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Post subject: help fender 75?
Posted: Sun Jul 05, 2009 8:18 pm
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I have a fender 75 amp that i need help determing what value/rating this resistor is to replace it. Not sure if the one thats in it is correct and its too burnt to see the color rings,and im having trouble reading the schematic. Here are some pictures of the area in question. They are marked in yellow. Also if anyone knows where I can find some mods for this amp for more gain.



http://i52.photobucket.com/albums/g16/M ... 314960.jpg


http://i52.photobucket.com/albums/g16/M ... 4960-1.jpg


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Post subject: Fender 75
Posted: Sun Jul 12, 2009 9:07 pm
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Wow Joe, this is kind of tough from where I'm sitting, but here goes. The resistor looks to be the 22K1watt carbon film connected to the .1uf-200 coupling cap at one end and the 100ohm carbon comp. running to ground. The other side is connected to a 820ohm 1watt cabon film with a .01uf cap across it. Hard to tell, but it is definitely one of the 1watt resistors. This is part of the negative feedback circuit in service to the phase inverter. You can verify this by identifying the surrounding components that are clearly marked. I'm only seeing two 330K and one 470ohm resistors in the immediate neighborhood(on the schematic) and of course the 100ohm resistor. I've only had one of these amps on the bench, and that was maybe ten years ago, but it seemed to be a sturdy hand wired amp. Actually, I've wanted to check out the Fender 30, sounds like a neat design to me. Anyway, hope this helps. Art


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Post subject:
Posted: Mon Jul 13, 2009 8:47 am
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Last edited by tinker tech on Wed Jul 29, 2009 11:08 am, edited 1 time in total.

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Post subject:
Posted: Mon Jul 13, 2009 5:19 pm
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Thanks for the info guys. I found out it is a 82k 1/2watt. Im replacing that resistor and a blown 470 1watt that is on one of the 6l6 sockets (both will be carbon comp's when im done). Im also geting a new acutronics reverb tank and a new light cover. Geting my parts from mojotone.com. I just let the repairs stack up on this amp over the years and finaly decided to get to them as this was my first good amp. and I miss its tone Thanks again!


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Post subject:
Posted: Mon Jul 13, 2009 5:28 pm
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Yep! I agree with Tinker, it looks to be the 82Kohm bias resistor. The 100K can be seen to the left. The 330k, 470, and 22K junction is to the right. Good eye Tinker! Looks like it's been replaced, the other resistors look to be carbon comb. I'm going to stick with it being a carbon film 1watt, because of the body color and size. Which would tell me there is another issue with this circuit. Obviously, I could be totally wrong! Art


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Posted: Mon Jul 13, 2009 5:48 pm
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Last edited by tinker tech on Wed Jul 29, 2009 11:08 am, edited 1 time in total.

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Post subject:
Posted: Mon Jul 13, 2009 10:10 pm
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I missed that earlier post guys. My Bad! Art


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Post subject: hello Fender musicans and tecks
Posted: Tue Jul 14, 2009 5:03 pm
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I have a 73 or 74 twin reverb, 100 watt, 2 x 12's. playing right now, NOT missing anything. Playes great and sounds like my old lead players 63 twin Reverb. needs the pots cleaned but after a cleaning inside, it will be new. The unit has to go as one, no parts for tecks, sorry. the buy as one price will be about 1200.00. This amp is exception for sure. :) :(


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Post subject:
Posted: Thu Jul 16, 2009 12:50 pm
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Joe,
It looks like you've got it nailed down. I have a 75 that I bought in 83. I did a cap job as well as replaced a few resistors that were out of spec recently and it is sounding great. Do you really need more gain with this amp? The thing just about brings down the house in stock form.
Jim


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Post subject:
Posted: Tue Dec 15, 2009 10:19 pm
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hi i have a fender 75 amp found him in a second hand shop for not much money. put new tubes in the old thing and away it gos for more than ten years now. just replacet the on off switch it has to 10s celestions speakers from 1981. sounds great. :D


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Post subject:
Posted: Thu Dec 24, 2009 9:29 am
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Is this a head/cabinet version or the combo? I've never seen a 75 combo with two tens in it.


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Post subject:
Posted: Thu Dec 24, 2009 1:16 pm
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hi teamo and merry xmass the 75 combo i own had one 15 in it when new but someone change it to two ten in 1983 to celestions g50h type speakers . sounds good to me . have a gooday/ from aus. cheers. :D


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Post subject:
Posted: Fri Dec 25, 2009 9:43 am
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Hi Cliff.Lee,
A Merry Christmas to you too. I have the 75 combo with a 1x12. I got it used in 1983. It was a high school graduation present. It had a Peavy speaker in it for years and I finally changed it to an Eminence. It is much improved with an efficient speaker. Don't know why but whenever I read about someone with a 75 they all seem to have non-stock speakers in them. I believe that you could get a JBL or an EV speaker when bought new. Those were quality speakers and it doesn't make much sense that people pulled them out. Well how does it sound with the 10's in it?
Teamo


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Post subject:
Posted: Sun Dec 27, 2009 3:29 am
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hi teamo the old 75 sounds just fine to my ears anway.nice bass clear treble. tryed it in a old 2/ 12. sealed box home made it sounded real big. do not konw why they dump the standed speakers like the big 15. they must sound pretty big whit them.maybe they where looking for a diffrent sound like the two tens or one 12. back in the 80s. have a nice day, :D cliff.


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Post subject:
Posted: Wed Mar 10, 2010 3:06 pm
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Mine has the original 15" and I would never change it. Earhartear Webers are a good alternative for vintage Fender. I would be really interested to run a 2x10 cab with it.


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