flashman Posted April 9, 2004 Share Posted April 9, 2004 Anyone have experience running Forte 1 speakers (mine are 4 ohm, 96db sensitive) in SET mode vs. Push-Pull? I have the Cayin TA-30, currently running in Push-Pull, and am enjoying it. But I am intrigued by the capability of the amp to go into SET mode by pulling a few power tubes and adjusting the bias. I favor jazz/folk but do occasionally listen to rock. By the way, for those who are interested, I have a CD recording (Reader's Digest, of all places) of Ella Fitzgerald and Louis Armstrong singing "April in Paris." I was stunned at the clarity of the CD... from an original recording in '58, I believe. There are some modern day recordings that don't sound this good. Guess it all points to the quality of the original recording equipment. Sorry for the side bar thought. Thanks for any thoughts on subject. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted April 9, 2004 Share Posted April 9, 2004 I was reading online about the capacity to change over to triode mode and thought it interesting. Hope you'll try that and post your take on the change in sound. Quote Link to comment Share on other sites More sharing options...
artto Posted April 9, 2004 Share Posted April 9, 2004 flash, do you have a schematic for that amp? I haven't been able to find much on it. And the ability to go from push-pull (class AB it seems) to SET class A simply by pulling an output tube from each channel & increasing the bias voltage by 2x seems kind of fishy to me. In the meantime I've got a call into a friend of mine who designs these kinds of things & hopefully he may shed some light on this. Thanks Quote Link to comment Share on other sites More sharing options...
NOSValves Posted April 9, 2004 Share Posted April 9, 2004 There really nice amps and sold by Paul at Bizzy Bee audio Artto but the switch a SE is just stupid if you ask me. Paul is a great guy but can be silly some times Craig Quote Link to comment Share on other sites More sharing options...
flashman Posted April 10, 2004 Author Share Posted April 10, 2004 Here's the schematic on the Cayin TA30. I pulled it off of Paul's web site. It's not very professionally done so I am not sure whether it will help. Anyway, thanks for any advice. http://www.angelfire.com/biz/bizzyb/CAYIINPICS/TA-30schematic.jpg Quote Link to comment Share on other sites More sharing options...
3dzapper Posted April 10, 2004 Share Posted April 10, 2004 flashman, You are "Officially Appointed" as the first to switch your amp to SE mode. You will do it today and listen to Ella and Louie and report back to the forum tomorrow with your results. Because of the short time restraints, there will be no requirements for charts, graphs or spectral analisys. Your personal listening observations will suffice in this test. Artto, he will be switching to SEP (single ended pentode) not SET (triode) unless of course he has a triode/pentode mode switch. In which case he will be in (pseudo) strapped triode mode. Rick Quote Link to comment Share on other sites More sharing options...
ben. Posted April 10, 2004 Share Posted April 10, 2004 What's so stupid about it? The way I see it, if you can get another flavor from the same amp for fairly low cost, that's a good thing. Now, if it sounds like crap that's a different story. If the performance levels are good in both modes, I'd love to have something like that. I do realize that's a big if, but it seems like a lot of folks are torn between the two topologies. In my case, the vast majority of my listening is done below 95 dB (sadly, much of it probably doesn't hit 85 dB). But when no one's home, it can get turned up a bit, too. I would guess that the Cayin is really optimized for PP performance, so it wouldn't be the ideal for my needs. Quote Link to comment Share on other sites More sharing options...
artto Posted April 10, 2004 Share Posted April 10, 2004 I dont make any claim to fame as to my technical abilities regarding electronics, or in this case more specifically, vacuum tube amplifiers. However, I do know enough, to NOT be dangerous. And it seems to me that an amp is either optimized for one type of operation, or it is compromised for use in multiple operating configurations. Granted, there may be something truly new & unique here (Cayin TA-30), but from what I can find on the amp, & from my relatively feeble knowledge of electronics design (I can read but not write, IOW understand but not design or fix the stuff), I fail to see how anyone can take a push-pull class AB amp, & simply by removing one of the output tubes & doubling the bias voltage, turn it into a single-ended amp. Furthermore, there seems to be much confusion regarding some terms/definitions. Paul at BizzyBee Audio makes no claims as to this amp being converted to SET. He does say SE. Single-Ended. He does not mention triode. A Single-Ended amp does not have to be triode as Rick 3dzapper pointed out. In fact, the term Single-Ended amp doesnt necessarily imply that the design is a tube amp. You can have Single-Ended transistor amp designs too! And, as far as I know, the power supply design of push-pull verses SE amps are substantially (fundamentally?) different. Simply pulling one of the output tubes seems folly to me. Perhaps someone can explain how one pulls this off. Seems to me this would play havoc with the power supply & output transformers, even if the power supply is strong enough to provide class A bias. I live a hop, skip & a jump from Naperville (plenty of relatives there & I grew up in the area) so Ill be paying Paul at BizzyBee a visit myself. flash...thanks for the schematic, its crude but it'll do. Quote Link to comment Share on other sites More sharing options...
ben. Posted April 10, 2004 Share Posted April 10, 2004 I certainly agree, Art. Do report back. It's smart marketing, anyhow. Quote Link to comment Share on other sites More sharing options...
artto Posted April 12, 2004 Share Posted April 12, 2004 ---------------- On 4/10/2004 1:06:09 PM bclarke421 wrote: I certainly agree, Art. Do report back. It's smart marketing, anyhow. ---------------- Well I finally got hold of my friend. He said its an 'old trick'. Has been done many times in the past, usually as a 'marketing gimic'. This can be done with many tube amps as long as they have an air gap transformer so the magnetic flux doesn't get saturated, & the power supply can provide enough current. Technically speaking, it's not a a true class A amp, which by definition, has to meet certain voltage & current specifcations. So in summary, the Cayin TA-30 is NOT a SET (Single Ended Triode) amp. Nor can it be operated as such by simply removing one of the output pair of tubes & bringing up the bias voltage. It is a push-pull design. It is, in all likely hood, optimized for class AB push-pull operation. It can be used in a Single-Ended mode of operation but is not a true class A amplifier. And when operating in Single-Ended mode, the tubes are operating as pentodes, not triode! I might add, do not try this if you're using amps that are like mine (Luxman MB3045) (EAR509) as these amps employ a cross-shunt or 'balanced bridge mode" design with cross coupled driver to output tubes, which forces the opposite tube pair off at the zero crossing point to basically eliminate crossover distortion & reduce high frequency distortion. Very different transformer design/deployment. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted April 12, 2004 Share Posted April 12, 2004 It's stupid because of exactly what Mark stated above. Single ended yes, Single ended done right ???? A single ended amp uses a single ended output transformer simple as that. Any push pull amp with enough bias adjustment range can do the very same thing nothing special at all about it. I own this amp and like it very much ! I'm also very good friends with Paul but it doesn't mean I have to agree with this silly marketing scheme. Craig Quote Link to comment Share on other sites More sharing options...
tkeady Posted April 13, 2004 Share Posted April 13, 2004 I just bought a Cayin TA30 from Paul and I'm really happy with it. I'm running it through Forte II's so when I saw your post it generated interest. I'm new to this tube thing and looking to tie my Thorens TD 160 to the Cayin. So I need to research phono preamps, any info on the NAD PP-2? Can I get info on the Fitz/Armstong CD I want to purchase a one. Tom Quote Link to comment Share on other sites More sharing options...
3dzapper Posted April 13, 2004 Share Posted April 13, 2004 I inadvertantly ran one channel of my Jolida as an SE amp. Unbeknown to me one of the Sevtlana EL-34s decided to commit Hari Kari. After a series of posts here about tube sockets, I decided to change out the OE ones for some others I had. When I went to set the bias one of the tubes read zero, must be my bad soldering I thought and swapped positions on two tubes for kicks. Sure enough it still read zero. Not suprizingly it also read zero on the old Heathkit. How long was it dead? I don't know but the amp sounded ok. The balance control wasn't centered that's all. Got a new pair from Uncle Ned and all is well. Rick Quote Link to comment Share on other sites More sharing options...
richieb Posted April 14, 2004 Share Posted April 14, 2004 Also own TA-30 and tried running SET by removing tubes 2 & 4. At the time I was using Triangles Celius speakers rated at 90 db. I did not like what I heard. Did not sound nearly as good as normal (PP). However, I did not re-bias as some of you say must be done. Not being a tube amp expert, I called Paul at BzzyBee to ask about the bias settings. He told me I had to do nothing but pull the two mentioned power tubes, that the amp was self-biasing, and enjoy. I like everything about this amp and it is killer with my Fortes. I will see how it performs when I pick up Cornwalls this weekend. Have not tried SET with Forte but was not impressed with the French made Triangles. Rich Quote Link to comment Share on other sites More sharing options...
NOSValves Posted April 14, 2004 Share Posted April 14, 2004 The TA-30 is a great value and sounds very good for the $ like most of the off shore amps out today they do a admirable job with just So So transformers. I bought one just so I could see what was what. Its a nice amp for the MONEY but not the end all by no means. Craig Quote Link to comment Share on other sites More sharing options...
JBryan Posted April 14, 2004 Share Posted April 14, 2004 I used to pull tubes out of guitar amps like the Fender Twin Reverb all the time to reduce the power to keep the roomates and neighbors happy. A friend does this trick with his Dynaco ST-70 and is happy with the results. He also changes out the 5AR4 with a SS rectifier - with the amp powered up! I've also seen him change hot tubes in running guitar amps - he has no fear but I wouldn't recommend this level of risk/stupidity to anyone who cares for their gear - or life in general. Have fun, Bryan Quote Link to comment Share on other sites More sharing options...
artto Posted April 14, 2004 Share Posted April 14, 2004 ---------------- On 4/14/2004 6:45:38 AM richieb wrote: Also own TA-30 and tried running SET by removing tubes 2 & 4. Did not sound nearly as good as normal (PP). However, I did not re-bias as some of you say must be done. Not being a tube amp expert, I called Paul at BzzyBee to ask about the bias settings. He told me I had to do nothing but pull the two mentioned power tubes, that the amp was self-biasing, and enjoy. Have not tried SET with Forte but was not impressed with the French made Triangles. Rich ---------------- Rich...........to repeat AGAIN, IT IS NOT S E T !!!!!!!!!! The "T" in 'SET' (generally) stands for Triode. The Cayin, when operated as described is SE (Single-Ended), in this case PENTODE (or SEP)Just because an amp is operating in Single-Ended mode does not automatically imply that it is operating as a triode. In fact, even solid state amps can be designed for Single-Ended operation. One could conceivably use the term SET here too, as in 'Single-Ended Transistor' amp. Not to mention 'Single-Ended Tetrode'. In any case, it is NOT converted to any form of 'SET'. The amp is obviously NOT 'self-biasing'. Otherwise, why would Paul Grezybek, Cayin's US importer/dealer post biasing instructions for this amp, and specific rebiasing instructions for Single-Ended mode operation on his web site? Furthermore, it has become apparent to me that Mr. Paul is somewhat full of BS as he states on his web site "The amp is now transformed into a single ended 4-watt per channel amplifier. No other tube amp in the world offers both push-pull and single ended!" This is obviously a false & misleading statement. As previously noted by myself, Craig, Mark & others on this thread, this in fact is nothing new, has been done in the past, and in fact can be done with many (but not all) push-pull tube amps. "from the horse's mouth"................. http://www.cayinusa.com/ Quote Link to comment Share on other sites More sharing options...
texas42 Posted April 14, 2004 Share Posted April 14, 2004 Everyone is still dealing with semantics...As probably the first person in this forum to buy the TA-30, I can attest it is an extremly nice sounding amp for the money and can compete with with the ASLs and Jolidas for even less money. I've never had the desire to pull tubes to run it single ended as it sounds great the way it is. And isn't great sound the bottom line? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted April 14, 2004 Share Posted April 14, 2004 Artto, Now don't be attacking my buddy here. He is full of bullsh!t but aren't we all in some fashion ? He is a very nice guy that does exceptional work no one is perfect and surely not me or you ! Craig Quote Link to comment Share on other sites More sharing options...
artto Posted April 14, 2004 Share Posted April 14, 2004 ---------------- On 4/14/2004 10:30:06 AM NOSValves wrote: Artto, Now don't be attacking my buddy here. He is full of bullsh!t but aren't we all in some fashion ? He is a very nice guy that does exceptional work no one is perfect and surely not me or you ! Craig ---------------- Speak for yourself Craig. Quote Link to comment Share on other sites More sharing options...
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