Why Is The Supro Thunderbolt Considered A Great Amp?

[rp]

I've encountered a lot of old amps in my past, never came across a Thunderbolt. I know the Page Hendrix history/myth but looking at the schematic I see a dull low gain amp. I know it was designed way back when as a bass amp but that could be said of the Fender Bassmans but they were designed for gain and weren't lame for guitar. The preamp cathode resistors are very high here (though fully bypassed) the second stage has 270K for the plate which ups the gain a bit I guess, and it has a paraphrase which is its acclaim to some. Half the tweed Fenders have a paraphrase and people don't overly worship those. And, it has an unused triode and we know how popular that is around here

Page and Hendrix would sound great plugged into a clock radio. Anyone own/owned one? Built one? What's the big deal, or no big deal?

[tubeswell]

I built a clone circuit of the '65 (tube rectified) version with a 12" speaker and a few refinements (switchable single-parallel v1 and a James TB tonestack) and it sounds pretty cool I think.

The schematic:

[img724]https://farm4.staticflickr.com/3707/954 ... 3b68_b.jpg[/img]

The amp is the one in the natural woodgrain combo cab in this pic

[img768]https://farm9.staticflickr.com/8463/837 ... 7198_b.jpg[/img]

It sounds quite primitive bluesy with a little weber speaker. With a simple voltage tweak (bypassing the last 100k supply resistor in to V1 with a jumper), its more like a TV front fender. My own sound byte ('Bustin Surfbards') is attached.

There's a couple of sounds of a real t-bolt here

http://www.youtube.com/watch?v=NRAJqdZcz5k

[TUBEDUDE]

That Supro sounds mighty sweet to me.

[M Fowler]

Pete the T-Bolt sounds good

[rp]

Tubeswell, I didn't think to first check youtube. I does have a nice cheap amp 'hollow' sound. So much so I thought you might be using a thinline, like a Casino or a Granada. The you tube vid brought the same thing to mind, your cleans are better. Maybe the nice clear surf lines? Maybe the 'verb? Reverb is like frying, everything tastes good when it's fried. You also goosed up the front end. I thought of that too but if I start improving it I'll just wind up with a mid 50's Tweed.

I checked an other vid too, no sustain to the thing, that also has it's appeal, part of the hollow sound. I wouldn't call it an awesome must have in your quiver of collectables, sounds like pretty much any cheap vintage amp. If I had the parts around I'd likely do it but otherwise, I'm not sure it's worth the cost of a set of trannies to build one. Plus I get the feeling I'd have to build a 1X15 cab with a very thin baffle and find a Jensen P15Q to get it right. Too much work.

I missed the 100K at the end of the power string, that and the lack of cap on the output bias also add to the lameness looking at the schematic. Bet that latter is the biggest part of the bouncy hollowness. Did you try bypassing the cathode power resistor? Bet that 'ruined' it - made it sound like most other amps.

Beats me, I never did meet a vintage tube amp of any sort that didn't have at least one cool tone in it, I guess the Thunderbolt just fits in to that.

[martin manning]

I think the Thunderbolt is said to be a great amp because for a while people believed Jimmy Page used one to record a lot of early LZ. It's now believed that it was another Supro amp that he used, model number unknown, with a replacement speaker. http://www.gibson.com/en-us/lifestyle/p ... mmy-pages/

[10thTx]

I think this is a pretty decent Supro Thunderbolt video:

http://www.youtube.com/watch?v=bHU8uspH30w

With respect, 10thtx

[ampmike]

Yea,That was cool,That amp sounded nice and did get a nice Led Zep tone,Got to keep a eye out!!

[rp]

Saw that vid too. It sounds ok, I thought the distortion tone was better on the tubeswell vid link. Given the supposed (early pre UK) Hendrix, Page, Brian Setzer provenance I thought maybe a one trick pony but it must have a killer early rock sound. I've heard amazing sounding little Supros, Valcos, I just figured the Thunderbolt was the Holy Grail of the lot. Meh.

I bet the 5B6 running right betters it. Guarantee any Tweed Super or Pro slays it clean or dirty.

[wyatt]

I restored two, didn't care for either.

Big, bland and thumpy sounding and when it do overdrive it was stiff. Many of the others I talked to who bought or built one agree (nor did they like theirs). Ted Weber figured maybe it would appeal to a surf player. Most do not sound as LZ as one of those Youtube videos.

One of mine did find a home with a pro player though and it had a high-profile TV appearance.

[tubeswell]

Did you try bypassing the cathode power resistor? Bet that 'ruined' it - made it sound like most other amps.

Yeah I did bypass the RK on the big bottles and it sounds a lot rockier and has more power.

(FWIW I was using a plain ole strat for the surfbards tune)

As for the 'goosing up', one may be left wondering what to do with the extra triode. This way I could flick back to a single triode in V1 by plugging it into the right jack. (And the low impedance from the parallels triodes is better for driving the TB tonestack)

What I can say is that with the big bottle bypassed and the 100k supply resistor bypassed, it is a very loud clean amp, and I'm surprised by the extent to which the PI is balanced. (Different from the tv-front fenders)

Clean sound attached with bypassed big bottles

[BIG Dave]

There is one currently for sale on the Boston Craigslist. Seller is "accepting offers".

http://boston.craigslist.org/gbs/msg/4339613213.html

[teemuk]

It's kinda like those little Pignoses. HUGE roster of famous guitarists recording influental albums using them in the studio although they had just two tones: Super quiet clean and ratty distortion that actually still blends quite nicely to certain type of music.

So yeah, if you dig hard enough and have the chops there's some greatness to it. Of course it helps when you happen to be Clapton or Frank Zappa.

Would I buy that Pignose? HELL NO! It's a one-trick-pony toy that doesn't do anything a decent new amp couldn't do much better. But they did make some history 40 years ago, if you value that stuff over everything else that influences decision to buy certain gear.

[rp]

Clean sound attached with bypassed big bottles

That sounds way better, fuller, more oomph, but looses some of the woody hollowness, which had its charm too. I'm still not convinced it's worth cloning, I think the 5B6 would be more useful - if that's the right word for any of these relics.

[tubeswell]

If ya build it yourself, its not a relic (unless you 'relic' it these days)