h82missafire said:
Rod-core inductors are very compact, very linear, low cost devices. Yet as Tekko has accurately described. are fecal matter when it comes to radiating or inducing interference.
The best inductors, interference wise, are toroids. Additionally, there are some shielded drum core inductors from several vendors, but all of what I've found are surface mount only. I don't know if they would fit in such tight quarters, though. Check for instance, Tyco Coev's MGDQ6 series.
That is what I was thinking too Tekko, but fitting them in might be a problem unless you put them on the bottom of the board.
FYI, I hooked a 12v, 1.2 amp smps and some small test speakers with my Lightspeed and a cheapie DVD player and no loud hum but I don't have time right now to listen more.
More later.
FYI, I hooked a 12v, 1.2 amp smps and some small test speakers with my Lightspeed and a cheapie DVD player and no loud hum but I don't have time right now to listen more.
More later.
OK, I did a little more listening on a set of better speakers and using 12v smps, there is a bit of what I would call "white noise". A slight hiss. I'm going to try the other inputs, using shielded cable and see if that makes any difference. The next is test is linear PSU, then different inductors.
I think this has promise though. A little shy on the bass but the mids and highs are good.
I think this has promise though. A little shy on the bass but the mids and highs are good.
Are you sure? The Zobel caps on the one I bought are marked '105', ie 1uF. I think the resistors on mine are 10 Ohm as well. (10R + 1uf sounds realistic, but the resistors are only 1W at the most, and the caps are very small).
Mine only arrived two days ago , so I've not tried it yet, (and I could be wrong about the Zobel components, though I don't think so. How are your conponents marked?).
Mine only arrived two days ago , so I've not tried it yet, (and I could be wrong about the Zobel components, though I don't think so. How are your conponents marked?).
Re: Photos
If it helps at all, the large version of the photo should let you see a lot of the components on the Version 1.1 board that I got.
Large photo of board - it's bigger than your screen, probably, so hover over the lower right (in IE) until the icon to expand it shows up
Though the C1 type can't be read easily there, in another photo it pretty clearly looks to be 224 to me:
Closeup of C2
Other photos here:
Photos of Sure 4 Channel Amp
I have some other photos I could add, if there's something someone is particularly interested in.
If it helps at all, the large version of the photo should let you see a lot of the components on the Version 1.1 board that I got.
Large photo of board - it's bigger than your screen, probably, so hover over the lower right (in IE) until the icon to expand it shows up
Though the C1 type can't be read easily there, in another photo it pretty clearly looks to be 224 to me:
Closeup of C2
Other photos here:
Photos of Sure 4 Channel Amp
I have some other photos I could add, if there's something someone is particularly interested in.
Received mine today and hooked it up to a pair of test speakers and a 24V 3A SMPS with an old Sony Diskman (with a real line out) into a "passive preamp" with a 50K pot volume control as a source. I just had it laying on the bench not shielded from anything with the non-shielded SMPS within 6 inches.
It had zero hum or buzz but there is definitely a hiss. However I had to be within 8 inches of the speaker to hear it. The first test speakers were 87dB/1W/1M. My son with much younger and better ears than mine couldn't hear the hiss more than 10" from the speakers. In fact the fan on the SMPS was audible from much further away.
It would be nice if it were dead quiet but since my normal listening position is quite a bit farther than 8" from my speakers the hiss is really a non-issue.
More listening with better speakers and sources is in order but so far I'm quite happy.
It had zero hum or buzz but there is definitely a hiss. However I had to be within 8 inches of the speaker to hear it. The first test speakers were 87dB/1W/1M. My son with much younger and better ears than mine couldn't hear the hiss more than 10" from the speakers. In fact the fan on the SMPS was audible from much further away.
It would be nice if it were dead quiet but since my normal listening position is quite a bit farther than 8" from my speakers the hiss is really a non-issue.
More listening with better speakers and sources is in order but so far I'm quite happy.
V1.1 is marked on the board, but I think that is the pcb version mumber.
It would be interesting to know what other people have got fitted on the board. 1k is a very high value for the Zobel resistor, and I can't see it having any useful effect. If you had 220n and 10R fitted it would be more understandable. Have you measured the resistors to see if they really are 1k?
It would be interesting to know what other people have got fitted on the board. 1k is a very high value for the Zobel resistor, and I can't see it having any useful effect. If you had 220n and 10R fitted it would be more understandable. Have you measured the resistors to see if they really are 1k?
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