Insides of a Supro Thunderbolt+ Reissue

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HollowAxisHollowAxis Frets: 117
edited November 2015 in Amps
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  • equalsqlequalsql Frets: 6084
    Great pics you've posted there. That's a weird build with the preamp board and tube being placed on a separate board mounted on it's side.  The filament wiring is quite unusual too with a mixture of direct wiring and PCB routing.

    Looking at the last picture, is there a PCB support next to the left side of the left power tube socket?  It doesn't look supported enough at that point.
    (pronounced: equal-sequel)   "I suffered for my art.. now it's your turn"
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  • HollowAxisHollowAxis Frets: 117
    edited November 2015
    Yeah, its a strange layout. 
    Why is there one 12AX7 facing forwards on it's own board? I have no idea.
    Any thoughts on why that makes any sense at all?

    I think there is a support screw right in front of the 12AX7 that is facing downwards. 
    Doesn't look like there is one on the left of the left power tube socket. 

    I count 7 support screws along the edge of that big board.
    I'll check tomorrow when I'm at practice. 

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  • 57Deluxe57Deluxe Frets: 7329
    I dreamt I had bought this amp - but the Tolex wasn't blue/grey but Beige/Grey... Or did I dream I dreamt it??
    <Vintage BOSS Upgrades>
    __________________________________
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  • ICBMICBM Frets: 71951
    That looks quite poorly-designed and built considering that it's not at all a cheap amp.

    It's not the PCB or even the odd separate bit with the extra valve socket, it's things like the location of high-power resistors next to electrolytic caps and under wiring, the haphazard arrangement of everything, caps more or less over the top of the rectifier valve, apparent lack of an HT fuse…

    I would definitely want to increase ventilation if at all possible short of fitting a fan. And I might even consider that.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • jpfampsjpfamps Frets: 2723
    Yeah, its a strange layout. 
    Why is there one 12AX7 facing forwards on it's own board? I have no idea.
    Any thoughts on why that makes any sense at all?

    I think there is a support screw right in front of the 12AX7 that is facing downwards. 
    Doesn't look like there is one on the left of the left power tube socket. 

    I count 7 support screws along the edge of that big board.
    I'll check tomorrow when I'm at practice. 

    The 12AX7 is in that position to keep the signal path from the input and tone controls short.

    Keeping the filament supply of the PCB helps with the layout, and is sensible as the filament supply needs to carry a lot of current.
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  • HollowAxisHollowAxis Frets: 117
    edited November 2015

    jpfamps said:
    Yeah, its a strange layout. 
    Why is there one 12AX7 facing forwards on it's own board? I have no idea.
    Any thoughts on why that makes any sense at all?

    I think there is a support screw right in front of the 12AX7 that is facing downwards. 
    Doesn't look like there is one on the left of the left power tube socket. 

    I count 7 support screws along the edge of that big board.
    I'll check tomorrow when I'm at practice. 

    The 12AX7 is in that position to keep the signal path from the input and tone controls short.

    Keeping the filament supply of the PCB helps with the layout, and is sensible as the filament supply needs to carry a lot of current.
    Makes sense.
    Thanks!
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  • SassafrasSassafras Frets: 30273
    Are the valve sockets plastic or ceramic?
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  • HollowAxisHollowAxis Frets: 117
    edited November 2015
    Sassafras said:
    Are the valve sockets plastic or ceramic?
    I don't know. Can't find info on that anywhere.
    I'm sure they'll answer an email if I ask them.
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  • ICBMICBM Frets: 71951
    Ceramic by the look of it. It probably won't help much though since the risk of overheating, carbonisation and arcing is from the board, not the sockets.

    I really don't understand the logic of building it all-PCB like that given the amount of hand work there is to attach all the flying leads. It would have been much better to chassis-mount the rectifier and power valve sockets separately, and keep the rest of the circuit on a PCB along with the preamp valves.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • NerineNerine Frets: 1971
    I think that looks rather nasty.
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  • andy1839andy1839 Frets: 2197
    @ICBM so with something like this, the component count looks low, would changing this to ptp on turret boards be possible/advisable/worth it?

    I've always wondered whether it's a worthwhile upgrade to an amp.

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  • ICBMICBM Frets: 71951
    Certainly possible. Or you could do it the old Supro way and make it truly point-to-point :).


    Given the low component count it may be the easiest way.

    Advisable and worth it? Maybe. In the short term, probably not - it's a lot of work, although it is possible that being able to improve some of the component quality would make the amp sound better. But if the PCB starts to cook or suffer other problems due to the poor layout in the long term, it would be.

    For what it's worth I've just been testing an Orange Tiny Terror Hard Wired Edition, which is just that - a fully PTP version of a normally PCB amp. The HW sounds very noticeably better - I'm not a fan of the normal TT, but this one does sound very good. My guess is that it's due to the larger, high-quality components throughout rather than the lack of PCB.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • andy1839andy1839 Frets: 2197
    @ICBM, cheers bud.

    Always wondered about doing it.

    Thread can get back on the rails now. :-)

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  • jpfampsjpfamps Frets: 2723
    ICBM said:
    Certainly possible. Or you could do it the old Supro way and make it truly point-to-point :).


    Given the low component count it may be the easiest way.

    Advisable and worth it? Maybe. In the short term, probably not - it's a lot of work, although it is possible that being able to improve some of the component quality would make the amp sound better. But if the PCB starts to cook or suffer other problems due to the poor layout in the long term, it would be.

    For what it's worth I've just been testing an Orange Tiny Terror Hard Wired Edition, which is just that - a fully PTP version of a normally PCB amp. The HW sounds very noticeably better - I'm not a fan of the normal TT, but this one does sound very good. My guess is that it's due to the larger, high-quality components throughout rather than the lack of PCB.
    The transformers for the HW TT and regular TT are the same, so any differences can only be due to the components are layout.
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  • ICBMICBM Frets: 71951
    jpfamps said:
    The transformers for the HW TT and regular TT are the same, so any differences can only be due to the components are layout.
    Exactly. The difference is substantial, much bigger than I was expecting - all the caps and resistors are different, and even the pots are much larger types. I'd take a guess this is more important than the PCB, although it's not going to be possible to do a final comparison to prove it since the HW components are too large physically to fit on the PCB.

    A much closer comparison is 1973 Marshalls, when they changed from turret-board to PCB while keeping the components the same and the layout very similar - I really don't think there's a consistent difference between those... I don't think you can plug into a 1973 Marshall and be able to say whether it's turret or PCB just from the sound.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • english_bobenglish_bob Frets: 5128
    ICBM said:
    Certainly possible. Or you could do it the old Supro way and make it truly point-to-point :).


     
    That sort of PTP always looks like a complete rat's nest. It doesn't help when it's inside an amp that's been accumulating various crap inside it for forty-odd years. If I bought a boutique handwired amp, opened it up and found that inside I'd be pissed off. Does that sort of wiring make it more difficult to troubleshoot an amp? Does it increase the likelihood of shorts?

    Don't talk politics and don't throw stones. Your royal highnesses.

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  • ICBMICBM Frets: 71951
    It does make it more difficult to work on and possibly to troubleshoot, but as long as the components are properly secured and any close bare wires are insulated from each other, there's no risk of shorts. There can be a problem with vibration fractures in the solid leads to unsupported components though.

    As with everything, the devil is in the details rather than the method itself.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • jpfampsjpfamps Frets: 2723
    If I bought a boutique handwired amp, opened it up and found that inside I'd be pissed off. Does that sort of wiring make it more difficult to troubleshoot an amp? Does it increase the likelihood of shorts?
    You obviously wouldn't buy a Matchless then!



    Or a Carr amp

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    Trouble shooting isn't so much the problem, although changing components can be very troublesome on some amps built like this.
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  • english_bobenglish_bob Frets: 5128
    jpfamps said:
    You obviously wouldn't buy a Matchless then! Or a Carr amp
    I couldn't afford one. I think age definitely adds to the rat-nesty-ness, when things have gone a bit rusty and dirt and beer and shit have found their way inside the chassis. Ultimately I guess if I bought an amp that sounded good and gave me no immediate concerns that it was about to burst in to flames I don't know that it would bother me that much what it looked like under the hood.

    Don't talk politics and don't throw stones. Your royal highnesses.

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