It is currently Mon Mar 16, 2020 10:50 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 191 posts ]  Go to page Previous  1 ... 6, 7, 8, 9, 10, 11, 12, 13  Next
Go to page Previous  1 ... 6, 7, 8, 9, 10, 11, 12, 13  Next
Author Message
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Tue Jun 07, 2016 11:24 pm
Offline
Professional Musician
Professional Musician

Joined: Tue Nov 27, 2012 6:56 am
Posts: 1677
Location: Coastal Bend, Tx.
From the old GT web site, the Fender labeled tubes were color coded based on output rating.
Blue = GT 1-3 range
White = GT 4-7 range
Red = GT 8-10 range
You may be right about the 1980-90's GT tubes being the final US tube production leftovers, I was in a different world those days. The KY plant quit producing tubes in early 85 when GE sold the equipment, etc to GT . The new owners produce radar, fuses, BAC equipment. I haven't researched anything from the Canadian GE plant.
The Soul of tone referenced the GT tubes Fender acquired for the custom shop line of amps in 2003. I couldn't narrow down a date when Fender started to label tubes, if I were to guess it would be after the CBS acquisition.
I have no doubt the GE employees at US/Canadian plants and elsewhere were more highly skilled craftsmen at tube production than any Chinese worker may ever be.
Appreciate the insight, thanks.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Sun Jul 17, 2016 7:49 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
Hey Beemer
Thought you might want to know this.
I put the new rectifier 5V4G in the Super with a close matched pair of vintage RCA's 8)
I have them running within 1.5 ma of each other.

Funny thing is I had to add treble to my EQ after removing the old Mullard and those fender labeled GE's

Image

Pretty sure your dead right about the new Rectifier being a relabeled Mullard GZ34, nearly exact same running specs and it even has the hole in the centering pin 8)

Thank you again !!!

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Mon Jul 18, 2016 6:58 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Glad the Philips is working well. It's a Sylvania design. Very good tube. You may hear some change in tone in first few weeks of use. When I put one into my DR, the tone actually sounded brighter, than the Mullard GZ34 that was in the amp. The tone kinda mellowed out a bit, after a week of regular use.

The Philips-Sylvania (USA) design are known to last as long as the Mullard-Philips design (European).

Good to have some other options for the GZ34/5AR4. Good NOS Mullard GZ34 are outrageously $$$, these days.


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Mon Jul 18, 2016 7:13 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
I suppose the swapping out the GE for the RCA's at the same time makes comparison of the two rectifiers kinda difficult.
But my treble went up a full # at first and then Two as I played it more and my Tone is Sweet warm and smooth !

What more can ya ask for ???

Not sitting in with a band yet so I can't say how well it will cut through the mix, hopefully before the summer is gone I'll have a chance or two, I certainly have the Clean headroom and power to smooth out wrinkles at 30 paces LOL !!!! :lol:

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Last edited by blues bondsman on Mon Jul 18, 2016 10:32 am, edited 1 time in total.

Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Mon Jul 18, 2016 8:15 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Chris,

Ok. That makes sense. GE 6L6GC are super tough tubes (not that the RCA are wimps.) :lol:
They have a "tight" sound initially. Not the "relaxed" mids-high response as a blackplate RCA, out of the box. They will relax after much use (like over a month of regular use).

As for rectifiers. IMHO, they make-or-break the consistency and reliability of any amp (hi-fi or guitar). The last 5-10 years, I scour the Net for good ones. Have a pretty nice supply of 5Y3GT types, 5U4GB, and GZ34/5AR4, now.

Just got a nice deal on some mil spec 6-volt Raytheon 6X5WGT. And some Mullard EZ80s. Hard to make any tube driven unit reliable without a good rectifier. Or one needs to convert to solid-state and lose some of the tube magic.

Image

Image


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Sun Sep 18, 2016 10:55 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
Following up on the new rectifier from Beemer
Still sounds oh so sweet !
Have yet to check the bias again, but it sounds perfect !!!

I'll check bias some time in the next week and see how close to the original setting with the new rectifier.

New job has me running around like a crazy man, not much time to chat here sadly.
Had all my buddies come get their amps due to no time and that made me fairly unpopular
oh well

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Sun Sep 18, 2016 5:36 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Chris,

Thanks, for the follow-up. I've replaced 4 or 5 amps with the Philips-ECG mil spec 5AR4 (marked 5V4GA). All work fine. Same voltages as Sylvania 5AR4. I've sold six to others that have either guitar or hi-fi amps. No problems. Seem to be sturdy and reliable. A heck of a lot cheaper that US made 5AR4-labeled rectifiers. And European GZ34.

Have a good Sunday Night!


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Tue Oct 11, 2016 3:19 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
And then................................
All of the sudden I have white noise from my sweet amp :cry:
The amp has to be over 2 on the volume to overcome it, it is there with no cords attached reverb unplugged etc.....
No tubes appear to be microphonic, just the sound of a TV tuned to a non existent station with the volume up, however it's there even with my amp volume at zero on both channels.
Man you all know whats next right ? a long messy search for a carbon comp that's toasted, a bad lead that somehow crossed to close to high voltage or a ceramic cap that is failing.
All new electrolytics as far as I remember, and then the fact that it just started all of the sudden.

I do so love to tinker and make these old beast's sound great but I just don't have the time I used to.

PS all pots checked for noise while moving back and forth and Notta !
V-4 was a touch scratchy when tapped, nothing too serious.

Sadly she is my one and only amp right now, wish I had a Blues jr or the like to play while she is down :roll:

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Wed Oct 12, 2016 12:31 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
May want to try contact cleaner on the sockets, tube pins, and jacks. Just a little. I like Deoxit.

Could be the 12AT7 phase inverter tube is bad. You have another 12AT7 to try out?

Good luck! Keep us posted.


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Wed Oct 12, 2016 4:06 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
I swapped out the 12ax7's without any change and yes I do have a stash of 12at7's.

I'm stuck in meetings all day today, I'll give it a try tonight.

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Wed Oct 12, 2016 6:55 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Chris,

Good luck! :)


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Thu Oct 13, 2016 3:13 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
After much tube swapping and testing I started eliminating tubes one at a time
V-1 pulled = still white noise
V-2 pulled (v-1 returned) = white noise
V-3 = same (with v-2 returned)
V-4 = Jackpot ! zero noise

Somewhere in V-4's circuit is a bad carbon comp (guessing at this point) Really bad I'm guessing.

Thanks as always to Beemer for the offline help and coaching.

Time to pull the chassis and start check'n it out.

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Thu Oct 13, 2016 3:23 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Fender straps the two 12AT7 anode halves together and runs the tube hard. Like close to 15mA limit, on idle bias. Good to use a tough mil spec type 12AT7. I like the Sylvania 12AT7WA (or -WC).

http://tctubes.com/Sylvania-JAN-12AT7WC.aspx


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Thu Oct 13, 2016 3:35 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Tue Jul 17, 2007 3:08 pm
Posts: 2889
I found a good 12AT7 for v-3
The noise didn't go away till I pulled V-4 so.................

But anyway, I'll pull the chassis soon and start checking for duds

_________________
Keepn' the Blues Alive

2004 50th Ann. Limited edition AMSE Stratocaster
2017 50's Baja Telecaster BSB

1968 Bandmaster with 2X12 cab C-rex speakers
VHT Special 6 Ultra combo

Visual Sound Route 66
Cmatmods Signa Drive


Top
Profile
Post subject: Re: Road worn 1974 Super Reverb restoration
Posted: Thu Oct 13, 2016 3:59 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Chris,

Good you got it down to one section. Noise could also come from V5 (7025, 12AX7). Reverb recovery tube.

Cables between the amp and tank, too! (I know you already knew that --- posted for reader's sake).

Also, for those hunting down noisy resistors and cold solder joints --- this sometimes help narrow down those areas. Spray on specific components and listen for changes in noise levels.

https://www.amazon.com/MG-Chemicals-Sup ... super+cold

:)


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 191 posts ]  Go to page Previous  1 ... 6, 7, 8, 9, 10, 11, 12, 13  Next
Go to page Previous  1 ... 6, 7, 8, 9, 10, 11, 12, 13  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: