brentrocks Posted July 3, 2011 Share Posted July 3, 2011 The 'ol '66 Gibson Saturn amp has been a workhourse lately...I have been jamming on it alot. I was talking to a friend locally, whos brother is a really good amp tech. I was telling him that the amp had been making some little noises, which kinda sounded like vibrations? He advised me to get some electrical contact cleaner, pull all the tubes and clean the sockets and the tube pins....and...test the tubes to see if any of them were bad. He said that if you tap on the tube with the power on and in the on position, not standby....if you tap on the tube with a small piece of wood, like a chopstick, that tube will make a really bad noise through the speakers if it is bad. Well, non of my tubes made a noise. And after i had cleaned the sockets and pins, the amp did seem to sound a little cleaner....I also tightened all the bolts and screws on the speakers, cab and chasis. Looking from left to right....these are the tubes in this amp: RCA 6L6.........power tube RCA 6L6.........power tube RCA OA2.........????? no clue RCA 6FQ7/6CG7...????? no clue RCA 6EU7........????? RCA 6EU7........????? Sylvania 12AU7A..??? RCA 6EU7........????? RCA 6EU7........????? As you can see i only recognize the power tubes....can anyone tell me what the function of these others are? It seems like the 6EU7s are pre amp tubes? Link to comment Share on other sites More sharing options...
DetroitBlues Posted July 3, 2011 Share Posted July 3, 2011 Where's KBP810 when you need him? I suspect any built in effects such as reverb or tremolo may use the two larger tubes. Most likely all the smaller tubes are preamp tubes, they may be mismatched because they were compatible to what was in there.... Link to comment Share on other sites More sharing options...
kbp810 Posted July 3, 2011 Share Posted July 3, 2011 RCA OA2.........Is a voltage regulator, it's basically a tube version of a zener diode RCA 6FQ7/6CG7..Wow! I had to look this one up, lol - looks like a preamp tube, seems similar to 12ax7 but different pin placements. RCA 6EU7........Also similar to a 12ax7, also different pin placements Sylvania 12AU7A..just like a 12ax7, but much lower gain factor; I've swapped these for a 12ax7 in my Tweed Champ before, kind of sounded cool but the volume dropped way off - I have a few 12au7's sitting around that are probably not going to see much use on my end, so if you ever need a replacement let me know! Link to comment Share on other sites More sharing options...
kbp810 Posted July 3, 2011 Share Posted July 3, 2011 Great pic! I love the site of blue and orange glows in a 6L6 Link to comment Share on other sites More sharing options...
brentrocks Posted July 3, 2011 Author Share Posted July 3, 2011 RCA OA2.........Is a voltage regulator, it's basically a tube version of a zener diode RCA 6FQ7/6CG7..Wow! I had to look this one up, lol - looks like a preamp tube, seems similar to 12ax7 but different pin placements. RCA 6EU7........Also similar to a 12ax7, also different pin placements Sylvania 12AU7A..just like a 12ax7, but much lower gain factor; I've swapped these for a 12ax7 in my Tweed Champ before, kind of sounded cool but the volume dropped way off - I have a few 12au7's sitting around that are probably not going to see much use on my end, so if you ever need a replacement let me know! Thanks you for the explination! I should have paid more attention when i had them out.... the 6EU7, 6FQ7 and the 12AU7A have the same pin pattern then? they ate just different types of preamp tubes? Link to comment Share on other sites More sharing options...
brentrocks Posted July 3, 2011 Author Share Posted July 3, 2011 I have a few 12au7's sitting around that are probably not going to see much use on my end, so if you ever need a replacement let me know! thank you for offering!!! do you think i should look into new tubes, considering that they are so old, or just keep playing it until something goes pop or hissss? Link to comment Share on other sites More sharing options...
kbp810 Posted July 3, 2011 Share Posted July 3, 2011 thank you for offering!!! do you think i should look into new tubes, considering that they are so old, or just keep playing it until something goes pop or hissss? I would keep on playing 'em! Though might not be a bad idea to procure a backup set. the 6EU7, 6FQ7 and the 12AU7A have the same pin pattern then? they ate just different types of preamp tubes? The 12au7 has the same pin pattern/wiring as 12ax7's, the 6eu7 and 6fq7 are different. They are essentially different types of preamp tubes (and/or phase splitter), with slight variations in each. It seems like the 6FQ7 might have been used to drive an effect in the amp, possibly the tremolo and/or reverb (having a hard time finding a clear/viewable schematic for this amp to try and confirm) Also looks like it's a 9 pin variant of a 6sn7 tube, which I familiar with for it's use as a power tube in very low watt amps (1-2 watt output) Link to comment Share on other sites More sharing options...
brentrocks Posted July 3, 2011 Author Share Posted July 3, 2011 I would keep on playing 'em! Though might not be a bad idea to procure a backup set. The 12au7 has the same pin pattern/wiring as 12ax7's, the 6eu7 and 6fq7 are different. They are essentially different types of preamp tubes (and/or phase splitter), with slight variations in each. It seems like the 6FQ7 might have been used to drive an effect in the amp, possibly the tremolo and/or reverb (having a hard time finding a clear/viewable schematic for this amp to try and confirm) Also looks like it's a 9 pin variant of a 6sn7 tube, which I familiar with for it's use as a power tube in very low watt amps (1-2 watt output) thanks so much for the advise!!! i can get a complete set, power/preamp tubes for $180 at the TUBE DEPOT, so i think im gonna get a backup set, like you suggested. I'm probably gonna take that amp to the thursday night pre-party jam at the country inn, so if i need a tube, at least ill have one available. it will be interesting so hear the difference a new set of tubes will make in that old amp....i might just pop them in for a quick jam just to hear the difference....then put the old ones back in? Link to comment Share on other sites More sharing options...
DetroitBlues Posted July 5, 2011 Share Posted July 5, 2011 Sounds like you got all figured out! Nothing like trial by fire taking out to a jam session! Link to comment Share on other sites More sharing options...
brentrocks Posted July 7, 2011 Author Share Posted July 7, 2011 I tried the new tubes in it tonight and i didnt really hear a BIG difference. A little more power, little more volume...the tremolo seemed to be a little more vibrant I decided to pull out the chasis...HOLY CRAP!!! Thats a lot of wires and stuff!!! Link to comment Share on other sites More sharing options...
kbp810 Posted July 8, 2011 Share Posted July 8, 2011 WOW, now that's one heck of a busy chassis Link to comment Share on other sites More sharing options...
Steiner Posted July 8, 2011 Share Posted July 8, 2011 Looks like "Paint by numbers." Link to comment Share on other sites More sharing options...
DetroitBlues Posted July 8, 2011 Share Posted July 8, 2011 You're one brave soul to take that head out of the amp. A while ago, I had a Fender Superchamp XD. If it wasn't for GC selling me a crappy amp I traded it in for, I'd still have it. I wanted to pull the head out and put it in a 1x12 combo cab replacement. I never had the nerve to try it.... Link to comment Share on other sites More sharing options...
H Posted July 8, 2011 Share Posted July 8, 2011 Cut the green wire. Uh wait, cut the RED wire.... BOOM! Link to comment Share on other sites More sharing options...
FredZepp Posted July 8, 2011 Share Posted July 8, 2011 Cut the green wire. Uh wait, cut the RED wire.... BOOM! Link to comment Share on other sites More sharing options...
DetroitBlues Posted July 8, 2011 Share Posted July 8, 2011 This chain will self distruct after 60 seconds of viewing it.... Link to comment Share on other sites More sharing options...
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