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Old 6th March 2009, 08:41 AM   #341
Tony X is offline Tony X  France
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Quote:
I've had a similar problem with a Gainclone.
Your hum was on one channel, Dario. Mine was symetrical on both L and R.

Quote:
Picture of the enclosure with rca inputs?
See http://picasaweb.google.co.uk/anthon...efConnections#

Note, while waiting for an Italian villa the MyRef is squatting in a cardboard box which coincidentally originally housed equipment I bought to reduce the fan noise from my PC.

The RCA etc. connections are on a piece of black, plastic strip.

Quote:
1) Tie the RCA grounds together at the source
Did that - no change.

Quote:
2) Last resort is lift the cable ground on one channel and tie the AMP rca grounds together.
Then did that and hum reduced to bearly perceptible levels at normal volume settings.('') At full volume setting hum was, however worse but that does not bother me as I get all the volume I need at 5-10° on the pot.

Thanks for your help, Troy. Why, though, did you say "as a last resort"? Is there some risk to this way of wiring?

We will see if the amp behaves differently when it's properly housed in an earthed metal box when it arrives.
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Old 6th March 2009, 09:37 AM   #342
Reality first!
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Quote:
Originally posted by Tony X
Your hum was on one channel, Dario. Mine was symetrical on both L and R.
Sure but my problem was unexpectedly due to an overheated RCA panel connector.

Have you tried to change RCA connectors?
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Old 6th March 2009, 09:47 AM   #343
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Quote:
Originally posted by AndrewT
You only need to block the DC once.

If you know that ALL your sources are already fitted with a DC blocking cap then you can omit the extra cap at the input to the power amplifier.
Andrew you're right but what you 'need' isn't the same as 'safe'.

Let me explain with an example:

If you're driving a motorbike you don't need an helmet but if you do an accident wearing it could save you're life...
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Old 6th March 2009, 11:19 AM   #344
AndrewT is offline AndrewT  Scotland
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Hi Clave,
which of my DC blocking option suggestions is not safe?

I cannot see/understand the helmet analogy.
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Old 6th March 2009, 11:40 AM   #345
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Quote:
Originally posted by AndrewT
Hi Clave,
which of my DC blocking option suggestions is not safe?

I cannot see/understand the helmet analogy.

The helmet analogy is like this.
You are the absolute safest rider in the world.
You will never crash your bike.


But what if some idiot hits you?

You cant control the idiots on the road.
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Old 6th March 2009, 12:34 PM   #346
troystg is offline troystg  United States
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Quote:
Originally posted by Tony X


Your hum was on one channel, Dario. Mine was symetrical on both L and R.



See http://picasaweb.google.co.uk/anthon...efConnections#

Note, while waiting for an Italian villa the MyRef is squatting in a cardboard box which coincidentally originally housed equipment I bought to reduce the fan noise from my PC.

The RCA etc. connections are on a piece of black, plastic strip.



Did that - no change.



Then did that and hum reduced to bearly perceptible levels at normal volume settings.('') At full volume setting hum was, however worse but that does not bother me as I get all the volume I need at 5-10° on the pot.

Thanks for your help, Troy. Why, though, did you say "as a last resort"? Is there some risk to this way of wiring?

We will see if the amp behaves differently when it's properly housed in an earthed metal box when it arrives.
Original post:
Am I correct in seeing only 2 wires leave the pot (red and black)?

You should have 3. Left hot, right hot and at LEAST one common ground.

Edit: After looking again I see 4 wires leaving the pot. So that is good. Since there is no chance of signal ground leakage between RCA connectors (plastic mount strip) I would suggest you lift one RCA cable shield at the source side and tie the grounds together at the pot.


EDIT:

PS, cardboard, wood, metal.. Who care what it looks like your ears can't see it!.. As long as it is safe, and as long as you don't brag about the housing, only the sound!
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Old 6th March 2009, 12:43 PM   #347
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Quote:
Originally posted by AndrewT
Hi Clave,
which of my DC blocking option suggestions is not safe?
Hi Andrew,

your suggestions are perfectly safe but requires self-discipline.

If you put DC blocking caps both on pre/CD and power-amp you're safe even if you 'forget' that last mod (pulling out DC coupling caps...) you did one year ago in that CD Player...

Obviously you gain safety in spite of performance.

If you're perfectly and forever careful you don't need it.

You can be perfectly careful everytime, but your wife/son/friend?

Everyone must balance for himself safety and performance.

Quote:
Originally posted by Rainwulf
You cant control the idiots on the road.
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Old 6th March 2009, 12:47 PM   #348
udailey is offline udailey  United States
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Love the box!. Take that down to your local snake oil sales man and see if he will let you test some speakers on it LOL Watch the blood drain from his face when its the best those speakers have ever sounded.

I retract everything I ever said in anticipation of the DEQ2496. I only hope they let me return it. When its inline with the signal the toys/bells/whistles on this thing are fun. You can make the image move around the room and become wider/narrower but I cant get the thing to let the signal pass cleanly even when I push the BYPASS button. It gets way way better in bypass mode but when I remove it totally and just listen with the lightspeed inbetween the source and the amp its a world better.
I dont know why it got the rave reviews but its not my cup of tea. Peter has one to and he suggests that while its not a great sounding device that it is a great piece of equipment for using as a reference when you are building a crossover.

Uriah
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Old 7th March 2009, 11:43 PM   #349
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Default testing your myRef

I've got a sort of stupid question: when you're testing your myRef for the first time, do you have to hook up the board's ground connection to get speaker output?

I've got a heatsink attached, an input connected from my mp3 player and a cheap speaker connected to the output terminals. When I power up the board I don't hear a relay click but the LED glows. When measuring across the test LED I get about 2V.

I don't get any sound out of the speaker.
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Old 7th March 2009, 11:53 PM   #350
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Default Re: testing your myRef

Quote:
Originally posted by marc brown
I've got a sort of stupid question: when you're testing your myRef for the first time, do you have to hook up the board's ground connection to get speaker output?
Never mind, just read this thread from the beginning and answered my own question.

I didn't wire up both of the transformer taps to supply +24V -24V yet so that's why the relays not clicking and the LED is so dim. I was feeding it +24V 0V
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