aphex944
500+ Head-Fier
- Joined
- Aug 25, 2003
- Posts
- 699
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- 11
I recently built a CK²III DIY amplifier. I decided on this one for it's relatively cheap part cost, and interesting design. I was also encouraged by the few impressions I've read on various forums, including this one.
On the bench, it measured to be very quiet. However, with a capacitive load(used a 2200pF cap), the amp oscillates. I'm sure it's fine with every headphone out there, but it's still disconcerting that the amp doesn't have much headroom at all(like if it was driving a very long headphone cable). It's also thermally unstable, and the output transistors really need heatsinks. We had to keep on going back and adjusting the trimpots as it never really settled down.
This was disappointing, but I was in for a real shock once I listened to it. In it's stock form, the amp is positively horrid sounding. It has a very "dirty" sound to it: voices, cymbals, etc. have a gritty texture and almost offensive balance. There is NO smoothness whatsoever, and the bass is very poor. Overall, the sound is very upfront without much air, and generally lifeless and boring. A friend that was listening as well came to the same conclusions. It reminded us of a headphone output on a cheap CD player. We were using AKG K 271s, Beyer DT 880s, and DT 990s. The ONLY good thing I can say about it is that the noise floor is very low; the background is very quiet.
We're going to try swapping out the JFETs for some BJTs. As far as audio is concerned, we've always found that JFETs have a "dirty" sound to them. I hope this really changes the character of the amp and at least makes it listenable, because right now it's not
It's always disappointing putting money and labor into something that doesn't turn out right. Has anyone else had a negative experience with the SOUND of this amp? I'd like to highlight though that AMB did an excellent job with the board layout and parts recommendation. The board fit the case perfectly, and overall it was a decently easy build.
Pictures to follow!
On the bench, it measured to be very quiet. However, with a capacitive load(used a 2200pF cap), the amp oscillates. I'm sure it's fine with every headphone out there, but it's still disconcerting that the amp doesn't have much headroom at all(like if it was driving a very long headphone cable). It's also thermally unstable, and the output transistors really need heatsinks. We had to keep on going back and adjusting the trimpots as it never really settled down.
This was disappointing, but I was in for a real shock once I listened to it. In it's stock form, the amp is positively horrid sounding. It has a very "dirty" sound to it: voices, cymbals, etc. have a gritty texture and almost offensive balance. There is NO smoothness whatsoever, and the bass is very poor. Overall, the sound is very upfront without much air, and generally lifeless and boring. A friend that was listening as well came to the same conclusions. It reminded us of a headphone output on a cheap CD player. We were using AKG K 271s, Beyer DT 880s, and DT 990s. The ONLY good thing I can say about it is that the noise floor is very low; the background is very quiet.
We're going to try swapping out the JFETs for some BJTs. As far as audio is concerned, we've always found that JFETs have a "dirty" sound to them. I hope this really changes the character of the amp and at least makes it listenable, because right now it's not
It's always disappointing putting money and labor into something that doesn't turn out right. Has anyone else had a negative experience with the SOUND of this amp? I'd like to highlight though that AMB did an excellent job with the board layout and parts recommendation. The board fit the case perfectly, and overall it was a decently easy build.
Pictures to follow!