Thunder 1 with Reverb, What tubes are recommended

dogman

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I am thinking about retubeing my Thunder 1 Reverb and am a little overwelmed with the options out there. I know that there are those here that can give me pros and cons on different Tube makes. All the help will be appreciated. Thanks in advance.
dogman
 

capnjuan

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Hi Dogman; first off, you should contact our member Coastie99 via PM using this link to his member's page. He has a stash of 6GW8s and 6BM8s; I know he'd be glad to help you out. The T1 RVT has two 12AX7s in the preamp, two 6GW8s for primary output, a 12AX7 and a 6BM8 in the reverb amp, and a 6CA4 rectifier.

6GW8s: they have been out of production for some time and are only available as either NOS or used. The 6BM8 has been brought back by Electro-Harmonix and is available new if Coastie can't make you happy. These two tubes types were developed in Europe for the post-war table radio market; both types are two tubes in one bottle ... a triode section like 1/2 of a 12AX7 and a pentode section used for output. US manufacturers fooled around with both but none of the domestic stuff can touch Siemens / Telefunken / Mullard / Amperex / Tungsram for tone. I don't know what Coastie has in his stash but these makes are the top of the food chain for both types.

12AX7s: there are as many fans (and detractors) of new ones as there are brands of new ones. The NOS/used Euros - see list above - command the big prices ... $75 and up ... followed by '50s/'60s RCA black plates for $45-$60. If you have the money, you should consider putting some of it into one really good 12AX7 for V1 - the first preamp tube. If you have any money left, the next chunk should go into the reverb 12AX7, and whatever's left into V2 which in that amp, is more of a worker bee. Finally if you like bottom-fishing, there are hundreds of good-sounding, low-mileage GE, Sylvania, and RCA gray-plates on eBay for $10-$15. You can get 5 of them for what 3 new 12AX7s cost increasing your odds of getting several inexpensive, good-sounding keepers in the group.

The rectifier tube is inexpensive and widely available: 6CA4

As far as new tubes go, I had good results tubing up a Gibson GA18 preamp with a pair of premium gold pin JJs; musical, articulate, but a little bright to my ears ... a condition I fixed by putting a new JJ 12AT7 in V1 ... I thought they were worth the money. Good luck with you amp.
 

dogman

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Capn, thanks for the info. I appreciate all the help now and in the past, you always have some great advice. I will PM coastie99 and see what he has to offer.
 

capnjuan

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Hi Dogman; I've exchanged emails with Coastie and the member to whom ... as it turns out ... he sold most of his stash of 6GW8s. That member is fishing through what he has to see what he might could do.

The 6GW8s are going the way of the 7027, 8417, 7189 ... This is the results of an eBay Search for 6GW8s and, as you can see, the pickings are getting pretty slim. The only pair currently being offer are described by the seller as: "These tubes test on the low side of good as well as in the "?" category in my Hickok 600A. They are perfectly serviceable." With all due respect to the seller, it isn't clear how the tubes can test "?" and still be " ... perfectly serviceable ...".

Other possible sources for 6GW8s ... and ... they need to be reasonably well-matched:
http://www.kcanostubes.com/
https://www.tubeworld.com/index_high.htm
http://www.tubedepot.com/nos-6gw8.html

Several times, our member default and I have discussed the ins and outs of re-wiring the tube sockets on T1 / T1 RVTs to accept 6BM8s which, by itself, is simple enough but neither of us have found any reliable information on the 6GW8's Zout or Load Resistance ... it might or might not be the same as the 6BM8. If not, the original Guild output transformer might not work very well with 6BM8s ... if at all. Finally, there's the issue of re-setting the bias or idle current.

So ... something that at first seems as simple as just moving some tube socket connections around ... well ... could turn into a big can of worms.

Anyway, I hope you can find something suitable.
 

coastie99

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And, regretfully, Coastie can be of no help.

I searched last night, and found no tubes among my collection. Seems that, after sending a selection to the afore-mentioned member, I sold the remainder locally.

Sorry I can't be of assistance Dogman.

If I had a firm assurance from T1 owners that they would buy any tubes I could find here, I'd keep an eye on our NZ version of Ebay. These tubes come up for sale every-so-often, and are priced cheaper than ones I've seen on Ebay.

http://www.trademe.co.nz/Electronics-ph ... 573396.htm
 

taabru45

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I wish I'd a bought a few cases of those tube things when I was in my 20s, and they were about a buck apiece..... :shock: :lol: Steffan
 

zulu

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the hitherto unidentified aforementioned member zulu has a few sets of 6GW8 tubes, but is in the process of having them tested. Best case scenario is that they all test good, and I might part with a pair. :idea: All of us who have been ECL eighty sixed out of the tube market should keep a eye out and perhaps make a post if some valves show up on the market.

I'm currently running ruby tubes for the 12ax7 duties and am happy, but would love to try some boutique preamp tubes someday.
 

Ian

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Might be handy if you could let us know what the equivalent valve designations might be. I have a fair stock of old ECL82's and loads of small signal valves of the ECC83/82/81 variety. I'm not wanting to sell the lot by any means, but I might be able to help someone out if they were after something special. As an aside, I also used to be in the Hifi business so have a few contacts about the traps with good valve stocks, so if I havent got it I may be able to point you in the right direction.

Cheers, Ian
 

coastie99

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guitardude said:
Might be handy if you could let us know what the equivalent valve designations might be. I have a fair stock of old ECL82's and loads of small signal valves of the ECC83/82/81 variety. I'm not wanting to sell the lot by any means, but I might be able to help someone out if they were after something special. As an aside, I also used to be in the Hifi business so have a few contacts about the traps with good valve stocks, so if I havent got it I may be able to point you in the right direction.

Cheers, Ian

Gidday Ian, from just down the road.

I'm in the process right now of building a Gibson GA8T ( ECL82-powered ) clone. I could certainly use some nice Mullards or Telefunkens if you have some please.

Hope all is well with you, and you've come to grips with the condition.

Cheers, Gary.
 

Ian

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Hi Coastie,

PM sent and I promise to have a better look through at the weekend when the light is better...

Might I suggest red painted ping pong balls tied on with string to confuse the iroquois ?

Cheers, Ian
 

coastie99

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guitardude said:
Hi Coastie,

PM sent and I promise to have a better look through at the weekend when the light is better...

Might I suggest red painted ping pong balls tied on with string to confuse the iroquois ?

Cheers, Ian

I use brown paper packages tied up with string.

Recommended by Julie Undrawers.
 
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