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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Tue Oct 08, 2019 4:51 pm
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You need to review the circuit layout of your amp, versus the proper layout/schematic. I'm not sure which circuit your amp is currently using, but look at the example AA270 one I linked. Look at the bottom layout and compare the wiring to your amp. You should do static continuity tests, to be sure all is correct.

Good luck! :mrgreen:

http://ampwares.com/schematics/twin_reverb_aa270.pdf


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Tue Oct 08, 2019 5:09 pm
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stratele52 wrote:
july 10 you wrote ;

" I recently restoration and recap all the capacitors with good quality japanese caps, "......

Now is it the second recap in few month ? :?: :?:
___________________________

1,2,3 ; Did you do some work on the circuit and or pots wiring ?

Post good picture of inside your amp.

How to bias ? Tube use lethal voltage.
You need voltmeter and know hoe to use it
A bis probe or two 1 ohms resistors.

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July 11 Retroverbial wrote ; "What I think is, you don't have a clue as to what you're doing.

Yes, you are right this is the second time that i change the caps include filter caps.
As i mentioned before i didnt change the circuit and wirings, i just change the caps.
I measure the voltage of both 6l6 tubes ( with 3rd pin of tube and ground) and both of them are about 430 Vdc.
Here are the photos.hope the pictures are clear and have good details.

http://www.mediafire.com/folder/0hpiqfu ... pie/shared
So help me for biasing and if you have any idea please tell me to solving middle/volumes pot problem.
In the near future i will order this set of tubes. But before ordering i should solve the pot problems. Now i have pair of russians 6l6 and one sylvania 5u4 rectifier and different brands of pre amp tubes that installed on amp.all the tubes on amp are work good but i think they are too old and over used.

https://www.amazon.com/Fender-Blackface ... B0057IPPGO


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Tue Oct 08, 2019 5:19 pm
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TimsAudio wrote:
A quick google search reveals Gilmour only Fendered with Twins, not a Super.
The super is brighter because of smaller, brighter speakers and a smaller midrange cap in the tone stack

The harshness comes from too much Treble, a common Super issue. The EQ pedal should take care of that, so the amp may need a little help if it didn't.

Changing out the mid cap from .02 to .047 and the phase inverter cap from .001 to .01 will match the Twin specs. It will lower Treble and focus on midrange tones.

The speaker harshness can be tamed with 4 inch disks of 3/4" open pore foam. Sew these gently into the backside of the speaker grille in front of the center of the cones.

Would you please more describe and tell some detailed information about changing those caps for getting better middle tones?
I will be in heaven if my amp have more clear and nice mids :)


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Tue Oct 08, 2019 6:09 pm
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I'm surprised it works at all.

You need to take this amp to a pro before you burn it up.
Image


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Tue Oct 08, 2019 6:36 pm
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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 12:43 am
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vinyl wrote:
I'm surprised it works at all.

You need to take this amp to a pro before you burn it up.
Image

There is no pro around here,bad luck


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 1:04 am
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ali_k wrote:
vinyl wrote:
I'm surprised it works at all.

You need to take this amp to a pro before you burn it up.
Image

There is no pro around here,bad luck

As i mentioned i want to learn to repair.
I can easily change the broken caps.
Its so simple.


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 2:27 am
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ali_k wrote:

:roll:
Arjay

I want to expirience and learn to repair by myself.its such a real fun and joy for me.[/quote]


I don't know how we can do that by the web. It need too much time.
There are lots of books you can read about that


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 2:53 am
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Be sure to follow the layout, carefully. Like the polarity of those darn electrolytic caps. That's why the cap in your photo is popped. It was wired wrong.

Image


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 3:03 am
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ali_k wrote:
ali_k wrote:
vinyl wrote:
I'm surprised it works at all.


Image




Bias caps polarity are wrong :shock:

That is what you think is a high quality Japan caps ? I never use those cheap caps in good amps.


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 4:18 am
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stratele52 wrote:
I never use those cheap caps in good amps.

I wouldn't use those caps in ANYTHING.

:roll:
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: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 4:45 am
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Retroverbial wrote:
stratele52 wrote:
I never use those cheap caps in good amps.

I wouldn't use those caps in ANYTHING.

:roll:
Arjay



+1000 :lol:


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 5:26 am
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stratele52 wrote:
ali_k wrote:

:roll:
Arjay

I want to expirience and learn to repair by myself.its such a real fun and joy for me.



I don't know how we can do that by the web. It need too much time.
There are lots of books you can read about that[/quote]
I allready view a lot videos in youtube from
gerald webber ,

And D-labs
https://m.youtube.com/watch?v=RBYPT_2ICXw

And also uncle Doug
https://m.youtube.com/watch?v=dl729dEJ3To
If you now any other good toturials or videos please send me.


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 5:26 am
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Location: Iran - Tehran
stratele52 wrote:
ali_k wrote:

:roll:
Arjay

I want to expirience and learn to repair by myself.its such a real fun and joy for me.



I don't know how we can do that by the web. It need too much time.
There are lots of books you can read about that[/quote]
I allready view a lot videos in youtube from
gerald webber ,

And D-labs
https://m.youtube.com/watch?v=RBYPT_2ICXw

And also uncle Doug
https://m.youtube.com/watch?v=dl729dEJ3To
If you now any other good toturials or videos please send me.


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Post subject: Re: Fender super reverb SF ab763 modification
Posted: Wed Oct 09, 2019 5:29 am
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BMW2002Ti wrote:
Be sure to follow the layout, carefully. Like the polarity of those darn electrolytic caps. That's why the cap in your photo is popped. It was wired wrong.

Image

Thank you so much for telling the problem
I'll correct that.


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