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thunder bolt 305
- Thread starter 552fl
- Start date
Shadetree Mechanic
Delaware Base Station 808
I have the 101 but it is completely different. I never could find a manual or schematic. I think the 305 is a 2 driving 4 but not sure. The drive knob would adjust the driver tube power going into the final tubes.
Hey there shade tree if you don't mind me asking what are you getting out of it on average and peak Watts? I see there's a one thunderbolt 101 on eBay now..just picking this one up from a friend he has two and they're both being going through right now at a very good price to complement my Heathkit sb220... Thanks for the reply very much. You have a merry Christmas Rodger in Florida
Shadetree Mechanic
Delaware Base Station 808
The 101 has two 6LQ6 tubes and I can get about 100w pep out of it. The tubes might be a little soft but I am only pushing it with 3w swinging to 12w. Merry Christmas to you too.
Doh! The schemo is on cb tricks after all.
http://www.cbtricks.com/Amp/thunderbolt/305/graphics/thunderbolt_305_sch.pdf
This one has the wacky "borrow grid-leak voltage from the final grids and feed to the driver-grid bias" setup.
The 10k pot seen just to the left of the driver tube V1 in the schemo is the "drive", or "swing" control. Can't remember how it is labeled on the front panel.
I do remember it tends to limit the peak power a bit if you push the radio's modulation too hard.
The high resistance values in the grid circuits limit grid current, and peak power along with it.
But only if all the resistor values are original. If any of them are burned, that might lead to an overheated driver tube.
73
http://www.cbtricks.com/Amp/thunderbolt/305/graphics/thunderbolt_305_sch.pdf
This one has the wacky "borrow grid-leak voltage from the final grids and feed to the driver-grid bias" setup.
The 10k pot seen just to the left of the driver tube V1 in the schemo is the "drive", or "swing" control. Can't remember how it is labeled on the front panel.
I do remember it tends to limit the peak power a bit if you push the radio's modulation too hard.
The high resistance values in the grid circuits limit grid current, and peak power along with it.
But only if all the resistor values are original. If any of them are burned, that might lead to an overheated driver tube.
73
Shadetree Mechanic
Delaware Base Station 808
It depends on how long you want the tubes to last. AM is hard on tubes, it might do 100w pep per tube for a while.
Nomad,
The dual transformers reminds me of a recent post of your addressing suicide prevention!
Also makes me think the manufacturer was cutting some corners here.
And the 2 relays in the keying circuit? Maybe to support the Pre-Amp? or save a nickel???
73's
David
The dual transformers reminds me of a recent post of your addressing suicide prevention!
Also makes me think the manufacturer was cutting some corners here.
And the 2 relays in the keying circuit? Maybe to support the Pre-Amp? or save a nickel???
73's
David
Second relay is for the receiver preamp.
My theory is that buying a large quantity of one part saves money, compared to buying one small transformer for 2-tube models and a larger one for 4-tube amplifiers.
These guys used a transformer big enough for 2 tubes, and put two of them in a 4-tube model. D&A used the same strategy, but with a transformer sized to run four tubes. Two of them in the 8-tube model, and three of them in the 12-tube. Four of them ran the 16 tubes in the "Warrior" model.
73
My theory is that buying a large quantity of one part saves money, compared to buying one small transformer for 2-tube models and a larger one for 4-tube amplifiers.
These guys used a transformer big enough for 2 tubes, and put two of them in a 4-tube model. D&A used the same strategy, but with a transformer sized to run four tubes. Two of them in the 8-tube model, and three of them in the 12-tube. Four of them ran the 16 tubes in the "Warrior" model.
73
I think I will like it very much if I can't use it as a driver I will just use a straight out then
552fl,
I just finished making some repairs/adjustments to a friends Kris 600SSB. It also is a 1 driving 3 box however the driver is a 6JG6A (maybe a little less output than your 6LQ6 driver??). I was seeing 325 max watts on SSB with about 10 watts input. If you are planning to drive your SB-220 with something like that, it might be a bit stiff. If the Thunderbolt has a "Low Power" side, it might be worthwhile to just use that setting as a driver.
This, of course, is just my opinion. Take it for what it is worth. Good Luck.
73's
David
I just finished making some repairs/adjustments to a friends Kris 600SSB. It also is a 1 driving 3 box however the driver is a 6JG6A (maybe a little less output than your 6LQ6 driver??). I was seeing 325 max watts on SSB with about 10 watts input. If you are planning to drive your SB-220 with something like that, it might be a bit stiff. If the Thunderbolt has a "Low Power" side, it might be worthwhile to just use that setting as a driver.
This, of course, is just my opinion. Take it for what it is worth. Good Luck.
73's
David