stretch2011 wrote:I'd love to have it, just don't need it. That's just too much for what I do.
So, put a PPIMV in it. Then you have an amp that can do some decent, band-level cleans, AND bedroom-level crunch. The 18-watt can only do cleans at bedroom level.
But the 18-watt iron is certainly cheaper, and will be a lighter weight project over all, if that's important to you.
I build and repair tube amps. http://amps.monkeymatic.com
stretch2011 wrote:So I have another question for you guys. I'd love to build a 1986 super bass. But I don't need 50 watts of volume through a non-master amp. I'd love to have it, just don't need it. That's just too much for what I do. If I bought the 18 watt marshalls transformers and used el84's instead of el34's what would I have to do to the circuit board? Could I essentially keep the 50watt super bass circuit board and pair different transformers and tubes? I havn't tried anything like this before so I'm going to have to ask for some help.
Yes but you should change power tube bias resistors from 220k/220k to 470k/470k. The 5k6 power tube grid resistors might be just fine if not increase to 8k1
I think the 470R PI bias resistor might need to be increased to 820R or 1k2.
I've found that diode rectification is best and keep the voltage rail higher to get best tone.
The reason I chose 18watts is based off volume of my tweed deluxe 12 watter. In practice its loud but I still need to boost slightly for solos, so I was thinking 18watts would put me right on the money and still have the clarity of non master'd tube clipping. As far as a PPIMV, I'm not familiar with it. I assume its similar to a VVR but what's the difference?. And thanks M Fowler for the Numbers. I assumed biasing would be different but exact numbers are always a plus.
Last edited by stretch2011 on Thu Oct 30, 2014 9:45 pm, edited 1 time in total.
Why do you say that for diode rectification and rail voltage? Is that specifically for the amp I'd like to build or an overall consensus? Only reason I ask is I like a little sag in my fender amps, I've yet to play a tube rectified Marshall. And i just started building tube amps so needless to say i know very little. Whata the difference between rail voltage and B+ voltage and thus the difference a higher railvoltage would make on the B+ voltage. I know on Jmp type marshalls keeping the the B+ in around 390v which gives a creamier tone unlike a jcm800 with B+ in the low 400's which is more aggressive.
In my case I have tube rectifier in my JCM800 18w build, I started with 5y3 then 5u4 and eventually 5AR4/GZ34 then the fizz went away and the amp gave up it's tone.
Hmm it would be interesting to hear a non master, master, ppimv, and a vvr all beside each other to see the tonal differences. Another novice question assuming ppimv and master volume amps are different, idk. Where is the master volume at? BC when I read it on a schematic I see it on the first pre amp tube....I'm going to have to do some reading
Thanks you guys. You know what's funny? Dana hall was my drummer for alittle while....I should know exactly how those vvr's work, but I didn't get into building amps till after I left the band.
I retain a certain amount of frustration over the issue of Allman's speakers. In the mid-70's I was hearing that they were the Altec 417-C speakers. Since then, I've heard JBL and Cerwin-Vega. Is there anything definitive? Who owns the cabs now -- Greg Allman, the Macon city dump?
Last edited by jaysg on Wed Nov 12, 2014 7:17 pm, edited 1 time in total.
