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N(DOA)FRVD (it lives! sorta...)
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BluesmanDave



Joined: 17 Nov 2008
Posts: 2815
Location: Sacramento CA

PostPosted: Thu Jan 21, 2016 12:17 pm    Post subject: N(DOA)FRVD (it lives! sorta...) Reply with quote

New DOA Fender Reverb Day!

So there was a west coast blues player named Steve Samuels, who was famous for playing really killer guitar despite having only 1.5 arms. He played with William Clarke for a while, released a good solo record, and then kinda disappeared into personal problems.

Steve with William Clarke
His solo album Saturday Night Blues

He passed away last year, and his sister has his gear up for sale in a local music shop. Among other items were his constantly-rebuilt, rebodied-at-least-once Danelectro, his Brownface 3x10 Bandmaster, and this:







I've wanted one of these for years, not least because of Steve, along with Hollywood Fats. I finally asked the guy who runs the shop to plug it in - dead. We tested the fuse - it was fine. I had to go, so I told him to throw the sister a lowball offer, just to see what would happen. She took it.

SO! Now I get to see if I can bring it back to life! (Before I cry uncle and take it to my tech this weekend, anyway.) The pilot light and fuse are good, there's power to the onboard accessories jack, which is in parallel with the power transformer - that makes me think the power transformer is cooked. I haven't actually put a meter on it to see if it's generating current. Anything else y'all would suggest checking while I'm in there?
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Last edited by BluesmanDave on Fri Jan 22, 2016 10:40 am; edited 1 time in total
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Bootsypratt



Joined: 01 Dec 2006
Posts: 1236
Location: Columbia, SC

PostPosted: Thu Jan 21, 2016 12:42 pm    Post subject: Reply with quote

No tubes?
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BluesmanDave



Joined: 17 Nov 2008
Posts: 2815
Location: Sacramento CA

PostPosted: Thu Jan 21, 2016 2:28 pm    Post subject: Reply with quote

Bootsypratt wrote:
No tubes?


Tubes! There's a 12AX7 (a new Groove Tubes rebrand of something overseas), a 12AT7, and a 6K6 (which is right behind the divider in the back panel). The schematic number is 6G15. This is the layout this one has.


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Last edited by BluesmanDave on Wed Feb 03, 2016 12:28 am; edited 1 time in total
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RolandR



Joined: 03 Sep 2003
Posts: 8908
Location: Coastal Calif.

PostPosted: Thu Jan 21, 2016 5:24 pm    Post subject: Reply with quote

Hope you get it working. It's nice. Very Happy

Just curious, do you plug that Fender reverb unit between your guitar in front the amp or can you plug it through an effect loop assuming you have a modern amp with an effect loop?

Which would perform better?

p.s. I know nothing about stomp boxes. All my amps (tubes) are either cranked up or have "cascading" preamp tube sections.
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BluesmanDave



Joined: 17 Nov 2008
Posts: 2815
Location: Sacramento CA

PostPosted: Thu Jan 21, 2016 5:40 pm    Post subject: Reply with quote

RolandR wrote:
Hope you get it working. It's nice. Very Happy

Just curious, do you plug that Fender reverb unit between your guitar in front the amp or can you plug it through an effect loop assuming you have a modern amp with an effect loop?

Which would perform better?


It's designed to be run in front of an amp. Sounds like it could be run in an effects loop without damage, but it's not meant to be. Plus, it predates effects loops by about a decade. Here's how Fender explains it in their literature for the reissue version:

Quote:
The ‘63 Fender Reverb is designed to go between a low level instrument (such as a guitar) and a high input impedance amplifier (such as any Fender tube amplifier or the high sensitivity input on any Fender solid-state amplifier). It should be used only with the clean channel of the amplifier as distorted reverb sounds very unnatural. If you want to use the ‘63 Fender Reverb with high gain or distortion, you may use either a distortion pedal inserted before the Reverb Unit or connect the Reverb Unit in the effects loop of the amplifier and use the high gain/distortion channel of the amplifier. However, since most of the sonic benefits of the ‘63 Fender Reverb result from the fact that the reverb signal is generated before the tone controls and preamp gain circuitry of the amplifier, we do not recommend using it in the effects loop.

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tangelolemon



Joined: 26 Jan 2009
Posts: 2691
Location: Brooklyn, NY

PostPosted: Thu Jan 21, 2016 5:58 pm    Post subject: Reply with quote

try replacing the rectifier diodes
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Old Black



Joined: 18 Jan 2006
Posts: 1975
Location: Minneapolis

PostPosted: Fri Jan 22, 2016 10:11 am    Post subject: Reply with quote

I built that circuit a few years ago (married to a brown vibrato circuit). Those units do more than just add reverb - they color the sound nicely with subtle harmonic distortion.
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BluesmanDave



Joined: 17 Nov 2008
Posts: 2815
Location: Sacramento CA

PostPosted: Fri Jan 22, 2016 10:39 am    Post subject: Reply with quote

OK! I got it up and running - turns out the culprit was a badly corroded on-off switch. Thank you, DeOxIt D5! While I was in there, I cleaned all the jacks, pots, and RCA connectors to and from the tank. Now it seems as though I have a bad tank. With all the controls absolutely dimed, I get a very subtle slapback echo - like the transducer on the front end of the spring is trying but not succeeding. To test the hypothesis, I ran the RCA leads to a known good reverb tank (of entirely the wrong kind) and it works perfectly. Any thoughts as to troubleshooting or repairing the pan itself?
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Mr. Clevername



Joined: 08 Dec 2006
Posts: 2448
Location: San Francisco, CA

PostPosted: Fri Jan 22, 2016 12:56 pm    Post subject: Reply with quote

Open up the pan and check the wires from the springs - they are subject to metal fatigue but seemed easy to fix when I watched an experienced tech do it. At least that's what I remember . . .
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BluesmanDave



Joined: 17 Nov 2008
Posts: 2815
Location: Sacramento CA

PostPosted: Fri Jan 22, 2016 2:01 pm    Post subject: Reply with quote

Mr. Clevername wrote:
Open up the pan and check the wires from the springs - they are subject to metal fatigue but seemed easy to fix when I watched an experienced tech do it. At least that's what I remember . . .


Are you talking about the wires to and from the transducers and the RCA jacks?
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tangelolemon



Joined: 26 Jan 2009
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Location: Brooklyn, NY

PostPosted: Fri Jan 22, 2016 5:56 pm    Post subject: Reply with quote

yes, exactly. If it's the original Gibbs-Hammond tank it's really worth trying to repair, as the modern replacements from MOD, accutronics, etc. aren't quite the same.
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Mr. Clevername



Joined: 08 Dec 2006
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Location: San Francisco, CA

PostPosted: Sat Jan 23, 2016 11:30 am    Post subject: Reply with quote

Yup - I'd also clean and tighten up the jacks.
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BluesmanDave



Joined: 17 Nov 2008
Posts: 2815
Location: Sacramento CA

PostPosted: Sat Jan 23, 2016 11:52 am    Post subject: Reply with quote

I have continuity at both jacks, the resistance numbers are what they should be for each. I can get it to make noise if I "tickle the springs," I can even get it to make noise if it's hooked up backward, so both the transducers are working. The whole unit works fine with another tank hooked up. It's as if there's something mechanically wrong. I'm stumped.
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jaybones



Joined: 22 Mar 2014
Posts: 426

PostPosted: Sat Jan 23, 2016 3:20 pm    Post subject: Reply with quote

How do the springs look? I had an amp rebuilt, and 2 of the 3 springs were broken. I had no idea that the amp wasn't performing as well as it was supposed to.

When I got it back, I turned it on the first time and the sigh or cough of the springs warming up was way more pronounced than it was before. And my normal reverb settings were way higher than I needed them now.

Turns out all 3 of the springs had been replaced with brand new ones.

Not to be insulting, but I'm sure if a spring was broken you'd notice it.
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tangelolemon



Joined: 26 Jan 2009
Posts: 2691
Location: Brooklyn, NY

PostPosted: Sat Jan 23, 2016 7:26 pm    Post subject: Reply with quote

i once was stumped similarly with the onboard reverb on an old Twin.

Turned out that it was a bad reverb cable. When you tried the new tank, did you use the same cables, or did the tables go with the substitute tank?

Also, never underestimate the havoc that corrosion on a connection can have!
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