These are some pics of my work to repair and refurbish a 1965-1967 Guild Thunder 1 RVT. Some revisions were made to these amps while they were in production; cabinet details, chassis backpanel, and maybe electronics. 2X12AX7 pre-amp, 2X6GW8 outputs and 6CA4 rectifier. The stand-alone reverb amp has a 12AX7 and a 6BM8 output; and a pretty fine reverb it is; nicely variable although not as 'wet' as some others. When new, my copy looked more or less like this one with 'ears' on the upper front edges of the cabinet and, as matsickma described it, the 'fishscale' grillcloth.
I bought it on eBay as a 'project'; as some of us have learned :evil: , there are projects and then there are projects. I ranted before about it but, in short (pun intended) it was DOA as (1) one of the multi-section caps had leaked electrolytic paste on the chassis (2) the pins of the rectifier tube were 'corrosion-welded' to its socket, and (3) someone had tried to fix it by buiding a solid state rectifier with diodes on the pins of the dead tube.
I sent the amp to a friend who rebuilt the power and bias supplies and made some other improvements. The questions were could it be made to work again and, if so, would the quality of its tone justify a pretty extensive effort to rehab the particle board cabinet and fix some manufacturing problems along the way. The answers turned out to be yes. The following pics show the results of all this.
This is the stripped front of the amp cabinet showing the 'ears':
Because they stick out and are made of particle board, they are subject to shipping and other casual 'injuries' - left and right - as shown below:
The 'Fix' is to cut them back so they lie more or less in the same plane as the faceplate, as they do on later versions:
The horizontal chassis supports provided both lateral weight-bearing and resistance to front-to-back movement. The left half of the following pic shows the original support (broken) through which a machine screw passed (the dark, banded area) up and through the corner of the chassis to give positive contact ... provided of course the piece of funky wood didn't break like this one did. The right half of the pic shows the 'Fix'; pairs of opposed angles with epoxied rubber tabs to provide load-bearing / cushion and yet another angle at the rear, machined and drilled, to provide an attachment point for the chassis:
The footswitch bracket was missing ... :evil: ... but another was fabricated from aluminum stock at the ShopzOfJuan: temporarily mounted inside left, now down low on the right:
Views of the chassis below: power supply including rectifier and output tubes on the left - pre-amp and reverb transformer on the right:
The 'bar' in the middle is, IMO, a Band-Aid. This chassis isn't stiff enough to support its own weight. In later versions, the chassis has a vertical steel, electrically-safe backpanel that provides the missing stiffness and protection. This is how it works on the early T1 RVTs: the left half shows the bar - it's 'anchored' on one end by pinching it between the faceplate and the volume pot (Yup!) and on the other with a screw into the back chassis lip. The right half, correct orientation, shows how the chassis weight is 'suspended' by a bolt through the top between the legs of the handle into a tapped hole in the strap...:
View of the tube deck, from left to right: T1 and 6CX4 rectifier behind, two Weber 3X40ufX450DC multi-section caps, the output transformer and two 6GW8 outputs, two 12AX7 pre-amp tubes, another Weber cap, and, what sets this amp apart from almost any other, the stand-alone 12AX7/6BM8 reverb amp with its own 8" speaker:
Partial reassembly showing the re-built chassis support on the left, the original but with new rear support angle on the right, new reverb can, 'Monster' shielded, audio-grade reverb return cable, #12 OFHC speaker drops, suspension 'bar' in place, and new baffleboard / grillcloth assembly through-bolted to the 'sculpted' replacment batten strips - originals were thin strips of particle board glued and stapled to the cabinet:
The amp now has a 25 watt 12" Celestion G12M 'Greenback' and a 35 watt, 8" Celestion G8L reverb speaker in lieu of the CTSs that were original; they went to my friend to help pay for the power supply rehab not to mention that the 12" CTS had a 1" hole in it :evil: but who's complaining...
Except for tolex, the finished product from the front:
...and from the back including view of reverb supply 'Monster' cable:
The amp is warm, robust, and musical; the 12" Celestion and boosted power supply filtering provide excellent bass, a common shortcoming of amps of the period. The controls include treble and bass and pull-for-bright on the volume and a footswitch to operate the tremolo which responsive and vibrant and the deep, dry reverb. I think this amp is everything that our friend and fellow BB member Jay Pilzer said it is and, in this case, more; more bass and, thanks to the upsized power supply, more punch.
I like the amp but I'd probably like it more if I didn't feel like it beat me up. It was also intentionally built to be a 'clean' amp; I tried pumping the feed from my Marshall BluesBreaker II through it - came out clean anyway :shock: and I have a preference for the crunchy thing. As of the date of this post, the link to the SchematicHeaven schematic is 'Suspended'; if anyone wants a copy, let me know, free (the schematic that is) to a good home!
cj
I bought it on eBay as a 'project'; as some of us have learned :evil: , there are projects and then there are projects. I ranted before about it but, in short (pun intended) it was DOA as (1) one of the multi-section caps had leaked electrolytic paste on the chassis (2) the pins of the rectifier tube were 'corrosion-welded' to its socket, and (3) someone had tried to fix it by buiding a solid state rectifier with diodes on the pins of the dead tube.
I sent the amp to a friend who rebuilt the power and bias supplies and made some other improvements. The questions were could it be made to work again and, if so, would the quality of its tone justify a pretty extensive effort to rehab the particle board cabinet and fix some manufacturing problems along the way. The answers turned out to be yes. The following pics show the results of all this.
This is the stripped front of the amp cabinet showing the 'ears':
Because they stick out and are made of particle board, they are subject to shipping and other casual 'injuries' - left and right - as shown below:
The 'Fix' is to cut them back so they lie more or less in the same plane as the faceplate, as they do on later versions:
The horizontal chassis supports provided both lateral weight-bearing and resistance to front-to-back movement. The left half of the following pic shows the original support (broken) through which a machine screw passed (the dark, banded area) up and through the corner of the chassis to give positive contact ... provided of course the piece of funky wood didn't break like this one did. The right half of the pic shows the 'Fix'; pairs of opposed angles with epoxied rubber tabs to provide load-bearing / cushion and yet another angle at the rear, machined and drilled, to provide an attachment point for the chassis:
The footswitch bracket was missing ... :evil: ... but another was fabricated from aluminum stock at the ShopzOfJuan: temporarily mounted inside left, now down low on the right:
Views of the chassis below: power supply including rectifier and output tubes on the left - pre-amp and reverb transformer on the right:
The 'bar' in the middle is, IMO, a Band-Aid. This chassis isn't stiff enough to support its own weight. In later versions, the chassis has a vertical steel, electrically-safe backpanel that provides the missing stiffness and protection. This is how it works on the early T1 RVTs: the left half shows the bar - it's 'anchored' on one end by pinching it between the faceplate and the volume pot (Yup!) and on the other with a screw into the back chassis lip. The right half, correct orientation, shows how the chassis weight is 'suspended' by a bolt through the top between the legs of the handle into a tapped hole in the strap...:
View of the tube deck, from left to right: T1 and 6CX4 rectifier behind, two Weber 3X40ufX450DC multi-section caps, the output transformer and two 6GW8 outputs, two 12AX7 pre-amp tubes, another Weber cap, and, what sets this amp apart from almost any other, the stand-alone 12AX7/6BM8 reverb amp with its own 8" speaker:
Partial reassembly showing the re-built chassis support on the left, the original but with new rear support angle on the right, new reverb can, 'Monster' shielded, audio-grade reverb return cable, #12 OFHC speaker drops, suspension 'bar' in place, and new baffleboard / grillcloth assembly through-bolted to the 'sculpted' replacment batten strips - originals were thin strips of particle board glued and stapled to the cabinet:
The amp now has a 25 watt 12" Celestion G12M 'Greenback' and a 35 watt, 8" Celestion G8L reverb speaker in lieu of the CTSs that were original; they went to my friend to help pay for the power supply rehab not to mention that the 12" CTS had a 1" hole in it :evil: but who's complaining...
Except for tolex, the finished product from the front:
...and from the back including view of reverb supply 'Monster' cable:
The amp is warm, robust, and musical; the 12" Celestion and boosted power supply filtering provide excellent bass, a common shortcoming of amps of the period. The controls include treble and bass and pull-for-bright on the volume and a footswitch to operate the tremolo which responsive and vibrant and the deep, dry reverb. I think this amp is everything that our friend and fellow BB member Jay Pilzer said it is and, in this case, more; more bass and, thanks to the upsized power supply, more punch.
I like the amp but I'd probably like it more if I didn't feel like it beat me up. It was also intentionally built to be a 'clean' amp; I tried pumping the feed from my Marshall BluesBreaker II through it - came out clean anyway :shock: and I have a preference for the crunchy thing. As of the date of this post, the link to the SchematicHeaven schematic is 'Suspended'; if anyone wants a copy, let me know, free (the schematic that is) to a good home!
cj