Still don't get it right
the gain of my preamp is to high so when the volume is 0 there is still a lot of sound
i have the regular board of vicol with 6 relais
want to make the steps bigger to reduce the volume
I have try the calculator of JvE Logarithmic Attenuator Calculator
1.5 dB steps
10k 10k 6.8k 4.7k 3.3k 1.5k
39R 680R 3.3k 10k 27k 56k 10k
2.0 dB steps
10k 10k 8.2k 5.6k 3.9k 2.2k
6.8R 270R 1.8k 6.8k 18k 39k 10k
what do i wrong
the gain of my preamp is to high so when the volume is 0 there is still a lot of sound
i have the regular board of vicol with 6 relais
want to make the steps bigger to reduce the volume
I have try the calculator of JvE Logarithmic Attenuator Calculator
1.5 dB steps
10k 10k 6.8k 4.7k 3.3k 1.5k
39R 680R 3.3k 10k 27k 56k 10k
2.0 dB steps
10k 10k 8.2k 5.6k 3.9k 2.2k
6.8R 270R 1.8k 6.8k 18k 39k 10k
what do i wrong
Which one is the correct value for R31 ? In first release (ver 1.0) R31 for R2R 82K and shunt 16K. Now in rev 1.1 R31 for R2R 10K and shunt 82K.
Didiet
Didiet
Didiet,
The correct value for R31 R-2R operation is 82K.
There is a mistake in rev 1.1 drawing which I'll correct.
Regards,
Tibi
Last edited by a moderator:
tvicol
if I use the Jos calculator, your board is 10K use 6 relais 1 db attenuation
then the resistor value are;
10k 8.2k 5.6k 3.9k 2.2k 1k
270R 1.8k 6.8k 18k 39k 82k 10k
if i compare it to your value it's totally different
could you please explane
which steps must i do to get it work right on your board
thanks
if I use the Jos calculator, your board is 10K use 6 relais 1 db attenuation
then the resistor value are;
10k 8.2k 5.6k 3.9k 2.2k 1k
270R 1.8k 6.8k 18k 39k 82k 10k
if i compare it to your value it's totally different
could you please explane
which steps must i do to get it work right on your board
thanks
The values are pretty the same, depends only the reference in/out which is reversed.
For 1dB step attenuation and 63dB total attenuation, you must have:
R30 - 1K
R31 - 82K
R32 - 2K5
R33 - 47K
R34 - 5K8
R35 - 27K
R36 - 15K
R37 - 16K
R38 - 53K
R39 - 11K
R40 - 390K
R41 - 10K
For 1,5dB step attenuation and 95dB total attenuation, you must have:
R30 - 1K8
R31 - 68K
R32 - 3K9
R33 - 33K
R34 - 10K
R35 - 22K
R36 - 33K
R37 - 15K
R38 - 150K
R39 - 10K
R40 - 2M7
R41 - 10K
However I suggest you to go for something in between and choose 1,2dB step attenuation for a total of 76dB, which I believe will be more than OK.
R30 - 1K5
R31 - 82K
R32 - 3K3
R33 - 39K
R34 - 6K8
R35 - 22K
R36 - 22K
R37 - 15K
R38 - 82K
R39 - 12K
R40 - 820K
R41 - 10K
Regards,
Tibi
Thanks for clarification. Howto calculate value R-Shunt, so i can expand to 64 step for R-Shunt?
Didiet
Sorry for late replay, but I do not get mail notifications from this thread ... :-(
Our volume-controller can operate in shunt up to 32 steps.
A shunt calculator you may find on this page:
50-Step Shunt Attenuator Resistor Calculator - Neville Roberts
Regards,
Tibi
I want to make controller version and pga2310 atmega8515. We all components but I need some help with a VFD display!
It's CU20029ECPB-U1J. 2x20 character VFD.
This display has 4 levels of brightness, but do not know how I can change these levels.
Here is the datasheet of display : http://www.meditronik.com.pl/doc/a0-a9999/vfd20x2h.pdf
Can someone help me?
It's CU20029ECPB-U1J. 2x20 character VFD.
This display has 4 levels of brightness, but do not know how I can change these levels.
Here is the datasheet of display : http://www.meditronik.com.pl/doc/a0-a9999/vfd20x2h.pdf
Can someone help me?
Hi rob86,
Looks like you can use bascom command LCDCONTRAST
LCDCONTRAST x ' X = 0 to 3
from datasheet SOFTWARE COMMANDS - you have "Brightness Set 0 - 3"
Looks like you can use bascom command LCDCONTRAST
LCDCONTRAST x ' X = 0 to 3
from datasheet SOFTWARE COMMANDS - you have "Brightness Set 0 - 3"
Hi Rob, nice to hear another project finished and working. I plan to build one identical to yours. Could you tell me wich pcb-s did you used?
Thanks!
Thanks!
Of course i have read almost all of messages. I was hoping to find a project to etch my own pcb's.
This is quite a long thread! is there a group buy for any of these projects that is still active? What is the best method for volume attenuation? Is it stepped resistors or using a chip? I'd like a good volume control for my Phase Linear 400 Amplifier.
Hello Wanted: Digital control with a chip on the controller PGA2310, with output to LCD display. In this forum, I've seen similar. Could you please help me to give firmware scheme and seals in one file, I'm pretty hard to read the whole forum because I do not know much English. I live in Kazakhstan. If it is possible for soap xaker.66666@mail.ru. Thanks in advance.
My project is finished now and partially working. Not tested yet the remote control part but so far the most annoying thing is that the LCD backlight is not working. When i'm shorting E and C of transistor that is responsible with backlight i have light. Also on the pic 17 of uC wich is triggering the transistor i'm not measuring any change with DMM. I have tried all software and same result, not backlight. Any ideas ?
An externally hosted image should be here but it was not working when we last tested it.
