Gitfiddler Posted July 6, 2014 Posted July 6, 2014 In my seemingly never ending search for better tone from tiny amps, I swapped out a perfectly good matched pair of Groove Tube 6V6's out of my Champ II Tweed head. In their place I loaded a matched set of JJ 6V6 'S' tubes I had from another amp project. The JJ's are supposed to be robust tubes that can handle higher plate voltages, so I expected strong performance. As soon as the JJ's were loaded and the amp turned back on, the amp made a strange low frequency pop...then died!! Nothing! No light. No sound. Nothing! OMG! Did I blow a transformer from my favorite little Champ beast! Or worse! Nope, just a blown fuse, thankfully. Well, to test that theory, I inserted that same set of JJ's in my other Champ II. The fuse blew immediately. Fortunately, I had a set of 1-amp slo blo fuses and replaced them in both amps. I also re-installed the original Groove Tube 6V6 tubes. Now the amp sounds fine, but what happened? Why would the same tube type blow fuses?
212Mavguy Posted July 6, 2014 Posted July 6, 2014 Well one thing's for sure, I'm not gonna put those JJ's of yours in any of MY amps! Something likely is up with one of those tubes. 6v6's are among the easiest to find and cheaply in vintage old stock. Besides purchasing matched pairs of old stock tubes, an unusual way to get great 6v6 tone is accumulate a bunch of VOS singles over time, assemble a pair with similar current draw, but different makes/brands. I have a couple of well matched pairs of dissimilar ones, the best sounds of both brands comes through in the blend. Pretty unchaseable tone that way too. Also have a few other loose ones to choose between for my BF circuit Champ. The thundering herd tends to prefer vintage RCA blackplate 6v6's, my ears prefer the round plate Tung Sols. Sweeter they are. Look for the 322 code on the base, Delco, FoMoCo, and Tele-Tone all used the Tung Sol build. Also, particularly in 6v6 amps, I often sub 6f6g's for 6v6g's…from the 1940's and early 50's. The pinout is identical and the wattage is similar, the 6f6's are easier to drive into distortion, and they are waaaay cheaper than 6v6g's. Their tones are wonderful. I often got 6f6g singles for less than 10 bucks apiece on ebay. Pairs can be had as well but not as inexpensively as the singles. But if you want to go the store bought method of tube buying using new production 6v6's your tone will definitely be inferior to that best that your ears could have. Once you hear old stock 6v6 type you likely will be spoiled and ruined forever.
slider313 Posted July 6, 2014 Posted July 6, 2014 Bottom line is, one of those JJ 6V6's has a short. It can happen with any power tube; new production or new old stock.
davesultra Posted July 6, 2014 Posted July 6, 2014 Bottom line is, one of those JJ 6V6's has a short. It can happen with any power tube; new production or new old stock. Agreed! If you are looking for a new production 6v6 I would strongly recommend the Tung-Sol 6v6, my understanding is that they can handle really high plate voltage levels.
Kuz Posted July 6, 2014 Posted July 6, 2014 Agreed! If you are looking for a new production 6v6 I would strongly recommend the Tung-Sol 6v6, my understanding is that they can handle really high plate voltage levels. Actually the Tung Sol 6v6 RI are only a 12watt tube and you have to be very careful with higher voltages. I had two sets just red plate on me. The problem is they sound great but recent QC is bad. The TAD 6v6 tubes are 14 wats and very rugged but don't sound as good. But the TAD 6v6s can handle the higher voltages where the Tung Sol RIs might not.
Gitfiddler Posted July 6, 2014 Author Posted July 6, 2014 Thanks guys. I'll have the JJ's checked out with a friend's old tube tester to see which of them are defective. I'll look into Tung Sol and TAD, but the Champ is 18 watts. Is that a problem? It is amazing how each tube swap alters the character of this little amp. Aside from the scary moment with the blown fuse, this has been a fun and educational project.
davesultra Posted July 7, 2014 Posted July 7, 2014 Actually the Tung Sol 6v6 RI are only a 12watt tube and you have to be very careful with higher voltages. I had two sets just red plate on me. The problem is they sound great but recent QC is bad. The TAD 6v6 tubes are 14 wats and very rugged but don't sound as good. But the TAD 6v6s can handle the higher voltages where the Tung Sol RIs might not. Wow, that's crazy to hear. The tech I spoke with told me they up to most tasks. I should have asked Mike over at KCA, I usually only buy NOS anyway.
Kuz Posted July 7, 2014 Posted July 7, 2014 Wow, that's crazy to hear. The tech I spoke with told me they up to most tasks. I should have asked Mike over at KCA, I usually only buy NOS anyway. Do a google search on "failed Tung Sol 6v6 Reissues". I heard (and experienced ) the failure rate has gone way up over the past couple years. But again, I love their tone.
jmac Posted July 7, 2014 Posted July 7, 2014 I think I had the same problem with the JJ 6V6 S too. Cost me $168.00 to figure it out.. Sometimes a bad rectifier tube can cause a fuse to blow..
Gitfiddler Posted July 7, 2014 Author Posted July 7, 2014 Tube reviewers are all over the board on 6V6's, but the strongest recommendations appear to be in favor of the TAD's. Also, I found others commenting about JJ failures like the one I experienced. As for the fuse blowing due to a bad rectifier tube, the Champ II has a solid state rectifier. So that leads back to the 6V6 as the likely suspect. Check out this comparison review from "The Tube Store": http://www.thetubestore.com/Resources/Product-Reviews/6V6-Tube-Review
Kuz Posted July 7, 2014 Posted July 7, 2014 A great review but it is several years old. I have read it many times before.
slider313 Posted July 7, 2014 Posted July 7, 2014 A great review but it is several years old. I have read it many times before. Also, take it from where it comes; a tube vendor. They happen to sell all the products reviewed. I don't see a review of old smoked glass Sylvania's, RCA's, Raytheon's, GE's, etc. They say this about the Gold Lion,"You won’t get better tone and reliability from anything else on the market"...........but leaves out that they're the most expensive new production 6V6. I could find plenty of NOS choices for the same price....or less.
Gitfiddler Posted July 7, 2014 Author Posted July 7, 2014 I have the original smoked glass 6V6's in my Super Champs and they sound amazing! Not sure of the brand (GE or RCA), but will check when I get home tonight. What's your take on Cryogenic treated tubes?
slider313 Posted July 7, 2014 Posted July 7, 2014 What's your take on Cryogenic treated tubes? Same as my take on Cryogenic treated condoms.
Hfan Posted July 25, 2014 Posted July 25, 2014 Well one thing's for sure, I'm not gonna put those JJ's of yours in any of MY amps! Something likely is up with one of those tubes. 6v6's are among the easiest to find and cheaply in vintage old stock. Besides purchasing matched pairs of old stock tubes, an unusual way to get great 6v6 tone is accumulate a bunch of VOS singles over time, assemble a pair with similar current draw, but different makes/brands. I have a couple of well matched pairs of dissimilar ones, the best sounds of both brands comes through in the blend. Pretty unchaseable tone that way too. Also have a few other loose ones to choose between for my BF circuit Champ. The thundering herd tends to prefer vintage RCA blackplate 6v6's, my ears prefer the round plate Tung Sols. Sweeter they are. Look for the 322 code on the base, Delco, FoMoCo, and Tele-Tone all used the Tung Sol build. Also, particularly in 6v6 amps, I often sub 6f6g's for 6v6g's…from the 1940's and early 50's. The pinout is identical and the wattage is similar, the 6f6's are easier to drive into distortion, and they are waaaay cheaper than 6v6g's. Their tones are wonderful. I often got 6f6g singles for less than 10 bucks apiece on ebay. Pairs can be had as well but not as inexpensively as the singles. But if you want to go the store bought method of tube buying using new production 6v6's your tone will definitely be inferior to that best that your ears could have. Once you hear old stock 6v6 type you likely will be spoiled and ruined forever. Thanks for that tip Mavguy. When matching current draw, are you going by the seller's rating or do you have to use a tube tester? I suppose if you know where to test you could measure the current in the circuit as well? Same as my take on Cryogenic treated condoms. Well, I wouldn't want to poke any holes in that argument. Seriously, Gibson has come out with cryogenically treated frets, believe it or not. Ask the old boys from Heritage on their take at PSP..I can hear Marv now.."that's BS". http://www2.gibson.com/News-Lifestyle/Features/en-us/Why-Cryogenically-Treated-Frets-Are-Better.aspx
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