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Tube amps and speaker ohms

In your opinion , do push pull amps work better with 8 ohms or 4 ohms. .I am under the impression the lower the ohms, the more power is demanded from the amp....Another question, are there low powered SET amps ,and high power SET amps?
I'm looking at a 40 watt 845 tube amp for my 8 ohm, 89 db speaker.. just cked the Thor has a 86 db W18 midwoofers(2 per cabinet) and a 88 db tweeter. Will an 845 amp rated 40 watts be able to drive the 86/88 db speaker? With authority, bass, mids, highs, in dynamic sound stage? Synergy? Or poor match?
bartokfan
divad68
6 posts
 
Thanks for the advice. The Yaqin MC100B that I was looking at has 4 x KT88's and adjustable bias for each tube - access via marked holes in the top plate. I'm not frightened to get into the techie stuff so that appeals to me. A screwdriver and multimeter job, I guess?

Think I'll take a gamble on this one. Can probbaly get hold of one for approx £400 and if I get on with it then I can look to upgrade to something more classy.
ebitda
2 posts
 
Great vintage monoblocks if you can find them. The put out 100 w/ch and weigh about 45 lbs each. The irons are monstrous, but they sound increadible with low efficiency/low impediance speakers.
trelja
3,223 posts
 
I think the point Newbee made about the EL34 versus KT88/6550/KT90 is something that REALLY needs to be lauded. EXCELLENT POINT!!!

The EL34 is a tube that is going to be in many of these amplifiers. And, while it is my favorite of the traditional push-pull amplifier tubes, it does has its shortcomings. As Newbee pointed out, you are going to give up those low frequencies (and overall power) in exchange for those wonderful mids. Please be aware of this.

Another tube to consider is the KT77 made by JJ. VERY powerful bass, and good power overall. You still don't match those EL34 mids. Consider it a great tube slotting between the EL34 and the KT88. In more than a few amps, we actually heard MORE emphatic bass with the KT77 than the bigger tubes, combined with some seriously better midrange.
Post removed 
newbee
4,767 posts
 
Tvad - FWIW, dealing with like kinds, ie SED's, I found the 6l6GC slightly mellow thru the upper mids/highs compared to the EL34 in both of my Primaluna amps which were primarily designed around the EL34 or the KT88 and to my ears both sound best with that the tube around which it was designed. I've been sort of interested in hearing an amp designed around 6L6's but I haven't found one yet. I tried them in my Baron but they were to hot - I'd have to get it modded (it takes 5881's).

JJ is the only maker of KT77's right now that I'm aware of. On AA several posters have been high on the sound they make, but there is some strong comments on quality control and pin size. FWIW - you probably already knew that.
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