arteom
1000+ Head-Fier
- Joined
- Sep 5, 2006
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Yeah I saw that, one of the sexiest builds I've seen. But I don't know if it would be too proper to copy it, wouldn't mind at all doing so if it was, and of-course if he didn't mind .
Which BOM are you comparing to? The EHHA rev.A or the original EHHA? It seem that you have the original version, and you should follow the original BOM as well. The heatsink pads are made for a different heatsink in the original boards, that's why the heatsink would not fit. But yeah, the supplied heatsink is a little small. If you want to build the rev.A version you can get boards from jeff, and if you want, I've got a BOM at mouser that takes the difference between the two versions.
the same thing happened to me this summer. My kit was also the same age as hollands. I didn't check the heatsinks yet, but there's some wrong and missing resistors.
The heatsink holes have always been a bit weird with the original ehha board I think, I think it had something to do with the pcb manufacturer or something and you are supposed to remove the pins and just not use them or something (from the heatsink). Mine definitely have no pins at all on them. But really, your heatsinks are 5/8" tall? Maybe it would be different being used for speaker duty or something but my heat sinks really never even get very warm.
Yes, it would be possible to replace those fixed resistors with pots.
R22, R23 will be very tricky as mismatched pot settings will imbalance the complementary halves of the O/P stage.
Correct on the comp caps. You don't even really need them below 7.8. They were just needed to prevent the sq wave from ringing. You can see how much the slew rate drops with the big comp caps and I think you might notice this on very fast transients even though your ears can't possibly follow the audio at these speeds.
BTW, I know that the heatsink holes are a bit off. This is not Jeff's fault but mine because I suggested a particular supplier. This was for necessary reasons at the time to prevent the EHHA from going the way of the SOHA. No more to be said on this.
However, since none of you are likely to solder the heatsinks into the board, the easiest thing to do is to pull the mounting pins out of the heatsinks rather than trying to drill out the holes.