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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 3:45 am
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BMW2002Ti wrote:
Reason I say that is for every bad Fender OEM OPT --- I see, maybe, 50 fried output stages (prolly closer to 100). Which may toast the OPT. Usually due to shorted output tubes, bias stage gone wild, current sucking instabilities in previous stages of the amp, shot main filter caps, and arcing rectifiers.

Anyhow, good luck with the new iron!

:D


OEM OPT mean ?


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 8:39 am
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"OEM"......original equipment manufacturer

"OPT"......output transformer

HTH......hope this helps

:mrgreen:

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: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 9:00 am
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TIH

Thank's it help for sure.

Output Transformer , why not only OT ? This is not good american language ?


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 9:24 am
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I personally prefer and use "OT". Others like "OPT". No idea why.

Arjay

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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 9:32 am
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OT output transformer
PT power transformer

OPT mix of both = confusing


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 10:42 am
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Stratele & Arjay,

The use of "OPT" is a holdover from what I was taught a bazillion years ago, by some Ham Radio and hi-fi guys. Their units often had many transformers. Not just a power and an output tranny. But, several interstage, coupling, isolation, etc transformers. In the tuner sections, the receiver sections, the various pre-amp gain stages & output stages (for both transmitter & receiver stages).

To avoid confusion, each STAGE used an abbreviation. "OP" was for OUTPUT. For example, the Fender 400PS uses a 6L6GC & interstage tranny to couple & drive the gain and 6550 output stages.

So, you could say it is an OP driver tube, or OPD tube. Sometimes these style amps also have a buffer stage in this section. Or an OPB buffer tube.

This driver section tube is then coupled to an OPIT (output interstage tranny).


http://www.webphix.com/schematic%20heav ... /400ps.pdf

So, the term OPT kinda stuck with me.

Sorry for the confusion. :D :?: :D :!:


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Wed Jan 30, 2013 11:56 am
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Thank's BMW2002Ti, for usefull information , I always learn with you.


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Thu Jan 31, 2013 11:24 am
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wow...you guys are nuts. A debate over OT and OPT.
Actuall info out there regarding too....

nuts I tell you.... :lol:


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Thu Jan 31, 2013 11:33 am
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BMW2002Ti wrote:
Reason I say that is for every bad Fender OEM OPT --- I see, maybe, 50 fried output stages (prolly closer to 100). Which may toast the OPT. Usually due to shorted output tubes, bias stage gone wild, current sucking instabilities in previous stages of the amp, shot main filter caps, and arcing rectifiers.

Anyhow, good luck with the new iron!

:D


good stuff to know...thanks
But I have checked and or replaced the items you mentioned above. So I am pretty sure its the OT.
Kind of funny.....I was getting a 74 Vibrolux healthy for a freind and it had a weak OT.
Wound up using an OT from a previous BMR I had VC'd. Parts in stock>>>:)


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Thu Jan 31, 2013 1:26 pm
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mxvin wrote:
wow...you guys are nuts. A debate over OT and OPT.
Actuall info out there regarding too....

nuts I tell you.... :lol:


It is a debate about undestanding what is write, too short for words used and not everyone recognizes them.


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Fri Feb 01, 2013 9:19 am
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Hello mxvin, I have had low amp volumes on 2 older fender amps I have purchased. Both times I have found the phase inverter tube to be weak/unbalanced. If you have electronic skills this can be checked easily by measuring both plate voltages on the phase inverter tube and comparing to the schematic that usaully has the voltage for those points. In my case I had a 40 to 60 vdc difference between sides that just putting a new tube in brought the difference down to 5 to 10 vdc. All of this was after even testing the tubes on a tube tester and getting an ok. It may not be your problem but it is easy enough to check.


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Fri Feb 01, 2013 12:27 pm
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connuchar wrote:
Hello mxvin, I have had low amp volumes on 2 older fender amps I have purchased. Both times I have found the phase inverter tube to be weak/unbalanced. ...............................
All of this was after even testing the tubes on a tube tester and getting an ok. It may not be your problem but it is easy enough to check.



+1 Connuchar

For your information a tube tester can't tell if tube will work in a tube amp. Almost all tube tester use a low voltage , most tubes will work fine at low voltage but won't work at higher voltage.

Guitar amp work at high voltage. The PI tube ( which was good on Tube tester ) do not work as you see yourself.

I wish mxvin try some know good tubes and do some voltage and resistor check in Phase Inverter before ordering $$$$ Mercury magnetic transformer $$$$$.

We 'ill have the answer soon.


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Fri Feb 01, 2013 1:31 pm
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stratele52 wrote:
connuchar wrote:
Hello mxvin, I have had low amp volumes on 2 older fender amps I have purchased. Both times I have found the phase inverter tube to be weak/unbalanced. ...............................
All of this was after even testing the tubes on a tube tester and getting an ok. It may not be your problem but it is easy enough to check.



+1 Connuchar

For your information a tube tester can't tell if tube will work in a tube amp. Almost all tube tester use a low voltage , most tubes will work fine at low voltage but won't work at higher voltage.

Guitar amp work at high voltage. The PI tube ( which was good on Tube tester ) do not work as you see yourself.

I wish mxvin try some know good tubes and do some voltage and resistor check in Phase Inverter before ordering $$$$ Mercury magnetic transformer $$$$$.

We 'ill have the answer soon.


Thanks Guys.....appreciate the heads up on the PI. I have checked all the voltages prior to even starting this thread. The amp is "otherwise" healthy thats why I am shot gunning the OT. I got a Classic Tone for 47.00. Would not spend the big $$ for a MM.


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Fri Feb 01, 2013 2:50 pm
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Realy not expensive Classic Tone. I tough MM was more expensive.

Thank's mxvin


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Post subject: Re: Can Output Tranfromers get "weak"
Posted: Fri Feb 01, 2013 3:04 pm
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stratele52 wrote:
Realy not expensive Classic Tone. I tough MM was more expensive.

Thank's mxvin

Classic Tone is Magnetic Components.....47.00
Mercury Mag similar OT is about 120.00.


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