Is it possible to pull 2 of the 4 power tubes in a Traynor and cause no harm to the transformers?

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2/26/2000 4:37 AM
Dave	Is it possible to pull 2 of the 4 power tubes in a Traynor and cause no harm to the transformers? I'm dying to plug this amp in but was advised that it may fry the transformers. In a Marshall this works. Why not a Traynor?     Dave

 

2/26/2000 5:23 AM

Todd

First, what type of Traynor?     Just pulling two output tubes doesn't necessarily   "work". You also need to change the output   impedance by a factor of two because you're   taking away two tubes. Same is true of a Marshall   else you have a output transformer mismatch.   Traynors use Hammond transformers for the most   part which are far more durable than anything   Marshall ever used so initially I would say   you're OK to pull two tubes. BUT, I would half   the output impedance as well (cut one of two   8-ohm speakers in a 2x12" cab for example).   Let us know what model you're talking about and   somebody can chime in with personal experience.   TJK

 

2/26/2000 5:30 AM
Dave	This amp is a '68 Custom Special. Bass amp?It came with an 8x10 cab.     Dave

 

2/27/2000 6:50 AM
Richie	When you pull 2 tubes.. the voltage will   change in the amp.So depending on how the   bias circut in this amp or any other amp.   You should bias it,if you run it this way.   Loves the Traynor 8X10 cabs,Richie{~}==:::

 

2/28/2000 12:51 PM
Stephen Conner	double not half Hi folks,     If you pull two tubes you need to *double* the output impedance, e.g. connect a 16 ohm speaker to the 8 ohm tap. Not half it!     Can't see why you would want to reduce the power of a bass amp though     Steve C.

 

2/28/2000 3:54 PM

R.G.

Double, half, doesn't matter much If you pull one tube from either side of a push-pull primary in a tube amp, it will not harm the transformers in general, unless there was already something close to killing them or they were damaged to begin with.     Tube amps in general are not harmed with a load mismatched 2:1 high or low. The available power goes down for either mismatch, as the tubes are usually run at the point of maximum power out.     If you raise the output load a lot to where it begins to look like the output load is kind of open, you start to get the behaviors of a tube amp without a load, and that can damage transformers and tubes because it can make for oscillation and voltage spikes. But 2:1 too high isn't enough to hurt any amp in good condition.

 

3/2/2000 8:08 AM

danlawrence

Re: Half a double still leaves No Quarter Thanks for bringing up the subject. I've read a number of times that, at least in some cases (most Fenders if I recall) one can pull two non-consecutive output tubes and run the amp without damage. I suppose I'm not completely clear about how and when I should approach this option. I'm not sure I could classify amps for A/B/push/pull on sight or by reputation. Must I get clearance from NASA before proceeding. Am I asking a redundant question. Further help greatly appreciated.     dl

 

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