Preamp Tubes to Tame Brightness?

psychodave

Well-known member
Is this safe to do? I’ve done it a few times briefly by accident and remember it sounding a bit tighter/more focused, less thick
It's safe. I do it with every amp I have ever owned. 8 ohm at the head, 16 ohm cab, or 4 ohm head, 8 ohm cab.
 

fearhk213

Well-known member
I was going to recommend JJ until I read you hated them haha.

I may be a dissenting voice here, but I don't find the RFT particularly dark. There are definitely brighter and more present tubes, but there was always a sharpness that poked through when I've done tube rolling with them in V1. They do sound cool and may work for what you want. They just weren't what I expected after reading tons of threads saying they're great for darkening up a bright amp.
 

Mr. Willy

Well-known member
For new production, the Genelex Gold Lion is a smooth preamp tube. It’s on the darker side but sounds better than a JJ (I hate JJ’s, won’t use them). I thought it sounded pretty good.

For NOS, I love old RCA tubes. They're not dark or bright to my ears. Just nice and even. Natural sounding, if that makes sense.
 

braintheory

Well-known member
Mullards will work too.
My favorites in most EL34 type amps including my ‘67 tremolo 50 and ‘79 JMP2203, but I don’t find they darken amps at all really, but would add thickness to single notes like the OP is asking

Actually re-reading the OP’s post, I think Mullard is the best I’ve tried if you wanna thicken up single notes and also have great rhythm tone and will at least be darker than JJ’s. I say try those, tefunken ribbed plate ECC83’s and maybe also Bugle Boy’s. I bet at least one of them will work well. I don’t like as much the way my American tubes translate in my Marshall’s
 

Rex Rocker

Active member
CP Svetlana is like a Tung Sol with less top-end harshness. I actually prefer them to Mullards since Mullards can get a little tubby on the low mids.

Honestly, those Svetlanas are sleeper tubes. As clear as Tung Sols without the sometimes harsh high-end.
 
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braintheory

Well-known member
CP Svetlana is like a Tung Sol with less top-end harshness. I actually prefer them to Mullards since Mullards can get a little tubby on the low mids.

Honestly, those Svetlanas are sleeper tubes. As clear as Tung Sols without the sometimes harsh high-end.
Are you referring to vintage or modern for the Mullard and Tung-Sols? Because both are very different. The vintage US made Tung-Sol 12AX7’s sound to me very fat, warm, growly, but a little tubby, not at all like the current Russian ones. The vintage UK Mullards never came off tubby to me, but rather clear, open and punchy. Haven’t tried the current made ones actually

I have one Svetlana pre that can be good in some amps, but seems like it’s less gainy and thinner sounding than other pre-tubes I’ve got. I don’t think it’ll do what the OP wants in thickening single notes, but I can see maybe it’s characteristics giving clarity to some amps. Sounds good in my SLO. I would still look to speakers, cab or guitars first to help over pre’s, but doesn’t hurt to try it all
 

PatF

Member
Maybe clip in some snubber caps to bleed off some treble? There is a good article on the Valve Wizard website.
 

Samhain

Well-known member
CP Svetlana is like a Tung Sol with less top-end harshness. I actually prefer them to Mullards since Mullards can get a little tubby on the low mids.

Honestly, those Svetlanas are sleeper tubes. As clear as Tung Sols without the sometimes harsh high-end.
Thats exactly right and why ive been using them the last couple years.
 

Rex Rocker

Active member
Are you referring to vintage or modern for the Mullard and Tung-Sols? Because both are very different. The vintage US made Tung-Sol 12AX7’s sound to me very fat, warm, growly, but a little tubby, not at all like the current Russian ones. The vintage UK Mullards never came off tubby to me, but rather clear, open and punchy. Haven’t tried the current made ones actually

I have one Svetlana pre that can be good in some amps, but seems like it’s less gainy and thinner sounding than other pre-tubes I’ve got. I don’t think it’ll do what the OP wants in thickening single notes, but I can see maybe it’s characteristics giving clarity to some amps. Sounds good in my SLO. I would still look to speakers, cab or guitars first to help over pre’s, but doesn’t hurt to try it all
No, I meant CP.
 

PDC

Well-known member
2nd for the Genalex Gold Lion. Noticeably darker than (for example) an EH 12AX7, but not dull or muddy. Just smoother and rounder top end.
 

TheGreatGreen

Well-known member
I see you’ve been reading TheToneDig’s book. How’s it so far?

In fairness, it does seem like the guy is looking for a zebra to solve a problem that a horse could easily handle.

How exactly do Treble and Presence controls fall short in “taming brightness,“ exactly? The guy hasn’t even mentioned what specific Marshall circuit he’s talking about.

If it’s a modern master volume Marshall, Treble and Presence should work fine. If you absolutely have to spend money, put an EQ in the loop or something. You’re going to get infinitely more flexibility out of that than the extremely subtle changes you may or may not perceive with preamp tubes, not to mention their modern manufacturing consistency issues. Any given two of the same type could be brighter or darker, fatter or thinner, whatever. You never know with tubes these days. seems like amp or external EQ controls would be a lot more reliable and predictable to me at least.
 

glpg80

Well-known member
I like my Greenbacks - I’m not changing speakers.

No, not currently using V30s.

The circuit could have a snubber cap added - I’ll experiment further. It’s nowhere near stock which is why I’m not traveling down that road.

I do appreciate all of the preamp tubes discussion. The change I need is subtle and not severe. I’m looking to tame high end and give notes girth on the top end, problems not necessarily inherent to Greenbacks but mainly my amp as it currently stands.

For those that mention mullard - are we talking NOS?
 

braintheory

Well-known member
I like my Greenbacks - I’m not changing speakers.

No, not currently using V30s.

The circuit could have a snubber cap added - I’ll experiment further. It’s nowhere near stock which is why I’m not traveling down that road.

I do appreciate all of the preamp tubes discussion. The change I need is subtle and not severe. I’m looking to tame high end and give notes girth on the top end, problems not necessarily inherent to Greenbacks but mainly my amp as it currently stands.

For those that mention mullard - are we talking NOS?
I meant the vintage ones. I wouldn’t bother with current made pre-amp tubes in it, but guessing some will disagree. Greenbacks should be great with it, especially if pre-rola
 

MetalHeadMike

Well-known member
In fairness, it does seem like the guy is looking for a zebra to solve a problem that a horse could easily handle.

How exactly do Treble and Presence controls fall short in “taming brightness,“ exactly? The guy hasn’t even mentioned what specific Marshall circuit he’s talking about.

If it’s a modern master volume Marshall, Treble and Presence should work fine. If you absolutely have to spend money, put an EQ in the loop or something. You’re going to get infinitely more flexibility out of that than the extremely subtle changes you may or may not perceive with preamp tubes, not to mention their modern manufacturing consistency issues. Any given two of the same type could be brighter or darker, fatter or thinner, whatever. You never know with tubes these days. seems like amp or external EQ controls would be a lot more reliable and predictable to me at least.

This x1000...been saying the same thing for years.
 
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