Is this normal (possibly overheating)

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Sam Laming

Sam Laming

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I played my Herbert the other day, it's all working fine, always is, but when I play it for a few hours straight such as recently and change to clean the 2 distortion channels completly dull down to a very horrible tone and basically nearly cut out, my amps always fine afterwards, say turn it off and leave it a while before I play but is this normal in all tube amps? I was playing it for about 3-4 hours I think.
 
Mine did something similar, if not the same thing. I tried switching preamp and poweramps tubes, but it didn't fix it. I eventually sent it to Uwe and they fixed it up.
 
Sam Laming":81bfa said:
I played my Herbert the other day, it's all working fine, always is, but when I play it for a few hours straight such as recently and change to clean the 2 distortion channels completly dull down to a very horrible tone and basically nearly cut out, my amps always fine afterwards, say turn it off and leave it a while before I play but is this normal in all tube amps? I was playing it for about 3-4 hours I think.
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Please try different tubes first
 
Well these tubes are quite new, I think I got my amp last year and I don't play it everyday but seeing as they still work I'll keep them in until they go bad because tubes = expensive, I just find it odd that it doesn't cope with the time span of my playing sometimes, if the problem continues after I change the tubes a few years down the line/however long they take to go bad I'll post again :)
 
Sam Laming":53665 said:
Well these tubes are quite new, I think I got my amp last year and I don't play it everyday but seeing as they still work I'll keep them in until they go bad because tubes = expensive, I just find it odd that it doesn't cope with the time span of my playing sometimes, if the problem continues after I change the tubes a few years down the line/however long they take to go bad I'll post again :)
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I'd like to also add that current production tubes are of nowhere near the build quality and tonality of old production tubes of US, European, and Japanese manufacture. You may want to look into changing the preamp tubes with NOS tubes. --It will be expensive, but worth it because they will not only sound better than current production, but last longer as well.

Also, if you've had the output tubes have been in the amp for over a year judging by the way that you play, ( IE several hours at a time) it's time to change them out. Output tubes will not last nearly as long as preamp tubes. I usually retube after 6 months to a year or so, though some amps will eat power tubes quite quickly. Years ago, I used to have an old Orange OR80 that I had to use then current production Sylvania 6CA7's in because it would eat a set of Siemens/RFT EL-34's in 3-4 months.

The only acceptable output tubes that I've used from current production have been JJ's, current production Shuguangs, and SED/Winged C's.
 
Is it in a case? Try putting a fan behind it next time and see if it does it. It needs some air if it's in a case...or next to a wall, I bought a rack fan for that specific purpose.
 
I agree with Lexicon Devil, I would replace your tubes and most likely it will clear up your issue. Keep in mind that even when you buy new tubes sometimes you get bad ones. I just replaced my 6l6 tubes (Sovtek, these have been a good sounding tube for my Soldano and it is what they put in the amps from the factory) in my Soldano Avenger. I bought the tubes from the Tube Depot and installed them in my amp. I was getting a high pitch sound comming out of the amp. Usually this means that it is a preamp tube problem but it was not. I received bad power tubes. I called the Tube Depot and the sent me a second shipment of tubes and once I installed them my amp sounded kick ass. When you do replace your tubes I would keep the old tubes to compare to the new ones. My old tubes did not make any noise but had a loss of definition so I new it was the new power tubes that were bad.


Lexicon what tube do you recommend the JJ's or the SED/winged? I just got my VH4 about 2 1/2 months ago and I think that the tubes are already going bad.
 
nat120":7f9d1 said:
Lexicon what tube do you recommend the JJ's or the SED/winged? I just got my VH4 about 2 1/2 months ago and I think that the tubes are already going bad.
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I have a set of JJ E34L's in a Seymour Duncan amp that I have. I installed them, and got about 2 hours worth of playing time out of it before I heard a Pffft sound and lost all sound save for a slight buzzing in the OPT. I went into panic mode, and shut the amp off, thinking that the the tubes went bad, or the OPT was going. THe Diezel that I had just gotten. I emailed Herr Diezel about this in panic mode, thinking that the amp that I got was also problematic, then I finally got smart and connected a 9V battery up to the speaker lead and then the speaker terminals and deduced that I had blown speaker.

However, to stay on the subject, The Diezel has the Shuguang EL-34B's in it, which in my opinion sound about as good as the JJ's. They both sound a little bit differant from each other, but this is also the case with NOS tubes from differant factories. I'm not too sure about the =C= EL-34's, but their 6L6's are decent, so I imagine that their EL-34's are also good.

JJ's may possibly be a bit more reliable than the Shuguangs, but I really don't know at this point. The tubes that you definately want to avoid though, are the Shuguang/Sino EL-34A's which definately suck. --They sound cold and trebley, like all the warmth has been sucked out of your amp. Older production Sovteks were the same, so I still tend to be leery of the brand.

If you can afford to part with your soul, or perhaps one or both of your testicles, Mullard XF-2's, Telefunkens, or Amperex EL-34's are what you want, but you will definately shell out some SERIOUS cash for a matched NOS quad. Not only do they sound good, but they last a lot longer than current production tubes.
 
Thanks for the reply Lexicon. I have had my Diezel VH4 for about 2 and 1/2 months. The amp has been making sounds (like if you had a cheap tuner that was engaged). They are not very loud but you can tell something is wrong. I have not had that much playing time on the amp yet. You can especially here it if you go to channel 3 or 4 and then switch back to channel 1. You can here it in all channels though. I think that it is the power tubes, so I will be replacing them. I am wondering how reliable the stock tubes are? I am thinking not the best. I may try the JJEL34's. At first I was thinking that it was my Gmajor so I unplugged everything including the foot pedal and it still does it. If it still does it after I replace the power tubes I will try the preamp tubes.

What do you think Lexicon or Peter?
 
nat120":0b064 said:
Thanks for the reply Lexicon. I have had my Diezel VH4 for about 2 and 1/2 months. The amp has been making sounds (like if you had a cheap tuner that was engaged). They are not very loud but you can tell something is wrong. I have not had that much playing time on the amp yet. You can especially here it if you go to channel 3 or 4 and then switch back to channel 1. You can here it in all channels though. I think that it is the power tubes, so I will be replacing them. I am wondering how reliable the stock tubes are? I am thinking not the best. I may try the JJEL34's. At first I was thinking that it was my Gmajor so I unplugged everything including the foot pedal and it still does it. If it still does it after I replace the power tubes I will try the preamp tubes.

What do you think Lexicon or Peter?
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If you get the JJ's, the ones that you want are not the EL34's, you want their E34L's or their KT-77's which will handle higher voltages, and therefore theoretically last longer. That being said, I doubt that their KT-77 is actually a true Kinkless Tetrode like the original GEC/Marconi Osram KT-77 Gold Lions, then again, you'll also not be shelling out in excess of $2,000 for an NOS quad of them like Audiophools will, either.

I hope you know to change the 12AX7/ECC83 in the PI position when you change the power tubes, this is the 12AX7 closest to the power tubes, and is also the only other tube in the amp that gets the same high voltages that the power tubes get.
 
V 1, JJ ECC83 ( Copy of a Telefunken E83CC), Shuguang 12AX7. The new Tung Sol 12AX7 is supposedly really good as well.Groove Tubes had a Mullard Reissue 12AX7 that allegedly sounded really good, but had problems with microphonics when it first came out. Any tube that you put in V1 should also be further checked and passed for microphonics and low noise, as all of the other preamp tubes will further amplify any noise present in that tube.

If you have the cash, consider these NOS 12AX7's (In order of least expensive to most expensive) :

Tungsram
EI ( but only those made before the Yugoslavian civil war)
RFT
Tesla (NOT JJ)
GE Grey plates
Philips ( Fab may vary from several fabs in the US/ Europe, I have one that's actually one of the last of the good EI's)
Brimar
Mullard
Telefunken ECC83 ( look for '<>' on the bottom to ensure it's the real thing)
Amperex
Telefunken E83CC, again look for the '<>' in the center of the bottom of the tube to ensure that you're not shelling out $$$ for a JJ that somebody printed a counterfeit Telefunken logo on.(The TFK E83CC is special low noise 12AX7, has a differant, and smaller plate stucture than their standard ECC83, JJ makes a copy and calls it their ECC83, whilst JJ's normal 12AX7 is billed as an E83CC, go figure :confused: )

You can use Shuguang or JJ 12AX7's in the other positions, however those furthest from the PI should probably be checked and passed for microphonics/low noise. Allegedly the newer production EI's ( The company just ceased production) are decent enough to use as a PI, however they were reporting 70% fail rates for mechanical as well as microphonics, so they're not so good for the actual preamp tubes.

Also, avoid Cryogenically treated tubes, as it's a lot of cash spent on something that really doesn't work. Wiping your ass with the cash spent on cryotubes/cryovalves Etc,etc, ad nauseam would probably be a better use of the cash spent on them. --Leave all the esoteric shit to the Audiophools.
 
Harma STR and Retro series are very, very good!

The Cryo Harma Retro is the top... my old (1975) Marshall MKII takes my finger tone to the bone; if you kown what i mean…

;)

Regards
 
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