Anybody who likes SMD headphone amps?
Mar 22, 2003 at 7:05 AM Thread Starter Post #1 of 19
peranders

peranders

Member of the Trade: Sjöström Audio
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Here you can find my cool SMD headphone amp. I have got samples from AD and Texas. I will test a OPA134, OPA627, AD8610 and a SMD BUF634. I'm amazed that you can get 3 samples of OPA627 for free!!

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Anyway, the pcb's are arriving any day now. This is my first SMD audio project. I do it all the time at work since many years back so I thought it would be fun to test it in audio. Next project will be a vinyl amp in SMD and then a power amp 2 300 W MOSFET but this is the future....

Is the sound better in SMD parts than hole mounted? I have no idea. I wonder though if very small resistors like 0204 have phenomina which hole mounted don't have (noise, voltage dependency etc). What happens in these very thin and tiny resistance layers
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Mar 23, 2003 at 5:11 PM Post #3 of 19
Quote:

Originally posted by Tomo
I got few chips ready under my sleeves. Thanks for sampling.
I am thinking BUF634 with AD8610 on ya board what do you think?


I will test this opamp, seems to be very good. Notice that max voltage is 27,3 volts.
 
Apr 16, 2003 at 5:23 PM Post #6 of 19
Thanks, Morsel (BTW: Are you the only lady around? I have never met a female with electronic skills, not even a sales person! Electronics are VERY much a guy thing, and in particular diy.)

The pcb has groundplane at the downside, not clearly visible in the picture. Later on I will take a better picture. Not also that my other pictures at my homepage are taken with the same Minolta F100 but with a professional lighting and tripod. This picture is taken with flash at my desk. Huge difference in quality!

Yes, the data is not confirmed yet but I wrote it down so you can see where it can land.

I will also test Right Mark if my sound card is good enough.
 
Apr 17, 2003 at 11:51 AM Post #7 of 19
Today I have both tested and listened to OPA627, OPA134 and AD8610 (at +- 15V, didn't die!). Electrically AD8610 is outstanding, can handle too large signals excellent, offset at the out 0.046 mV cold and 0.079 mV warm!!!
The OPA627 can't handle large signals at high frequencies very well. It may be better if the signal is DC connected.

OPA134 is also excellent but have slightly higher offset, 2.5 mV at the output.

I have also tested the buffer at medium speed mode and high speed mode, no visible or audioable change.

Soundwise all opamps do their work very good. I (my ears) can't hear any major difference.
 
Apr 18, 2003 at 2:59 AM Post #8 of 19
Wow looks really nice. I would love to try and build one if it was battery powered, I think that would make one sweet portable amp. I think it would be nice to test out my skills as well by using SMD parts.

Anyways, nice job! I like it
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Apr 21, 2003 at 7:03 PM Post #12 of 19
There is a rule on Head-Fi that you can't volunteer anything that would make you money(FS posts on used stuff is okay, since presumably you're selling it for less than you bought it for). I suggest that you take a Mall-Fi ad out if you want to advertise on Head-Fi, because this post likely won't be here long. If you're content with a FS post on Headwize, fine, most people here read both AFAIK.
 
Apr 22, 2003 at 12:07 AM Post #14 of 19
cool smd amp, argh maybe after my ee98 ee97 class i'll attempt it ;after i finish up my other amps; after i get some money in this summer; sucks waiting
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