6V6 in an Express

Gibsonman63 · Post by **Gibsonman63** » Wed Mar 23, 2011 8:29 pm

I am really having to control my volume during practices and my amp doesn't sing and sustain on 2 like it does on 4 or 5 on the volume control.

Is running my amp on 6V6 power tubes as easy as sticking them in and rebiasing or are there other considerations? What is the recommended bias current?

What would be the recommended 6V6? Currently I am running NOS Siemens EL34s and I am very happy with the sound.

Cliff Schecht · Post by **Cliff Schecht** » Wed Mar 23, 2011 8:47 pm

First things first, you will not notice a big decrease in volume between EL34 and 6V6. The 6V6's have less headroom and a sweeter tone, won't rip your head off as 34's will, but they will be just as loud as far as the human ear can tell.

A great thing with this conversion is no rebiasing is required for the 6V6's. Just drop them in and enjoy (~-30V is what I use for both IIRC).

With that said, I love 6V6's in my Express and have a great pair of 1940's coated glass JAN 6V6's that sound perfect for the Express. You can find them reasonably priced still but I don't have a source myself, I'm set for life with the tube sets I have (most are from hamfests/swapmeets). My personal favorites are Sylvania made coated glass black plate sets. For new 6V6's (I haven't tried many), I would start with the Tung-Sol RI.

Gibsonman63 · Post by **Gibsonman63** » Wed Mar 23, 2011 9:03 pm

Thanks Cliff.

A little less headroom may do the trick. As it is, I can't quite get to the sweet spot at studio volume and a have some amps I can use the 6V6s in if it isn't doing it for me.

JamesHealey · Post by **JamesHealey** » Wed Mar 23, 2011 9:07 pm

I don't think the 6V6 sound any quieter but they definitely sound "smaller" in the mix.

I use my Express with a 2x10 cab loaded with 10" Tayden Speakers which are very good copies of the old 18w Marshall 2x10 greenbacks.

I use 6V6 and 10" speakers to bring the overall punch and size of the amp down to fit into the mix better I can run this rig nice and loud without any volume complaints.

But with EL34 and 4x12 loaded with G12M25 Pre-Rolas It's too loud.

vincenz · Post by **vincenz** » Thu Mar 24, 2011 7:35 am

I agree with James, from my own (small) experience, 6V6 are not quieter, but have a little less headroom. Compare to EL34, I find they sounds flat, less "3D", with less overtones...

I prefer running a good set of "full throttle" NOS EL34, and attach an Airbrake to manage the audio level... my 2ct

Gibsonman63 · Post by **Gibsonman63** » Thu Mar 24, 2011 11:24 am

I built an airbrake, but I really don't care for it. To my ears, it needs some frequency compensation once you get to -6dB and below.

I have a couple of NOS 6V6s in my Princeton. I'll give it a whirl tonight and see how it sounds in rehearsal. Smaller cabinets may be in order as well as James suggested.

Gibsonman63 · Post by **Gibsonman63** » Thu Mar 24, 2011 11:01 pm

I have a pair of NOS Sylvanias that I am trying out because I had them on hand. The amps doesn't get as clean with these tubes. It is a little creamier sounding and slightly darker. The volume is about the same, maybe a hair lower. I'll see how it cuts through the mix in about an hour when the guys show up.

One thing I noticed on the NOS Siemens EL84s that I took out. When you handle the tubes you can feel the insides rattle agains the glass. It could be why this head has no tolerance for speaker cabinets, but they sure sing when you get to about four on the volume.

overtone · Post by **overtone** » Fri Mar 25, 2011 7:30 am

rattling EL84s, in the OP you had EL34s?
I recently had an EL34 that had a rattle which worried me. There was a small chip of glass floating around in there. I tested it while expecting a bang or something and it performed perfectly. It was from the old RFT factory who made those Siemens and I understand why you like them. I really like those in quads.

Reeltarded · Post by **Reeltarded** » Fri Mar 25, 2011 9:27 am

Get a Variac and use it as a master volume.

JamesHealey · Post by **JamesHealey** » Fri Mar 25, 2011 10:24 am

because turning your heaters and negative bias voltage down with the B+ is a great idea..

wooo

Gibsonman63 · Post by **Gibsonman63** » Fri Mar 25, 2011 10:31 am

JamesHealey wrote:because turning your heaters and negative bias voltage down with the B+ is a great idea..

wooo

Sarcasm, I presume.

The 6V6s aren't bad. Really a different animal. Kinda raunchy in a good way. I may have to a few different ones.

Reeltarded · Post by **Reeltarded** » Fri Mar 25, 2011 11:40 am

Lowering voltage is shrouded in BS. I have never hurt anything, and I have been *starving* amps for omg 25 years. Right down to the lights going out.

I have yet to see one episode of cathode stripping.

Try it. It's like crack. They tell you it's bad, but then you just can't get the glazed look of ingnorant bliss off your face. Beats any attenuator to pieces.

Gibsonman63 · Post by **Gibsonman63** » Fri Mar 25, 2011 1:50 pm

I have been curious to see if my old Fenders sound any different at 110 volts. Those always read high against the schematic.

Lonely Raven · Post by **Lonely Raven** » Fri Mar 25, 2011 2:25 pm

Gibsonman63 wrote:I have been curious to see if my old Fenders sound any different at 110 volts. Those always read high against the schematic.

Yeah, my voltage in my neighborhood is regularly 124v

dmouse · Post by **dmouse** » Fri Mar 25, 2011 2:42 pm

Wouldn't a VVR do the same?

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