Crate VC 50 to Rocket Reverb?
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- johnnyreece
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Crate VC 50 to Rocket Reverb?
I recently scored a broken down VC 50 for cheap. Was thinking of ripping out the board and using what's left for a budget Rocket Reverb. She's heavy...it's the 3x10 combo. I've attached a schematic that does include a voltage chart. I think by swapping in a tube-ish rectifier (will either use a Weber copper cap or just run my own sag resistor since I don't have the 5V taps) I can get B+ in line. Any thoughts?
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- johnnyreece
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Re: Crate VC 50 to Rocket Reverb?
I've been going over this schematic and am seeing something that looks funny...From the looks of it, the heater tap on the PT is putting out 8.8VAC. From there, they rectify it for DC and send it to the 12AX7 tubes. However, it looks like they're sending 8.8VAC to the power tubes. Can someone clear this up for me?
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Re: Crate VC 50 to Rocket Reverb?
That's what it looks like ... Crate has done some funny things to perfectly good amp circuits ...
Maybe that's how it became a VC50 and not a VC30 ???
Maybe that's how it became a VC50 and not a VC30 ???
Re: Crate VC 50 to Rocket Reverb?
I think it's 8.8V peak-to-peak, which would be about 6.22V RMS.
- johnnyreece
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Re: Crate VC 50 to Rocket Reverb?
Makes sense. I completely ignored the P-P in the measurement...akahoushi wrote:I think it's 8.8V peak-to-peak, which would be about 6.22V RMS.
Re: Crate VC 50 to Rocket Reverb?
I hate to jump the thread, but I took a look at the schematic, and I have a question. What are all the optocouplers for? I don't think I have seen that kind of setup before.
Skeez
Skeez
- johnnyreece
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Re: Crate VC 50 to Rocket Reverb?
From what I understand, they're for the channel switching. They also frequently go bad (as I believe they have in this case, too).
- johnnyreece
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Re: Crate VC 50 to Rocket Reverb?
Sorry to drag this back to the top, but I'm curious: Anyone know what C30 and C31 are for in the circuit? I'm reusing the switches that have the built in lamps, so I don't know if they're necessary for that or not. Thanks for the help! This thing's coming along, slowly but surely.
Re: Crate VC 50 to Rocket Reverb?
No, they are not part of the switch illumination. The switches just have bulbs in them.
- johnnyreece
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Re: Crate VC 50 to Rocket Reverb?
Thanks. I know I have to have some circuitry for the standby switch (or else I'd have full B+ hitting the bulb), but I wasn't sure on the mains switch. I appreciate you easing my mind!
Re: Crate VC 50 to Rocket Reverb?
I assume you saw the resister to ground on the B+ side.johnnyreece wrote:Thanks. I know I have to have some circuitry for the standby switch (or else I'd have full B+ hitting the bulb), but I wasn't sure on the mains switch. I appreciate you easing my mind!
- johnnyreece
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Re: Crate VC 50 to Rocket Reverb?
Sure did. Thanks for mentioning it, though! I got the power section complete and powered it up. Both switches lit up and didn't explode, so it seems I at least got that part right! VVR seems to work well, too. Now I just gotta finish wiring the board in. Hoping to have it up and running this weekend.