Loses sparkle and highs as it warms up
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Stevem
- Posts: 4987
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
L
Your already 5% down on what you should have for voltage, if you get to 10% when hot then your issue is found!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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Stevem
- Posts: 4987
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
A
Is this reading with 5881s in the amp, or EL34s?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Loses sparkle and highs as it warms up
Well I should probably mention that I am in Europe and using American version of the amp through step up/down transformer. I am not able to feed the amp with exactly 120 Volts, it is getting 115 or 116 Volts to begin with. (Europe also has only 50 Hz freq.)
Now this sad, the facts are as follows:
-Heater voltage with all the tubes removed 5,9 - 6 VAC
-Heater voltage with the tubes in 5,6 - 5,7 VAC
The tubes currently in are 12ax7's and 6L6 GC STR's
-ALL the VOLTAGES through out the amp are a bit lower then in Schematics.
(Measurements taken with amp in the bedroom. Readings under heavy usage I will post probably Monday night after rehearsal).
Do you guys think that my problem is in a bit lower voltage I am giving to my amp to begin with? If that's the case the only other option I have is to use another step/up down transformer which would feed the amp with 127 Volts. Those are the two options i have, either 115 or 127 VAC. Should I do that? Or this is not a big deal and we should keep looking inside the amp?
P.S.
Just tried feeding the amp with 127 V. The heater voltage jumped to 6,6 VAC without tubes and to perfect 6,3 VAC with all the tubes in!
Now this sad, the facts are as follows:
-Heater voltage with all the tubes removed 5,9 - 6 VAC
-Heater voltage with the tubes in 5,6 - 5,7 VAC
The tubes currently in are 12ax7's and 6L6 GC STR's
-ALL the VOLTAGES through out the amp are a bit lower then in Schematics.
(Measurements taken with amp in the bedroom. Readings under heavy usage I will post probably Monday night after rehearsal).
Do you guys think that my problem is in a bit lower voltage I am giving to my amp to begin with? If that's the case the only other option I have is to use another step/up down transformer which would feed the amp with 127 Volts. Those are the two options i have, either 115 or 127 VAC. Should I do that? Or this is not a big deal and we should keep looking inside the amp?
P.S.
Just tried feeding the amp with 127 V. The heater voltage jumped to 6,6 VAC without tubes and to perfect 6,3 VAC with all the tubes in!
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Stevem
- Posts: 4987
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
G
10% above or below 6.3 is the max and at 5.7 your at the under point, does it drop to less when the amp acts up?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: G
I will know that next week, I will post answer as soon as I get back from rehearsalStevem wrote:10% above or below 6.3 is the max and at 5.7 your at the under point, does it drop to less when the amp acts up?
Re: Loses sparkle and highs as it warms up
Well the good news is there is no change in the heater voltage when the amp worms up. I am getting more and more convinced that the problem is in the mains voltage over here in Serbia, for example at the practice pad I get only 110 V from the step-up transformer, in that case my heater voltage is only 5,3 VAC That simply is not enough for an amp that is made for 120 V which is listed on the back of the amp. I think I will have my step up transformer rewound to give out a little bit more volts... In the mean time I biased tubes very cold, that kind of solved the situation with the sound, I do have less sustain and I have to turn a volume button a tiny bit more but I can live with that until getting the step-up transformer redone..
Re: Loses sparkle and highs as it warms up
+1 on the ear fatigue syndrome.
Not only because of the loud amp, after a couple crash cymbal hits with full force within one meter of your ears you lose highs sensitivity for a couple hours or worse.
Further proof is that it does not happen at low power levels.
Not only because of the loud amp, after a couple crash cymbal hits with full force within one meter of your ears you lose highs sensitivity for a couple hours or worse.
Further proof is that it does not happen at low power levels.
Design/Make/Service Musical stuff in Buenos Aires, Argentina, since 1969
Re: Loses sparkle and highs as it warms up
I would think that if you measure 6.3v on the heaters with the 127v provided from your step down transformer, that you have the "propper" winding already.
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JazzGuitarGimp
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- Location: Northern CA
Re: Loses sparkle and highs as it warms up
I was thinking the same thing. How do the measured high voltages compare to the schematic when using the 127V transformer?brewdude wrote:I would think that if you measure 6.3v on the heaters with the 127v provided from your step down transformer, that you have the "propper" winding already.
Lou Rossi Designs
Printed Circuit Design & Layout,
and Schematic Capture
Printed Circuit Design & Layout,
and Schematic Capture
Re: Loses sparkle and highs as it warms up
Yes, but that was lucky moment during the night when the town is at sleep and voltage in the grid is up, during the day when all the consumers and industries are running at full capacity mains voltage can fall way down, at the practice pad I get only 106 Volts out of step down transformer, and that was the problem. Everything solved now, I got two step down transformers, one to use in low grid conditions and one for better conditions.. Sound is great, very consistent throughout the rehearsal and/or shows..brewdude wrote:I would think that if you measure 6.3v on the heaters with the 127v provided from your step down transformer, that you have the "propper" winding already.