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Trying to choose a project...

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I've been reading, researching, and lurking on these sorts of boards for a while and I think I'm ready to build my first amp. I originally had grand plans, parallel single ended amps using tertiary windings and transmitting tubes etc. I've toned down my expectations a bit, but I'm at an impasse trying to figure out what to try first. Here's what I have on hand tube-wise:
12av5
1625
5v6
6sn7, 12sn7
6sl7, 12sl7
12j5
2e26
6146 and variants like 6159, 6dq6, etc.
A bunch of oddball singles and pairs like 6sa7, El39, 2c22, 2c34, 6sc7, 6sc7, 6f8g, etc.
My current amps are a commercial product that uses 6as7/6080 tubes in a parallel single ended configuration, so I have a bunch of those tubes too. In general, I've been buying good diy tubes whenever I saw a good price on them in preparation for this time, so I have a decent amount of them to choose from. Now all I have to do is put some of them to use!:)

I have narrowed it down to wanting a single ended amp as my first project. In particular I'm interested in ultralinear single ended operation and so called partial feedback amps. Part of me wants to go old school and make a single ended amp with the 12av5 in triode mode, but I'm not sure I'd have enough power to satisfy me (currently running 90db sensitive speakers). I've thought about trying 5v6 single ended ultralinear but I haven't been able to find much info on that... Maybe using them in a partial feedback configuration like the RH807 amp? ANy ideas on what will sound great with the stuff I currently have and would be pretty easy to design? Thanks!

Isaac
 
No thoughts eh?

Well I've been thinking on my own (so there!:) and i think I'll do a single ended triode 12av5 for my first project. They have the reputation for responding like a 6b4g, so I've been looking at various 2a3 designs for inspiration. I'm hoping that I can use some of the 12sl7 tubes I own and have a 12 volt party:) Reading the 2a3 driver thread, it also looks as though I could use a 12j5 per channel, is there any advantage to using two 12j5 tubes instead of a single 12sn7? Any advice is appreciated!

Isaac
 
I don't know much about the 12AV5, but some triode-wired beam power tubes can sound pretty good. The 1625 is equivalent to an 807 or 6L6G and would make a good triode / UL candidate if you can get the sockets. Also you could experiment with 6146, lotsa power there! Some of those bif tetrodes had sill amounts of power. You might want to use a bit of NFB to get the distortion down.

One thing, for a driver for a SE triode/UL you will need grunt: Maybe a 12SN7->12SN7 would be good; perhaps a 12SL7->12SL7 cathode follower. 12SL7 conventional or SRPP will be too weak.

Also if you build a low distortion, high power driver stage you can use it to experiment on a whole lot of different output tubes, find the one you like best.
 
Hey, thanks for the suggestions guys! I have since bought some new tubes that I think will make for an easier first project. I scored a good price on a bunch of RCA 16gk6, think I'll try some various pp configurations with them. I really like what I see on

these pages. I also like the fact that I can use the same tube as a driver and an output. All I have to do is get some sockets and some transformers and I'm ready to go. Has anyone used those sockets that are already in a PCB board? It looks to me like it might be easier to solder that way, I've had trouble with my ham fisted soldering attempts on those little sockets before... Oh and I do have the sockets for the 1625, I made sure that I could get those befoe I bought the tubes...:)


Isaac
 
DigitalJunkie said:
2E26 (and it's cousins) make pretty good audio tubes,with a fair amount of power.. I've seen a few PP amp circuits with them.

They also make great RF amps up into the 2Meter region. :D


I've heard that they can make some sweet sounds, that's why I bought a bunch. I have since found out that to get the best out of them they need a separate, regulated power supply for the screens and perhaps even a tertiary winding on the output transformer, not to mention worrying about RF parasitics. All that together has made me come up with something else for my first scratch build, I want something a little simpler the first time around:)

Isaac
 
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