Opinions on my Guild Thunder 1 Twin

Hi. I just won a Guild Thunder 1 Twin on an ebay auction for $150 (here is the link: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0266240387). From what I've read, the Thunder 1 Twin has better bass response and an overall better tone than the one speaker models.. has anyone had the chance to A/B the 1x10" and 2x10" versions?

Thanks,
-Adam

Hi Adam, welcome, and congratulations on your new amp. I've never A/B'd the two speaker layouts but maybe someone else has. CJ

Adam, you might not want to post your email in plain text for spam harvester reasons.
I haven't heard a T-1 with 2-10's either. I'm looking forward to your impressions when you get it.

It looked like a fine amp - I'll be interested to hear your impressions. I was sorely tempted - that was a GREAT price if it all works - but I just couldn't justify it.

I've just put up a post Oh The Tone - overamped and underskilled, that's me.

Hope the T1 Twin is perfect for you.

I'v had just about every type and combination of Thunder 1 made over the years including access to a friends T1-Twin. I would rate the Twin superior sounding and the best of the non reverb models. The T1 RTV's reverb is the best sounding of the thunder series but if I had a shot at a T1-Twin or T1 I would definitly grab the T1-Twin. The T1-Twin was the last model T-1 offered by Guild and became available later 1967/early 1968 as Guild changed from Beige tolex back to Black tolex covered amps. GG Jaguar's web site has a description and illustration of the Twin and standard T1.

http://www.ggjaguar.com/t1s.htm

M

I just got it in the mail. Everything works, and I'm happy with the purchase. It isn't as smooth as my other amps, but it has a cool dark, creepy kind of tone, which works well with my type of playing.. i haven't tried any pedals out yet, but look forward to how it reacts to distortion pedals; i know that my chorus pedals will sound killer through it.. I'm not impressed with it's tremolo effect.

-adam

Hi Adam79 and congratulations on your new-to-you amp. Considering that the amp is nearly 40 years old, it's something of an accomplishment if it works at all. The tremolo function in your amp relies on capacitors and resistors that, unless it's been serviced recently, are just as old as the amp.

The tremolo is functioning when the amp is turned on; when you 'turn on' the tremolo, you unground its function. That means that the passive components that provide the oscillation have been working since the amp was first turned on and are approaching the end of their useful lives, as is the shiny aluminum cylinder thing sticking straight down from the chassis; the multi-section can capacitor.

The most common cause of crappy tremolo is/are the tremolo capacitors that should be changed when the power and bias supply filter caps are changed. If you want a schematic for it, PM with your email address and I'll shoot it out to you but, without some bench time, your amp will never work at or near its optimum. The trem thing is a pretty easy fix. Good luck! CJ

Good ifo capn. I need to develop better tech servicing skill if I am going to hold on to Guild amps and survive to talk about them.

adam79,

Most people who try the tremelo on a Guild amps say it is superior in tone to most other brands. all my amps have working tremelos and I haven't ran into a Thunder 1 that didn't work. However I have heard of few reports of tremelo issues. If you like tremelo you may want to get your unit serviced. One other item may be considered before servicing. If the tremelo effect is low someone may have turned down the "strength". On T1 amps you only have a ON/OFF switch to activate the tremelo. Their is not Strength control. However if you look inside the amp under the chassis you will see a hole with a screwdrive adjustable POT. You may try adjusting this little attenuator to increase the strength of the tremelo. (Note: On the Thunder 1 amps with reverb Guild added a seperate panel control to adjust the strength of the tremelo.)

Check out my version of the "twin" in this auction. (For some reason no one other than non-payers are interested in this amp?!)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MESELX:IT&item=300268230256

M

matsickma said:

Check out my version of the "twin" in this auction. (For some reason no one other than non-payers are interested in this amp?!)

Click to expand...

In your auction you write: "For auction is a Guild Thunder amp. The amplifier has been modified to accommodate a 15 inch speaker. This amp was assembled from a T1-12 amp section and installed in a T1-Twin cabinet."

What is a T1-12 amp section, and why did you need to use is for the amp tweak?

thanks,
-adam

Hi. My amp came with the original 10" CTS speakers. Has anyone switched to ceramic speakers and gotten a warmer tone? What would be the replacement speaker of choice in your opinions? Also, same goes with the tubes? What were the amp's original stock tubes? As with the speaker, is there any recommendation on upgrading to a better quality tube, or are the stock ones already considered to be good? Oh yeah, one more question.. what is the purpose for the line polarity switch on the back? and which spot should it be set to? up or down?

Thanks for all the help,
-Adam

Hi Adam; PM sent re/ the schematic. If you have CTS speakers identifiable by their original plastic bells or, if gone, square, flat magnets about a 1/2" thick and bear 137 as the three leading digits in their EIA code, they are ceramic.

Your amp runs 6GW8 tubes; similiar only to, but not directly replaceable by, 6BM8s; both are an unusual combination of triode and pentode sections in the same bottle. There are new old stock (NOS) domestic 6GW8s however this tube was chosen by Guild as much for its operational characteristics as sound quality. Coastie, one of our BB members, has a considerable stash of 6GW8s - if you want to do a little 'tube rolling', he'd be the man to get in touch with. I happen to know that he has pair of killer Tungsram 6GW8s ... but assuming he'd let them go, it might cost you several cases of Heinekens (called 'boxes' where he lives).

If you like the amp and 'tube rolling' doesn't get you what you want, you might consider contacting another BBer, 'default', and talk to him about re-wiring your output sockets for 6BM8s. The 6BM8 is back in production from Electro Harmonix and there are really great-sounding used Euro versions of this tube available; Amperex, Tungsram, Mullard, and Telefunken. There are also Euro 6GW8s (although fewer of them) which, to my ear, are more pleasing than domestic ones. However to use 6BM8s in the Thunder amps, there are 4 wires on each output tube socket that have to be relocated. If I had a Thunder series amp, I probably wouldn't hesitate to make this change.

If you have a 3-wire power cord, the polarity switch doesn't matter; in fact it should be disconnected altogether. If you don't have a 3-wire power cord, for safety's sake, that's next on your list. Polarity switches are left over from the days of ungrounded (2-wire) house and commerical power wiring; if it hummed in one position, it was switched to the other to kill the hum instead of yanking the plug from the wall and turning it over.

On the speakers, since my interests run to farty old box amps with alnico speakers, I don't have any suggestions. But if it were my amp, I'd tug the speakers out and check the cones for rips, tears, holes or general softening ... they can get limp as paper towels. Good luck! CJ

Hi Adam.

Nice score! I also picked up a T-1 Twin on eBay a few weeks ago, but not nearly as nice, and no speakers.

After getting the schematic from capnjuan, I spent a week cleaning it up. New power switch, new 3 wire power cord, ditched the polarity switch/death cap, new filter caps and two Celestion Vintage 10's. After reading up on this amp, I was concerned about it sounding sterile. Boy howdy, was I wrong. With a Les Paul plugged into the Hi Gain input and the volume dimed, I'm sounding like Mick Ronson/Hang On To Yourself! This amp smokes (in a real good way). The Normal input is warmer and rounder, but still breaks up nicely when dimed.

The only complaint I have is that the Tremolo is too fast, even on the slowest setting. It also takes about 10 seconds for the high voltage secondary to come up, and that's the AC B+ at pin 1 or 7 of the rectifier socket with the 6CA4 out. I don't know if this is a design feature of the power transformer, or if it's on the way out. Regardless, your gonna love your T-1 Twin.

As a side note, your filter cap section consists of a single 50uF cap, and a 4 x 40uF multi cap can. The cap can is usually pretty expensive, when you can find it, but Antique Radio Supply (tubesandmore.com) has new production, Mallory design 4 x 40uF cap cans on sale til the end of November. This is a direct replacement for the one in your amp, so you might want to jump on this. If your Twin is totally stock, you're gonna need one of these. Enjoy your Twin!

"If I were Brittania, I'd waive the rules" -Budgie

powdog said:

The only complaint I have is that the Tremolo is too fast, even on the slowest setting.

Click to expand...

Hi PD; the lowest speed is governed by the caps in the oscillator circuit and, no, I don't know cap-for-cap what you might change however I lurk and post on Plexi Palace / Vintage Amps and Music Electronics Forum where there are helpful, knowledgeable people. The speed question comes up frequently and there is alot of interest in slowing them down. Either of these BBs might have a thread on the subject and, if not, you can ask the question.

powdog said:

It also takes about 10 seconds for the high voltage secondary to come up, and that's the AC B+ at pin 1 or 7 of the rectifier socket with the 6CA4 out.

Click to expand...

Interesting ... what do you read for secondary AC voltages; pin 1 to ground, pin 7 to ground? Does the transformer get hot or smelly? Act quirky in any other respect? :? :? CJ

Just a note that the 40/40/40/40 cap has a max voltage of 350v. Too low for anything but the table-radio-tube amps.

I payed $200 (after shipping) on ebay for my T1-Twin. I'd love to switch out the CTS speakers for a pair of Celestion Vintage 10s, but they're $100 each and are 60 watts per speaker (I think the amp is only 12 or 15 watts!), but I don't have the money. I bought the amp as a practice amp for my bedroom, and demo recordings. I have no knowledge about fixing amps, so if I decided to get work done on this amp, I'm looking at $70/hr in labor fees.
How dangerous is it to use the amp with it's original 2 prong plug?

Thanks,
-Adam

Hi Adam:
Power cord: Let's look at this from the risk/reward side of things. Let's say the cord, installed, is $100. If you don't spend the money you are $100 ahead. Although the chance of a worst-case occurence is small, the outcome can be deadly which is to say that you've put a price of $100 on your life ... so if the worst happens and you say Hi to St Peter (not Townsend), you can always say: "yeah but I still have the $100 in my pocket".

Depending on how tooly you are, you could leave it alone if you can run a wire, firmly attached to the metal chassis, to the little screw in the center of your electrical outlet's wall plate. That provides a resistance-free path to ground for fault currents. If this is really a near-term choice between a cord and speakers ... well ... unless getting new speakers is going to achieve something substantial ... like sex with the prom queen ... or a record contract ... there really is no choice here. Suitable cords are $10-$15 all over the web. Anybody can do it; appliance or TV repair shop, Circuit City .... it doesn't have to be your local amp shop.

Speaking of speakers: https://taweber.powweb.com/weber/, on the left click Signature, scroll to 10" ceramic; two models for $30 plus shipping. IMO and for the money, these are better speakers than the Jensen reissues. You are correct, you don't need 60w speakers; the Webers are 20-25 watts ... not to mention that isn't a Marshall stack you have there. Good luck, CJ

Truly - even a true klutz like me can swap out a non-grounded for a grounded cord - and even if you have to hire someone, it might be $50. Hard to see how a comparable difference in tone for a $50 speaker upgrade can be in the same league.

john_kidder said:

Truly - even a true klutz like me can swap out a non-grounded for a grounded cord - and even if you have to hire someone, it might be $50. Hard to see how a comparable difference in tone for a $50 speaker upgrade can be in the same league.

Click to expand...

are you talking about swapping out the 2 prong chord for a 3 prong one? if so, are there any "how to" type things on how to do this?

thanks.

Hi Adam; Do you have a soldering iron? Are you comfortable using it? if not, got a friend who is?

capnjuan said:

Hi Adam; Do you have a soldering iron? Are you comfortable using it? if not, got a friend who is?

Click to expand...

yep, i got one. when you connect the chord to the amp does the 3 prong cable connect the same way as the two prong one, or do you need to install more parts to make the connection capable of powering the 3 prong? Sorry if my lingo is off, I'm just not familiar with fixing amps.

for right now, I'l gonna hold my breath and play the amp with the original chord, connected to a surge protector instead of straight into the wall jack, if that even makes a difference..?

thanks,
-adam