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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Wed Mar 09, 2011 12:13 pm
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THANKS AGAIN TO ALL!
ME AMP SOUNDS BETTER AND NO MORE slight BURN SMELL
the transformer is now just warm to hot NOT crazy HOT anymore.....

shimmilou, you R the shiz

and thanks to iamsomewhere for asking this in the 1st place
and to everyone else !!!

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Wed Mar 09, 2011 12:20 pm
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glad it worked out! funny most amps are cold biased:)


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Mon Mar 21, 2011 4:54 am
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twirlyboggs wrote:
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TEST POINTS FOR BIAS - D35 & D36


I'm not so strong in electronics! I guess that it is in between the D35 and ground that you measure 24mV. And in between D36 and ground also 24 mV?

The blue trim potentiometer is probably what you adjust on I guess?


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Mon Mar 21, 2011 8:20 am
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Hi evg,

Yes, measure from D35 to ground (chassis) that is TP 40, which is for V6. Measure from D36 to ground that is TP41 for V7. Each should read about 24 mV, one tube might measure a little different than the other, +/- a couple of mV and that's normal. Yes, the blue pot is the bias adjust, and the one pot controls both tubes bias. :)

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Mon Mar 21, 2011 9:30 am
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shimmilou wrote:
Hi evg,

Yes, measure from D35 to ground (chassis) that is TP 40, which is for V6. Measure from D36 to ground that is TP41 for V7. Each should read about 24 mV, one tube might measure a little different than the other, +/- a couple of mV and that's normal. Yes, the blue pot is the bias adjust, and the one pot controls both tubes bias. :)



Thank you, shimmilou.
I appreciate your response :)


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Fri Mar 25, 2011 7:18 pm
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Then I changed my output tubes for two TAD 6V6GT-STR. And I got adjusted BIAS. But a funny thing is that the two test points are shown on the wrong side of the diodes in the schematic that came with the amplifier! :shock: Well! It is late at night here now. So I can only really tested the new tubes tomorrow. :)


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Fri Mar 25, 2011 7:27 pm
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The on line schematics show the test point on the end of the diode WITHOUT the stripe. Is yours different? The other end of the diode will give no reading. :idea:

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Fri Mar 25, 2011 7:34 pm
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shimmilou wrote:
The on line schematics show the test point on the end of the diode WITHOUT the stripe. Is yours different? The other end of the diode will give no reading. :idea:


Well! Now I see that the test ponts is not displayed incorrectly. But they have turned the entire PCB wrong. It might be a bit confusing unless you had twirlyboggs photos to help. :)


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Fri Mar 25, 2011 7:48 pm
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:lol: It is getting late. Get back with us tomorrow! :)

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Sat Mar 26, 2011 2:30 am
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shimmilou wrote:
:lol: It is getting late. Get back with us tomorrow! :)


Yes! It was late! :D I live in denmark and it was about 3 in the morning when I post my last replay :wink:

Well! Here's what I meant:

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Sat Mar 26, 2011 5:51 am
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Ah, I see. Yes, it can be a little disorienting looking at the drawings and trying to translate that to the actual amp layout. But, you figured it out OK, good job! :) Maybe after you try out your amp, you can report back on your bias level and your thoughts on the sound of your new tubes, that would be cool. 8)

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Sat Mar 26, 2011 6:26 am
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shimmilou wrote:
Ah, I see. Yes, it can be a little disorienting looking at the drawings and trying to translate that to the actual amp layout. But, you figured it out OK, good job! :) Maybe after you try out your amp, you can report back on your bias level and your thoughts on the sound of your new tubes, that would be cool. 8)



My first impression is definitely positive. It is as if the speaker suddenly becomes controlled with an iron fist and you get a lot more juicy midrange. I play in a blues band and has previously tried the "Texas Blues" setting is shown in the manual. And it did not sound good. But with the new tubes it makes sense.
I use "Kinman blues" pickups on my Start.
I rehearse with my band on Thursday. Then I'll become a little wiser about how they sound.
:)


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Sat Mar 26, 2011 7:44 am
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evg wrote:
shimmilou wrote:
Ah, I see. Yes, it can be a little disorienting looking at the drawings and trying to translate that to the actual amp layout. But, you figured it out OK, good job! :) Maybe after you try out your amp, you can report back on your bias level and your thoughts on the sound of your new tubes, that would be cool. 8)



My first impression is definitely positive. It is as if the speaker suddenly becomes controlled with an iron fist and you get a lot more juicy midrange. I play in a blues band and has previously tried the "Texas Blues" setting is shown in the manual. And it did not sound good. But with the new tubes it makes sense.
I use "Kinman blues" pickups on my Start.
I rehearse with my band on Thursday. Then I'll become a little wiser about how they sound.
:)



Btw.: I set the bias to about 26 mV for the new tubes. The original tubes were set at 17-18 mV!


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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Sat Mar 26, 2011 8:03 am
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That sounds about right. Now, if you check your Plate DC voltage, the striped end of D37 for V6, and D38 for V7, you can calculate the idle wattage of your tubes. If your Plate voltage is about 420 volts, with 26 mV at the test point, that is about 23 mA of Plate current, so roughly 9.5 watts of idle dissipation. That is just under 70% of the 14 watt 6V6, which is at the high end of the 50% to 70% range, and a good setting for a little breakup on the output tubes. Thanks for sharing the info, I hope that you really enjoy your amp for years to come. :)

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Post subject: Re: Super-Sonic 22 Bias Level
Posted: Sat Mar 26, 2011 12:17 pm
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shimmilou wrote:
That sounds about right. Now, if you check your Plate DC voltage, the striped end of D37 for V6, and D38 for V7, you can calculate the idle wattage of your tubes. If your Plate voltage is about 420 volts, with 26 mV at the test point, that is about 23 mA of Plate current, so roughly 9.5 watts of idle dissipation. That is just under 70% of the 14 watt 6V6, which is at the high end of the 50% to 70% range, and a good setting for a little breakup on the output tubes. Thanks for sharing the info, I hope that you really enjoy your amp for years to come. :)


Thank you, shimmilou. I have an Plate voltage of 415 volts. So it must be fine enough
:)


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