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ε12 relay doesn't click

epsilon12

Re: ε12 relay doesn't click

Postby amb » April 20th, 2019, 5:25 am

salavat wrote:...
Power supply is 2 rails from one of the sigma 22 boards.

Can you describe the configuration with more detail? Is this a unbalanced or balanced build? How many β22, σ22 and ε12 boards are in the system?

...
I have 16V voltage between specified pin and ground of sigma 22 PS.

What “specified pin” are you referring to here?
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Re: ε12 relay doesn't click

Postby salavat » April 20th, 2019, 5:47 am

1) four channels of beta 22
2) two sigma 22, two toroidal transformers
3) one epsilon 12 board. connected as described on page (v.1.2)
4) 2 rails from the same sigma 22 boards, supplying 29 V (+ and -, no ground)
5) e12 connected to lab ps with 29 V (+ and i, 2 ps chained together), relay clicks, Q1 and Q2 with heatsinks. Temperature around 60 C on them, while working after 20 minutes
6) e12 connected to beta 22 boards (as in p.1) and rails (as in p.3):
- relay does not click
- U1 pin 4, 7 = over 25 V (25.6V something)
- U2 pin 4, 7 = over 25 V (25.6V something)
- U1 pin 7 and 6 = can set up to 1/2 of the 25.6V (something like 12.8) with dialing VR1
- U1 pin 6 and sigma 22 ground pin = 16V
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Re: ε12 relay doesn't click

Postby amb » April 20th, 2019, 9:36 am

Ok, here is the problem. You have two σ22s, each powering one stereo channel. But you have only one ε12, handling both channels. The ε12 gets its power from one of the two σ22s.

But in order for ε12 to work, it must be powered by the same PSU as what provides power to the amp boards. This is because the ε12’s own virtual ground must be adjusted to be centered between the positive and negative rail voltages of the amp, in order to establish the “zero” level matching the amp.

In your case, this is true only for the β22 boards that shares the σ22 that also powers the ε12. The other σ22 and β22s are isolated and “live” in a different voltage space than the ε12.

You should add a second ε12 to handle the other channel. That should take care of the problem.
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Re: ε12 relay doesn't click

Postby salavat » April 20th, 2019, 1:58 pm

Now it is powered from the same sigma 22. I actually tried to supply from both sigmas simultaneously (before reassembly), it worked too.
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Re: ε12 relay doesn't click

Postby amb » April 20th, 2019, 2:08 pm

You should never connect the outputs of two σ22s (or for that matter, any power supply) together! Each one will “look like” a short circuit to the other, and they may be damaged.
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Re: ε12 relay doesn't click

Postby salavat » April 20th, 2019, 9:06 pm

amb wrote:You should never connect the outputs of two σ22s (or for that matter, any power supply) together! Each one will “look like” a short circuit to the other, and they may be damaged.


So, what could be the problem with my e12? I've described setup as much as I can.
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Re: ε12 relay doesn't click

Postby amb » April 20th, 2019, 11:32 pm

Do you still have the other channel’s outputs connected to the input of the ε12? If so they could prevent the relay from activating.
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Re: ε12 relay doesn't click

Postby salavat » April 21st, 2019, 4:40 pm

You mean that if I have 2 other channels connected to e12 (those channels not supplied from the same sigma)? I will give a try.
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Re: ε12 relay doesn't click

Postby amb » April 21st, 2019, 10:01 pm

Yes.
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