73 Quad Reverb 100w. 'Restoration' into a head cab

Fender Amp Discussion

Moderators: pompeiisneaks, Structo, mhuss, HeeBGB

Post Reply
tubeswell
Posts: 2098
Joined: Thu Mar 27, 2008 6:42 am
Location: Wellington. NZ

73 Quad Reverb 100w. 'Restoration' into a head cab

Post by tubeswell » Wed Nov 29, 2017 4:25 am

Scored a 73 100W QR chassis/amp for very cheap. Trannies and Chassis date to late-ish October 1973.

Been gradually working on it over the last month. The insides have been badly mucked around with. The main (wax-impregnated) board has numerous band-aid components jumped off the board. I may yet re-do the main board with new board material, once I've tested it fully. Someone had installed a PPMIV at some stage in the past. The filter caps were still all original. I've since changed them, along with all the electrolytics. The OT Pr:Sec VAC checks out okay.

One of the 6L6 sockets had a blown 1R cathode resistor. I suspected something dodgy about this socket, so decided to replace all the 6L6 sockets and install new grid and screen resistors etc before test-firing. I reused the old wires and old tube clamps for mojo.

Someone has upped the bias supply with a small bucking transformer. It supplies the requisite DC but the workmanship is appalling. I will re-do this to with a 'stock' BF bias

The old lamp holder looked suspicious - someone had disconnected it and the contacts looked charred. I've fitted a new lamp holder and reconnected it.

The blown tube, reconfigured bias, and the disconnected Lamp point to previous power supply issues. Could be something dodgy may've happened with the PT. It checks out okay on a mains VAC test. However, the acid test for the PT will be with a new quad of 6L6s. I'll get around to that next week. Even if I have to replace the PT, it will have been a good score methinks

I spent today tolexing a DIY head cab for it. Going to run it with my 76 DSR cab (loaded with 2 x 15" orange-frame 'bels).
You do not have the required permissions to view the files attached to this post.
He who dies with the most tubes... wins

User avatar
drew
Posts: 438
Joined: Wed Jun 21, 2006 2:49 am

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by drew » Wed Nov 29, 2017 8:48 am

These were like a Twin Reverb but with four 12" speakers? What a back breaker.

tubeswell
Posts: 2098
Joined: Thu Mar 27, 2008 6:42 am
Location: Wellington. NZ

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by tubeswell » Wed Nov 29, 2017 9:32 am

Yeah the 100W Super Six Reverb, 100W Twin Reverb, 100W Quad Reverb, 100 W Bassman Reverb, 100W Vibrasonic Reverb and 100W Dual Showman Reverb from the same era, all used basically the same amp, same chassis, same boards/parts, same trannies etc, but with different faceplates, and combinations of speakers/cab configurations. (The Super Six and Vibrasonic used different OTs, but the OT for all the others is the same AFAICT. I measured the VAC ratio on this and it gives 2k5 plate to plate with a 4R speaker load). The chassis I picked up was sans cab and speakers, so I decided it'd be easier to make a head cab out of it. I already have a mid-70s DSR cab with 2 x Orange-frame D130F all set up for 4R that I will run this with.
He who dies with the most tubes... wins

User avatar
jjman
Posts: 721
Joined: Sat Oct 06, 2007 2:33 pm
Location: Central NJ USA

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by jjman » Thu Nov 30, 2017 1:29 am

tubeswell wrote:
Wed Nov 29, 2017 9:32 am
Yeah the 100W Super Six Reverb, 100W Twin Reverb, 100W Quad Reverb, 100 W Bassman Reverb, 100W Vibrasonic Reverb and 100W Dual Showman Reverb from the same era, all used basically the same amp, same chassis, same boards/parts, same trannies etc, but with different faceplates, and combinations of speakers/cab configurations. ..........
Some pretty rare amps there. Intact Quads very rare. And the elusive Bassman Reverb...... Good luck finding one of those!
If it says "Vintage" on it, -it isn't.

tubeswell
Posts: 2098
Joined: Thu Mar 27, 2008 6:42 am
Location: Wellington. NZ

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by tubeswell » Thu Nov 30, 2017 3:41 am

Cab's just about finished - awaiting SF grille fabric and fender 73 logo.
You do not have the required permissions to view the files attached to this post.
He who dies with the most tubes... wins

Paulg
Posts: 1
Joined: Mon Jul 31, 2017 2:31 am

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by Paulg » Wed Dec 06, 2017 3:31 am

good call!

User avatar
M Fowler
Posts: 12893
Joined: Wed Jan 16, 2008 2:19 am
Location: Moorhead MN

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by M Fowler » Wed Dec 06, 2017 2:34 pm

Good job Pete I have an old Bassman to recover.

tubeswell
Posts: 2098
Joined: Thu Mar 27, 2008 6:42 am
Location: Wellington. NZ

Re: 73 Quad Reverb 100w. 'Restoration' into a head cab

Post by tubeswell » Wed Dec 06, 2017 11:17 pm

Thanks Mark. I must admit applying tolex isn't my favourite job. I tend to get a bit impatient with the gluing. Having a lino roller/brayer is essential.
He who dies with the most tubes... wins

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests