Scott 510 amplifier chassis into Fender 5D5 Pro

[Diverted]

A good friend gave me a sweet early 50s Scott 510 radio with separate amplifier running push pull 6L6s. Since the voltages are very close to early Fender Pro designs, I decided to turn the amp chassis into a 5D5 clone. Glad I did: What a great amp!
The dark channel is so buttery and full, and the bright crisp and clean. It breaks up great at around 6 to 7 on the dial.
I was thinking about using the project to try a bunch of different mods but i think I'm going to leave the circuit 100 percent stock. I love it!

Ted

[Jazz P Bass]

Says a lot for HH Scott.

That is one beautiful wiring job on the chassis.

[Diverted]

Says a lot for HH Scott.

That is one beautiful wiring job on the chassis.

Thanks! All wiring was gutted and re-done by me. Not much left of the original Scott wiring.
It was a fun chassis to modify. Lots of room under there. The only things I had to do other than rewire were to install an octal socket where one of the filter caps was original, and go with a 5Y3 rectifier instead of the 5U4 called for by Fender. Also swapped out the octal preamp and phase splitter sockets to nine-pin sockets. While I could have kept the octals in place I would have had to buy three 6SC7s, which would have cost me $200 for three good glass ones. I have a billion 12AX7 and 12AY7s laying around so it was just easier (plus later variants of the 5D5 use mini preamp/PI tubes instead of Octals, so it's historically accurate).
Mounted the filter caps on top of the chassis also, and wired in a 6.3v bucking transformer (at bottom of wiring photo) to help keep the power transformer cool and bring voltages down almost to spec. Closed in on spec'd voltages further by putting a CL80 current inrush resistor in the AC line. Nice quiet amp with plenty of growl and some SWEET dark tones. I am currently running it with a 12" Celestion G12 Vintage 30.

Here's a before shot of the chassis.

[mozz]

HH Scott collectors will be furious. Being a collector of old tube radios myself, and a amp builder, i still would not have touched that chassis to mod it. Chances are you could have gotten some decent $$ selling it outright, and had some cash to build a 5d5 on a tweed style chassis. Just my opinion.

[nosaj]

HH Scott collectors will be furious. Being a collector of old tube radios myself, and a amp builder, i still would not have touched that chassis to mod it. Chances are you could have gotten some decent $$ selling it outright, and had some cash to build a 5d5 on a tweed style chassis. Just my opinion.

Well He still has the radio portion of it . I wouldn't have either, but I don't think twice about doing it to an organ because it's going to the dump anyways might as well get some use from it is my thinking. Somebody is always gonna be mad at someone because they didn't get it first.

nosaj

[bob p]

Nice build. Congrats on the successful tone quest.

I'm assuming that the big power resistor mounted on the right side of the chassis is cathode bias for the output stage. If that's right, then where's the cathode bypass cap hiding? I don't recognize it in the photo.

Another thought regarding the output -- I see that you've got spliced wires on both OT secondary leads. Just as a matter of anal-retentiveness, it might not be a bad idea to slide some HST over those splices to eliminate the remote possibility of a short due to wire movement. To me it's sort of a best-practices sort of thing to cover all splices with HST and all bare wires on long airborne leads with spaghetti.

On a related note, lately I've been thinking about which Celestion I might pair with a 5E5-A build. I'm wondering if you've tried anything other than the Vintage 30, as I'm looking for something a little less aggressive for jazz, but not totally dark sounding. I'm leaning towards AlNiCo, though I don't want something harsh on top, and the Golds can get that way. I've been thinking about the Cream 90 which is reportedly tighter on the low end and smoother on top.

[bob p]

HH Scott collectors will be furious.

My how times change. I have no qualms about what the OP did. In the old days we used to heap praise on members for these sorts of re-purposing builds. It used to be a rite of passage. It's how most of us earned our Official Ampage Secret Decoder Ring. But now we've got people chastising someone for doing exactly the type of thing that got this board going back in the old days. I shudder to think that now we have to fear the Scott-Nazis over things like this.

IMO Diverted should be rewarded with an Official Ampage Secret Decoder Ring.



Welcome to Captain Tboy's Secret Squadron!

[mozz]

"But now we've got people chastising someone for doing exactly the type of thing that got this board going back in the old days." ????

I chastised someone when i directly stated it was my opinion? You really need to take a reading comprehension course or something, get the bug out of your ass.

Next build he may even ask a collector if there's any value before jumping in. Being that you are so old and never made mistakes and never will, tell us about the old days when you re-purposed tube amps along with Al Gore starting the internet.

I just see it as " Oh man, you should have left that old Scott alone", I'll mail you a Philco cathedral to sacrifice.

[Diverted]

Radio receiver had a fried oscillator coil. No cabinet ...
I'm keeping it, never selling it and it will do me more good this way. Finding a cabinet for it would be a stretch, and I don't have the room for one either with a Magnavox Concert Grand and Windsor in my living room.
Sounds better now than it would have sititng in my basement on a shelf

[bob p]

No justification of your actions is necessary. You don't owe anyone anything. That Scott amp is your property and you did what was necessary to make it most useful to you. It looks like you got a nice result. Congrats on a nice build.

> it will do me more good this way

That's all that really matters.

[Diverted]

Thanks. It's a great little amplifier.

For what it's worth to those who mentioned Scott collectors. This is/was NOT an HH Scott amp. I have one (299C) and they are different beasts entirely. Scott Radio Labs built this amp. SRL had been known for making very high end sets in the mid to late 30s, like the beautiful Philharmonics and All Waves (which I would love to own). By the time this was built the company'd changed hands. They're decent sets but the styling is pretty bland in that late 40s/50s kind of way. Here's something I found online:

E.H. Scott Radio Laboratories was changed to Scott Radio Laboratories shortly after WWII when taken over by Hal Darr. In April 1950 the Scott Radio Laboratories were acquired and run by John Meck until receivership in 1956. Over the next few years the Scott Radio Laboratories name traded hands and appeared on a few high fidelity components before HH Scott filed a lawsuit ending the use of the Scott Radio Laboratories name. The Herman Hosmer Scott company was not related to the Scott Radio Laboratories although the latter purchased a license from the former to include their dynamic noise suppresor in Scott Radio Laboratories products.

[Diverted]

HI, yes. The finned resistor is the cathode resistor. I didn't have any 10w 250 ohmers lying around, but had this 50w finned so I used it. The cathode bypass cap is the fourth cap on the 40/20/20/20 500v cap you can't see, hidden under the bucking transformer. The power rail in the 5D5 only uses three high voltage filters (40/20/20) so the fourth was unused. Figured I'd use it for the bypass and ground it at the can, and save space on the circuit board. So I pulled it off the board before I laid out the rivets and cut it.

Yes, I have spliced wires I've gone in and heatshrink-wrapped them. Thanks.

Sorry, don't have any experience with the Cream, but I do love the Celestion. The highs are smooth and the bass is nice and buttery full but defined. I think it's a pretty awesome speaker for this and holds up well when you start getting into heavy breakup.

[Diverted]

Thanks for your perspective Mozz. Had this been an HH Scott, in a cab, complete without a fried coil and the correct speaker, it'd be playing in my living room now. However it is NOT an HH Scott amplifier.
Actually, it still is playing in my living room now, just in a different form I'm fine with that, don't feel like I've destroyed a particularly valuable, heavily collectible or rare set, and am glad that I've given it new life instead of a long nap in a cardboard box. Everyone has different opinions and their own idea of the right way to do things, and there's no absolute wrongs or rights.
As for building a chassis in a tweed-style amp, I have plenty of combo units. When I build I like to do things differently and I'm a fan of building one-off amp heads for around the house (they won't be gigged with). Here's a shot of a little amp I built in a vintage "vibration analyzer" I found on eBay. Hope the vibration analyzer collector/purists don't come after me now
Only kidding. Happy New Year.

[Diverted]

HH Scott collectors will be furious.

This is not an HH Scott-built amp.

[Diverted]

Im honored to accept my own Ampage Secret Decoder Ring!