6GW8 tubes Guild Thunder 1 amp?

[Boss]

Hi friends,

I went ahead and broke my cardinal rule of no tube amps a couple weeks back. I found a really clean, beautiful sounding circa 1966 Guild Thunder 1 amp.

She’s the 10” speaker/tremolo model, no reverb.

I’m using the amp for my solo jazz guitar gigs with my 1963 Artist Award, Delia. The tone is nice and full but too bright so I am turning the treble to 0 and the bass to 10. Last week it started rattling, almost as if the aluminum case around one of the tubes was vibrating.

My amp guy tells me it’s likely one of the 6GW8 tubes has gone microphonic (I haven’t brought it down to him to check out yet).

Now for the part why I hate tubes amps…these tubes are no longer manufactured and cost about $60 apiece.

Does anyone know a good source where I can get at least two, preferably four so I can have some on hand?

Follow up point, I will probably be replacing the original CTS Custom speaker with a brand new Eminence 10”. This one is in pristine condition and it looks like they go for a nice price on eBay. Is anyone looking for one and would like to buy it?

Thanks,
Charlie

 

[Boss]

Here is the speaker.

 

[Boss]

And here’s Eleanora (named after Billie Holiday).

 

[Default]

Try some silicone rings around the tubes, and see if that helps, but it is what it is.

 

[hearth_man]

I would check with vacuuntubes.net for better pricing.

 

[hearth_man]

Fat fingers... "Vacuumtubes.net"

Once you use a tube amp you can't go back. ICs and software driven modeling are amazing but they will never be a vacuum tube only circuit.

 

[jp]

If you're patient, you can usually score on eBay. My Rivera Super Champ uses a 6C10 which has become extremely expensive and rare. However, with some patience, I've been able to buy some NOSs for reasonable prices.

Of course, you do have to use discretion when deciding who to buy from. There are a lot of tube scammers, but with good judgment you can score enough at decent prices to keep yourself stocked. If you're lucky enough to grab a few RCAs or military JANs, you'll seldom need to change.

 

[Rambozo96]

Sounds like the same power tubes my Bogens use. I honestly don’t know why they’re so expensive. I didn’t think they were in high demand but anyway with those it is a waiting game as far as getting replacements for a decent price.

 

[Default]

They were generally used in HiFi equipment, so H.H. Scott and others used them predominantly.
There is no direct substitute for them. I have a chassis from a T-1 that is destined to be a rewire to el84s, but that will involve extensive rewiring and punching another socket, and I have too many projects already.

 

[Boss]

Well then here is another can of worms, after I get this tube problem fixed.

My model year omitted the tremolo depth pot (which was mounted on the back of the chassis for some reason, not in the face of the amp).

Does anyone have an idea what it would take to wire that circuit into my amp?

 

[mavuser]

Hi Charlie, those are the reverb tubes for Guild Maverick and Thunderstar amps. but in those amps u just need one of them. in the Thunder 1, u need a matched pair. def not so easy these days.

I have at least one vintage 6GW8 that is virtually NOS. I may have a second. but, I paid market value for them. ( they are sylvania and mullards). not really what u wanted to hear.

Something else u didn't want to hear, is...if u are looking to get into tube amps, and u are not happy w the T1 exactly the way it is right now, get that thing functional the way it is, bring it to Guitar Center, and use it as trade in credit for a brand new Fender laquered tweed pro Jr, or laquered tweed blues Jr. , and dont look back. they are made in Mexico, and are total sleeper amps. the non-tweed pro and blues jrs are also fantastic amps. but those laquered tweed ones are the deluxe (inside and out), and much more of a vintage (warm and punchy) tone.

but if u insist on chasing the Thunder 1, and bringing it to it's former glory/maximum potential (whatever that actually is, I have no idea...), I would keep an antennae up for any Guild amp that uses those tubes, and acquire them, and share tubes among the amps.
i'd be into parting ways with my maverick, especially since u are in NYC...which has all NOS Tubes, and some extras like i mentioned. as well as new (jensen) & original (cts) speakers. and new (accutronics) and original reverb tanks (i like the original better on the mav). with all of that and the Thunder 1 u would be good for a long time (probably for your lifetime), since they both have 10" speakers and then u would also have all of those tubes. i actually think u messaged me about the Maverick amp a while back. got a guitar to trade for it?

by the way great video on FB the other day! (the Guild hollow body unplugged on the porch). u were shreddin!

 

[mavuser]

also are u sure it is the tube, and not just the tube sockets? your amp guy and Default here at LTG would definitely know better than me. either way, those tubes are definitely discontinued with no reissues.

 

[Boss]

Wow man, thanks for all the tips, and glad you liked the video. We definitely should connect sometime, I have a ton of stuff booked now including my weekly gig at the restaurant in Brooklyn. Can you message me on Facebook or is there a private message function here on the forum?

 

[Boss]

I hear what you’re saying about buying an amp for spare parts. But if I acquire another amp right now it better be big enough for me to live in because the Mrs. is not having it! She’s already furious about the giant Model 3 I got a few months back!

it is definitely not compatible with my Brooklyn apartment lifestyle.

 

[mavuser]

it is definitely not compatible with my Brooklyn apartment lifestyle.

That's why I left the Thunderbird off my list of 6GW8 Guild amps!

 

[Default]

Well then here is another can of worms, after I get this tube problem fixed.

My model year omitted the tremolo depth pot (which was mounted on the back of the chassis for some reason, not in the face of the amp).

Does anyone have an idea what it would take to wire that circuit into my amp?

It's not omitted, these are the way the T-1 is designed. It's supposed to be "set and forget". The Thunder-1 RVT DOES have depth, but that amp is another beast.
I don't know why they chose to do that, but there were more than a few companies that wired their practice amps that way. (Looking at you, Gibson)

 

[fronobulax]

Can you message me on Facebook or is there a private message function here on the forum?

They are called "conversations" and you can start one by clicking on the name in an avatar and then Start Conversation.

 

[powdog]

If you run a jumper wire to pins 1 and 8 on the power tube sockets you can run a 6CZ5 or a 6CM6 tube with no other mods to the amp. You can still run the 6973 tubes too. Electro Harmonix makes new 6973s but they don’t sound like the RCAs.

 

[Default]

No, you absolutely can't. The 6GW8 is a dual triode/pentode tube. A 6CM6 is a pentode. You must be thinking of the 7189.

 

[powdog]

My apologies. I was indeed thinking of the 6CZ5 which is similar to a 6973 pentode. My Thunder 1 does run a pair of 6GW8s, I’ve just always referred to them as ECL86s. I must have had Valco on the brain.
Cheers.