Valve amplifiers

[nightyy]

If your speakers are 102db, IMHO you need to be looking at low power SET amps, say a 45, 2a3 or 801a. Push Pull amps will have way too much power for speakers of that sensitivity, you will get very little useable volume range.

Oh I think you have a point... I am currently using Class D Amps with low output (max. 15W) and can only use the volume poti from 7 o'clock to 10 o'clock, at very low levels left and right channels are not equally loud (I guess the poti is too unprecise)

So what I should be looking for are amps that are "single ended", and those mostly use tubes likes a '45', 801, 2A3, and I also saw low output amps that use:


300B
http://www.triode.co.jp/english/02.html
6BM8
http://eeaudio.com/eeaudio_008c.htm

I see a lot of DIY and semi-commercial products on the market. How do they differentiate from the 'commercial' products regarding sound quality and durability?

[Ali Tait]

I didn't mention 300b as you get about 7 to 9 watts which still might be too much!

The valves I mentioned will give 1 to 2 watts/ch, which might not sound a lot, but should be fine with your speeks.

If it's a very good SE amp you want, I'd speak to Nick (Lurcher) about it. What you spend with him will far outstrip the same spent on a commercial product IMHO.

[NRG]

Dont forget Ali, as per the recent AT discussions, some head room is needed, its better to operate well within the power rating rather than driving the amp too hard as distortion rises and compression can set in, so 8 to 9W may give you that bit of headroom...

[Ali Tait]

Aye, but we are talking 102db efficient speakers Neal, don't need a lot of power with those!

[NRG]

Agreed but thats not my point Operate the amp at a low power level where distortion is low and theres no risk of compression, operate a flea powered one at 50 or 75% of its rated power output and you increase both.

[nightyy]

One advantage would be that I would not be so limited in further choice of speakers. With a really low powered amp I will be forced to look for 100db+ speakers again.

And speaking of existent speakers: My Klipsch RB-25 are rated at 94db/Wm, how would a 2A3 amp handle them?

[Ali Tait]

My OB's are around that figure, and I find 15w/ch more than enough.

[Ali Tait]

Agreed but thats not my point Operate the amp at a low power level where distortion is low and theres no risk of compression, operate a flea powered one at 50 or 75% of its rated power output and you increase both.

Not disagreeing either, headroom is a good thing, how much power do you need with 102db speeks to have plenty headroon?

[Marco]

I agree with Neal.

Whilst I always enjoy listening to good examples of the low-power SE valve amp/high-efficiency speakers route, for the undoubted sonic qualities such systems have, I can also readily hear their deficiences, as at the end of the day everything in audio is a trade-off, and so you have to choose your compromises.

Although not 'perfect' either, I prefer the results gained by using huge and pretty efficient (95db) Tannoys, driven by 50W of pure Class A P/P, as the weight, scale, sheer authority, and near unlimited headroom, which is delivered with appropriate music, is crucial to achieving realism, and in turn, my enjoyment of music.

Next year I intend to go active, by adding another Copper amp to my system, which will not only remove the sonic deficienies of the passive crossovers in my Tannoys, but double the (pure Class A) power that I have available, which should give utterly stunning results!

Just as it is, sonically, that you can never have transformers or PSUs too big in a power amp, so it is that you can never have have too many QUALITY watts!

Marco.

[Ali Tait]

Aye mate, but there is a rather large difference between 95 and 102db.