New 36w Build Thread

Double-Bubble! Place for discussing the 36W version...

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GlassTornado
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Re: New 36w Build Thread

Post by GlassTornado »

Update: No more crazy noises, but also no tremolo. Volume and tone are all good and I can use the trem channel just fine, but no tremolo. Sounds like maybe the noises was something dying? Should be noted that I'm using the "b" improvement layout http://18watt.com/storage/18watt_layout ... ents_b.pdf except I didn't move c15 on mine. All resistors are fine. The pots seem to test good. All the voltages on v3 seem to match close to Mark D.'s voltages on this chart http://18watt.com/storage/Voltage-Chart.htm but it's the lower of the two (170 and 112). I assume that the lower voltages are present when the tremolo is on?
Last edited by GlassTornado on Mon 03/27/17 9:19 am, edited 1 time in total.
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Daviedawg
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Re: New 36w Build Thread

Post by Daviedawg »

Assuming you have used the 18 watt classic preamp: Two things to try. Swap the valve in V3. Some kick in better than others. The second is to have a higher plate voltage on pin 1 (if pin 2 is the screen connected to the trem). I have 190v as opposed to 145 on pin 6. Unfortunately I cannot recall how I achieved that. But probably to do with the value of R12 (Pedal Monkey 18 watt schematic). I have a note that I changed the value but not what it is now. It involved a few trials.

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GlassTornado
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Re: New 36w Build Thread

Post by GlassTornado »

I updated my last post noting that I used the improved "b" layout
http://18watt.com/storage/18watt_layout ... ents_b.pdf
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Daviedawg
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Re: New 36w Build Thread

Post by Daviedawg »

That's the same R12 which connects the plates and controls the voltages. The layout does not give values to the components so you need to see it on the schematic. In the classic it is 220k.

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GlassTornado
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Re: New 36w Build Thread

Post by GlassTornado »

Totally had to have been something stupid. I reworked my v3 tube socket and we're all good now! I'll have some new pics of the finished product soon. very soon!
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Daviedawg
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Re: New 36w Build Thread

Post by Daviedawg »

Good news.

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Graydon
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Re: New 36w Build Thread

Post by Graydon »

Gorgeous work on this build. I love the lacing too. I've built a few amps with lacing and its not that much more difficult to do and it looks great. When I install GDS transformers in a Marshall 18W reissue, I usually reuse the factory lacing which is somewhat "light-duty" compared to authentic lacing but at least the job looks "factory" when its done.

Also, don't get too worked up over the supposed preferred filament wiring. Millions of amps have been built the way you did it and they sound just fine. I read an article a while back that discussed the theory of why "twisting" reduces noise and the basic tenet was that for audio frequencies, we don't even need to twist the wires - they just need to run side by side. So zip cord would probably work just as well although you'd never hear the end of it on the cork-sniffers forums! :-)

Your lead dress looks great. Keep up the good work. You could work for Harry Joyce I think.
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geoff 1965
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Re: New 36w Build Thread

Post by geoff 1965 »

this one's for you Graydon!
no twist or zip cords,the amp is dead quiet no hum or hiss!
sorry purist's!
003.JPG
notice the "phase switch" between the el84's
006.JPG
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Last edited by geoff 1965 on Sat 07/01/17 2:10 pm, edited 1 time in total.
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CurtissRobin
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Re: New 36w Build Thread

Post by CurtissRobin »

Very nice, indeed! Enjoy that puppy and post some sounds in the Hear It! section when you get a chance. We love hearing every build although we don't get that.
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