universal chip pre-amp project

[mjf]

hello.
........yes, 3k or 3,3k paralleling should give you a gain around 14.
greetings

[digi01]

Originally Posted by cjkpkg

So, if my math is correct, paralleling a 3k resistor in series with R5, R6 would yield about 750R...1/(1/1000)+(1/3000)=751.9

(10+1)/.7519 = 14.6

yes.

one more thing,the R9,R10 fixed the source impedance(looking back into the output of UCP).does the power amp have a pot?trying to turn on it at least two clock or bypass it.

z

[cjkpkg]

The only pot(s) I use are on the outputs of the preamps I use - the aikido and the UCP.

I have to check and see if I have any 3k resistors on hand...I will try this out in the next couple days.

[cjkpkg]

OK,

All I had was some 1.5K resistors on hand so I put those in as digi had suggested on the bottom of the board.

So far so good...the gain has picked up considerably.

Thanks for the help!

[cjkpkg]

I just hooked up the UCP to the SimpleSE and with the additional gain it sounds fantastic...

[40 watt]

I have populated one of the UCP V1 boards for simple stereo and am awaiting appropriate transformer[s] Can I use non-polarized electrolytic caps for the 1-47uf caps? It's all I have for now but I have more polarized caps coming in an order I placed for various things at Digikey.

I was also wondering, after reading app notes of LM4562, which I'm using on pre-amp board, about how to implement an LM4562 active crossover either pre or post gain of pre-amp board, for bi-amp situations. I'd love to get rid of the passive crossover of my 2-way speakers. Since I have a pair of the pre-amp boards, would each pre-amp board be used in a bi-amp setup? 4-gang volume contol into seperate crossover board in front of each pre-amp out to seperate power amps of choice? Tube, discrete or chip with resistor adjusted gain in pre-amp as appropriate?

Can this be done with a 2-gang stereo pot and one pre-amp board?

Or would such an active crossover go after the pre-amp and associated gain?

I'm just trying to get an idea of the simplest way of doing this and maintaining universality of the design.

Are other variations possible? LR intead of Butterworth?

[AndrewT]

go to the ESP site and do some reading.

[40 watt]

Originally Posted by AndrewT

go to the ESP site and do some reading.

What a great site from Rod! Project 09 was a most stimulating read. I'll have to read and re-read that and other crossover and opamp stuff.

An SMT board version would be a nice compliment to the UCP V1, in the spirit of maintaing shortest possible signal path, even though all the opamps seem to make longer paths acceptable.

Maybe this will make me familiarize myself with circuit board software, and see what I come up with, once I learn to crawl faster and maybe even stand up and walk...

As a side note I thought I'd let you know my DigiKey package showed uo
[like, the next day after I ordered it all ] and includes many variations of zoble components and coupling devices. ] My woofers are PE buyouts, a a variant of Vifa P17WJ polys and I like them alot. This variant is now non-replaceable. Even though they were inexpensive I like them so I takes no chances. I would like to thank you personally for continuing to push home the risk/reward ratio of consequences in minimalizing circuits.

Now, on to replacing all the electros in a nice old Luxman integrated I've had for awhile. The task at hand.... It's a nice amp, All Elna caps, original Silmics were all over the preamp, tone controls [opamps there too] and phono amp sections. I'm replacing them with Elna SilmicII's and Panasonic FC everywhere else, 25V. 50V, AND 100V. 15000uf 63V Panasonic THA for main big power caps. $50 for all the caps with lots of leftovers. Most of the caps were almost half-off price if I bought 10.

...but back to the thread.

SMT and opamp electronic crossover board for 2-way and/or 3-way anyone? Voltage from one transformer for both crossover and preamp? Is that as simple as having power connecor pads on the crossover boards to feed out to preamp board on a shared supply? they'd both be 12Vish.

Appropriate jumpers to Digi's wonderful preamp board?

I'd buy!

Digi?

[digi01]

Originally Posted by 40 watt

I have populated one of the UCP V1 boards for simple stereo and am awaiting appropriate transformer[s] Can I use non-polarized electrolytic caps for the 1-47uf caps? It's all I have for now but I have more polarized caps coming in an order I placed for various things at Digikey.

hi,i think non-polarized electrolytic caps for C1,C2,C3,C4 is good.i have tested 1uf non-polarized caps(i buy them for max232 gear) and 1uf 0805 packaged smt caps.the UCP work under the fix regulated LM7815/LM7915 power supply,sound great!
what kind of power supply are you using?unregulated or regulated?

zang

[digi01]

Originally Posted by 40 watt

I was also wondering, after reading app notes of LM4562, which I'm using on pre-amp board, about how to implement an LM4562 active crossover either pre or post gain of pre-amp board, for bi-amp situations. I'd love to get rid of the passive crossover of my 2-way speakers. Since I have a pair of the pre-amp boards, would each pre-amp board be used in a bi-amp setup? 4-gang volume contol into seperate crossover board in front of each pre-amp out to seperate power amps of choice? Tube, discrete or chip with resistor adjusted gain in pre-amp as appropriate?

Can this be done with a 2-gang stereo pot and one pre-amp board?

Or would such an active crossover go after the pre-amp and associated gain?

i like bi-amp concept but i have not working on it.
i think a 2-gang pot is ok.the active crossover go after the pre-amp.you can set up the UCP like a distribution amplifier,the below photo show one channel connection: