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Thread: Anyone taken an H or a 2 Channel Custom and put EL34s in it?

  1. #1
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    Anyone taken an H or a 2 Channel Custom and put EL34s in it?

    Thinking about switching out the tubes on my 2 Channel Custom from 6L6s to EL34s to soften the sound up a bit. Has anyone done this? I know the Guitar Sanctuary had a couple commissioned like this, but no videos / sound clips ever emerged Hoping that it will get a bit more crunch tone out of the amp. It's VERY good, exactly the right features, but I want a sound that is a bit more 'marshall-y'. Think Slash on his 'Slash' album. I know that there are a TON of different tones on that album, but would like to have my amp close to the 'Ghosts' tone.
    - cyclops

    Too many PRS to list in 5 lines...

  2. #2
    Senior Member 11top's Avatar
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    Quote Originally Posted by cyclops View Post
    Thinking about switching out the tubes on my 2 Channel Custom from 6L6s to EL34s to soften the sound up a bit. Has anyone done this? I know the Guitar Sanctuary had a couple commissioned like this, but no videos / sound clips ever emerged Hoping that it will get a bit more crunch tone out of the amp. It's VERY good, exactly the right features, but I want a sound that is a bit more 'marshall-y'. Think Slash on his 'Slash' album. I know that there are a TON of different tones on that album, but would like to have my amp close to the 'Ghosts' tone.
    Maybe consider getting a C and having the boost mod added?
    Sh*tter's full

  3. #3
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    I emailed PRS about doing the mods. They made the EL34 suggestion. Since it's fairly easy to switch the tubes, I'll probably try that first... I think EL34s, then possibly sent it to PRS to change the gain structure to add a bit more compression to the lead channel, and I'll probably be good Just wanted to know if anyone else had tried this.
    - cyclops

    Too many PRS to list in 5 lines...

  4. #4
    deus ex machina
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    There's nothing stopping you from putting EL34s in the amp. It should have enough range on the negative bias voltage supply to bias the EL34s properly (EL34s require less negative bias than 6L6s). EL34s are true pentodes; therefore, they do not have the characteristic mid-scoop that gives the 6L6 its big bottom and bright top end. The EL34 also has a softer vacuum and higher transconductance than the 6L6, which makes it break up earlier and more touch responsive than the 6L6.

  5. #5
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    Well, I changed the tubes over this weekend. Will be trying it with the band on Monday will let everyone know how it went. I did notice that it didn't have as much clarity as the 6L6s, but that should be OK. I've been running the treble backed off because of that clarity! I also think I have a bad tube on the reverb unit, the reverb gets noisy when turned up. Will replace the 12at7 before rehearsal.

    One thing... what is the normal bias on the 2 Channels? PRS tech support said it should be around 30, but my amp was biased at 11.6!!! Before I changed the 6L6s out, I wanted to see what it would be like at the 'proper' voltage. Tried them close to 20, and the tubes heated up like CRAZY. Backed it down to 11.6. When I switched the EL34s, I biased them at 11.6 as well, as Tech support said that the 6L6s and EL34s should run at the same voltage. I set the EL34s to 11.6 as well.
    - cyclops

    Too many PRS to list in 5 lines...

  6. #6
    Older getting younger
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    Interesting thread. It got me wondering if anybody went from EL34's to 6L6's in their 2 channel C?
    PRS electrics and bass, Taylor BTO GS Cocobolo, K26e Koa, 2012 FLTD 412ce-N and GS mini mahogany acoustic guitars; Bad Cat Cub IIR, Carr Rambler, Fender Supersonic 22, Univox, Fishman Loudbox 100, Loudbox Mini and Mark Bass amps
    In music, one must think with his heart and feel with his brain.
    I was joeprs on BAM

  7. #7
    deus ex machina
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    Quote Originally Posted by cyclops View Post
    Well, I changed the tubes over this weekend. Will be trying it with the band on Monday will let everyone know how it went. I did notice that it didn't have as much clarity as the 6L6s, but that should be OK. I've been running the treble backed off because of that clarity! I also think I have a bad tube on the reverb unit, the reverb gets noisy when turned up. Will replace the 12at7 before rehearsal.

    One thing... what is the normal bias on the 2 Channels? PRS tech support said it should be around 30, but my amp was biased at 11.6!!! Before I changed the 6L6s out, I wanted to see what it would be like at the 'proper' voltage. Tried them close to 20, and the tubes heated up like CRAZY. Backed it down to 11.6. When I switched the EL34s, I biased them at 11.6 as well, as Tech support said that the 6L6s and EL34s should run at the same voltage. I set the EL34s to 11.6 as well.
    It sounds like you may have a faulty meter. Do you have the meter set to read DC volts? Where do you have the postive and negative leads attached when taking the measurements? What is the plate voltage on your amp?

  8. #8
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    Ok, have been running the 2 Channel Custom with EL34s now for a bit, including a gig or two...

    I really LOVE the sound! The EL34s loosed the sound up a bit. Better midrange, especially on the Crunch channel. Now, driving the gain on the Lead channel is very usable. I'm a little past 3 o'clock on the Lead Channel's gain, and it's really nice. The clean sound has suffered a small bit. The 6L6s have a beautiful clean sound that the EL34s don't really match. It's OK, though, as I mainly play crunchy The EL34s work better with the OCD pedal. Using the OCD basically gives me a solid 4 channel amp Clean for my normal clean sound, Clean + crunch OCD for a very open crunch, Lead for my normal sound, and Lead + OCD for anything that needs the extra oomph. Sound seems to settle better with the band. I don't have to use my compressor pedal at all now, either.

    I do plan to send the amp to PRS to have the weird hum with the reverb knob fixed.
    - cyclops

    Too many PRS to list in 5 lines...

  9. #9
    Older getting younger
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    Glad to hear that the EL34's are working for you.
    PRS electrics and bass, Taylor BTO GS Cocobolo, K26e Koa, 2012 FLTD 412ce-N and GS mini mahogany acoustic guitars; Bad Cat Cub IIR, Carr Rambler, Fender Supersonic 22, Univox, Fishman Loudbox 100, Loudbox Mini and Mark Bass amps
    In music, one must think with his heart and feel with his brain.
    I was joeprs on BAM

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