I have heard a lot of amps, but heard my first 845 (a Chinese integrated) a year ago, and in comparison with other tube power amps was bowled over by the distinctive effortless muscular rich meaty sound. I have an excellent preamp and at that time it was way beyond my budget. I’ve been looking out to get that sound ever since . .
I now have the rare (here in Australia) opportunity to buy a 2nd hand pair of 845 Chinese power amp monoblocks. Extremely well reviewed in several forums and a number of mags (won a TAS award) esp for its value. On the face of it, buy it . .
Googling exhaustively, the only area of concern all the comments - an intriguing comment in a detailed review:
“Unlike most other 845 based designs, there is none of the indigenous-to-845s plumpness and excessive warmth in midbass . .”
The sound for an 845 is * "lean".
I am newish to diy, know different caps can change sound, as of course can different drivers or speaker alignments.
If I purchase and find this sound lean – how easy it to give it to tweak it – or any - SE amp to a little more ~ meaty/ rich/ warm sound ~ by e.g. cap positions & brands?
Thank you
I now have the rare (here in Australia) opportunity to buy a 2nd hand pair of 845 Chinese power amp monoblocks. Extremely well reviewed in several forums and a number of mags (won a TAS award) esp for its value. On the face of it, buy it . .
Googling exhaustively, the only area of concern all the comments - an intriguing comment in a detailed review:
“Unlike most other 845 based designs, there is none of the indigenous-to-845s plumpness and excessive warmth in midbass . .”
The sound for an 845 is * "lean".
I am newish to diy, know different caps can change sound, as of course can different drivers or speaker alignments.
If I purchase and find this sound lean – how easy it to give it to tweak it – or any - SE amp to a little more ~ meaty/ rich/ warm sound ~ by e.g. cap positions & brands?
Thank you
If I want a warmer sound from an amp I like to use carbon resistors. Another trick could be to replace 6SN7 like stages (if any) with some similar device like a 12AU7 for example.
I find the resistors will warm and soothe the tone whereas the 12AU7 adds a kind of richness to the sound.
BTW, I have heard that the OPT's in some chinese amps might be undersized, don't know.
I find the resistors will warm and soothe the tone whereas the 12AU7 adds a kind of richness to the sound.
BTW, I have heard that the OPT's in some chinese amps might be undersized, don't know.
Changing the bias so that it's in the non linear region (lower current) tends to make them sound "fatter" because it adds more 2nd harmonic. Also changing the value of the plate resistor on the driver tube. Or if it has a active load then change the value of the pull-down resistor on the following stage. Either of these may or may not, effect the power output. It will depend upon how the design is setup as-is and how much you want to change it. But, on the bright side a "lean" SET amp will still sound fatter then most push-pull amps.
rick57 said:
It probably wouldn't be accurate to make a blanket statement here but in my experiences the 6SN7 sounds fairly (very) clean and accurate whereas the 12AU7 adds a rich warmth that fills out the sound. Almost a blooming warmth but not in a tubby way. (sorry about the adjectives
)From my uses I have found the 12AU7 when underbiased sounds a bit like many underbiased triodes to me (maybe a little thin and a little harsh/nervous)(YMMV). I like the contribution once you get the current up beyond a few mA.
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