Having completed my first DIY speaker build in years (Seas A26), I'm really wanting to try a lower power tubed amp again. The A26 is a true 88dB efficient, 8 ohms minimum speaker, with an ultra-simple x'over too, no less.
I listen mostly at moderate levels, with the occasional loud burst, but my open floor plan room's on the large size (speakers 7' apart, me 9' back, another 10' behind me, to my left is the dining area).
In your experience, am I good with 10-15 clean watts here, or stick with EL34, etc. ?
I listen mostly at moderate levels, with the occasional loud burst, but my open floor plan room's on the large size (speakers 7' apart, me 9' back, another 10' behind me, to my left is the dining area).
In your experience, am I good with 10-15 clean watts here, or stick with EL34, etc. ?
Lower power tube amps can have better highs, but sacrifice bass. The reverse goes for higher power.
I'd go with what is more important to you. That speaker is capable of very good, articulate bass
with the right amplifier, but tends to do better with ss amps in the bass.
I'd go with what is more important to you. That speaker is capable of very good, articulate bass
with the right amplifier, but tends to do better with ss amps in the bass.
Last edited:
Paul Joppa provided the 'phile community with a useful rule of thumb for mating amps and speakers. Joppa's Rule states that for "typical" listening spaces an amp/speaker combo should be capable of producing 102 dB. SPL peaks at a 1 M. distance. Given the OP's large listening venue, erring on the high side (if at all) seems indicated.
Applying Joppa's Rule to that 88 dB. sensitivity yields a power requirement upwards of 30 WPC. From rayma's remark, I infer that there are dips in the speakers' impedance curve and we should regard them as 4 Ω, instead of the nominal 8. Unfortunately, that derating entails a 3 dB. sensitivity penalty. IMO, PP KT88s are appropriate and either of the tried and true Mullard or Williamson topologies will serve well in a DIY effort.
If the OP can borrow a Harman-Kardon Citation II or McIntosh MC275 that's in good repair, an excellent idea of what "correct" tube amplification will do with the speakers can be ascertained.
Applying Joppa's Rule to that 88 dB. sensitivity yields a power requirement upwards of 30 WPC. From rayma's remark, I infer that there are dips in the speakers' impedance curve and we should regard them as 4 Ω, instead of the nominal 8. Unfortunately, that derating entails a 3 dB. sensitivity penalty. IMO, PP KT88s are appropriate and either of the tried and true Mullard or Williamson topologies will serve well in a DIY effort.
If the OP can borrow a Harman-Kardon Citation II or McIntosh MC275 that's in good repair, an excellent idea of what "correct" tube amplification will do with the speakers can be ascertained.
A pair of EL34 can give you a bit more than 50 clean rms Watts, so probably you could be ok with them, but for sure in a large room it is safer to have more watts. Then it's your choice to parallel another pair if tubes or switch to a single more powerful one.
In all honesty an EL84 push-pull might not be the be all and end all, but even with 88dB/W/m -sensitivity speakers you might be surprised at how sufficient it can be. I currently run a pair of old Penaudio Rebel 2's in a slightly larger room than that, and although I now use my EL34 PP monoblock pair to run them, even my smaller EL84 PP integrated was perfectly enough for all listening I've had time to do. And those Penaudios are far from 88dB sensitivity, probably more like 85dB.
I'd go with more power than EL84 with 88db speakers.
That said, I have 83db speakers where 10W is enough (but they are near field - I'm about 1M from them).
It comes down to the acoustics and size of the room you are in. If I were you, I'd be looking for 30W+ and I'd use cheap triode strapped sweep tubes to do it - the whole thing would cost less than making an EL84 amp due to the transformers and tubes being cheaper, too 🙂
That said, I have 83db speakers where 10W is enough (but they are near field - I'm about 1M from them).
It comes down to the acoustics and size of the room you are in. If I were you, I'd be looking for 30W+ and I'd use cheap triode strapped sweep tubes to do it - the whole thing would cost less than making an EL84 amp due to the transformers and tubes being cheaper, too 🙂
@kodabmx
Since you're here, and knowledgeable about Russian tubes (of which I am not) is the 63PS-e the best Russian alternative to the 6L6GB/5881/6L6GC family (I know, not all the same) or EL34/6CA7? I'm not asking regarding a specific OPT or amp, just looking for a bit of understanding.
Since you're here, and knowledgeable about Russian tubes (of which I am not) is the 63PS-e the best Russian alternative to the 6L6GB/5881/6L6GC family (I know, not all the same) or EL34/6CA7? I'm not asking regarding a specific OPT or amp, just looking for a bit of understanding.
I prefer 6P3S to the E. Works as well but less money. My first power amp used 6P3S.
6P3S-E is an uprated version. Both are equal to 6L6/6L6G/5881, but not the GB or GC versions (lower Pd).
6P3S-E is an uprated version. Both are equal to 6L6/6L6G/5881, but not the GB or GC versions (lower Pd).
The 6Π3C-E (6p3s-e) is an excellent 5881 "equivalent". The tube New Sensor markets as the Sovtek 5881 is 6Π3C-E.
NEVER, ever, buy direct from New Sensor. Reliable dealers, like Jim McShane, sell New Sensor products at prices less than those quoted on the NS web site.
Also, if you can get stock that predates New Sensor's acquisition of the Reflektor (Saratov) plant, you do yet better $ wise.
Also, if you can get stock that predates New Sensor's acquisition of the Reflektor (Saratov) plant, you do yet better $ wise.
I just went by the price in your link...
I see now that they are only 17$ from Tube Depot: TubeDepot.com | Sovtek 5881 / 6L6WGC Power Vacuum Tube
Still expensive compared to the tubes I use these days but not that terrible I guess.
All of the tubes I'm interested in are long out of production. 🙁
I see now that they are only 17$ from Tube Depot: TubeDepot.com | Sovtek 5881 / 6L6WGC Power Vacuum Tube
Still expensive compared to the tubes I use these days but not that terrible I guess.
All of the tubes I'm interested in are long out of production. 🙁
I am currently living with a 3.2 watt triode EL84 Class A PP. Speakers are currently about 84 dB. I am fine (unless i want to crank it — rarely)
EL84 is a very nice output tube. It is hard to make a bad EL84 amplifier. A good one can be REALLY good.
dave
EL84 is a very nice output tube. It is hard to make a bad EL84 amplifier. A good one can be REALLY good.
dave
I dunno what voltage/current/load you use, but with EL86 at 320V/40mA into ~2k5 Raa I get almost 10W out.
Or for a cheaper alternative to making an EL84 amp, Greg7 could use 6P1P and any design for 6V6 he likes.
Or for a cheaper alternative to making an EL84 amp, Greg7 could use 6P1P and any design for 6V6 he likes.
Why pay $17 for 6L6's when you can get 1625's for $5 all day long?😉
(Back to ebay to hoard more....)