I just took my YBA-1 Bass Master in for a check up. Soon it will need new >tubes and my question regards what tubes get WHAT sound....I need specifics >before I order a set. I use Svetlana's in my Music Man head. BUt it looks >like there are these KT-66's out here? Please inform me what you all are >using and what you think of the quality of sound, etc. You can use many different output tubes in your YBA1. However, if you want to keep things simple - no socket rewiring and bias changes optional rather than essential, stay with the same general tube type as you are using now. Early YBA1s came with 7027s, which are unreasonably expensive. The 6L6, 6L6GC, 5881, and KT66 are all electrically very similar to the 7027. (5881s might fail in a Bass Master Mark 2, but would probably work fine in a standard Bass Master.) There are good versions of these tubes available. The tube basing (socket wiring) is different but compatible. You don't need to change anything. Some of these tubes have lower maximums than a 7027, but that doesn't matter much in a YBA1, as the tubes are not stressed very much. Later YBA-1s used 6CA7s (in big bottles - they look like a 6L6GC). Many early Bass Masters were converted to 6CA7s, because even in the late 60's 7027s were expensive and hard to find. Sockets wired for 7027s are not compatible with 6CA7s. EL34s are electrically compatible with 6CA7s - they have the same bias and socket requirements. I wouldn't spend a lot of money on tubes, - my experience with Svetlana has been good, but there are other good but not outrageously expensive tubes out there. A good cheap source of tubes is Antique Electronics Supply. http://tubesandmore.com/ 7027 substitutes (AES): 6L6GC-SVET BEAM POWER AMPLIFIER, SVETLANA $14.45 5881 (SOVTEK) TETRODE, BEAM POWER, SOVTEK $8.25 5881WXT (SOVTEK) TETRODE, BEAM POWER, SOVTEK $10.50 6CA7 Substitutes (AES): EL34-SVET PENTODE, HIGH PERFORMANCE, AUDIO POWER, SVETLANA $14.95 E34L (TESLA) PENTODE, TESLA $13.60 E34LS (TESLAVOK) PENTODE, CLEAR, TESLAVOK $11.90 6CA7 (CHINA) PENTODE, CHINESE $8.60 I've heard good things about triode electronics, but I haven't tried them personally. http://www.triodeel.com/ --------------------- Here's a link to some effective mods, courtesy of Sean Kilback & JC Maillet (thanks guys!): http://members.nbci.com/shuffleswing/TraynorTweaks/TraynorTweaks.htm I have performed a few of these on the BassMaster I picked up last week. I have substituted a 100 pF ceramic cap on channel 2 for the original .001 uF (1000 pf) cap. I wish my town had a better parts supplier! I can not get silver mica caps here, but the ceramic works fine, and there is no more "ice pick" treble!!! This channel still has a character of its own and blends nicely with channel 1 (jumper cable). I wish I had done this procedure on a BassMaster I owned previously... I have also added a grounded cable/strain relief (fit into existing hole - great!), and will be replacing the 4M-ohm vol. pots with 1 Meg pots. Question - are the volume pots linear or audio taper? I know this sounds silly, but I need to know!!!(I think they are audio...). Why do I ask? No one in my town carries pots with values of 1M or higher. LOL! Also - audio taper pots are not readily available. The electronics wholesalers say these types of pots are not used much anymore...what a joke. Looks like I'll have to order these over the internet, unless one of you kind guys (or gals) has some you would not mind selling! Glen H. -------------------- Yeah Glen, the 1M pots are audio taper. You can get Alpha brand from Mouser. If you don't have a Mouser catalog, you should get one immediately! They have very fair prices and do not have a large minimum order. Those 1MA Alpha pots are like 1.99 each. If you order those from Mouser, be sure to order more than you need; occasionally you'll find a bad one. TAP --------------------- Subject: Re: YBA-1 jumping Glen makes some great points regarding jumpering multi-channel amps. I think the common approach is to plug your guitar into the ch1 top (higher gain) input, then jumper the lower gain input into the ch2 higher gain input. Confusing? Of course, whatever sounds best to you is the one to go with. >NOTE: This is NOT the same as bridging a power stage, or daisy >chaining from the output of one amp into the input of another >amplifier - that will almost certainly end with disaster (ie. blown >output tranformer). "Daisy chaining" as I understand it means running amps in parallel, not series. Parallel means using either a splitter to run a cable to both amps inputs at the same time, or plugging into one amps input and running a cable from an auxilliary input to another amps input. Stevie Ray used this method. I certainly agree that running amp output into another input (ie. series) is dangerous. Although, isn't this the type of experiment that led Randy Bachman to Gar Gilles to create the Herzog? :-) This story is on the most excellent www.garnetamps.com site. cheers, Sean ------------------- Has anyone had the chance to do a side by side component comparison between the REALLY EARLY Traynor amps ('65 / '66 vintage), and the later "rounded side" amps up until about late '69 / early '70. I have had the opportunity to do just that. I compared both power trannies and output trannies on a '66 tube-rectified Bassmaster with the turret board circuit, vs. my own '67 - '69 amps. I own a '67 Signature, a '68 Bassmaster, 2 x '67 (?) Voicemasters and a '68/69 Voicemaster. Here is what I found; Outside of the SS rectifiers on my amps, and differences in the part numbers stamped on the transformers - there was NO DIFFERENCE. In terms on the core sizes and footprints of the transformers and the chokes used, all the above units up until late '69 / early '70 were identical to the '66. I didn't check primary impedance on the OT or anything like that to see if there were internal differences. I admittedly didn't check B+ voltages either. However, I have modded the '68 Bassmaster to include a series 'sag' resistor in the power supply, and to my ears, the tone was indistinguishable from the tube-rectified '66. The '66 trannies were original, so either I am missing something, or all mid to late '60's Traynors should be just as desirable as the really early ones for tone. A ten to fifteen minute mod to include a $.40 power resistor (if you care about sag), and POW - if you like that classic early sixties 'marshally" tone, you are in the zone. Since then I have swapped out the 4M volume pots for 1M ones, and that has helped alot as well. So, has anyone else done anything similar to my comparison with different results? I would love to hear about it. I hope the rest of the world stays "asleep at the switch" for a little while longer about Traynors. That means more for you and me. Regards, Craig ----------------------- FYI - I really like the EL84 sparkle and shimmer of my Matchless D/C-30. I used to be a huge fan of 6V6GT tubes, my Deluxe Reverb got lots of use in an earlier life. I really like the punchy tone my YBA-1 had with one 6CA7 and one 7027A. I was really enjoying that amp, getting vintage Zep and Black Crows tones. If I had that circuit in a combo with a master volume, I'd be thrilled. Regarding 6CA7s and EL34's, I always wanted an amp with Mullards in it. Out of curiosity, I did a taste test with a Matchless Chieftain. Since it's cathode biased, I could swap tubes in and get a feel for their relative tones without rebiasing it. I did this with a friend last year, but just did it for myself last weekend. Mullard EL34's are a tad dark sounding, but smooth as butter. Siemens have a harder edge tone, maybe brighter with more midrange. Sylvania 6CA7's sounded brighter than Mullards, bigger than Mullards, and louder than Mullards (could just be my set of tubes). I've never played a Hiwatt amp, but they are legendary for loud and clean tones. The Sylvania 6CA7's gave me that impression, but the clean part of their tone didn't make me want any more overdrive. They had clarity and grind, I was amazed. That's what I left in my Chieftain, a pair of used Old Stock Sylvania 6CA7's. They are not perfectly matched, but I liked the punch, clarity, and grind they offered. I guess my dream tones are sorta in the vintage JTM45/Vox spectrum. Your tastes are different than mine. I tried a YBA-1 with 6550's, and used to own a Marshall with 6550's. I don't care for the sound of those tubes. I thought it was a tad too harsh for my tastes. I'm not a fan of the Black Sabbath/Ozzie guitar tones. But it's a very useful tone, and tons of people love them! So check them out - find out for yourself if you like them. Don't know if any of that helps.... Timothy G. Casey, QEP