Very quick TSL100 question.

TheShadowNinja · 10-20-2009, 03:52 PM

When I turn my amp on (either standby mode or normal) there is a fuzzy background hissing sound for about 5 minutes, and then comes and goes less and less frequently until it goes away and is silent. The amp works tonally all of the time whether it is hissing or not.

I reckon its to do with the valves warming up, but was wondering if it was a more serious problem.

Its more of an annoyance than a problem though!

PS

To those who were following my progress with this amp before, thanks so much for your words of wisdom- ive learnt a ton from this site and saved myself tons of money fixing it myself rather than sending it off to a tech

NICE ONE!

Wilder Amplification · 10-20-2009, 04:13 PM

Quote:

Originally Posted by TheShadowNinja

When I turn my amp on (either standby mode or normal) there is a fuzzy background hissing sound for about 5 minutes, and then comes and goes less and less frequently until it goes away and is silent. The amp works tonally all of the time whether it is hissing or not.

I reckon its to do with the valves warming up, but was wondering if it was a more serious problem.

Its more of an annoyance than a problem though!

PS

To those who were following my progress with this amp before, thanks so much for your words of wisdom- ive learnt a ton from this site and saved myself tons of money fixing it myself rather than sending it off to a tech

NICE ONE!

In standby the only thing pulling current is the heaters in the valves. I wonder if this could point to a possible power transformer going south...there's no way sound could be coming through the speakers in standby mode unless the standby switch itself were bad and was somehow arc'ing internally. Where does it sound like it's coming from?

TheShadowNinja · 10-21-2009, 05:54 AM

"Where does it sound like it's coming from?"

Im not sure what you mean. If you are talking about the actual hissing sound, its comes from the speakers- kind of a washy white noise sound. I know the valves are a bit old, but I cant afford to change them at the moment and besides, it works fine after 5 minutes. Very strange.

I'll retest the amp today and report back

Wilder Amplification · 10-21-2009, 01:34 PM

Quote:

Originally Posted by TheShadowNinja

"Where does it sound like it's coming from?"

Im not sure what you mean. If you are talking about the actual hissing sound, its comes from the speakers- kind of a washy white noise sound. I know the valves are a bit old, but I cant afford to change them at the moment and besides, it works fine after 5 minutes. Very strange.

I'll retest the amp today and report back

OK that doesn't make sense. When the amp is in standby mode, there's no high voltage on the valve plates, so there shouldn't be any current flowing through the output transformer, hence it shouldn't be possible to have any sound coming through the speakers in standby mode.

I'd put the amp in standby and place my ear right up on the speaker to verify that it's not coming from the speakers. Otherwise you may very well have output transformer issues.

TheShadowNinja · 10-21-2009, 06:37 PM

ok. good news. the amp doesnt make the hissing sound on standby after all. I was getting slightly confused. But yes, as soon as you turn off standby the hissing noise is right there.

Valves getting old/need replacing? They arent that old though, thats the problem- and I rebiased them yesturday.

Wilder Amplification · 10-21-2009, 06:58 PM

Quote:

Originally Posted by TheShadowNinja

ok. good news. the amp doesnt make the hissing sound on standby after all. I was getting slightly confused. But yes, as soon as you turn off standby the hissing noise is right there.

Valves getting old/need replacing? They arent that old though, thats the problem- and I rebiased them yesturday.

Does it do it on all channels?

Does it do it regardless of volume position?

How did you bias them (i.e. where did you connect the meter, what was the meter set to) and what did you set the bias current to?

MartyStrat54 · 10-21-2009, 07:07 PM

A professional musician has to change his tubes every three months. Some casual players can go three years. The bottom line is that if your tubes are making the noise, they are telling you, "Replace me, or I'll make bad trouble for you later."

When you rebiased your tubes, how far off were they? Did they drift to a warmer reading? If you don't have money for a new set of tubes, what's going to happen if one of your old tubes has a meltdown inside your amp. That's going to cost a lot more than a tube job...and yes, you will still need to buy a set of tubes.

stookiebhoy · 10-27-2009, 04:45 PM

I had this very same problem last year, then the amp started blowing its fuses. Turns out it was the output transformer that was going, but when you're in the middle of a gig you just replace the fuses and get on with it, so that's what I did. Big mistake.........don't make the same one I did, get it checked before it costs you a fortune.

Wilder Amplification · 10-27-2009, 06:10 PM

In my experience, when bias drifts it more often than not drifts downward as the plate resistance of the valve goes up due to wear. If a valve's bias drifts upward, this points to grid leakage and the valves should be replaced immediately. Leaky coupling caps between the phase inverter and the output valves can cause this also. First thing to try would be new valves in this scenario and if the same thing happens, more than likely you have leaky coupling caps at the PI output.

I never rebias as they drift...this way I can hear the tonal change as they wear and once it gets bad enough to where I can't get a decent sound out of the amp no matter what I do, I know the valves are worn and need replacing.

Letting power valves blow is playing Russian Roulette with your amp. When valves blow, they have a tendency to take other shit with them as they more often than not internally short. This short is not testable via a multimeter as it's more common to be a "leakage short". But when they short, they take out screen resistors, valve sockets, PI coupling caps, grid load/bias voltage feed resistors (VERY BAD IF THIS EVER HAPPENS) and even output transformers. You can end up with a much more costly repair bill than what it would cost to take it in and have the valves replaced/amp rebiased.

MartyStrat54 · 10-27-2009, 07:02 PM

On the power tubes thread, a member posted a new JJ that went into a hot bias drift and got so bad the internal parts of the tube caved in and destroyed the base of the tube and the socket in the amp. Very nasty.

I agree that a power tube that has been "fuctioning properly" will usually drift to the cool side. I'm just really pessimistic about current production tubes. I've seen/heard horror stories about one day old power tubes and one month old power tubes. A guy buys a set of four and there is a very good chance that one will fail, or have some sort of internal quality control issue. Then you add 450VDC to the mix and it can turn into a light show.

The thing I'm concerned about (and I have heard this many times) is that the OP is broke, so he is going to let this issue slide. He came on the forum for advice. Advice has been given, but money prevents the advice from being applied. I truly wish you all the best and I hope that your amp makes it.

Note: Veteran tube amp players "always" have a spare set of known good power tubes and a known good set of preamp tubes. This is very important to have for multiple reasons, namely troubleshooting and getting yourself out of an amp jam. I strongly suggest that you somehow obtain a complete spare change of tubes.

TheShadowNinja · 10-28-2009, 06:29 AM

buying a set of valves today, not going to play my amp until ive fitted and biased. Thanks very much everyone, you have shown me just how important this is.

I'll update when its all done.

Wilder Amplification · 10-28-2009, 06:33 AM

Quote:

Originally Posted by MartyStrat54

On the power tubes thread, a member posted a new JJ that went into a hot bias drift and got so bad the internal parts of the tube caved in and destroyed the base of the tube and the socket in the amp. Very nasty.

I agree that a power tube that has been "fuctioning properly" will usually drift to the cool side. I'm just really pessimistic about current production tubes. I've seen/heard horror stories about one day old power tubes and one month old power tubes. A guy buys a set of four and there is a very good chance that one will fail, or have some sort of internal quality control issue. Then you add 450VDC to the mix and it can turn into a light show.

You know, I'm really starting to wonder how many of the current production valves that people have had problems with were Groove Tubes matched batches.

10-20-2009, 03:52 PM	#1 (permalink)
TheShadowNinja Junior Member Join Date: Jun 2009 Posts: 28	Very quick TSL100 question. When I turn my amp on (either standby mode or normal) there is a fuzzy background hissing sound for about 5 minutes, and then comes and goes less and less frequently until it goes away and is silent. The amp works tonally all of the time whether it is hissing or not. I reckon its to do with the valves warming up, but was wondering if it was a more serious problem. Its more of an annoyance than a problem though! PS To those who were following my progress with this amp before, thanks so much for your words of wisdom- ive learnt a ton from this site and saved myself tons of money fixing it myself rather than sending it off to a tech NICE ONE!

10-21-2009, 05:54 AM	#3 (permalink)
TheShadowNinja Junior Member Join Date: Jun 2009 Posts: 28	Re: Very quick TSL100 question. "Where does it sound like it's coming from?" Im not sure what you mean. If you are talking about the actual hissing sound, its comes from the speakers- kind of a washy white noise sound. I know the valves are a bit old, but I cant afford to change them at the moment and besides, it works fine after 5 minutes. Very strange. I'll retest the amp today and report back

10-21-2009, 06:37 PM	#5 (permalink)
TheShadowNinja Junior Member Join Date: Jun 2009 Posts: 28	Re: Very quick TSL100 question. ok. good news. the amp doesnt make the hissing sound on standby after all. I was getting slightly confused. But yes, as soon as you turn off standby the hissing noise is right there. Valves getting old/need replacing? They arent that old though, thats the problem- and I rebiased them yesturday.

10-21-2009, 07:07 PM	#7 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Very quick TSL100 question. A professional musician has to change his tubes every three months. Some casual players can go three years. The bottom line is that if your tubes are making the noise, they are telling you, "Replace me, or I'll make bad trouble for you later." When you rebiased your tubes, how far off were they? Did they drift to a warmer reading? If you don't have money for a new set of tubes, what's going to happen if one of your old tubes has a meltdown inside your amp. That's going to cost a lot more than a tube job...and yes, you will still need to buy a set of tubes. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

10-27-2009, 04:45 PM	#8 (permalink)
stookiebhoy Member Join Date: Oct 2008 Posts: 33	Re: Very quick TSL100 question. I had this very same problem last year, then the amp started blowing its fuses. Turns out it was the output transformer that was going, but when you're in the middle of a gig you just replace the fuses and get on with it, so that's what I did. Big mistake.........don't make the same one I did, get it checked before it costs you a fortune.

10-27-2009, 07:02 PM	#10 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Very quick TSL100 question. On the power tubes thread, a member posted a new JJ that went into a hot bias drift and got so bad the internal parts of the tube caved in and destroyed the base of the tube and the socket in the amp. Very nasty. I agree that a power tube that has been "fuctioning properly" will usually drift to the cool side. I'm just really pessimistic about current production tubes. I've seen/heard horror stories about one day old power tubes and one month old power tubes. A guy buys a set of four and there is a very good chance that one will fail, or have some sort of internal quality control issue. Then you add 450VDC to the mix and it can turn into a light show. The thing I'm concerned about (and I have heard this many times) is that the OP is broke, so he is going to let this issue slide. He came on the forum for advice. Advice has been given, but money prevents the advice from being applied. I truly wish you all the best and I hope that your amp makes it. Note: Veteran tube amp players "always" have a spare set of known good power tubes and a known good set of preamp tubes. This is very important to have for multiple reasons, namely troubleshooting and getting yourself out of an amp jam. I strongly suggest that you somehow obtain a complete spare change of tubes. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

10-28-2009, 06:29 AM	#11 (permalink)
TheShadowNinja Junior Member Join Date: Jun 2009 Posts: 28	Re: Very quick TSL100 question. buying a set of valves today, not going to play my amp until ive fitted and biased. Thanks very much everyone, you have shown me just how important this is. I'll update when its all done.

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