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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 7:57 am
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Ah. well now its got me wondering. Could it hurt the amp? I could delete it and see how she sounds if it wouldn't hurt the amp.


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 8:40 am
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If it ain't broke, don't "fix" it.

:mrgreen:

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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 8:52 am
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Retroverbial I understand what you mean, you are not wrong . But sometimes it is not always simple.

I remember few times some friend buy guitar and they like it very much. When they show me the guitar I said , good guitar but it nead a set up for play better. The guy said why ? It play right now, everything is easy.....and after the set up he say " Wow!! thats is better, lot better.

Same thing appened when I check amp, wiring dress , bias , tubes, capacitors.

But sometimes not better , same as before.


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 2:19 pm
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The resistors came in, so I will be trying to find one exactly 1 ohm. I am not sure where to test the voltage though. I am thinking it will be either side of the resistor off of pin eight.


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 2:40 pm
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Your 1 ohms resistor is for mesuring bias ? You take mesurement each side of the resistor or from ground to pin 8.

One side of the resistor is at ground and the other side at pin 8 of 6L6
Mesure in millivolts and you know , millivolts = milliamp on 1 ohm resistor


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 3:42 pm
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Everything seems to have gone well. The tubes were running to hot as suspected and are now both Imageat 38.5 mvdc. Thanks to the balance pot and trim pot.


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 3:45 pm
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yes I am going to clean up the solder drop. :?


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 4:14 pm
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Be careful to not heat too much the 1 ohm resistor. Hold it with plier, close to the body if not sure


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Post subject: Re: question about aa270 layout
Posted: Tue Oct 25, 2011 4:54 pm
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stratele52 wrote:
Be careful to not heat too much the 1 ohm resistor. Hold it with plier, close to the body if not sure


+1

Soldering to a chassis requires some serious heat. A heat-sink is recommended to prevent thermal damage to sensitive components. I use a pair of smooth-jaw hemostats (aka a "roachclip") for such scenarios.

HTH

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: question about aa270 layout
Posted: Wed Oct 26, 2011 1:08 am
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Soldering to a chassis requires some serious heat. A heat-sink is recommended to prevent thermal damage to sensitive components. I use a pair of smooth-jaw hemostats (aka a "roachclip") for such scenarios.
-Retroverbial

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Post subject: Re: question about aa270 layout
Posted: Wed Oct 26, 2011 1:35 am
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yes, I understand what you are saying aboutthe heat. I was concerned as well. I left a short peice of the original ground wire to solder to on both sides. I didn't solder directly to the chassis. In the future I will use the hemostats I think I already have a pair in my tackle box. Thanks again for the information. (schooling). :wink:


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Post subject: Re: question about aa270 layout
Posted: Wed Oct 26, 2011 1:48 am
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Congrat , you do the best thing with using the piece of wire already solder to chassis.


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