Search found 1225 matches

by C Moore
Sun Jul 22, 2018 4:41 am
Forum: Marshall Discussion
Topic: Valvestate 65r
Replies: 4
Views: 1006

Re: Valvestate 65r

I am not used to working on PCB amps, or worrying too much about flux residue. I had a small bridge from one trace to another and it was hiding under some flux. Anyway.....this still hums really bad. I have just a basic knowledge of tube amps and really know nothing about Solid State stuff. Do trans...
by C Moore
Sun Jul 22, 2018 3:13 am
Forum: Marshall Discussion
Topic: Valvestate 65r
Replies: 4
Views: 1006

Re: Valvestate 65r

Well, i have got the new caps in...and the Mains Fuse (F2) snaps immediately.! I know its Possible "something else" went wrong.....bit i suppose i should pull the boards, and see if a did not create a short somehow. Maybe a little solder blob or whisker is shorting something.? I drew a nice map that...
by C Moore
Sat Jul 14, 2018 3:18 pm
Forum: Marshall Discussion
Topic: Valvestate 65r
Replies: 4
Views: 1006

Re: Valvestate 65r

Thank You.....i will give that a shot. :)
by C Moore
Thu Jul 12, 2018 11:50 pm
Forum: Marshall Discussion
Topic: Valvestate 65r
Replies: 4
Views: 1006

Valvestate 65r

Working on a friends (his son) amp. He said it started to "Hum" just recently. 1. Is it Reliable/Accurate to use the Hz setting on a Multi Meter to measure the noise.? If i hook my meter to the speaker wires, and it says 120, does that mean the problem IS indeed 120 and not 60Hz.? 2. Right near the ...
by C Moore
Fri Feb 03, 2017 7:46 pm
Forum: Speakers and Cabinets
Topic: [QUESTION] Birch Plywood vs Poplar vs Pine
Replies: 21
Views: 18416

Re: [QUESTION] Birch Plywood vs Poplar vs Pine

Would anyone be able to describe tonal characteristics of each wood? Which is brighter, with is darker, which has more lower mids? Any responses that don't have scientific data and test rigor are going to be subjective opinion. Too many variables just within the wood structure / density of each spe...
by C Moore
Fri Feb 03, 2017 6:34 pm
Forum: Technical Discussion
Topic: PRS J-MOD 100 (John Mayer)
Replies: 23
Views: 4314

Re: PRS J-MOD 100 (John Mayer)

Agree on most of the above. I'd like to point out it's actually a single channel amp for $ 6-K apparently. Tolerable cleans, the OD sounds like a Hot Rod Deville to my ear... Hey Andy - I want to be clear, and fair.....i am not taking a cheap shot at Amp Builders. Not Doug Sewell or you or anybody ...
by C Moore
Fri Feb 03, 2017 3:45 pm
Forum: Technical Discussion
Topic: PRS J-MOD 100 (John Mayer)
Replies: 23
Views: 4314

Re: PRS J-MOD 100 (John Mayer)

SIX THOUSAND Dollars.....for just the head.
One THOUSAND One Hundred for the 2x12 cab.
Who on Earth, or rather Why, would anybody spend that much money for a guitar amp.?
by C Moore
Thu Nov 17, 2016 12:08 am
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

Regards to what we are discussing in tube guitar amps.......What ARE the charge carriers.? Is current flow taking place because something is being "boiled off" the tube cathodes.? Or is that all just a simplification to accommodate a basic understanding of tube function.? Thermionic Emission..... Is...
by C Moore
Wed Nov 16, 2016 6:01 pm
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

I thought the term Current was defined as... the flow of electrons. Then there is: Conventional Flow (i guess you can call it current if you want) and Electron Flow Those two terms are only a discussion of Polarity/Direction. Neither of them own the physical part of electricity.....Current/Electrons...
by C Moore
Wed Nov 16, 2016 2:29 pm
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

Yes...i am confused as well. I thought "current" WAS the.....flow of electrons. So when i read........."Screen current isn't being drawn through the cathode and thence through the screens, thence to the power supply node. Rather, its the electrons that travel in that direction (Conventional current,...
by C Moore
Tue Nov 15, 2016 8:23 pm
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

The more current drawn, the more ripple will stand out, as the pulses of DC try to fill the caps. Statically, the supply looks very clean, under heavy load, not so much. So the combination of the caps and the values of the resistors in the string, while providing isolation between stages, also prov...
by C Moore
Tue Nov 15, 2016 2:00 pm
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

OK, Yeah.....good point about the screens. :idea:
I Appreciative It...Thanks Again
by C Moore
Tue Nov 15, 2016 4:41 am
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

Yeah...that makes sense...Thank You. So how important is that screen cap as far as DC Ripple is concerned. Is most of the ripple gone after the reservoir, and the following caps are mostly providing Decoupling...if that is the correct term.? Or do the Screen and Pre Amp caps provide a lot of ripple ...
by C Moore
Tue Nov 15, 2016 3:31 am
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

Re: screen current

Is it possible to stick with electron flow.? :) My question is.....if screen current is being drawn from the cap after the choke...through the cathode...through screens...back to pos of cap...and back to tranny.......how do the electrons keep track of where they came from and are going to.? If Plate...
by C Moore
Tue Nov 15, 2016 2:22 am
Forum: Technical Discussion
Topic: screen current
Replies: 21
Views: 3703

screen current

It has been a year since i really touched an amp. I am very rusty, and was not an expert to begin with. That Said..... ...when the screens draw current, it comes "up" through the cathode with the Plate Current, right.? In the Bassman schem below.....is the cap after the choke the source for the scre...