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Post subject: I just pulled out a 69 Super reverb must of sat for 25 years
Posted: Wed Dec 15, 2010 7:19 am
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HELP I turned this amp on and it is very week do I change all tubes and filter caps before I try it again How can I tell what model it is it is stamped on the chassis T35069 it has a GZ34 5AR4 in it should it be a 5u4 GB I am not the original owner this is what was in it. Might it be a AA1069 any Idea will help[/list]


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Posted: Wed Dec 15, 2010 1:24 pm
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If it is indeed a silverface it should be a 5U4, the blackface had the GZ34. Sounds like someone attempted mods.


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Posted: Wed Dec 15, 2010 2:17 pm
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if it did have some sort of mod and I put in a 5U4 and take out the GZ34 will this be a problem and I I continue to use the GZ34 and there was not a mod will this be a problem


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Posted: Wed Dec 15, 2010 3:08 pm
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With a GZ34 it should run hotter (the power transformer) than with 5U4 because he draws more voltage. You can see on the schematics how Fender compensated for the difference between silverface and blackface.

If you leave the GZ34 in and the chassis get too hot to the touch try a 5U4 and rebias.

By the way, Fender was known from the factory to put in different tubes than indicated on the chart.


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Posted: Wed Dec 15, 2010 4:49 pm
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Thanks I do have a Zenith 5u4gb I will give it a try Will that have any effect on the weakness of the amp or do I need to change the filter caps and or the 6L6 power tubes. It also has chocolate drops for the tone caps Being it was made in the 50th week of 69 would this be a AB1069 model


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Posted: Wed Dec 15, 2010 5:07 pm
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Hi Mud and welcome to the forum ! I would consider power tubes, PI tube, filter caps and bias cap replacement. As for the rectifier tube, IMO; the stock PT is a 125P5D(same for '63 thru '71). It has a 5 volt filament tap for the rectifier tube rated at 3 amps. The 5AR4/GZ34 draws 1.9 amps. The 5U4GB draws 3 amps. So we can see that the trans is working harder and at it's max rating, with the 5U4GB. This didn't seem to bother Fender because the rating was probably conservative. The only other consideration would be the voltage drop across the tube and the current capacity. The 5AR4/GZ34 has about a 20 volt drop and delivers 250ma. The 5U4GB has about a 60 volt drop and delivers 275ma. So I guess it's your choice, a little less heat & tighter sound---or a little more heat & more sag. Art

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Posted: Wed Dec 15, 2010 5:12 pm
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I believe the 68-69 had the aluminum frame around the grill cloth. Also the chassis number T35069 means 1969. If the amp sat for that many years I would definitely do the caps.


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Posted: Wed Dec 15, 2010 5:45 pm
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Yeah I agree with Atolleter, it should be the AA 1069. And like he said, the amp's changes from the earlier design, would benefit with the compensation of the 5U4GB. Otherwise the amp may be too sterile sounding. Art

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Post subject: Re:
Posted: Sun Dec 19, 2010 2:08 am
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aclempoppi wrote:
Yeah I agree with Atolleter, it should be the AA 1069.


It'll depend upon the build date, Art.

Anything made prior to October of '69 will be the AB568 revision. Subsequent to that would make it the AA1069.

An ink-stamped date somewhere on the chassis will determine the circuit.

HTH

Arjay

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Post subject: Re: I just pulled out a 69 Super reverb must of sat for 25 y
Posted: Mon Dec 20, 2010 7:03 am
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Thanks I do appreciate the time you all have taken with this the ink stamp is T35069 I think it means the 50th week and that should make it Dec 69 If any one know if I am correct please let me know and if I am wrong let me know also


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Post subject: Re: I just pulled out a 69 Super reverb must of sat for 25 y
Posted: Sat Dec 07, 2013 5:42 pm
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" With a GZ34 it should run hotter (the power transformer) than with 5U4 because he draws more voltage. "

This is not correct. Just the opposite. The GZ34 draws less heater current than the 5U4GB (2 amps versus 3 amps). The heater current demand of rectifiers causes more PT heat than the PIV voltage.

Now, if you feel the heat off a 5U4GB versus a GZ34, it may appear cooler. Prolly because the larger bottle used in most 5U4GB versus the GZ34.


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Post subject: Re: I just pulled out a 69 Super reverb must of sat for 25 y
Posted: Mon Mar 16, 2015 9:54 am
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Well it been a while since I did anything but practice my guitar. I started this post just before receiving my 1st electric guitar since I was 16 (did not get to far except make a lot of noise at that try). Left home at 18 and played harmonica for the next 44 years (present). Received my cheap Epiphone SG310 for the winter holidays 2010 ( have upgraded everything in it except the body a neck) In Feb of 2013 I bought a New Fender Am standard and love it.
At some point I changed out the Caps under the doghouse maybe 3 years ago and I was still not happy with it, did lot of research, still could not get it to bias over 24ma had ticking in the vibrato hissing just not right, it was still loud though, I kept saying I will deal with this when I retire, as my free time if lucky is 2 to 3 hours a night, so I can mess with my amp or play my guitar I chose Play as I need to make up for lost time, as I have a variety of thing to play out of mostly SS stuff,
Last week I brought it to a tech to have a go at it. I was sent his name by a forum member I think it was "atolleter" and than speaking to a friend who re cones speakers he mentioned this person and recently while searching on line for a Princeton Reveb I saw an amp for sale giving praises to this AMP Guru, so I gave him a call.
He had it 1 week. When I brought it the symptoms were; Noise, Insufficient Bias Current, Vibrato Tick, other little odds and ends.This is what he did:
Clean and tightened all tube sockets, pins, input and output jacks, rewired AC cable to fuse and switch, Removed the ground switch and Replaced it with a Bias control, (now I have the original Balance pot and a Bias pot, best of both worlds) Replaced the Vibrato bug with LED and New Photocell ( no more ticking) Replaced some roasted resistors in the Hi Voltage supply, Replaced the 5U4GB that was week with a 5AR4C he says that is the tube that should be in there ????? :?. I seem to have very good results it is quite and sounds great
He set balance and bias and checked power;
38 watts @ Clip to 2 ohms
Bias Current 34 ma
Bias Voltage -45.3V / 44.6V
High Voltage 442V No Signal/ 400V
I am very happy but it is loud
Now lets talk speakers here is what I have
2 of these
Image
1 of this I think it is the same as above different year
Image
and 1 of this
Image
Image
any help on the speaker and or recommendations will be appreciated
Thank you
mud


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Post subject: Re: I just pulled out a 69 Super reverb must of sat for 25 y
Posted: Mon Mar 16, 2015 10:02 am
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The two speakers marked with "137" as a preface to their EIA codes are CTS alnico's -- these were commonly installed in Super Reverbs of all eras and IMO are the best-sounding OEM drivers that Fender used. The third speaker is a ceramic Oxford 10L5, also a stock model that was periodically installed in these amps and also the Vibrolux Reverb.

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Post subject: Re: I just pulled out a 69 Super reverb must of sat for 25 y
Posted: Mon Mar 16, 2015 10:34 am
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Retroverbial wrote:
The two speakers marked with "137" as a preface to their EIA codes are CTS alnico's -- these were commonly installed in Super Reverbs of all eras and IMO are the best-sounding OEM drivers that Fender used. The third speaker is a ceramic Oxford 10L5, also a stock model that was periodically installed in these amps and also the Vibrolux Reverb.


Thank you for the fast reply so I assume they will play nice with each other in this unit If I were to put in set of newer speakers what would you recommend for this SFSR


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Post subject: Re: I just pulled out a 69 Super reverb must of sat for 25 y
Posted: Mon Mar 16, 2015 11:40 am
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Were the amp mine, I would find another pair of Fender-marked CTS alnico's. Re-cone them if necessary. Ebay is a good place to search.

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