Marshall LM 6100/Framus Cobra...Tube suggestions?

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Looks like after a good 10/20 years respectively, it's finally time for me to retube my amps:

Marshall 6100 LM
V1-V7: unbranded, presumably stock
V8-V11: 5881, currently stock Sovtek
++: super quiet
+: smooth and pleasant top end
+: huge amounts of gain
-: Crunch mode A (uses V2A and V6) much lower in volume to Crunch modes B&C (which use all of V2 & V6)
-: Lead channel very flabby
-: not very articulate overall and quite indirect
--: clean channel flat and not rich (if that makes sense)

Framus Cobra (pre- backplate-bias-pot-version)
V1-V5: 12AX7A-C
V6-V9: JJ E34L
++: dry and aggressive
+: highs have bite without being unpleasant
+: bottom end well defined and flexible with Deep control
--: currently has lots of hum/fizzing/weird noises (presumably power tubes?)

The preamp tubes in the Marshall are terrible so i'm planning on replacing them all. This is what i have in mind soundwise:

6100:
V1 (Clean): more openness, more hifi-ness (think fender maybe)
V2/V6 (Crunch): maybe lesser gain factor in V2 so to bring modes A, B & C closer together in terms of volume; more definition; less highs, more mid-character
V3-V5 (Lead): more definition, more spank, less lows; i wouldn't mind to have less gain if that comes as a side effect
V8-V11: if anything, more definition, more dynamics

In general, i feel i reelly would love more character in the mids and less highs in this amps, since i'm mostly using it for rock stuff and aim for a rounded, fleshy sound

I don't necessarily plan to replace all of the Framus' preamp tubes but the power tubes need to be replaced i guess.

Cobra:
V1 (All Channels): Clean sounds great. But I'd try some supposedly "high end" tube just to see if it makes a difference overall
V2-V3 (Crunch & Lead): happy so far
V5 (PI): I'd like something supposedly high end just to see if it upgrades the amp
V6-V9: i like the frequency response the amp currently has. I don't do power amp saturation so i guess clean headroom, responsiveness and clarity is what i'm after

Any suggestions are highly appreciated, thanks guys!

[Cynical]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

From the sounds of things, you're pretty darn happy with what you've currently got in the Cobra, and it makes no sense to randomly try "high end" stuff hoping to find something better. I'd just get another set of what you've got in there.

[Traffic]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

True. So, does 12AX7A-C designate specifically the TAD tubes that come up when googling that label?

[Rex_Rocker]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

True. So, does 12AX7A-C designate specifically the TAD tubes that come up when googling that label?

12AX7-C's are probably just Chinese Shuguang 9th Gens. They're cheap, and generally well-regarded for high-gainers.

I'd try a Sovtek LPS in the PI for some added girth and openness, and perhaps a Tung Sol in V1 for some added width, but other than that, I like Chinese Shuggies, personally.

[chadd]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

I love those E34Ls in my Road King, they sound fantastic. The Tung-Sol 12ax7 is a solid tube and I'm really fond of the EH 12ax7 for tone stack.

[Lake Placid Blues]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

I'd try a Sovtek LPS in the PI for some added girth and openness, and perhaps a Tung Sol in V1 for some added width, but other than that, I like Chinese Shuggies, personally.

This applies to the 6100 too. For your indistinct 6100, the Tung Sol 12AX7 is known to be more bright and clear so that would be fine for V1, v2, and V5. However, be careful about possible cathode follower path ways with the Russian preamp tubes. It looks like the cascading signal path through V3 and V4 have cathode followers and v6 has a cathode follower tone stack. Best use Chinese at those positions. The PI is V7.

The Sovtek 5881 from the 90's is actually a 30 watt plate dissipation tube, so be careful to not install 23 watt original spec 5881 tubes. Actually, just use 6L6GC which are 30 watt PD tubes and are rated to handle the voltages found in the 6100. And be sure to rebias.

[chadd]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

I liked the Svetlana 6l6gc in every amp I tried them in, great sounding tubes

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Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

However, be careful about possible cathode follower path ways with the Russian preamp tubes. It looks like the cascading signal path through V3 and V4 have cathode followers and v6 has a cathode follower tone stack. Best use Chinese at those positions.

Yes, 3-6 actually seem to be CFs... so, what about the russian tubes there?

[Lake Placid Blues]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

Use Chinese tubes there instead.

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Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

Because...? i wanna learn the details

[Rex_Rocker]

Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

Because...? i wanna learn the details

Many of the Russian tubes have spiral filaments. Spiral filament 12AX7 tubes have problems in cathode follower circuits due to the fact that most cathode follower circuits in guitar amplifiers exceed the maximum cathode to heater rating of 100 volts.

A few Russian tubes do not have spiral filaments, though. CP Svetlanas don't. Neither do Sovtek WA/B/C. I haven't tried Svetlanas, but Sovtek WA/B/C's are pretty meh (kinda dark, tubby, and low-gain, almost like a weaker JJ ECC83S), and I'd still choose Chinese Shuguangs over them.

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Re: Marshall LM 6100/Framus Cobra...Tube suggestions?

thanks for your input guys