To 'Bay or not to 'Bay: Thunderbird Auction

capnjuan

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matsickma said:
The first two Guild Thunderbird amp models and the Superbird amps did not install a reverb "pan" in the cabinet as is done on most amps. Instead they installed a reverb "tray" up inside the amp housing. Ok, now I get it; on the 'inside'.
You can purchase reverb pans or trays today form Sound Enhancment Products, Inc. Guild used Gibbs reverb units... The people at Sound Enhancment Products can usually crossreference a Accutronics unit for many Gibbs units. Tried it with them on the T1 RVT can ID; clearly marked - they were stumped...they wanted input/output impedance...over my head.

PICS_120504051.jpg


This looks like the 'pan' in the back of my parent's 1963 Dodge.M
Thank you Mike, most helpful. J
 

capnjuan

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gilded said:
A) The 15" is a '67, not a '57 (as the Seller believes). Nice catch!
P / Q / R.. Isn't this Jensen-speak for voice-coil size like Weber w/ it's 100 = one inch, 125 = 1 1/4", 150 = 1 1/2"?
A 'senior member'... Yup, getting the impression I'm older than nearly everyone here ... not that great a feeling reallly...as I understand it, the 'S' only means the speaker came from a large lot; it's suggestive of the possibility that the Jensen 'standard spec' whatever that was, might have been watered down a bit to accomodate a 'wholesale' transaction.
Combined with a 15" size, that might not sound ... Probably not terrible, maybe good, but not the best 15" speaker you ever heard ... At the risk of sounding like a weenie, I'd almost want to hear any 40 year-old 15" speaker before I bought it; I threw out a Magnavox last year; the cone had degenerated to the consistency of a paper towel; that's a lot of acreage to absorb moisture.
The 'silver' 8" Jensen...Wonder what the ohm rating is? ...It would be a 4 ohm speak if it came out of a Champ. I was told over on the Gear Page to follow the 1/2-double rule; if an OT is looking for 8ohms, no less the 4 or more than 16...if looking for a 4ohm load, no more than 8; if looking for 16, then no less than 8ohms.
Wonder what kind of ohm load the amp is seeing from those 8" speaks? 4ohms?
The CTS speaker looks just like the one in my Thunder 1 RVT. Worth keeping.
I wonder if it's been cut a bit short and will always show the edge of the baffle on the sides? Will take some skill to pull original cloth and replace; must allow a little space for cloth on edges of new baffle.
I'd leave the plywood baffle-board in place, because it might help keep the crumbly Particle-board cab together....some water damage in a corner, right? That could be really bad in shipping, right? Yes and yes.
There's no telling what's going on in the reverb section. It might be simple, it might not. See matsickma's post; might not be that bad.
Power Transformer...the paint is dripping off the trannie...Now, I just suspect 'foul play'. Old age breeds fear and paranoia, don't it?? Old age and exposed to being hosed on deBay.
I'm out on this amp but not because of any concerns with it; it has all the risks associated with an older amp - I mean all the stuff we been talking about is the same stuff faced with every old amp. I'm informed and relieved by Mike's post re/ location of 'pan' - that the amp, other than the whippy dippy with the speakers, hasn't been 'Farmered'. cj
 

capnjuan

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john_kidder said:
On the other hand the Captain has been expressing a desire for a Tbird. John
Thanks John but sitting this one out; not because of make / model / or this particular TBird but still fidgeting w/ Maggie M10A an hour away in Ft Lauderdale - see discussion and link to vids in post by Default/Steve ... the vibrato thing makes them amps that sing and dance. Annnnd, a lot to be said for bypassing the shipping thingie...
J
 

gilded

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Nope, I'm out, too.

I think my limit was gonna be 200-ish anyway, not for any T-bird, but for that T-Bird. I was trying to factor in the extra $$$ on shipping and the 'never gonna be original' deduction.....

One thing that worries me about the speaker load on the 2 8" speakers is the possibility of a mismatch, like one speaker with 4 ohms and one with 8 ohms.

A 'P' designation on a Jensen ain't bad, but I don't know the exact wattage they're built to handle. 20-25 watts, maybe?
I would think the Voice Coil dimension would be 1.5", but maybe it's more. The 'back side' of the cone doesn't look bad in the pics, but there is nothing about this amp that says, "hey, I'm fine just the way I am.
 

matsickma

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Hi John,

The addition of the 2nd 8 inch speaker does drop the load down to 4 Ohms. With a solidstate amp that would improve the outpower power of the amp. With a tube amp the output transformer, tapped for 8 Ohms, will now have an impedance mismatch so you would not get the full benefit of power transfer to the 8 inch speakers. I suspect it will be somewhat louder with the pair but not 2x the power. I forget the relationship between Power and Loudness but a 2 dB change in Loudness is on the threshold of human perceptability. A power change of 2 is 3 dB. However I am not sure if Loudness is on the same scale as Power. (Sorry my rarely used college EE and acoustics training is making this a complicated chat.) Typically you do not want to have a different speaker load from the transformer load or you can damage the output transformer. I would be concerned about this on the higher power side of the amp but suspect that even with the mismatch the low powered reverb output amp would not generated enough heat to melt the wire shellac insulation or iron core lamination of the transformer.

Interestingly, I had been considering modifying a T1RVT with the addition of 15 inch speaker. I did it to a T1 Twin "Baby Bass" and liked the result. I anticipated having to replace the 8 inch with a 5 inch or smaller. I certaintly like the configuration of the Thunderbird.

I am considering being in the auction only because I am to busy to start another project (i.e., the existing list is already pretty long).

M
 

john_kidder

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matsickma said:
I am considering being in the auction

That'll be your firm "considering" there. Nicely done. We'll all await reports about the reverb mystery, even though I'm sure you nailed it for us earlier.

I have mentioned already to the seller that he'll need to be really careful in shipping - viz that area in the lower left of the cabinet that seems to have been wet at one time. Get it home safe.

Cheers,
 

capnjuan

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He did more than 'consider' it John; he won it.

matsickma( 412) US $360.00 Sep-22-07 13:03:22 PDT

Congrats Mike; we're gonna be all over ya for report! Kings X on the shipping.

Best regards,

John
 

gilded

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Congrats, hope it works out real well for you!

Harry (aka gilded)
 

matsickma

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I sent the seller my standard set of instructions on how to pack the Thunderbird. I told them I will make payment after they acknowledge my instruction and either confirm my technique or tell me theirs.

In any event I'll keep you informed.

I need another Thunderbird Amp like a hole in the head but I am very interested in how this amp will sound.

The biggest problem I find with the Thunder early series Thunderbird amps is the microphonicness of the amp in the cabinet. This amp would probably do better with external speakers.

Here is a question: What Guild amp do you think is the most rare of them all? (I'll provide my un-scientific study answer after I receive some of your inputs. I am basing my answer on the fact that i have NEVER seen one.)

M
 

john_kidder

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matsickma said:
sent the seller my standard set of instructions on how to pack the Thunderbird.

  • We could all probably use them. Feel like passing them along here?

The biggest problem I find with the Thunder early series Thunderbird amps is the microphonicness of the amp in the cabinet. This amp would probably do better with external speakers.
  • 've noticed that as well - there is a noticeable reduction in feedback/microphonicness (is that a word?) when I run the Thunderbird main out to a 2x10 cabinet

We are all eager to hear your review of the new "farmered" amp.
 

capnjuan

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'The farmer in the dell, the farmer in the dell... '
 

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matsickma said:
Here is a question: What Guild amp do you think is the most rare of them all? (I'll provide my un-scientific study answer after I receive some of your inputs. I am basing my answer on the fact that i have NEVER seen one.)

M

My vote would be for the SuperBird. I've only seen it in an advertisement.

Howard
 

matsickma

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Hi All,

I have been busy and out of touch for a while. I'll respond to a few post I left open inthe next day or so.

I received the farmed-out Thunderbird on Friday. I was going away for the weekend so had limited time with it.

First off the packing was performed as I asked so the amp arrived in tact. I provide info on packing technique win a follow up. However, the ON/OFF and BtandyBY switches got broken off. :cry: . One thing I noticed about this amp before I bought it was that it had the origional switches. That isn't to common. Well I got to deal with that for now.

I'll follow up with more info.

Mike
 

capnjuan

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'Farmed out'... :lol: glad to hear it got there in one piece!
John
 

matsickma

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OK. Here is an update on the farmed Thunderbird amp...

I received the amp with the origional plastic toggle switched broken off. It took a while but I finally goy some $ consideration from the sell to fix the broken switches. With that out of the way I started messing around with the amp. I got it working by drilling little holes in the switch stubs and used a nail as a lever to turn the switch on.

I was pleasently suprised at the tone of this amp with the 15 inch Jensen. The speaker is very bright and full sounding. The speaker breaks up a bit making the amp very blues sounding. The reverb works ok but is a little swnsitive to cabinet vibraton. When I pull the amp housing out to repair the switches I check to see if the reverb tray is isolated properly from the amp. Overall I am very happy with the tone. I am disappointed with the switches breaking. Most of these amps come with replaced switches-now I know why.

Finally, the issue with wood filings on the bottom of the speaker cabinet is not due to the replcement of the front speaker baffel board for the 15 inch speaker. Rather it is due to the particle board bottom board beginning to decompose. Tis is the bane od these amps. I may put a coat of polyurethane on the cabinet particle board to keep it from flaking. I may also reinforce it.

M
 
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