Tube novice here. KT88 or EL34?

The basic difference as I understand it is that for the same given amount of power the KT88 has more slam and tighter bass whereas the EL34 has more midrange "magic" going for it.If you get between 2-3K hours out of the tubes think about what the replacement cost will be.Go to ww.thetubestore.com to see an average price.I have a Mesa baron which uses 12 6L6 tubes one that is less associated with audio equipment than guitar amps.I have thought about getting the mods don for $500 which would allow me to use EL34's.Some amps have designs like the Rogue where you can just drop in the KT88,EL34,or 6550 (a tube a lot fo folks like as it has more dynamic slam than the EL34 but is much cheaper than the KT88).One last thing.What's a low of fun istube rolling i.e trying new tubes to get different peformnance.The new tubes are not as high a quality as older tubes made in the 50's and 60's.They are called NOS or New Old Stock (if in fact they are new).Tube were so widely used before the introducton of Solid State electronics many of the tubes from back then are still avalible.But you will find that the output or power tubes as they are alternately called are prohibitely expensive.But in all power amps you have input/driver tubes and in a intergrated amp these tubes handle the line stage (pre-amp) functions.These tubes can be 12AX7's,12AU7's etc (many web tube sites will show charts to indicate which tube is a variation another i.e. a 6922 is a version of the6DJ8).As opposed to output tubes they will last longer (up to 10K hrs.)You can experiment with telefunkens (the King),Mullards,Amperex etc to make major changes in the quality of the amps sound but getting these NOS tubes.As far as the power tubes go most of them are now manufactured in former communist countries as there military electronic stayed dependent on tubes long after the west had gone solid state.if you need to replace your power tubes one brand stands out that being Svetlana.Another better brand is Sovtek.The least expensive ones but the worst sounding are the chinese tubes.It's a matter of taste but since I listen to more jazz than rock and am a cheapskate I would pick the EL34 amp as I dig midrange.But after you have the amp come back and ask or do a search on tube types and get a set of NOS drivers no matter what amp you get.The results can be startling and tube rolling is fun.Welcome to the nutty retro world of glass audio!!!!!
Chazzbo

Arthur, you should contact the manufacturer to see if one the amps would allow you to run either tube, EL34 or KT88.

In many situations(such as in my Jadis amp), the manufacturer makes an EL34 version and a KT88 version. You can run both in the KT88 version, but just the smaller tubes in the EL34 amp. It has to do with biasing and the output transformers used on the amp. The KT88 version has much larger transformers, and cannot support either tube. Also, some amps will allow you to run a different output tube via a small component change, such as a resistor in the Jolida in the 302B and 502B.

With the EL34, you will not produce 50% of the KT88 power. Most of the time, the range is 20% - 35%, I normally tell people to expect about 1/3, and set them up for the worst. Often, the results are not so different. The one area where you will definitely notice the loss is the lower frequencies. The differences in tubes is quite apparent in the bass.

Personally, if it were me, I would first check with Unison to see if I could run EL34 in the KT88 amp, and find out whatever differences exist between the two products. If the differences in amplifiers extend to larger capacitors and/or transformers, then you are making a wise purchase by opting for the more expensive amp. That is definitely the one I would buy. If like the Jolida, however, the differences lie in a small parts difference, and the main difference is the output tube, I would opt for the cheaper amplifier. In that case, if the parts differences were minimal(if at all), you could always "upgrade" your amp to the more expensive version later via a local technician. On top of that, most people prefer sound of the EL34 Jolida 302B to the 6550 502B.

From you wish list, sounstaging and musicality, you could probably be happy with either. Depending on the KT88 you run, it can be quite a sweet tube. And, the bass is very good with this tube. Punchy. Ethereal, however, is really more in line with the EL34. Many people would not say this is accurate, but is sure is enjoyable.

The one question I would ask to you is, which version of the amp is the one that made such an indelible mark on you? Ultimately, that may be the one for you to buy. I am just guessing, but was it the EL34? Personally, I would set myself up for a long term purchase, and go for the amp where I could get whatever sound I desire.

Thanks for all the replies so far! My speakers are are 89dB anechoic so I suppose I may be limited in the SET department, especially since they dip to 3 ohms. I am also looking at the Antique Sound Labs integrateds that seem to be pretty and for a good price. I will be auditioning some soon. I would like to go with SETs but am not sure if I get a dealer to let me borrow one to try on my speakers. I may have to buy and try. Thanks for any and all comments - they are appreciated. Arthur

My 2 cents... If you decide to go with an EL34 based integrated, you might want to ad Conrad Johnson's CAV-50 on your list (avg. $1300 here on Agon)
besy of luck
shahen

Arthur, sounds like your speakers will not like a SET or low powered tube amp. I would recommend that you stick with a push/pull design that uses pentode tubes (EL34's, 6550's, KT88's, or KT 90's for the most part) and puts out at least 40 to 50 WPC. The ASL integrated could be a great and ecconomical place to start. FWIW i find that the same tube in different amps will sound different(and a different brand of the same type of tube will sound different in the same amp) so sound wise its not just about EL34's or KT88's. It all in the application. good luck......