Electric Supply" and was happy with the price and service.https://vacuumtubes.net/
I've seen those videos and they are a great intro. I just received and have been looking through "A beginners guide to tube audio design" by Bruce Rozenblit. Excellent so far. Technical enough but not way over my head. He's starting at the beginning and building.
For those who have built the original, not "monoblock" 50W Engineer's Amplifier -- i.e. both circuits and ps on one board -- somehow I blew the HV trace one one channel. Until the WTF moment, I have no idea why this happened, but the trace was open.
The fix was to simply bridge the trace with another wire.
The Engineer's Amp on my build does a bit better than the illustrations in Pete's writeup, but the 50W monoblock version pair does better still.
The fix was to simply bridge the trace with another wire.
The Engineer's Amp on my build does a bit better than the illustrations in Pete's writeup, but the 50W monoblock version pair does better still.
If you look at the 6HJ5 data sheet https://frank.pocnet.net/sheets/049/6/6HJ5.pdf, you'll see that there are 2 connection points for G1, G2, and G3. That's the only reason I can think of for that notation.
You must be using the PCB's without the direct mount sockets?
jeff
You must be using the PCB's without the direct mount sockets?
jeff