!!!!! Help - Ssm2164 !!!!!

[audioPT]

Hi!

I've been reading, searching, testing, trying to learn PIC and AVR programming, burning some chips and my neurons, among other things.

Finnaly, I've found somo interesting: the Analog Devices SSM2164.

This is a quad VCA with low distortion, operating in Class A (adding a resistor).

The moral of this history is the following one:

I need to control the volume of my six inputs (5.1) amplifier - I'll use it in the pre-amp.

My question is this, as I can't find the answer in the datasheet:

The VCA is controlled by a 100k pot. If I connect pins 3, 6, 7 and 14 of IC1 and 3 and 6 on IC2 together (control pins) and connect them to the central tab of the pot, does it work like a "Danish Audio Connect" CT2 ??

Down here is the basic schematic of one SSM2164.

Regards

Pedro Martins

[audioPT]

Sorry,

Forgot to write this:

I've been thinking using the Aleph P 1.0 volume control, with the ADC0801 with relays, but after some accounting... more than 200 Euros in relays...
The DACT is cheaper...
But the SSM's are almost for free... 1,5 Euros each!

[audioPT]

As nobody answered me, I've tried all by myself.

And I've got good results.

Low noise and no distortion audible. I'm going to measure the outputs with my PC and some cute software to check the %'s.

I'll use a buffered pot to drive all the control inputs.

Thanks anyway

Pedro Martins

[Upupa Epops]

DACT is based on rotary switches made by EBE, which are probably the best switches on the world. This was used in early machines for example by firm Burmester. It is precise device and is realy expensive. If you have high claims, use it. SSM will have all parametres worse, but I mean, that for using in comercial multichanel machine is good enough.

[audioPT]

Thanks for the reply Upupa Epops

More than 200€ is the cost of DACT switch

With those 200€, I hope contruct the preamp.

I've been working with my breadboard and I'm getting all the stuff I want.

Yes, it's true, the noise of the SSM's and some NE5532/4 can be heard when I get the volume to max position, but this is the cheapest way to get it.

This stuff isn't for me. It's for my sister, so the 'sound quality' is good enough

Basicaly, 2 SSM2164, 10 NE5532 and 2 NE5534, a lot of resistors and capacitors, a pot for the volume, a +12, -12, +5V PSU and a power switch. This is the preamp. The power stage is made with 7 ESP3A, 2 of them bridged for the sub.
A 19" 3 units Box handle all the stuff inside.
This is a compact multichanel integrated amplifier.

Great, isn't it??


I'll put here the schematics, PCB's and photos.

Regards

Pedro Martins

[carlmart]

Originally posted by audioPT
Yes, it's true, the noise of the SSM's and some NE5532/4 can be heard when I get the volume to max position, but this is the cheapest way to get it.

If noise is an issue you can always use upping stages.


Carlos

[audioPT]

How is that?

Upping the input levels of all channels and reducing the gain of the output stages?

I've tried that, and the SSM's started clipping

[sam9]

Take a look at this one, maybe the THD+N would work out a little better.

http://www.analog.com/UploadedFiles/...SSM2018T_b.pdf

[sam9]

You might also want to look at:

http://www.thatcorp.com/datashts/2181data.pdf

These are orderable through ProfusionPLC but a bit pricey.

This all just a suggestion, I haven't used these -- it is just backgound data from an idea I've thought about ocassionally.

[audioPT]

Thanks for all replyes!

I attach my first design of the preamp and if someone can comment, or help, I'll apreciate a lot.

It's 'very' uncomplete

The volume control is a pot connected to + 5V and Gnd, where the center tap connects to C33 and the control inputs of the SSM's.

The outputs are taken from U7, 8,9 and 10.

I'll post the complete schematic as soon as I test the output configuration.


Legend:
Do Selector -> From Selector
6 Canais DVD -> To the output of the DVD
E -> Left
D -> Right
FE -> Front Left
FD -> Front Right
LFE -> Low Freq Effects
SE -> Surround Left
SD -> Surround Right