WAG, the KT 88 version will have 2x the power of the EL34. The EL34 may have a sweeter mid-range.
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arthur, you must hear the speakers and amp together if you can. you can't assume that because the Royd's sounded good, the Paradigm will. Its not just about sensitivity its also about impedence. do you know what the impedence curve of the paradigm (and the Royds) looks like? do you know its minimum impedence? do you know the sensitivity level of the Paradigms and the Royds). 12 watts of power doesn't sound like much unless you speaker has a high sensitivity level and an easy impedence load.
Abal, I have always felt there is something magic about a good KT88 in most amps designed for 6550's that I have owned. I have recently joined the Cary SET crowd after years with the bigger iron. With that said you may want to look at the 300B integrateds out there. I think I am sold on the magic of the singe ended triode.
While I really like Cary gear, you may want to look at something like a Kora Electronic Concept (www.kora.net) "Design 30." That was one of the finest EL34 based integrated amps I have heard. Some guy has one on the gon for around $1450. That is a bit steep but a great sounding integrated. I am not sure I really answered your question. Just some thoughts.
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!!!!!
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
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......
Antique Sound Labs has a 30W push-pull EL34 integrated for a very good price that was designed for inefficient loads (according to their website anyway) that is tempting.
However, I still like the SET idea since I have my SS for real power. Maybe I could get a second pair of very efficient speakers just for tubes? Any inexpensive ideas on this? This is pure addiction! Thanks. Arthur
Hi if you are looking for musicality the EL 34 is your tube of choice and i will add the EL84 as the most musicall from the 3(KT88,EL34,EL84)/PENTODE FAMILY
The most musical tubes for future reference are the 45,2A3,6080,6AS7G,300B/TRIODE FAMILY.
In choosing the unison for integrated is a wise choice,they are quite musical indeed.
I wish Croft Amplification could bring back their intergrated amps from the UK.
The most popular tube in the US,are those 2 your are questioning about the KT88 slam,power,and the EL34 for low power and musicality.
Be carefull what speakers you will be using!!
What it works for one tube/speaker does not work for all kind of speakers.
First find the best amplification and combined them with a speakers that gets the musical taste you are looking for!!!
Hope this help/