Other Amps

I’m gonna make a Supro!

1

The thread on amp kits put me onto the Watts site - whoever linked to that THANKS! It's odd - I had seen that site before about a week earlier when looking for cloth covered wire, but not really looked at the kits.

Anyway, I just ordered one of these: http://tubeamplifierparts.c...

A Supro 24 style amp. It seems to have most of the parts I would have chosen myself. The only things I might have changed are the pots (I like PEC) and the coupling caps (I like Sozo over Mallory). But I think I'll just build it the way it comes. Original Supro amps are a rarity where I live so this will be interesting to try.

Has anyone else tried the Supro 24 kit?

2

Jimmy, please post a build thread for us geeks!

3

Least we know they'll be built much better than the originals!

4

That's a good choice... I still say 1960-1966 Supro sounded damn near as good as Fender.

5

Haha! Well ok, I will post some pics as i go. I have emailed them to find out how wide the chassis is. I wonder if I have a cab which it might fit?

I don't really need any more amps, but I thought the price seemed reasonable and I just love to build an amp. I have never played a Supro, so I won't be able to comment on how authentic the tone is. But I can take it into my local guitar shop and compare it with the new ones when it's built i guess. Never used those power tubes before either.

6

Oooh this looks like fun. Enjoy the build!

7

You might want to convert this to use 6V6 power tubes instead of 6973. Finding decent 6973 power tubes is a real headache these days. Vintage ones cost $50 a piece. The modern Electro Harmonix one positively suck. You'd probably have to order 6V6 sockets and rewire things a bit at the sockets.

Before you scream "Heresy!" be aware that there are adaptors available so you can run 6973 tubes on a 6V6....but not the opposite. So making the amp able to run 6V6 power tubes will make your life easier and more versatile without burning any bridges.

http://www.ebay.com/itm/ONE...

9

Well that sucks! I have EH tubes on the way. I have only used their 12ax7s before - and that was briefly. Before they crapped out. EH = Sovtek anyway.

I am looking forward to hearing the 6973 - that was part of the appeal of building this amp. The kit hasn't arrived yet. Living in Australia makes these things take ages, but then I have grown good at waiting. I already have 6V6 amps - in fact I have been playing my beefed up tweed Deluxe a lot lately as it's such a sweet sounding amp.

Buying NOS these days is such a crapshoot.

10

The Electro Harmonix 6973 seems to me to be some Russian tube designed for some purpose other than audio that was found to be able to tolerate the higher plate voltages so it's on spec. But they sound very muddy and dull in my Magnatones. Vintage 6973 tubes like the RCA sound great but are so expensive. In my opinion they aren't THAt different than more common EL84 or 6V6 in terms of sound to be worth the trouble in a guitar amp (hi fi audio might be a different story)

You might be able to get by with 6CZ5 power tubes in this amp given the plate voltages on that schematic. They're still pretty cheap NOS and sound great.

6CZ5 tubes have the same pin out as 6973 but can only handle around 350 volts on the plates...maybe 375. (A 6973 was designed to handle 450v) Your schematic calls for 350v 6CZ5 tubes were used in Magnatones at 375v with no issues so you could be o.k. with these. They cost about $20 online NOS.

6CZ5 tubes are often marketed as a "fake 6973" or a "6973 substitute"

http://www.ebay.com/itm/Pai...

Personally though I'd probably just rewire the power tube sockets to take EL84 tubes and be done with it. I think EL84 tubes sound great.

11

BTW if you wanted to convert this to EL84 you basically just have to solder 4 wires to different pins on both power tube sockets:

instead of pin 3/6 connect that wire to pin 2

Instead of pin 7, connect that wire to pin 3

Instead of pin 9 connect that wire to pin 7

Instead of pin 1 connect that wire to pin 9

Leave the filament wires as they are.

And that's pretty much all there is to it.

12

Thanks GC - really appreciate it. I used to think EL84s were thin sounding. But then I had a Badcat Cub IIR for a while and that changed my mind big time! I have built amps with El84s before, so I'm getting an idea of what they can do.


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