My new baby

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#22
Beautiful

My god, it's gorgeous.:bawling: :bawling: :bawling:
Congratulations GrahamnDodder!

Now, to make it even better, allow me some suggestions.
You have space inside the box for a few more batteries.
With only one 9v battery you're using the op-amp at the very low voltage limit.
You'd be surprized at what that op-amp can do working at a voltage of between +/- 12V to +/- 18V.
I have a small portable headamp, that I use as a working tool (to test gear that doesn't have a headphone output), that has 4x9V batteries inside😱 .
That way, the op-amp, with fresh batteries, works at +/- 18V, and that also allows for voltage drops with time, the op-amp will work until the batteries are drained.
I made it at about 1 year, used it over and over and I didn't change the batteries yet.😉
Anyway, the main point here is that the op-amps like voltage, they produce much better sound with the voltage they like.
See if you can put inside the box at least 1 or 2 additional batteries.
 
#24
protos said:
Carlos , Graham
Do you get any hiss from using batteries?
Click to expand...

No hiss.
Anything.
Even with no source connected.
When I connect a source, I can only hear music.😎
I have my batteries wired in series (4), to get 36v.
Then, entering the board I have a pair of resistors to make a virtual ground, +/- 18v.
I don't like to use op-amps with single supplies.:dead:
 
#28
Carlos-

Thanks for the kind words.

regarding batts, I though about more voltage while building. But I am getting 50+ hours off of one garden variety 9v. Also, My little caps seem to handling the peaks pretty well with just the 4.5 volts per rail. Maybe I don't know what I am missing.

If I were to add voltage (and more mA-hours) I'd probably go with an 8-AA pack for 12 volts and lots more juice. Can the BB 2132 handle 18v per rail? What differences would I see at the higher rail voltages, other than more tired-battery-induced voltage drop before I got to the opamp's bottom threshold?

GnD
 
#29
Joe-

Thanks. I see you are from Canada. You have a little while to wait, but XM is coming. They are already partnering with a Canadian holding company and applying for the necessary licenses now. They'll ad a channel that does nothing 24/7 but extoll the virtues of Canadian beer and hockey (in french, of course) to keep the culture nazis happy, then you can get all the cool stuff, too... 😎

Where are you, latitude-wise? There are lotsa under-the-table users in Canada already. You just have to have a connection in the US for the billing address, until they get officially set up. That's easy enough.

As a source, I can tell you that it is completely addictive. Everything. All the time.

You can get info at www.xmradio.com .

All these cool DIY projects are nothing more than syringes to deliver my constant fix of XM...

GnD
 
#30
GrahamnDodder said:
Carlos-

Thanks for the kind words.

regarding batts, I though about more voltage while building. But I am getting 50+ hours off of one garden variety 9v. Also, My little caps seem to handling the peaks pretty well with just the 4.5 volts per rail. Maybe I don't know what I am missing.

If I were to add voltage (and more mA-hours) I'd probably go with an 8-AA pack for 12 volts and lots more juice. Can the BB 2132 handle 18v per rail? What differences would I see at the higher rail voltages, other than more tired-battery-induced voltage drop before I got to the opamp's bottom threshold?

GnD
Click to expand...

An op-amp likes voltage.
The difference between driving an op-amp on it's lower voltage limit (around +/- 5V) and it's upper voltage (usually +/- 18V) is sometimes like comparing a nasty JRC op-amp to a high end one, like the OPA2132.
What I'm telling you is that, aside from battery duration, not the most important factor, the op-amps have much better characteristics at higher voltages, and that you can see on the datasheets and hear for yourself.😉
You have a very good op-amp there, I like it a lot, but you don't know what you're missing.:bawling:
Yes, the OPA2132 can handle +/- 18V.
 
#33
GrahamnDodder said:
Carlos-
Thanks. I will give it a try.
Figure 3 9v's in series, which would give me 27v or 13.5v per rail. I am assuming that would get me safely into the sweet spot?
GnD
Click to expand...


That will be fine.😀
Much better that 8xAA batteries.
You would still have 12 V (or +/-6):dead: and it would be heavy as hell.:tons:
 
#34
Actually, a large bank of AA cells, while impractical, is probably going to be better than using 9V. They have more total charge and less series resistance. I'm about 90% sure of this, but I should (or maybe you should) look it up.

It would be interesting to see what the ACTUAL voltage of your rails are while playing music into your 'phones. They may sag considerably.

-Won
 
#35
My original CMoy ran off 24 AA batteries. That gave me ±14V. Draining 6mA off 2200mA batteries meant about 350 hours of continous play at decent levels before a recharge was required.

I tried it off a 9V battery and the difference is not negligible. It seems like every part of the sound is better with 28V, the bass, especially with the Sony MDR-V6, is astonishing, the overall sound is better. The OPA2132 definitely likes higher voltages. You might want to try the AD823AN (it is pin compatible with the OPA2132) it is a bit more forward. Especially with the V6, the sound is just awesome.

Hope this helps!
 
#38
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