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[turntable]

Originally Posted by ronenash

You are definitly right. I know a few things about electronics
When you turn up the volume on the preamp you are driving more current through the bypass capacitors and the power suply. This is as long as the preamp is connected to the power amp (even if the power amp is turned off). Driving more current through the capacitors will accelerate the burn in process. Do not turn the volume up too high to avoid clipping. You can safely turn it a but past you highest listening level.

Hi Ron

Are you saying if you turned your cj pre amp up to say 90, with CD playing on repeat and speakers turned off.
It will burn in quicker than doing the same thing with volume on 17 ?

[ronenash]

Originally Posted by turntable

Hi Ron

Are you saying if you turned your cj pre amp up to say 90, with CD playing on repeat and speakers turned off.
It will burn in quicker than doing the same thing with volume on 17 ?

Yes, but don't go that hi. A normal listening volume is between 40 and 50 in most cases, I would not go higher than 65-70.

Trying not to get too technical, all capacitor will have a constant voltage across them when music is not playing. At this state they are not burning in. They need an audio signal to burn in. When the amplifier has a signal flowing through it the voltage across the capacitor modulates in relation to the input signal. The higher the volume the higher this modulation will be and the faster the capacitors burn in. You do not want to over do it since the circuits will clip which is not a good thing.

One more thing to note is that in order for the signal to flow through the amp and its part you need to have a closed circuit. Basically what this means is that is the preamp is not connected to the power amp you can play music for days but burn in will not accure as you have an open circuit and no current flows through the amp. When you connect the preamp to the power amp you put a load on the preamp and close the circuit so that current flows through the amplifier. This happens even if the power amp is turned off. All power amps have a loading resistor in their input. Usually between 50k-100K Ohm. What you are basically doing when connecting the preamp outputs to the power amp inputs is puting a resistor across the preamp outputs.

I hope this was not too confusing.

[turntable]

Hi Ron, not confusing.
I switch the amps off during the night if burning in my pre

all cj pre amps for example attenuate the signal up to unity gain. I think on the cj, that is in the 70's on the vol control.
How could having the volume even at 75 or 80 clip the circuits?

Cj design them to go that high in volume depending on the gain structure and efficency of the speakers.

[bgiliberti]

I must have very efficient speakers (Harbeth 30) or else the CJ mf80 amp is very sensitive. My normal listening is at about 9' o'clock (ie, line is horizontal left, about 1/4 total rotation), and max listening is about 9:45 o'clock. My room sound meter shows 85db peaks at my listening position at my max normal listening volume. When I turn it off at night I put it up to maybe 10:45, so if I forget to turn it down before switching on the amp, it will not blow off my eardrums. If I put it straight up to high noon, it would be way louder than I could stand. I guess when you say 65 you mean like 2 o'clock?

[ronenash]

Originally Posted by turntable

Hi Ron, not confusing.
I switch the amps off during the night if burning in my pre

all cj pre amps for example attenuate the signal up to unity gain. I think on the cj, that is in the 70's on the vol control.
How could having the volume even at 75 or 80 clip the circuits?

Cj design them to go that high in volume depending on the gain structure and efficency of the speakers.

This is not accurate. CJ preamps typically have between 18 and 25db gain which is high compared to other manufacturers. If you turn the volume too high it will clip. That is unless your source component output is very low.

[ronenash]

Originally Posted by bgiliberti

I must have very efficient speakers (Harbeth 30) or else the CJ mf80 amp is very sensitive. My normal listening is at about 9' o'clock (ie, line is horizontal left, about 1/4 total rotation), and max listening is about 9:45 o'clock. My room sound meter shows 85db peaks at my listening position at my max normal listening volume. When I turn it off at night I put it up to maybe 10:45, so if I forget to turn it down before switching on the amp, it will not blow off my eardrums. If I put it straight up to high noon, it would be way louder than I could stand. I guess when you say 65 you mean like 2 o'clock?

i was referring to the digital volume control on remote cj preamps. It probably translates to the 12 o'clock position on non remote preamps.

[bgiliberti]

Thanks everyone. I wonder if my CJ "guru' Jeff (aka 'Tonepub') has additional thoughts on this. I seem to recall him saying that the preamp doesn't have to connected to anything to burn in the caps. I'm not trying to stir the pot at all, and quite possibly I have misunderstood what he said (I can't find his post, it may have been on another forum and it may also be out of date advice, since rescinded), but I wonder he has any additional views on this. (I would PM him, but as I am not yet a subcriber -- I plan to subscribe shortly -- I am not yet able to PM.)

[turntable]

Originally Posted by ronenash

This is not accurate. CJ preamps typically have between 18 and 25db gain which is high compared to other manufacturers. If you turn the volume too high it will clip. That is unless your source component output is very low.

I checked the Stereophile ART review - All of the higher end 6922 based cj pre amps have 25db gain. Unity gain is 66 on the digital 0 - 99 volume display

When I used to have my prem 16, combined with low gain prem 15 phono and LOMC's, it was not unusual to play music loud with the vol at 80 - 83 on the display. There was no distortion. Those volume levels were not possible with CD, as it would be too loud and would be distorting the speakers.

I was purely talking about running in your pre amp without the amplifier turned on.

anyway, burning in my GAT on 55 vol setting

cheers

[bgiliberti]

Originally Posted by turntable

I...burning in my GAT on 55 vol setting...

It has occurred to me, based on this discussion, that the reason it's going so slow for me (I am at 550 hrs and counting) is that I spent the first 250 hours running it with the amp on, but at low volume. I thought at the time that it would be better to have the preamp face a dynamic load from the power amp in term of burning in, but maybe that is not so good. At this point, I will do the equivalent of 55 on my analog pot with the power amp off, to get more juice through the bypass caps. What a long, strange trip it's been....

[ronenash]

Originally Posted by bgiliberti

What a long, strange trip it's been....

I am sure its going to be worth it. My previous experience with teflon capped preamps has been nothing but phenominal.