The new "My Ref" Rev C thread

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#141
schro20 said:

Just to be sure: do you mean that you connected power ground to the earth connector on the power?

I do not have the training to give advice on proper grounding and power setup for safety. But I can tell you what I do. I do connect power ground to earth (and the latter to the chassis if it is metallic).

It has been pointed out by others on this forum that such a connection is possible and that some prefer to have an RC filter on that connection.

I found the writing of Rod Elliott on power supplies and how to hook them up useful on this subject.

peter
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udailey said:
Yeah this is a topic that Peter and I will get a bit skiddish on. We dont want you hurting yourself somehow with our not so well informed advice.
So, with that disclaimer in mind and also considering the Brian and Russ both said to NOT ground to earth I will tell you that I am grounded with both amps to 0V but also to earth as well as all speaker and inputs ground. They all go to their respective place on the board but are then grounded to earth through two star grounds. WHY did I do that? Well I think if I had two of the kit boards that probably I would not be doing it this way, but I have a board without soldermask and maybe everything is normal on it but I dont think so. I have to ground this way or I get some serious DC to the speakers. Not the same problem you are having, but yeah some people are going to earth ground as well.
Uriah
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I know this is from a couple days ago, but nonetheless, here's some good info on the topic

Brian on grounding for the MyRef (btw, when using a metal chassis and uninsulated RCAs and binding posts like Apex Jr sells, how do you NOT ground the connectors as Brian recommends?)

Nuuk's power supply article <--VERY helpful for those confused about wiring transformers' secondaries

Rod Elliot's article on earth grounding
 
#142
hi guys,

I'm a nob here with a silly nob question. Hope can get some answers.

I'm using a single torroid with dual secondaries (4 wires). For connection 2 wires goes to AC1 and AC2 for each board. So what happen to the ground????? Do I need to use the ground terminal on the board when there's no center tap for a dual secondaries torroid???

and

how do I make a connection to a circuit breaker...?

Any suggestion....
 
#148
It's time to try some alternatives, so I've DC coupled (shorted C13) and 'socketed' C21:

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


An MKP1837 in place there:

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C9 and C32:

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C6, C11 (LM318's PS) and bypass caps

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


C17, C18 (LM3886 PS bypass caps)

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Now it will bring a big amount of listening to different components....

And also a bit of time troubleshooting one of the modules...

it worked good for 6 hours after 'socketing' and now it's mute...:bawling:

Edit:
Just trobleshooted, one of the socketed C9 caps was not correctly plugged-in 😀
 
#154
A little update on C9 alternatives.

This cap is critical and changing it has an important effect on sound quality.

I've tried so far:

Nichicon VR
Nichicon KW (audio grade cap)
Elna Silmic II (audio grade cap)
Panasonic FM
Rubycon ZL

VR was honest, nothing special, closed but fair.

KW was very good, nice balance, detail, dinamics but bass were a little 'resonant'

Silmic II was good, romantic sounding but closed.

Panasonic FM was very good, nice balance, detail, snappy dinamic but a little harsh and bass a little bloating.

Rubycon ZL was the strangest sounding very clear but also harsh with a totally wrong sound.

So, apart VR that was just a test, the worst sounding were the ZLs and Silmic IIs 😱

Those listening test were done without bypass cap.

With MKP1837 10nF bypass cap FMs gain was low and harshness still there 😡 , otherwise KWs gained a lot: the bass resonance is gone and highs are even better. 😎

Also Silmics had benefits from bypass but FMs and KWs were in another league. 🙄

Normally the Silmics after burn-in opens up so they could deserve a second opportunity in the future but now the best sounding are FMs and KWs with Nichicons (bypassed) as clear winners, IMHO.

I'll try some more bypass caps (I've Wima MKS2, AVX BQ, Evox-Rifa MMK all 100nF) :smash:
 
#156
correct. It you used the blue terminals for the inputs you can put a piece of wire between the two connections IN + and IN ground and it will make the amp silent as it gets. If you have noise or issues it is construction or INDUCED sound into the PCB from another source.
 
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