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Post subject: Reverb on my twin is lagging
Posted: Wed May 02, 2012 11:46 am
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Well,I went to fire up the twin after it sat for a month or so ,maybe two months tops since last time I fired it up.She seemed to work just fine last time I played her.I have been having the major surf itch lately and I really wanted to play some surf music.She fired up fine and when I went to hit the footswitch for reverb I noticed a pretty noticible hum...definitely more than usual and the reverb just doesn't have that lush sound it had before.As I turn the reverb knob up the hum definitely gets louder and reverb doesn't seem to get any better. :( Any suggestions what might be causing this.I gotta have reverb no question about it.Thanks in advance for any advice.I have already checked all connections leading to and from tank and inspected the underside of tank itself and springs and transducer connections appear ok.If I wiggle tank with power on I get that spring noise although it doesn't seem gnarly crash sound like when I have accidentally bumped it while playing before.That's as far as I have gone.A little help please guys
Thanks

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1990 Fender Red Knob - "The Twin"
1992 Fender Newporter - Acoustic
2000 Fender American Series Strat - Natural ash
2010 Fender Mustang 1
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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 12:05 pm
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Have you tried replacing your reverb driver and recovery tubes with known-good substitutes (respectively, V3 and V4)?

Arjay

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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 1:57 pm
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Retroverbial wrote:
Have you tried replacing your reverb driver and recovery tubes with known-good substitutes (respectively, V3 and V4)?

Arjay

I have not done that Arjay.That is why I was asking your guys expertise before I went any further.Is the reverb driver on my amp the 12at7 and the recovery the 12ax7 and exactly where would v3 and v4 be on my amp looking from the back at it.? Arjay....This is the red knob twin.

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1986 Fender Sidekick Reverb 35
1990 Fender Red Knob - "The Twin"
1992 Fender Newporter - Acoustic
2000 Fender American Series Strat - Natural ash
2010 Fender Mustang 1
2011 Fender Blacktop Jazzmaster -Sunburst
2012 Fender Champion


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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 2:27 pm
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Retroverbial wrote:
Have you tried replacing your reverb driver and recovery tubes with known-good substitutes (respectively, V3 and V4)?

Arjay


I'll bet Amplifier Tech's hate you for killing their busines :lol: :lol: :lol:

(Just a bit of ribbing Arjay :wink: )

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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 2:34 pm
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scarleg wrote:
Retroverbial wrote:
Have you tried replacing your reverb driver and recovery tubes with known-good substitutes (respectively, V3 and V4)?

Arjay

I have not done that Arjay.That is why I was asking your guys expertise before I went any further.Is the reverb driver on my amp the 12at7 and the recovery the 12ax7 and exactly where would v3 and v4 be on my amp looking from the back at it.? Arjay....This is the red knob twin.


Looking at the back of the amp, tubes count up from "1" starting from the right.

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Last edited by bluesky636 on Wed May 02, 2012 3:08 pm, edited 1 time in total.

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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 2:57 pm
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Disregard my previous......

My mind saw "Twin" and "Reverb" in the opening post, put two and two together, and ended up with "five".

:oops:

The reverb driver for the red-knob "Evil Twin" appears to be V8 and the signal is recovered by V9. Follow Bill's instructions for determining where these tubes are located -- you'll be counting from the right when looking at the chassis from the rear as mounted in the cabinet.

HTH

Arjay

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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 5:53 pm
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Retroverbial wrote:
Disregard my previous......

My mind saw "Twin" and "Reverb" in the opening post, put two and two together, and ended up with "five".

:oops:

The reverb driver for the red-knob "Evil Twin" appears to be V8 and the signal is recovered by V9. Follow Bill's instructions for determining where these tubes are located -- you'll be counting from the right when looking at the chassis from the rear as mounted in the cabinet.

HTH

Arjay
On this photo and according to Bill saying to count from right it would be the two in the back on the far right ..is that correct? Isn't the driver generally a 12AT7 or not necessarily? in which case v8 and v9 would be the two in the back left right by the small transformer.That is right where the tank wires plug into the chassis.Can one of you verify that for me according to photo.Thanks guys
Image

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1986 Fender Sidekick Reverb 35
1990 Fender Red Knob - "The Twin"
1992 Fender Newporter - Acoustic
2000 Fender American Series Strat - Natural ash
2010 Fender Mustang 1
2011 Fender Blacktop Jazzmaster -Sunburst
2012 Fender Champion


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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 02, 2012 9:25 pm
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scarleg wrote:
On this photo and according to Bill saying to count from right it would be the two in the back on the far right ..is that correct? Isn't the driver generally a 12AT7 or not necessarily? in which case v8 and v9 would be the two in the back left right by the small transformer.That is right where the tank wires plug into the chassis.Can one of you verify that for me according to photo.Thanks guys
Image


Well, I have to admit that I am quite baffled.

Here is the schematic I found at Ampwares for the Red Knob Twin:

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

Note that the four 6L6GCs are labled "V5", "V6", "V10", and "V11". One 12AT7 (the phase inverter) is labled "V4". None of the other tubes are labled with their tube type. The reverb driver and recovery tubes appear to be "V8" and "V9" respectively. However, for the life of me, I cannot figure out in what order to count the tubes to make them match up with the schematic.

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Post subject: Re: Reverb on my twin is lagging
Posted: Thu May 03, 2012 12:54 am
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Bump...anybody else able to tell me me which is V8 and V9.Thanks Bill and Arjay for getting me the info you have.I just need to find out exactly where that V8 and V9 are.Anybody else ...? Might this help and is that correct according to schematic.I'm no engineer...I just want my reverb back.
V7: Input for channel 1
V1: Input for channel 2
V3: Preamp in and out
V4: PI
V2: Overdrive
V8:Reverb Driver
V9 Reverb Recovery
V5,6,10,11 6L6

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1986 Fender Sidekick Reverb 35
1990 Fender Red Knob - "The Twin"
1992 Fender Newporter - Acoustic
2000 Fender American Series Strat - Natural ash
2010 Fender Mustang 1
2011 Fender Blacktop Jazzmaster -Sunburst
2012 Fender Champion


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Post subject: Re: Reverb on my twin is lagging
Posted: Thu May 03, 2012 1:57 am
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You know what you can do? Get a good 12AT7 and sub it in, one-12AT7-socket-at-a-time, into each 12AT7 position. And listen to your reverb.

This assumes that the tubes in the amp are in the correct position, at the moment.


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Post subject: Re: Reverb on my twin is lagging
Posted: Thu May 03, 2012 5:43 am
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scarleg wrote:
Bump...anybody else able to tell me me which is V8 and V9.Thanks Bill and Arjay for getting me the info you have.I just need to find out exactly where that V8 and V9 are.Anybody else ...? Might this help and is that correct according to schematic.I'm no engineer...I just want my reverb back.
V7: Input for channel 1
V1: Input for channel 2
V3: Preamp in and out
V4: PI
V2: Overdrive
V8:Reverb Driver
V9 Reverb Recovery
V5,6,10,11 6L6


Yeah, that is correct. I just can't figure out the order to count the tubes in the tube chart to make it match with the schematic. :?

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Post subject: Re: Reverb on my twin is lagging
Posted: Thu May 03, 2012 5:44 am
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BMW2002Ti wrote:
You know what you can do? Get a good 12AT7 and sub it in, one-12AT7-socket-at-a-time, into each 12AT7 position. And listen to your reverb.

This assumes that the tubes in the amp are in the correct position, at the moment.


+1

Probably the best approach at the moment. :wink:

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Post subject: Re: Reverb on my twin is lagging
Posted: Thu May 03, 2012 10:36 am
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Thank you all for the suggestions.Most appreciated.I will continue my process of elimination.

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1986 Fender Sidekick Reverb 35
1990 Fender Red Knob - "The Twin"
1992 Fender Newporter - Acoustic
2000 Fender American Series Strat - Natural ash
2010 Fender Mustang 1
2011 Fender Blacktop Jazzmaster -Sunburst
2012 Fender Champion


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Post subject: Re: Reverb on my twin is lagging
Posted: Thu May 03, 2012 2:02 pm
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Let us know what happens.

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Post subject: Re: Reverb on my twin is lagging
Posted: Wed May 09, 2012 6:49 am
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I assume you already tried just reseating the cables that go from the amp to the reverb can. If the amp sat for a couple weeks sometimes moisture gets in there and causes bad connections. I have similar issues with my Pro Reverb and the cables going to the reverb can.


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