The "Fumble", new build

[sonofmickel]

Sort of a Dumble low plate, Fender Blackface, Marshall.
I have the basic fender front end with a Marshall/Twin with mid control and a Dumblish P.I., Presence and Negative feedback and Master Volume. Also has a Magnetic Components 3.4k OT designed for Marshalls.

I have Fender voltages for max headroom on the preamp and PI is lower than the 124 lowplate schematic.

I think it sounds good at apartment levels. I'll test it out loud on Sunday.

Thoughts?
Improvements?

[Teleguy61]

I love the name.

[sonofmickel]

Thanks.
I've been playing this as a clean pedal platform and like it ok. It's more mid-flavored than a typical Fender. Not very scooped.

Does anyone see a way to increase headroom? I was thinking of raising the cathode resistors to 2k7 or 3.3k while keeping the Plate R the same 100k.

[oj]

Thanks.
I've been playing this as a clean pedal platform and like it ok. It's more mid-flavored than a typical Fender. Not very scooped.

Does anyone see a way to increase headroom? I was thinking of raising the cathode resistors to 2k7 or 3.3k while keeping the Plate R the same 100k.

I don't what to be a asshole, but what is Dumble in this build ?
To me its more a Fender whit more tajt bottom and the more mid flavor u expires is more do to lack of bass and a 25K mid pot.

Increasing headroom whit raising the cathode resistors, no no u are thinking backwards now,raising the cathode resistors will giv u less headroom.
Raising the plates is a better way , just raise our first plate to 150K and see how u like it.

[10thTx]

Changing 100k plate/ 1.8k cathode to 100k/2.7k will increase headroom.

Changing 100k plate/1.8k cathode to 150k/1.8k will decrease headroom.

with respect, 10thtx

[sonofmickel]

Will raising both Plate and Cathode R basically bias' the tube into a more saturated but balanced state?

I saw a calculator for this on the web a long time ago. I'll search for that.

Thanks for the help.

OJ...don't worry about being an a-hole. Team America explains how all of that stuff works together to make a symbiotic relationship.
https://www.youtube.com/watch?v=32iCWzpDpKs

[sonofmickel]

Well, I raised both a bit.
V1a, 120k plate 3k/1uf cathode.
Sort of liking this setup. Seems more compressed, I makes me want to "open the amp up" a bit. There is now a definite spot on the dials where the amp wants get a little grit on the notes - just a little.
Gain 10-11 o'clock, T-10:00, B-2:30, M- 2:30, Master-3:00, Presence-1-2 o'clock.

The clean set this way (but with the Master full-on) is very touch sensitive and has a little grit on top of the notes with my strat lil' 59 bridge pickup. With single coils it makes you want to play slide or do some country runs. It does not like distortion pedals with the Master full on. I have to bring the Master back to 3-4 o'clock for pedals it seems. Sort of like using the low input, just seems to takes pedals better.

Hitting the front with a modded OCD 1.4 and Barber Small Fry: The Small Fry with Dynamics set lower is instant jazz hands, everything sustains as long as I want.
Modded OCD(remove germanium diode) sounds pure early 80's rock. Not metal, rock.

I buttoned it up and I'm gonna gig this tonight.

[oj]

Changing 100k plate/ 1.8k cathode to 100k/2.7k will increase headroom.

Changing 100k plate/1.8k cathode to 150k/1.8k will decrease headroom.

with respect, 10thtx

Maybe this is a languish thing ?
But how I see it is like this
Bigger sving in a tube get bigger headroom

[sonofmickel]

Gig went well. Many compliments on tone.

Lowered the power string voltage 240v at V1a. Seemed to smooth the amp a bit.

Bogner Blue pedal > OCD > Barber Gain Changer > Vox Delay Lab > "Fumble"50 watt head > Blankenship 1x12 with Mesa Black Shadow and a custom made 2x12 closed back tweed cab with 2 Jensen Neo 100's.

However...I think 50 watts is too much to get to the sweet spot. I may patch a LarMar master volume in there and research some less efficient speakers.