VC23, my new PGA2310 project

[zman01]

Newbie with VC23 preamp

Hi all,

A newbie here .

I have gone through the thread and see that there are 2 power inputs 12-0-12 and 6/9VAC on the VC23 preamp board.

I have a 12VAC power brick - can I use that to connect both points? Or do I need another power source? (Got 4-6V power adapter also)

-Zia

 

[IBM5150]

Hi Zman - welcome! You sound like you are where I was at post #58. I used 12.6-0-12.6 and 12VDC 0.3 amp wall wart inside my case. My preamp is still working great although I no longer have the MiniDSP in it and put the VC23 in a new box.

Eric

 

[zman01]

Eric,

Thanks for the reply - that means you are using 2 power supply units right?

-Zia

 

[IBM5150]

Yes I considered tapping off one leg of the other transformer, but I didn't want to risk any noise or loss of performance, maybe it would be OK, not sure. See attached.

 

[zman01]

The preamp was put together yesterday and is working fine! Thanks Eric on and others who shared details of their projects on this thread.

I have noticed one thing - if the amp (Hifimediy T4) is on before the preamp, there's a nasty pop out of the speakers when I turn the amp on. Is that normal?

 

[IBM5150]

Glad you got it working. Yes that pop is normal. The usual order for powering components is preamp, source, then turn the amp on last. When shutting it down, turn the amp off first, then the other components - that should fix it.

Did you use a separate AC or DC power source or tap off the AC transformer?

Eric

 

[moeder]

Hello all!

Ahead of it all, please excuse my stupid question! I just received the vc23 from audiophonics together with a transformer with 2x12v and 1x9v secondaries. The two wires from the 1x9v winding go into the 9 v post, but I end up with 2x2 lines from 12v secondaries for the 12v post on the pcb. Can i just connect any of the two together as "0" and the others as the two 12 v lines (as in: blue - yellow+blue - yellow, where blue/blue and yellow/yellow are the 12 v secondaries?)

Thanks in advance!
Timo

 

[moeder]

Never mind. Resolved.

 

[platenspeler]

Hi,

Are there differences between the board sold by Audiophonics.fr and the one available on hifimediy.com? The audiophonics website says that dipswitch 4 controls whether the preamp amplifies or not (0 dB). But the hifimediy site says that switch 4 controls a "vendor option" and switching between on/off does not seem to make any difference in max volume setting.

I ask, because I have two VC23 boards at home and both start to be quite noisy (humm) above the 00 (dB) point, and I'm looking for ways to keep the noise down.

My simple PGA2311 board with only 6-0-6 Vac power and not so expensive components is dead quiet even at high gain settings compared to this deluxe board with all its possibilities.

Maarten

Ps. I just noticed that hifimediy does not sell/stock this board anymore...

 

[hifimediy]

Hi, VC23 use a OP buffer at the input to get higher input impedance, this might lead to some hmm noise when dB level. Use a 47k resistor after input caps to ground to solve this.

 

[platenspeler]

Thanks for your suggestion. Do you mean the side of C14 and C15 that is connected to the relays (other side is already grounded through R18 and R10). It does not seem to make much of a difference.

Still the noise above the volume setting 8 (about the 0dB point for PGA2310 I assume) is much more than the PGA2311 board I have.

Is it possible to remove the OP stage, as I do not need the additional 3x amplification? can you share the schematic of the board?

Thanks,

Maarten

 

[hifimediy]

Hi, I suggest keep the OP because the input impedance of PGA2310 is not big, so a buffer is always needed. If you can, keep the R7=R11 and R9=R14, then the OPs will become a buffer with gain=1.

 

[luckyaua]

Hi, very good projects...hifimediy!
if i want to use the Vc43 in my 7.1 setup between multichannel analog DAC output and analog input of my final power amp (4*stereo) is this board useful?
May i change with remote the volume of all channel simultaneously for setting main volume?

If i want to use this with balanced xlr signal may i use one for 4channel and another for other 4channel?

Thanks!

 

[hifimediy]

Hi, very good projects...hifimediy!
if i want to use the Vc43 in my 7.1 setup between multichannel analog DAC output and analog input of my final power amp (4*stereo) is this board useful?
May i change with remote the volume of all channel simultaneously for setting main volume?

If i want to use this with balanced xlr signal may i use one for 4channel and another for other 4channel?

Thanks!

Hi, yes it's ok for 7.1, and you can control all channel's volume by setting main value. And it's 4ch/board when xlr using.

 

[luckyaua]

Thanks for answer..

and you can control all channel's volume by setting main value

so there is ch.1..8 volume and main volume?
So i may set different levels for single channel and then setting main volume like AV receiver? or there is a main volume that set the same leve for all channel?

 

[hifimediy]

Hi, you also can set 4 groups of volume: 1&5, 2&6, 3&7 and 4&8 individually.

 

[luckyaua]

please...can you explain me all the volume possibility?
Thankx

 

[luckyaua]

the options if i've understand all...are:
-volume Ch 1-2-3-4-5-6-7-8 separately
-volume Ch 1+2+3+4+5+6+7+8 togheter
-volume Ch 1&5 or 2&6 or 3&7 or 4&8 by twin

so ...is possible after i've setting different starting values for single channel for example:
1&5 -20db
2&6 -15db
3&7 -18db
4&8 -15db
to upper main volume of 5 db for all so after i've at the end:
1&5 -25db
2&6 -20db
3&7 -23db
4&8 -20db ?

or i can only by main volume setting for example -25db for all channels?

 

[hifimediy]

1&5 -20db
2&6 -15db
3&7 -18db
4&8 -15db
to upper main volume of 5 db for all so after i've at the end:
1&5 -25db
2&6 -20db
3&7 -23db
4&8 -20db
It's right.

 

[luckyaua]

...ok
if i use 2 boards for 8ch balanced in/out i must use 2 display and 2 remote controller or i can use one only remote and/or one display.

Excuse me for questions...but i wonna be sure that this board is useful for me!