Mesa Boogie EL34 Siemens NOS?

Ron Resnick

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Jan 24, 2015
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Who is familiar with the sound qualities of the Mesa/Boogie NOS EL-34 STR 450 Siemens?

How does the sound of this tube compare to the sound of an NOS Mullard?

How does the sound of this tube compare to the sound of Psvane EL34C?

Thank you!
 
All I can tell you is that I have a quad and they sound quite good and were very dependable over the time that I used them, more so than a quad of NOS RFT's that I bought from a well known dealer. I've not compared them to NOS Mullard's, nor Psvane's.
 
All I can tell you is that I have a quad and they sound quite good and were very dependable over the time that I used them, more so than a quad of NOS RFT's that I bought from a well known dealer. I've not compared them to NOS Mullard's, nor Psvane's.
Thank you.
 
Who is familiar with the sound qualities of the Mesa/Boogie NOS EL-34 STR 450 Siemens?

How does the sound of this tube compare to the sound of an NOS Mullard?

How does the sound of this tube compare to the sound of Psvane EL34C?

Thank you!
The Mesa valves are in fact made by RFT (in the 80's). I have several sets (from various sources and labels, such as Siemens, Mesa, Rivera, RFT, etc.), acquired as stock for my guitar amps. Generally, my experience suggests they don't respond well to higher voltages (as found on some vintage Marshall guitar amps) and sound a bit drier and less rich in the midrange than say an xf4 Mullard in the same amp. As I have collected a large number of NOS valves over the years, enough to cover my needs anyway, I have no experience with the current production ones.
 
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Thank you, tedwoods!
 
The Mesa valves are in fact made by RFT (in the 80's). I have several sets (from various sources and labels, such as Siemens, Mesa, Rivera, RFT, etc.), acquired as stock for my guitar amps. Generally, my experience suggests they don't respond well to higher voltages (as found on some vintage Marshall guitar amps) and sound a bit drier and less rich in the midrange than say an xf4 Mullard in the same amp. As I have collected a large number of NOS valves over the years, enough to cover my needs anyway, I have no experience with the current production ones.
I hate bumping older threads but I've been binge reading this forum and can add a few things to this even though tedwoods said it so well.

I've owned Mesa Boogie amplifiers for 15 years and I'm in almost every Mesa Boogie FB group/forum and a lot of guitar forums. I've talked to a lot of people who have owned those amplifiers for 30-40 years. Not many people recommend the RFT EL34. I can think of specific amps such as the Mark II and Mark III where they will not do well in the simul-class sockets. I'm very sure I have read emails between Mesa Boogie and customers where they do not recommend those tubes in amps like that specifically. While I don't have much time with those tubes I read enough warnings from other people to avoid them. Unless you're confident and familiar with your gear I'd recommend another NOS EL34 tube.
 
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I'd recommend another NOS EL34 tube.
Which NOS EL34 do you recommend?

How are Mullard XF2s regarded these days?
 
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I'm not the best person to ask about EL34s. Most of my amps are fixed bias with a sextet of power tubes so I am limited in what I can choose. Tried some of the current EL34, Mullard XF4, RFT, Tesla and Winged C. I'd choose the Mullards.

Mullard XF2 are highly regarded. I have always heard excellent things about them and I don't recall anyone saying anything negative. They were used stock in a lot of famous British guitar amplifiers like Marshall and are the standard that people desire.
 
I'm not the best person to ask about EL34s. Most of my amps are fixed bias with a sextet of power tubes so I am limited in what I can choose. Tried some of the current EL34, Mullard XF4, RFT, Tesla and Winged C. I'd choose the Mullards.

Mullard XF2 are highly regarded. I have always heard excellent things about them and I don't recall anyone saying anything negative. They were used stock in a lot of famous British guitar amplifiers like Marshall and are the standard that people desire.
Thank you.
 
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In a guitar amp is so different than hifi. Accept for the robustness. They have to handle a good kick to make the reverb sing.
 
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In a guitar amp is so different than hifi. Accept for the robustness. They have to handle a good kick to make the reverb sing.
I recognize this is a hifi forum and I'll try hard to stick to the spirit of it. I'm a guitarist who's extremely passionate about tubes and I just want to share experiences and information. Only had XF4 myself but I wish I had XF2!
 
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In a guitar amp is so different than hifi. Accept for the robustness. They have to handle a good kick to make the reverb sing.
EL34s are output tubes. They are not used in reverb circuits, which are a part of the pre-amp circuit in a guitar amp and are mostly twin-triode driven by a 12AT7 and half a 12AX7. There are exceptions of course, the most notable one being the Fender outboard reverb standalone unit where a 6K6 is used, but these remain largely uncommon. The deciding factor for using or not using RFTs would be the B+ voltage rail of the amplifier. If it's anywhere near the ones "typically" used in guitar amps (not so uncommon in hi-fi ,as one would think...), a.k.a over 400V, then it'd be best to steer clear, as @CDawg has correctly suggested.
 
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EL34s are output tubes. They are not used in reverb circuits, which are a part of the pre-amp circuit in a guitar amp and are mostly twin-triode driven by a 12AT7 and half a 12AX7. There are exceptions of course, the most notable one being the Fender outboard reverb standalone unit where a 6K6 is used, but these remain largely uncommon. The deciding factor for using or not using RFTs would be the B+ voltage rail of the amplifier. If it's anywhere near the ones "typically" used in guitar amps (not so uncommon in hi-fi ,as one would think...), a.k.a over 400V, then it'd be best to steer clear, as @CDawg has correctly suggested.
Kick an amp and all tubes are shaken. For that matter, when I had my Fnder and Marshal playing loud, the entire amp section, tubes and all were vibrating wildly.
 
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Kick an amp and all tubes are shaken. For that matter, when I had my Fnder and Marshal playing loud, the entire amp section, tubes and all were vibrating wildly.
Yes, this is why I have installed vibration damping rings that reduce the ringing and vibration; especially useful in a recording studio setting.
 
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Yes, this is why I have installed vibration damping rings that reduce the ringing and vibration; especially useful in a recording studio setting.
Which rings did you use?

I've always wanted to have my amplifiers in an isolated environment rather than on top of a cab or somewhere a feet away. I'm getting some wild ideas after seeing guys on here with gear I wasn't aware of to see how far I can push it. Amps stands, acoustic curtains, etc.
 
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