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For Share: Remote Volume Control KIT

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#141
OK,looks like power supply comatiblity.

I had a nice email from Luzhu with some suggestions.

The clue is if it does power up in the correct state, EVERYTHING works, including the remote. No problems 🙂 🙂


So it looks as though the initial power-up reset is not working. This is because the PSU I am using, a big bench supply with digital meters, is very heavily damped giving it a safe (but slow!) risetime.

Adding a series mechanical switch to the +5V from the supply allows it to power up correctly every time.

Sorry for the scare!

Cliff
 
#142
OK, everything resolved for me.

Luzhu sent me the schematic of the controller pcb so I can see how the power-on-reset circuit works.

There is a 1oonF /100K (C1/R7) holding up the RESET line until the power is stable.

In my case this time constant is not enough as the supply is slow. So I added a 2u2 el elctro across C1 to increase it.

I don't have any SM components so used a HUGE standard one! See photo.

After 100 power up cycles, no problem at all.

As Luzhu emailed to me, this is designed to run on a standby (always on) +5V which doesn't get power cycled.

This is fine, but there is always the very first power on, which, if it isn't properly reset, can get stuck in a loop!


I suggest that C1 be increased to >1UF and you ship the complete schematic with the product.

Now I can connect it up, at last, and see how it sounds.

Cliff
 

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#147
Anyone remember their maths?

For fun I have plotted the transfer function to a spreadsheet, attached.

I simply put 10V in and measured the output for each step.

I then tried to normalise it so that -1dB is really-1db, but am not sure I believe what I have done!

It is monotonic so I am sure it is all working correctly.

Can anyone smarter than me check the workings, please?

I have also shown the measured output impedance for each step. Some purists are not going to like that! 😉 😉

Cliff (tomorrow some real audio !!)

Yuk! could not attach a .XLS - had to export to .TXT) 😱
 

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#148
Re: OK,looks like power supply comatiblity.

cliffforrest said:
I had a nice email from Luzhu with some suggestions.

The clue is if it does power up in the correct state, EVERYTHING works, including the remote. No problems 🙂 🙂


So it looks as though the initial power-up reset is not working. This is because the PSU I am using, a big bench supply with digital meters, is very heavily damped giving it a safe (but slow!) risetime.

Adding a series mechanical switch to the +5V from the supply allows it to power up correctly every time.

Sorry for the scare!

Cliff
Click to expand...

Congratulations 😀 😀
I have problems in loging on diyaudio in my district this days
That problem comes from the PSU , NEW REMOTE VOLUME ATTENUATOR AND SELECOTS V2 is coming:smash:
 
#150
Hi,

Newbie question thought 🙂

I think the design is great for the price 🙂. I just have some questions.

I assume this design is a ladder type attenuator or its variants?. The benefit of this design is "the signal only passes 2 resistors" However, i see that you only use 6 sets of resistors & relays per channels for 64 steps. Which means that the signal will pass more than 2 resistors? (because of the use of combination of the above sets to have 64 steps ?). In fact, it should have 64 sets of resistors & relay to get the best performance?
 
#151
Google R2R ladders to see how they work.

Can you hear the difference betwen two and three resistors in the signal path? *

Have you tried to?

I can't, and gave up all that minimalistic nonsense years ago.

However, as they say, YMMV.

Edit:

* I think that reference to two resistors refers to two different VALUES in the ladder.
 
#155
Koifarm said:
I live in Nieuw Amsterdam. First i have to receive the software and then figure out how to get it in the controller. I let you know when it is working. Send me your mail adress.

Below the parts with in gonna use with the volumecontroll.

Ronny

An externally hosted image should be here but it was not working when we last tested it.
Click to expand...



Hi Koifarm, I have to say sorry to you for the software >_<

I got notification from my brother Luzhu, he said that you'd betther take a controller board without LCD, for the reason that the software in the controller is unique and confidential. I wish you can comprehend🙂

Futher more, you have to buy hardware for the software programming. So my suggestion is that you should take a new controller board which have programmed the unique modified software for you ^_^

And, as I know, UCD AMPs have low input impedence as 10K. Newer V2 KIT is more suitable, I think the PCB of V2 will arrive in Monday next week, I will test V2 KIT as soon as possible.:smash:


best regards
Lu
 
#156
The volumcontroll will be placed before the tubebuffer who has a input impedance of 470K so that is no problem. But it is no problem for me to buy another kit which is modificated with a 20 sec delayed output signal. If you can deliver such a board/kit. Send me your offer/invoice.

Ronny
 
#157
Koifarm said:
The volumcontroll will be placed before the tubebuffer who has a input impedance of 470K so that is no problem. But it is no problem for me to buy another kit which is modificated with a 20 sec delayed output signal. If you can deliver such a board/kit. Send me your offer/invoice.

Ronny
Click to expand...

Hi Ronny, sorry to reply you late. I can't login diyaudio for days because Internet problems.


My VOL KIT V2 meet a little "POP" noise, so it will be delay .... 🙁

best regards
Lu ^_^
 
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