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jaudio 7th January 2005 03:33 PM

help with chip preamp
 
I need schematics for a good ic preamp. I'll take all the help I can get

arcom 7th January 2005 03:39 PM

Hi!

Do you need just a preamp, or should it include tone controls as well? You can try with TDA1524A from Philips or LM1036 from National.

Nisbeth 7th January 2005 03:55 PM

Have a look at project 88 or project 97 from sound.westhost.com


/U.

jaudio 7th January 2005 04:51 PM

Yes just a preamp

I made project 88 and 97 I'm looking for something different

Alcaid 7th January 2005 07:43 PM

What about this one?

http://www.pha.inecnet.cz/macura/buffer.gif

From here

jaudio 7th January 2005 08:21 PM

Thank You

That 1. I need at least four more

Nuuk 8th January 2005 08:45 AM

When you get bored with IC's, you may lie to step up to something like this . ;)

awpagan 10th January 2005 12:25 PM

Looking for more in on preamps
look at this
http://www.mhennessy.f9.co.uk/preamp/index.htm
keep you occupied for at least an hour or two?

federico moreno 10th January 2005 09:27 PM

simple preamp
 
Hi.
As Alcaid suggested, the PMA -Pavel Macura- buffer alternative is a very good one. Check out if you need some gain, ´cause the system in the picture doesn´t have any. But it´s easy to re-arrange and convert it in a preamp. Check out Burr Brown´s appl.note ¨combining an amplifier with the buf634¨ in the link below.

I´m using something very similar, with a gain of 2.5, based on opa602ap. The BUF634 runs in high bandwidth mode -with little heatsinks attached, because in that config. the chip gets real hot-.

I recommend you with great confidence the OPA602: it´s not too picky a chip to use in this application, very stable and with excelent dynamics, but paradoxically with a superbly smooth sound. You´ll never get tired of it.

I have checked OPA134, 604 and 627 too. The latter is very, very good and revealing. But I happen to like more the 602.
If you use some sockets, you can change opas and make decisions more easily.
Enjoy!

PS: the link,
http://focus.ti.com/lit/an/sboa065/sboa065.pdf[/URL]

federico moreno 11th January 2005 04:55 PM

chip preamp II
 
Jaudio, why don´t you try something very simple? -I mean a single opamp in some basic configuration, be it inverting or non inverting (it's up to your liking).
Previous to my experience with the opa/buf combo, I tried a simple topology for opa627: non inverting, gain 3, 2uF input cap, 100 k input impedance, 50ohms output resistor...
Add a good regulated PSU, +/-15v , with some fancy 2200 uF reservoir caps, and with good decoupling close to the chip -some paralleled 100n and 100uF from each opamp psu pin to ground-, and maybe you´ll get something interesting.
I have had very good results with that scheme. If you only need to feed a normal input impedance power amp with not very long interconnecting cables, you can skip the use of buffer chips.
Cheers


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