Posted by Bill Harbour on April 28, 2011 at 11:39am
I'm fairly new to the site and I've got a CBG almost finished. I've been building and designing guitar amps and pedals and wanted to share that with you guys. My photo album of some of my builds is at http://www.cigarboxnation.com/photo/albums/my-amp-builds and I've got a blog that details some of the other stuff that I'm working on. It's at
the artec is a cool little amp but only 2.5 watts. the amp slim would probably build would be 12 to 15 watts (or less). I'd like to know the chip number on the artec to figure the clean head room at 9 volts...may not be much.
This also prevents those knock-ya-onyer-butt shocks and the free
hair curlin.
It might even be cheaper in the long run if a tube needs replaced etc.
And it's safer to go low voltage.
swampapple slim said:
they are prob bad ive tried to drain caps i got nothing for power accept on switch ive touched enoughf stuff i should have been knocked on my ass prob. a problem i tried to get a shock cant but radio has 2 stations guite loud phono dead dog not even a hum in that position did last pic help any?took it off monitor have you seen my last pic? well i sure hope for somthing just need enoughf power to hear where im sittin no peeling plans i thank you for your help your the only avenue ive found prob. cheaper get a tube modeling amp 100 to 150 you think? Slim Bill Harbour said:
Slim...I found a schematic for a model RC-606 from 1947...RCA of course. It should basically be the same. If you've never worked on tube electronics you should be very, very careful. The potential coming across the plates of some of those tubes could kill you. There are two 15uF caps on the power supply. These are likely in one can and not seperate. I always suspect that the power supply caps on an old amp are bad. If they're not, they could hold enough voltage to hurt you very bad. So keep this in mind. Also, you could potentially put in more work to convert this radio than you would expend building a guitar amp from scratch! I'll study the schematic a little more as I don't understand the switching. There appears not to be any preamp ahead of the phase inversion, but the 6SG7 might be supplying some gain depending on the switching (phono switch on). The 6K6GT power tubes dissipate only 8.5watts compared to a 6V6GT that can dissipate 12watts, so you won't be pealing the paint off of the walls!
phono won't work...not good. I'll look at drawing a quick schematic that might work for guitar. you'll have to figure out how to apply it to the radio. but I will do the best I can to advise you.
Honestly...if you've never built any custom tube gear, you've probably bitten off more than you can chew with converting this radio. If I can't figure out the signal path through the switches, then there's not much I can do to help you.
Slim...I found a schematic for a model RC-606 from 1947...RCA of course. It should basically be the same. If you've never worked on tube electronics you should be very, very careful. The potential coming across the plates of some of those tubes could kill you. There are two 15uF caps on the power supply. These are likely in one can and not seperate. I always suspect that the power supply caps on an old amp are bad. If they're not, they could hold enough voltage to hurt you very bad. So keep this in mind. Also, you could potentially put in more work to convert this radio than you would expend building a guitar amp from scratch! I'll study the schematic a little more as I don't understand the switching. There appears not to be any preamp ahead of the phase inversion, but the 6SG7 might be supplying some gain depending on the switching (phono switch on). The 6K6GT power tubes dissipate only 8.5watts compared to a 6V6GT that can dissipate 12watts, so you won't be pealing the paint off of the walls!
Slim...if I'm understanding you correctly, you've got a CD with the service manual for the radio?? All I would really need would be the schematic. Send me an email at bcharbour78 at yahoo dot com and I'll send you my address. In the mean time, can you send me the model number of the radio?? Maybe that's on the diagram on your page...I'll look.
Replies
Slim if I could throw my two cents in, I would scrap all the 120volt
hardware and keep the cabinet, all the knobs and the speakers,
Go low voltage, all your amp needs could fit behind the volume knob
of your radios case. Check out the "ARTEC SDA (speaker drive amplifier) here is a link.
www.cbgitty.com/cubecart/amplifier-parts/cat_47.html
This also prevents those knock-ya-onyer-butt shocks and the free
hair curlin.
It might even be cheaper in the long run if a tube needs replaced etc.
And it's safer to go low voltage.
swampapple slim said:
Honestly...if you've never built any custom tube gear, you've probably bitten off more than you can chew with converting this radio. If I can't figure out the signal path through the switches, then there's not much I can do to help you.
Slim...if I'm understanding you correctly, you've got a CD with the service manual for the radio?? All I would really need would be the schematic. Send me an email at bcharbour78 at yahoo dot com and I'll send you my address. In the mean time, can you send me the model number of the radio?? Maybe that's on the diagram on your page...I'll look.
Bill