6 Channel volume control PT2325

[hansueli]

hello guys

What do you think about PT2325 for volume control?


I plan to use PT2328 with WIMAs MKS2 1uF 63V 5% for IRS2092 amplifier.




Do I need to have two decoupling capacitors? 1uF at output of PT2325 like datasheet and 10uF of input for IRS2092? Or is it possible to have only the bigger one? Would 15uF be better for IRS2092?




On schematic one resistor and capacitor have no value.


Will 100R be good and 100nF ?


Thanks


I modded a Sony BDV-E2100 with 3 PCM5102A as DAC and its works great.

I have also the 6 channel IRS2092 amplifier.


Thanks

 

[Mark Tillotson]

Use all the caps as shown in the datasheet, all the performance figures assume this. There are considerably more than 2 capacitors!


The datasheet text explains Cadj is 100pF for 1MHz operating freq - go with that. The R is
for filtering out noise on the digital rail - try 47 or 22 ohms, something like that.

 

[russc]

I believe the op was asking if he needs both an output cap from the volume control chip feeding the input cap of his power amp board.
If so, then no, not when they are in the same enclosure and permanently connected.
Only one cap is needed.
Were the boards in separate enclosures then a cap on the output of one & input cap on the other would be usual as you may mix and match your equipment without danger.

I guess 'R' is to drop the voltage to 10V if say you had 15V rail.
Cadj the datasheet suggests 100pf for 1MHz osc freq.

 

[hansueli]

Thanks fors the answers.


So I made some changement. I added footprint for 15uF capacitor of IRS2092. Cap I want to use for it is WIMA MKS4 15uF 50V RM22.5. They are very big.


If I want to use the controller without 1uF or 15uF I can solder wire instead of the caps.




I will us 7808 regulator for TP2325. Input is 12-18V.



Is the design of the PCB good?


What would be better as amplifier: IRS2092 with IRF6645 or TAS5630B?

 

[Kay]

has anybody a source for a datasheet with more than four pages?

I see 48 steps, but I don't 2dB step or anything else

 

[jaxcore]

Have you considered using the CS3118 chip instead? It's 8 channel and has really good specs (127db dynamic range).

 

[hansueli]

Hello jaxcore. Sorry but I find nothing with CS3118 on google.


Is this controlled by uC or DC?

 

[hansueli]

so with adding Cirrus Logic I found it but it's SPI or I²C.


I want DC funktion.


Or with SPI / I²C I can use the output from my BDV-E2100?

 

[russc]

try CS3308/3318 | Cirrus Logic

 

[jaxcore]

Oops, yeah that's CS3318:

CS3318-CQZ Cirrus Logic Inc. | Integrated Circuits (ICs) | DigiKey

You could make a 7.1 preamp with that. You'd use it the same way as the PT2325, but it has higher fidelity.

 

[Kay]

Have you considered using the CS3118 chip instead?

of course not,
the title above is PT2325

p.s.
CS3308/3318 are digitally controlled, not with DC (analog voltage)

 

[PRR]

> I see 48 steps, but I don't 2dB step or anything else

I see "0 ~ -100dB/per channel", which suggests 2dB steps?

 

[hansueli]

Exactly. Thats why I want to use TP2325 because its DC controllable.


Other option is an old chip from Renesas but they have no datasheet.

 

[stratus46]

so with adding Cirrus Logic I found it but it's SPI or I²C.


I want DC funktion.


Or with SPI / I²C I can use the output from my BDV-E2100?

DC control limits you to simple control of all channels. You can't alter gain of
1 channel vs another. 48 steps is a bit crude. I looked into gain control chips
before building my 6 channel preamp. I had a Chinese 6 channel remote
board based on the Mitsubishi M62446 and it was adequate but I wanted
better performance. I'm using 3 Cirrus CS3310 (same as PGA2311) stereo
chips and 3 NJW1119A stereo tone control chips all controlled by an Arduino
UNO board. Bass, Mid and treble have an 'all' control but individual channels
can be offset, same as the volume settings. The microcontroller route allows
far more flexibility. The TV controller also runs the audio system meaning
ANYBODY can run it exactly like a plain old TV. It does stereo when that is
all that's available and switches to 5.1. It's DIY. It's fun.

G²

 

[hansueli]

stratus46 sound good but much more complex and expensiv. Have you some pictures of the board?


Thanks

 

[Kay]

DC control limits you to simple control of all channels.

of course,
but here I expect no discussion for other solutions.

The PT2325 is cheap und a simple/good design.
Sometimes these are properties, I'm looking for.

(for individuell control, it's possible to use one PT2325 per channel,
or to form groups)

 

[stratus46]

stratus46 sound good but much more complex and expensiv. Have you some pictures of the board?


Thanks

Here are some pix if I didn't mess up. The top and bottom shots have all the ceramic bypass caps and resistors mounted. The resistors are all thin film 0.5% except for the 4 resistors around the LM317 and LM337 regulators which are 1% thick film, all 0805 size. Signal caps for the NJW chips are 2% film.

Board is 4 layer and has a few silk screen errors but the traces are all correct.

I don't know how to post the schematic yet. It was my first try using KiCad.

G²

 

[stratus46]

Here is the schematic of the 6 channel preamp. I didn't use any coupling caps so it's DC coupled. The power amplifier input has coupling caps and the DAC output has them too so it isn't really DC coupled overall.

Note that the CS/PGA chips gain ranges from -95 to +31 dB in 1/2 dB steps so it is a 'preamp'.

G²

 

[hansueli]

I thing having super high-end DAC but only cheap TPA3116 board does not mach so good.


Or have you modded your 5.1 TPA3116 board?


I already own a TP2325. I only need to make the pcb...

 

[stratus46]

The power amp board has no mods at all. I'm running on a 19 Volt supply so it
does a little over 20 Watts into 8 ohms. Distortion levels are not that great on
paper but not at all bad just watching TV. 6 channels for $30.

As far as the PCB goes, I used JLCPCB in China. I emailed files Wednesday
morning from Los Angeles and had the boards in hand the following Tuesday.
5 pieces were $53 including $17 2nd day shipping. I was very happy with that
and still have 4 pieces.

Good luck.
G²