2. amps-preamps
  3. 1173351750

Break in period

I have just acquired the Conrad Johnson CT5 preamp and CJ LP70S power amp. Would appreciate inputs /advice of fellow a'goners regd optimal break in period and is the break in period dependent on playback volume or amount of
gain. The reason I ask is coz a Stereophile review of the CT5(July 2006 ?)mentioned that the preamp was left in continous play mode for a week, that translates to 150 hrs.Given that i listen max 2hrs/day and more on weekends, that translates to a break in period of nearly 2 1/2 months !!
Have huge issues leaving the system running 24/7 coz of erratic power supply and neighbour's privacy etc
Would appreciate any/all advice
Cheers
128x128sunnyboy1956
gregm
3,405 posts
 
Pauly
Did you measure distortion levels and how do you know it is harmonic distortions
Actually there is -or used to be- some ATC measurements available s/where re, linear & nonlinear distortion on their models. Unfortunately haven't found it-sorry. I do remember seeing this though... if you're actually interested.
shadorne's avatar
Ag insider logo xs@2x
shadorne
7,477 posts
 
Gregm,

I have a very old pdf of a paper that Billy Woodman published which explains his driver construction philosophy. It includes plots of speaker distortion and discusses IMD distortion and the advatanges of active versus passive designs. Unfortunately, speaker distortion measurements are pretty sobering stuff - I doubt most audiophiles realize the relative amounts of distortion coming from speakers compared to the rest of their gear. (Certainly not those who spend $4 K on speaker cables and an amplfier and only $1 K on speakers.)
inpepinnovations1e75
395 posts
 
Yes, Shadorne, I have always wondered how people can hear the difference between 0.002% THD on SS amps and 3% 'natural' harmonic distortion on tube amps over speakers with some 5-10% THD and sometimes up to 100% when the speaker 'doubles'! Methinks that they are hearing differences due to frequency response differences which are quite discernable even over 10%THD of the speakers.
Salut, Bob P.
shadorne's avatar
Ag insider logo xs@2x
shadorne
7,477 posts
 
Methinks that they are hearing differences due to frequency response differences which are quite discernable even over 10%THD of the speakers.
Salut, Bob P.

Agreed. I expect you are referring to the higher output impedance of a tube (with ouput transformer) coupled with a typical bumpy speaker load. This results in a different frequency response/presentation from a tube/speaker combo versus an SS/Speaker combo.
gregm
3,405 posts
 
Shadorne -- that mustn't be what I'm referring to. I distinctly remember them comparing distortion figures (3%) I think between two ATC models at specific spl levels...Oh well.

the higher output impedance of a tube (with ouput transformer) coupled with a typical bumpy speaker load. This results in a different frequency response/presentation from a tube/speaker combo versus an SS/Speaker combo
Normally, yes. But one thing that is important in a spkr -- and one thing we do NOT know -- is the strength of each driver's magnet. A very "strong" driver (e.g. a Lowther, etc) paired with a SS will be overdamped and sound like Donald Duck unless tamed (i.e. at xover level). A hi output impedance paired to a very strong (i.e. electrically damped) driver may provide the optimum marriage...
More to discover