TMB - No Master

18watt-specific Tech Talk - Building, Fixing, Parts, Mods...

Moderators: CurtissRobin, colossal, zaphod_phil, Daviedawg, Graydon

Post Reply
sruffinc
Newbie
Newbie
Posts: 48
Joined: Sun 09/24/17 3:40 pm

Re: TMB - No Master

Post by sruffinc »

Sounds great! Classic Marshall crunch. After years of playing Fenders and trying to get a Marshall sound with pedals I realize there is no substitute for an actual Marshall circuit. Doesn't take much boost from a low gain overdrive pedal to really nail those classic rock sounds - AC/DC, Zep, etc.

Can't believe how quite the amp is. I used carbon comp resistors throughout and there is only the slightest hiss.

I love the Normal Channel, but the TMB Channel seems a bit too gainy, kinda strident on the top-end. Even with the TMB V1 cathode at .68uF/2.7k. I have 2uF/2.2K on the other channel. Maybe I have them reversed? Pin 3 is TMB right?

I also tried using a 2.7k resister on the V3 cathode and that seemed to increase the gain on both channels. Opposite of what I thought would happen. Would that affect the power tube bias?

Most everything I read is about increasing gain, and I'd like to tame it down just a bit. Maybe a 5751 or 12AY7 in V1?

Thanks for the help. This site is awesome!
1 x

User avatar
JMPGuitars
Super Duper Admin
Super Duper Admin
Posts: 3955
Joined: Tue 09/18/12 8:00 pm
Location: South Central, MA
Contact:

Re: TMB - No Master

Post by JMPGuitars »

sruffinc wrote:
Mon 11/04/19 1:22 pm
Sounds great! Classic Marshall crunch. After years of playing Fenders and trying to get a Marshall sound with pedals I realize there is no substitute for an actual Marshall circuit. Doesn't take much boost from a low gain overdrive pedal to really nail those classic rock sounds - AC/DC, Zep, etc.

Can't believe how quite the amp is. I used carbon comp resistors throughout and there is only the slightest hiss.

I love the Normal Channel, but the TMB Channel seems a bit too gainy, kinda strident on the top-end. Even with the TMB V1 cathode at .68uF/2.7k. I have 2uF/2.2K on the other channel. Maybe I have them reversed? Pin 3 is TMB right?

I also tried using a 2.7k resister on the V3 cathode and that seemed to increase the gain on both channels. Opposite of what I thought would happen. Would that affect the power tube bias?

Most everything I read is about increasing gain, and I'd like to tame it down just a bit. Maybe a 5751 or 12AY7 in V1?

Thanks for the help. This site is awesome!
Congrats on getting a great tone! We often debate the best parts to use in the build, but a clean build is always the best build regardless of the type of resistors or caps in an amp.

I don't have time to look at what you're trying to do right now, but try this out: look at the options for more gain that you've reviewed. Try the opposite. If a resistor is normally 100k, and it says use 120k for more gain, try an 82k instead. Make sure you know what part your modifying before you do tho. ;)

Maybe somebody else can chime in to help more with that.

Thanks,
Josh
0 x
'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright

Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info


Web Design: DolceVittoria.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale

Post Reply