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[codyjarret]

Rippin' playing and amazing Marshall tone right there. Nicely done, sir.

Thank you my friend.

 

[AndyK]

If this is too bright, it sounds like you're going to want a 47K slope resistor in your amp over the 33K.

A 470pF/47K tone stack will thicken the tone up, meatier bottom end and thicker leads.

Question - can I keep the 560pf cap I just put in, and replace the 33k slope resistor with a 47k? I tried the amp out last night, and it may be a little too bright.

560pF should be fine there, 470pF or 500pF would warm up the sound a bit.
You could try it with the 560pF/47K, but I personally like the 470pF/47K for a nice creamy top-end and tight bottom-end.

470pF mixer bypass cap and 470pF/47K tone stack is what I'm using in my '68 Major, here's a little clip of it.

Which one tightens the bottom - the slope resistor, or the cap?? In other words, what does changing the cap value do? Resistor value? Would using my 560 with a 47k tighten the bottom without warming up the top?
PS--I just ordered a .68uf 160v cap to add to V2A!

 

[H3000]

I like the first clip much better than the second.. the tone on the 3rd clip is f.ing awesome.
can I ask what mods have been done to the superbass does it have a master volume and which type is it and are there any other mods like tone stack etc, the superbass amps are usually shared cathode so is it still shared or did you change it to split cathode and did you alter the Negative feedback on the amp

Thank you so much for your feedback on the clips.

Split cathode V1a 330uF/820,V1b 1uF/2.7K.
All coupling caps are 0.022uF, bright channel coupling cap is a 0.022uF as well.
470k mixer resistors 500pF mixer bypass cap.
V2a cathode resistor 820r & bypass cap on V2a is .68uF.
33k/470pF tone stack.
100k NFB resistor on a 4ohms tap.
.022uF PI couplers with a 50pF fizz cap.
0.68uF cap on presence control.
No bright cap.
Lar/Mar PostPIMV mod.
Filtering is stock all 50uF+50uF.
The rest of the circuit is stock '76 Marshall 100w.

Cheer's Michael

Thanks for the info

 

[AndyK]

Thanks. I may try raising the slope to 47k, and leaving my 560pf cap - to temper the highs and beef up the sound, without lowering the cap/highs too much.

The amp came with a 250pf cap and 56k slope resistor, and had no highs and mushy lows.

 

[AndyK]

Thanks. I'll try the amp with the .68 bypass cap over V2A, and see how it sounds with the "stock" 33k/560pf tone stack values first. If it's still too bright, I may try a 47k slope, and leave the 560pf cap - I'll think about it.

 

[codyjarret]

Thanks. I'll try the amp with the .68 bypass cap over V2A, and see how it sounds with the "stock" 33k/560pf tone stack values first. If it's still too bright, I may try a 47k slope, and leave the 560pf cap - I'll think about it.

The .68uF V2a bypass cap should bump-up the gain and the lower mids, it might balance out your 33K/560pF tone stack highs.

 

[AndyK]

Thanks. I'll try the amp with the .68 bypass cap over V2A, and see how it sounds with the "stock" 33k/560pf tone stack values first. If it's still too bright, I may try a 47k slope, and leave the 560pf cap - I'll think about it.

The .68uF V2a bypass cap should bump-up the gain and the lower mids, it might balance out your 33K/560pF tone stack highs.

Cool! I'll let you know how it changes the tone when I get the cap from Valvestorm (a great place to get small electronic parts for amps).

 

[AndyK]

That Super Bass sounds AWESOME with that guitar Mike!! Very brown and juicy! Great playing too!!

OK, my head is spinning, but I've made progress on my amp (but it doesn't sound as good as ^^)!
I added the .68pf bypass cap over V2A, and that really made the amp come alive! More gain, better tone - a keeper!
Then, I found the amp was a bit too bright and piercing - so I changed to a 47k slope. MUCH better and browner. Now it sounds like a modded Plexi!
BUT, it still may be a little brittle. So, I may try the 470pf cap in the tone stack instead of the 560 after all!

Amazing what one tiny 10 cent resistor will do to the tone!

 

[AndyK]

I believe I have a 100k NFB resistor in there already.

What would a 470 do in the bright mix circuit compared to the 560?

 

[AndyK]

I'll check where the NFB wire goes. What does moving it change?

 

[AndyK]

Already on the 4 ohm tap!

I hooked the amp up to my wet dry fx, and it sounds great as-is! I'm going to live with it before making any more changes.

Thanks for all the help!!

 

[The Shaded One]

Awesome!

 

[codyjarret]

Already on the 4 ohm tap!

I hooked the amp up to my wet dry fx, and it sounds great as-is! I'm going to live with it before making any more changes.

Thanks for all the help!!

You're welcome my friend.

 

[codyjarret]

Awesome!

Thank you kindly my friend.

 

[codyjarret]

 

[jimo]

That sounds really good. I bet it would really sit well in a mix.

 

[Kapo_Polenton]

All this talk of Marshall goodness has me tweaking my DIY 2204. Michael, I'm running a 47k NFR to 8 ohm tap to get more that old school Marshall tone. I like the crunch with a .68 over 820 on V2A but it pumps the highs up significantly in this circuit.Treble peakers are killers in this circuit! I'm running 470k/500pf mixer and 470k/500 off the input jack. Any recommendations there? I'd love to bring down the brightness some. Is the attached drawing of yours still a spec you like? What does the 220k between the treble and the master do? Did you leave in the 100pf cap on the first preamp tube to smooth out the amp some or was that just left in from a ceriatone drawing? Your amps sound incredible I had to revisit this..

 

[AndyK]

From what I have recently learned (and this is just a guess), I would try a 100k NFB resistor to the 4 ohm tap, should add some brownness and tone down the shrillness.

That, and reduce the 500pf cap in the tone stack.

 

[codyjarret]

That sounds really good. I bet it would really sit well in a mix.

Thank you my friend.

You'll never get lost in the mix with this monster.

 

[AndyK]

Sounds amazing Mike! But, the "one wire" mod is really a bunch of value changes, along with that one wire!