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
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restock
826 posts
 
I have similar problems: A tube preamp with 23 db gain, a fairly high output CDP with 2.3V, a very sensitive amp. Overall this results in about 10db too much gain.

As for solutions:I also read about mixed results with the Rothwell attenuators and therefore ended up looking at the following attenuators:

- Endlers variable stepped attenuators
- EVS fixed volume attenuators

Overall the EVS seem like the best solution. Another alternative of course is to go completely passive.

Rene
clio09
2,978 posts
 
In looking at the Endler attenuators they appear to be a replacement to the active preamp, not used with it. Am I understanding this correctly? If they indeed can be used with an active preamp to reduce the gain, these might be worth a try.
hiend3
38 posts
 
Ive owned the audible illusions M3A 3 of them. the stepped attens are not a good thing for CD. I say sell the M3A, I switched the a eastern electric mini-max (used 500.00 and dont miss the m3A at all.
The Add on attn units ive tryed also roll off frequency extremes. You just cant win with that m3a's curve. even when you can get it matched the steps are still too far apart. I had a Tjoeb 4000 and reduced the level to .75 volts and still wasnt heppy...
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.
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