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Beta 22 Gain?

post #1 of 35
2/25/10 at 10:48pm
Thread Starter 
I apologize if this has been covered before, but I couldn't find a thread with this info.

I am planning a 3 board beta 22 build and ordering it from AMB Labs Kits - Glass Jar Audio. What gain should I get if I am planning on using this with Denon D2000? (One of the boards has to be active ground right?) I also am planning on making small bookshelf speakers in the future and using the B22 as a small speaker amp as well.

Also, how much hook up wire will I need to complete this project? I have some beldon 24awg silver plated copper wire and am planning on getting thicker wire for the power runs, but don't know how much to get. Does anyone have recommendations for hook up wire?

I feel like I'm forgetting something I wanted to ask, when I remember I'll post it.

Thanks for the help.
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post #2 of 35
2/25/10 at 11:03pm
I'm sure that you could find plenty of answers by searching "gain" in the beta thread. Post questions there too. It is easier to have all questions in one place for future reference.

Get used to searching, as you will run into uncertainty during this project, and it is best to know how to find the answer yourself. The answers are out there, as there are about 5000 posts on this amp which already address pretty much any issue you might have, in addition to AMB's page.

Anyway, Denons I wouldn't go above 5x, or you might get hissing. 5 Probably won't work with bookshelves though, so you might want to think about a switchable gain or sockets for the gain resistors.

Hookup wire, probably 20 feet of 18awg for power wiring and 20 feet of 24 AWG for hookup, though I would go about 10 feet high on both of those estimates.
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post #3 of 35
2/25/10 at 11:31pm
b22 is not switchable for gain. its more than R's that you have to set. you have to set the compensation caps, too. no way to do that (well).

denon is very efficient. gain of 2 or 3 is even enough for those. my d2000 is very hissy in my b22 that has a gain of 5. otoh, that gain works fairly well for my senn 650's.
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post #4 of 35
2/25/10 at 11:46pm
Thread Starter 
Thanks for the responses. If I go with the 2x gain, would I be better off using the b22 as a preamp rather than trying to power speakers?

Say I purchase akg k701's in the future, how would a 2x gain handle those?

tintin47, which b22 thread would you rec I switch to?
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post #5 of 35
2/26/10 at 12:18am
Here's the thread that tintin47 was referring to. Read as much of it as you can and you should be golden.

http://www.head-fi.org/forums/f6/rol...beta22-243379/
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post #6 of 35
2/26/10 at 12:29am
Don't forget about your source too. If your source is particular hot or not, that would play into your decision.
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post #7 of 35
2/26/10 at 12:38am
Quote:
Originally Posted by linuxworks View Post
you have to set the compensation caps, too. no way to do that (well)
overcompensation isn't the end of the world. I doubt anyone can hear the difference really.
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post #8 of 35
2/26/10 at 12:47am
Quote:
Originally Posted by Anonanimal View Post
Here's the thread that tintin47 was referring to. Read as much of it as you can and you should be golden.

http://www.head-fi.org/forums/f6/rol...beta22-243379/
There's about 3 more of those over at headwize, too, if you get bored with that one.
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post #9 of 35
2/26/10 at 3:14am
Thread Starter 
awesome thanks
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post #10 of 35
4/20/10 at 11:51pm
I heard B22 2 channels with gain of 5 ... I can only use 1/6 turn of the volume control (alps).

No hiss at all ... HD650, HD800.

In fact, I wonder if gain of 2 will impact the SQ (giving dull sound ??)
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post #11 of 35
4/21/10 at 12:28am
Quote:
Originally Posted by pompon View Post
In fact, I wonder if gain of 2 will impact the SQ (giving dull sound ??)
Holly old thread batman!
Ok only 2 months.

If you can use gain of 2 (and if you only spin the volume control up 1/6 of the way you can certainly use much less gain than you have now = yes you can use 2) you may find quite a few improvements.
Attenuators work better at lower attenuations: the higher the volume knob is set the better it works!
Although it may be a result of the cheap attenuators I use (I dont think so) I generally find that amps have more detail the higher up I spin the pot, yes this includes keeping the overall output level the same by mucking around with the gain.
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post #12 of 35
4/21/10 at 12:32am
Quote:
Originally Posted by nikongod View Post
Although it may be a result of the cheap attenuators I use (I dont think so) I generally find that amps have more detail the higher up I spin the pot, yes this includes keeping the overall output level the same by mucking around with the gain.

Especially true for attenuators like the PEC carbon pots. Horrible matching between channels at lower spin points.
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post #13 of 35
4/21/10 at 1:04am
Quote:
Originally Posted by sachu View Post
Especially true for attenuators like the PEC carbon pots. Horrible matching between channels at lower spin points.
Indeed, thats why the SPUD had gain of ~1 or 2 for low or high impedance headphones.
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post #14 of 35
4/21/10 at 7:50am
Quote:
Originally Posted by sachu View Post
Especially true for attenuators like the PEC carbon pots. Horrible matching between channels at lower spin points.
too true. i just changed the gain on my M3 from 11x to 6x yesterday for this reason. this particular PEC pot also has noise up to 9 o'clock as well.
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post #15 of 35
4/21/10 at 8:03am
the upside is that it does sound so much better than an ALP RK27..
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