Shoewreck
500+ Head-Fier
A friend gave me an amp ripped from his MM Sven speakers. It was built on a pair of TDA2030A's. I don't listen to loudspeakers at all, so finally I decided to use it to drive my headphones, as a PA can provide enough current for nearly anything and enough voltage for 600 Ohm cans.
The amp wasn't BTL, so wiring was easy. Here are some mods I made to get better match to my setup:
0) Two 6.3mm headphone jacks - I have two pairs of headphones to power.
1) Tone bypassing - just removed that pots and jumpered the holes for Bass control. Standard Baxandall circuit is so easy to bypass
.
2) Additional 100nF metal film PS filtering caps: I hope they mentioned them in the datasheet for a reason and the PCB already had pre-drilled holes for them.
3) Amp gain was cut from about 43 to about 33 - I dont need so much and I believe that stronger feedback would make that high-open-loop-gain amp sound better.
Mods to do:
0) Housing
1) More feedback - cut the gain to about minimum allowed 24dB as soon as I get going well-matched resistors.
3) Tantalum decoupling caps - having electrolythics in feedback is as bad as having them in signal path.
4) Class A biasing - actually I doubt if I need it. Given an AB mode amp with quiescent current of about 40mA it is unlikely co come off the pure class A PP with my cans.
And, finally, the impressions vs. my soundcard line out:
1) Great volume increase.
2) Attack became much sharper
3) A bit noise, almost out there with more feedback (and definetly in there with Grados
)
4) Some veiliness - this might be a kind of light distortion, or just the electrolythics. Feedback has helped a bit.
The amp wasn't BTL, so wiring was easy. Here are some mods I made to get better match to my setup:
0) Two 6.3mm headphone jacks - I have two pairs of headphones to power.
1) Tone bypassing - just removed that pots and jumpered the holes for Bass control. Standard Baxandall circuit is so easy to bypass
2) Additional 100nF metal film PS filtering caps: I hope they mentioned them in the datasheet for a reason and the PCB already had pre-drilled holes for them.
3) Amp gain was cut from about 43 to about 33 - I dont need so much and I believe that stronger feedback would make that high-open-loop-gain amp sound better.
Mods to do:
0) Housing
1) More feedback - cut the gain to about minimum allowed 24dB as soon as I get going well-matched resistors.
3) Tantalum decoupling caps - having electrolythics in feedback is as bad as having them in signal path.
4) Class A biasing - actually I doubt if I need it. Given an AB mode amp with quiescent current of about 40mA it is unlikely co come off the pure class A PP with my cans.
And, finally, the impressions vs. my soundcard line out:
1) Great volume increase.
2) Attack became much sharper
3) A bit noise, almost out there with more feedback (and definetly in there with Grados
4) Some veiliness - this might be a kind of light distortion, or just the electrolythics. Feedback has helped a bit.
