New error correction amp

Hi, PMA

According to a large number of our listening tests there is an audible difference between the same stage with and without error correction
Could you describe what sonic difference between one amp without error correction and the same amp with error correction (especially Hawksford type)?
Is it more audible in bass or midrange or treble?
 
lumanauw said:

Could you describe what sonic difference between one amp without error correction and the same amp with error correction (especially Hawksford type)?
Is it more audible in bass or midrange or treble?

Well - I do not prefer speaking about midrange, treble etc. The biggest difference is in smoothness, liquidity of sound of the circuit with error correction. Also better in musical instruments resolution/definition.
 
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PMA

Where do you get 2SK413/2SJ118 from?
I've searched for them but couldn't find.
Farnell says they are no longer manufactured.

How does the amp compare soniclly to your Class A 20W amp?
Does the amp need a lot of heatsink?
Are you running it from regulated supply?

I would like to try this design.

Bartek
 
PMA said:


Looks like interesting circuit idea. Have you already tried it?


Yes i have tested the circuit i posted. it sounded great however measured worse than the normal Class Ab biased version and was also unstable at low ICq. this was as installed in this DIY Headphone amp http://tangentsoft.net/audio/ppa/
driving assorted headphonens in the 32-300 Ohm range
the IMD and THD were 10 times worse than the Class AB circuit. However sonicaly this version sounded better as PMA pointed out. si i began a second circuit that actualy started to behave like the Dynamicaly biased circuits i read about in the 100 or so patents on the subject. in essence you get the same THD at half the Class AB Icq. well since the previous version had more THD and way more IMD than Class AB and required three times the Current to be stable is not what i was reading these circuits are for so i came up with yet.

attached is this second idea
 

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zygibajt said:
PMA

How does the amp compare soniclly to your Class A 20W amp?
Does the amp need a lot of heatsink?
Are you running it from regulated supply?

I would like to try this design.

Bartek


The new amp sonically resembles class A amps, but does not sound same. Sound of the circuit displayed also depends on opamp used. The conventional VFB opamps do not make good job, it was necessary to use fast CFB opamp - AD844. Please note the frequency compensation (680R, 56pF). For CFB opamps it is impossible to put capacitor from output to -input.

Heatsink requirements are much lower compared to the class A amp, because quiescent current is also much lower. The sound depends on quiescent current a bit. I would recommend quiescent current about 300mA.