2. amps-preamps
  3. 1137965724

CD output voltage too high for preamp: what to do?

I have an Audible Illusions preamp which is designed for a 1.5v input signal. I am told that this is standard. My Ayre CX-7e puts out 2.25v. They play beautifully together but I have too little control over volume: I cannot use the preamp vol controls beyond 9 o'clock because it is way too loud. Likewise it is hard to get just the right volume in the limited range available. This is worse with some CDs for reasons I do not know.
Audible Illusions will change the preamp attenuation board for $275, but before I do so I wonder how others have dealt with the problem of newer CD players with higher outputs than their preamps were designed for.
gmargo
bigtee
803 posts
 
I trust you did flip the gain switches to their lowest position (setting) in the M3A. They're 3 dip switches per channel. Two for bypassing the output caps and one for lowering the gain.
hifi57audio
15 posts
 
Best solution would be to have Ayre, or someone with the schematic to reduce the output of the CD player. I have no idea of the topology of the output circuit, be it discrete or op-amp based. I am assuming its solid state, maybe not. If it's tube, it should be quite simple. Barring that, I agree with Eldartford. A pair of high quality series/shunt metal film (or carbon comp.,if you want to go retro) resistors right across the solder tags of the CD input RCAs on your preamp will beat the snot out of adding another attenuator in series with your preamp volume control. Another attenuator adds increased capacitance; switch or slider contacts; and in most cases a reduction in the impedance your CD player has to drive. If you're interested I'll post the equation to determine the values.
downunder
1,329 posts
 
The endler variable attenuators can be used as a volume control or with an active pre amp. That is what I used them for. Put them at your amp inputs or pre inputs if you only want CD volume reduced.

As I said they work extremely well. They look a little ungainly but are totally transparent.
czbbcl's avatar
czbbcl
1,752 posts
 
Downunder

I noticed you have a premier 350, I do as well and since installing it in my system, I too have a gain issue. Do the Endlers have any effect on the sound other than attenuation and I assume by your comment that the Rothwells do effect the quality of sound.

Chuck
downunder
1,329 posts
 
Hi Chuck. I use the attenuators plugged into the amp inputs and on about 8db attenuation.That got rid of the gain noise I was experiencig between the pre and power. The Endlers are truely transparent, no real difference between the attenuators attached and not attached, except for the gain.
I was sceptical as well, but decided to try them and I am very pleased., The Rothwell attenuators are quite coloured and change the sound of the amp too much.

BTW, I don't use them anymore as I sold my VTL 7.5 and using a cj pre amp. The cj has the same amount of gain as the VTL, however there is no noise.
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