Tremolo clicking on silverface twin

Bandmaster, Bassman, Champ, Concert, Deluxe, Harvard, Princeton, Pro, Super, Tremolux, Twin, Vibrasonic, Vibrolux, Vibroverb and others

Tremolo clicking on silverface twin

Postby scooby on Mon Jul 14, 2008 2:04 pm

Does anyone know how to stop the tremolo from clicking when it's switched on? The speed of the clicking corresponds to the speed dial position.

Could it be a problem with the valve?

Thanks
scooby
Peasant
 
Posts: 35
Joined: Tue Aug 09, 2005 9:35 am
Location: Bristol, UK

Postby Baron Von Machinenmann on Mon Jul 14, 2008 3:10 pm

There's a Fender service bulletin on this from way back, it refers to "lead dress".

The official Fender solution (Service Bulletin number 9)
"The ticking caused by the Vibrato is caused by improper lead dress.

It can almost be "cured" by connecting a .01 mfd 600 volt mylar capacitor
on the 10 meg ohm resistor in the vibrato circuit. this resistor is located
on the parts panel. Remove capacitor across the 10 meg ohm resistor (old
modification) if in place."

(That is, run the cap from the junction of the 10 meg resistor and the
optoisolator to ground.)

"If this does not produce the desired results, then the leads should be
dressed as follows and excessive lengths shortened.

1. Dress the leads to the vibrato speed and intensity controls away from
the tone controls and filter leads.

2. "Bunch" the leads to the components on the parts panel which connect to
the tube socket of the 7025 (12AX7) vibrato tube."
ImageImageImage

John Lennon/Jimi Hendrix/Jimmy Page Fan
Baron Von Machinenmann
Administrator of Mirth
 
Posts: 17324
Joined: Sat Mar 08, 2003 8:01 am
Location: Central, New York

Postby chupy on Mon Jul 14, 2008 3:15 pm

Baron Von Machinenmann wrote:There's a Fender service bulletin on this from way back, it refers to "lead dress".

The official Fender solution (Service Bulletin number 9)
"The ticking caused by the Vibrato is caused by improper lead dress.

It can almost be "cured" by connecting a .01 mfd 600 volt mylar capacitor
on the 10 meg ohm resistor in the vibrato circuit. this resistor is located
on the parts panel. Remove capacitor across the 10 meg ohm resistor (old
modification) if in place."

(That is, run the cap from the junction of the 10 meg resistor and the
optoisolator to ground.)

"If this does not produce the desired results, then the leads should be
dressed as follows and excessive lengths shortened.

1. Dress the leads to the vibrato speed and intensity controls away from
the tone controls and filter leads.

2. "Bunch" the leads to the components on the parts panel which connect to
the tube socket of the 7025 (12AX7) vibrato tube."


WOW THANK YOU!! :rawk: I've never been able to figure this out. :oops: :lol:
chupy
 

Postby mxvin on Mon Jul 14, 2008 4:03 pm

I did the mod on my 74 DR....it actually works!!
mxvin
Certified
 
Posts: 155
Joined: Fri Aug 01, 2003 7:01 am

Postby Baron Von Machinenmann on Mon Jul 14, 2008 5:17 pm

99% of the time this relates to silver faces and sloppy wiring. None of my blackface amps ever did this.
ImageImageImage

John Lennon/Jimi Hendrix/Jimmy Page Fan
Baron Von Machinenmann
Administrator of Mirth
 
Posts: 17324
Joined: Sat Mar 08, 2003 8:01 am
Location: Central, New York

Postby Steve Gambrell on Mon Jul 14, 2008 5:20 pm

Yep, it's wiring. Something about the capacative reactance of the insulation. Hey, it's a Fender thang.
Steve Gambrell
Baron
 
Posts: 3329
Joined: Tue Sep 13, 2005 11:47 pm
Location: Home Sweet Carolina!

Postby Baron Von Machinenmann on Mon Jul 14, 2008 6:14 pm

Steve Gambrell wrote:Yep, it's wiring. Something about the capacative reactance of the insulation. Hey, it's a Fender thang.


Um,....no. :huh:

From a guy on another forum that knows these inside and out.

Most ticking comes from the tremolo oscillator being coupled into the reverb mixer at V4-B and is best addressed by lead dress. Pay special attention to the Pedal lead.

The Oscillator section, V5-A, cathode bypass cap is best located against the back wall of the chassis where it was found in the late 70's models!
ImageImageImage

John Lennon/Jimi Hendrix/Jimmy Page Fan
Baron Von Machinenmann
Administrator of Mirth
 
Posts: 17324
Joined: Sat Mar 08, 2003 8:01 am
Location: Central, New York

Postby Pacafeliz on Mon Jul 14, 2008 7:08 pm

Baron Von Machinenmann wrote:There's a Fender service bulletin on this from way back, it refers to "lead dress".

The official Fender solution (Service Bulletin number 9)
"The ticking caused by the Vibrato is caused by improper lead dress.

It can almost be "cured" by connecting a .01 mfd 600 volt mylar capacitor
on the 10 meg ohm resistor in the vibrato circuit. this resistor is located
on the parts panel. Remove capacitor across the 10 meg ohm resistor (old
modification) if in place."

(That is, run the cap from the junction of the 10 meg resistor and the
optoisolator to ground.)

"If this does not produce the desired results, then the leads should be
dressed as follows and excessive lengths shortened.

1. Dress the leads to the vibrato speed and intensity controls away from
the tone controls and filter leads.

2. "Bunch" the leads to the components on the parts panel which connect to
the tube socket of the 7025 (12AX7) vibrato tube."


cool sounds like a cool solution to the problem on my SF twin.
sad thing is, i don't understand a word what you're talking about... :oops:
oaklandanny too wrote:Pat...
This is way late in posting... but I want to say that she's beautiful, man!!! You are blessed and the world will be a better place because of your little girl. Mark my words... She will live in a better world than we live in now... because she will help change it. God bless!!!!

RIP OaklandDanny, thanks for EVERYTHING! God bless you, always!
Pacafeliz
King
 
Posts: 6967
Joined: Tue Feb 17, 2004 8:01 am
Location: Cologne, Germany

Postby Baron Von Machinenmann on Mon Jul 14, 2008 7:47 pm

It's not too complicated Pat, most of the time you only need to bundle and move the wires closer to the chassis. If you want to shoot me pics of your guts, I can circle the offending wires for you bro. :wink:
ImageImageImage

John Lennon/Jimi Hendrix/Jimmy Page Fan
Baron Von Machinenmann
Administrator of Mirth
 
Posts: 17324
Joined: Sat Mar 08, 2003 8:01 am
Location: Central, New York

Postby Steve Gambrell on Wed Jul 16, 2008 3:08 pm

Baron Von Machinenmann wrote:
Steve Gambrell wrote:Yep, it's wiring. Something about the capacative reactance of the insulation. Hey, it's a Fender thang.


Um,....no. :huh:

From a guy on another forum that knows these inside and out.

Most ticking comes from the tremolo oscillator being coupled into the reverb mixer at V4-B and is best addressed by lead dress. Pay special attention to the Pedal lead.

The Oscillator section, V5-A, cathode bypass cap is best located against the back wall of the chassis where it was found in the late 70's models!


I oversimplified things a bit. Of course the trem oscillator is the source of the "ticking," and I've heard it worse in some Fenders than others. Both my Voxes do the same thing, with the AC15 being the quietest.

Thank you for correcting me, Baron, Sir. May I have another :worry: ?
Steve Gambrell
Baron
 
Posts: 3329
Joined: Tue Sep 13, 2005 11:47 pm
Location: Home Sweet Carolina!

Postby chupy on Wed Jul 16, 2008 3:18 pm

Let's say the tremolo don't tick but works in a Bandmaster and a Pro Reverb, but fade's out after 15 minutes?
chupy
 

Postby Baron Von Machinenmann on Wed Jul 16, 2008 3:30 pm

Could be the roach assembly, possible cap issue etc.
ImageImageImage

John Lennon/Jimi Hendrix/Jimmy Page Fan
Baron Von Machinenmann
Administrator of Mirth
 
Posts: 17324
Joined: Sat Mar 08, 2003 8:01 am
Location: Central, New York

Postby The Pup on Sat Jul 19, 2008 1:24 am

From a previous post:

Some years ago service bulletin #9 was issued on the cure to ticking in the vibrato of older Fender amps. We still get calls on this so let’s review the solution here:

The vibrato consists of a photo-cell and a neon lamp held together by a piece of 0.025 heat shrinkable black tubing. One side of the photo-cell or LDR goes to a control
potentiometer and the other side goes to ground. One side of the NE-2 neon lamp goes to a 100K ohm resistor and the other side goes to a 10 meg ohm resistor (also tied to the
plate of the 12AX7 vibrato tube).

The solution calls for adding one capacitor and dressing the leads: Connect a 0.01 mf 600 volt mylar capacitor from the junction of the 10 megohm resistor (where it connects to the neon lamp on the eyelet board) to ground (where the LDR connects to ground also on the eyelet board). Dress the leads to the vibrato speed and intensity controls away from the tone controls and filter leads. Bunch together the leads connecting the components on the eyelet board to the tube socket of the 12AX7 vibrato tube.

Incidentally, the vibrato oscillator is a phase shift type oscillator that uses three capacitors between the plate and control grid of the first triode to shift the phase approximately 60 degrees each or 180 degrees in all to provide regenerative feedback for sustaining oscillation. These capacitors (usually one .02 mf and two .01 mf) have a higher incidence of failure than most of the other components in the vibrato circuit (outside of the tube). They should be checked or replaced right away if the circuit is not oscillating."
The Pup
Prince
 
Posts: 4132
Joined: Sat May 14, 2005 7:01 am

Re: Tremolo clicking on silverface twin

Postby Hiwatt Bob on Tue Feb 17, 2009 7:41 pm

ok--here's a pic of my DR--can someone point out on this pic where (and how) to 'dress the leads'? i'm 99% sure i know what caps to replace to slow it down.

..yes--the previous owner went ape with the silicone. :Doh:

again--the help is much appreciated.

Image
http://www.myspace.com/rygiboges

'72 Hiwatt DR504
'79 Hiwatt FL112
'76 Fender Deluxe Reverb
Zvex Nano
Hiwatt Bob
Baron
 
Posts: 2089
Joined: Fri Jun 11, 2004 7:01 am
Location: here and there

Re: Tremolo clicking on silverface twin

Postby supershifter2 on Thu Oct 20, 2016 9:58 am

Old thread but same problem. I have a 72 SF Twin reverb no master v , AA270 circuit. Ticking vibrato so I installed a .01uf 630V mylar cap across the 10m resistor. Ticking is not as loud now. I'm going to try a .022uf cap as per the 73-up with MV and boost schematic. Another problem I would like to fix is the hum when reverb and vibrato are switched on at the same time. Anyone have any ideas about getting rid of that hum ?
supershifter2
Peasant
 
Posts: 8
Joined: Thu Apr 17, 2014 10:26 am

Next

Return to Fender

Who is online

Users browsing this forum: No registered users and 4 guests