18Watt.com

Im working on basicly ZP superlight tmb 36 watt , Theres a few things im not sure on the power amp. Screen resistors, can i share the 100 ohm R just run 2 wires off each? and the 8.2k grid resistor can i run 2 wires off each of those as well? Also for the cathiod resistor bypass cap should it be shared or should each R get a cap? and last i was looking at ceriatone 1/2 powerswitch dont understand how it works. thanks mark

It's best to treat it as two 18W power stages in parallel. So you you have two push-pull pairs, each with their shared cathode resistor, grid and screen resistors. The only place they combine is at the PI and the anode connections to the OT.

What about sharing all powertubes with one large resistor, ac30 show 50 ohms that sounds pretty hot, im getting right about 300v on plates, i have a 75ohm r 25watts i was thinking about trying, whats the downfalls of using one shared resistor? i have 2 150ohm resistors now. mark

Ive finshed this amp its not a lot louder than a 18watter but man can it push some air, and thomp, i used rocksmumbles values on v1 and a shared 68 ohm 25watt cathiod resistor, i also used vintage mustards and sozo caps,, preamp voltages seem a little low and need a little tweaking or maybe not, less than 140v powertube voltage plates 307, 300 screens with a 5u4, with a 5ar4 raising that about 10v it should be just right, i realy like the sound of this amp tonestack is very useful, next id like to try this with some big bottles kt66 i think would make this a really nice stage amp

...its not a lot louder than a 18watter but man can it push some air, and thomp,..

That's exactly what you get with a 36W.

...next id like to try this with some big bottles kt66 i think would make this a really nice stage amp

I would recommend EL34s, as a pair of those will work real nicely with 36W iron.

Quote:"Ive finshed this amp its not a lot louder than a 18watter"

Yeah,right. My 36 watters are so loud I pretty much have to use master volumes.That 3db sure kicks some serious ass with ear drums!

Yes, but 18Ws are real loud too. And 3dB *isn't* a big difference in volume level - that's basic science.And menger's findings match pretty much what other 36W builders have said, going right back to Graydon and Richie - ie it's more about an increase in the clean range than of the sheer loudness. It's the same story when you go from a 50W Plexi to a 100W. I also have no doubt that your 36W amps are real loud, but I have to guess there's something more involved than just the 18W vs 36W thing.

I agree with you zp, The 36 is all the best things of a 18 with more body, I love them both, As far as which is louder, Thats up to the person playing the amp, If i wanna have a little more when i jam ill use the 36 with a 2 or 4 12 cab, when i go to bro inlaws to jam rock ill take one of my lights, If i go trying out new guitars ill bring my one of my classic clones, They all sound awsome and turn heads when i bring mine out, and if i wanna be real real loud ill just hook all the amps up for a wall of marshalls, really everytime you play you should have a marshall left a marshall right and one right behind you, anyways the superlight makes for a excellent 36 watt