[Jukebox-list] AMI Continental 2 - Increasing Volume

[Jay Hennigan]

David Allan wrote:
> Hello everyone and here is my first post in the group, tentatively done, as
> I do not want to be repeating what has already been asked elsewhere!
> I have an AMI Cont 2 which plays/sounds great but an annoying problem is, at
> the start of each single played, just after the tone arm has been dropped,
> and for the first 10/15 secs of each record...not just while the box is
> warming up... the volume starts off very quietly and then build up to the
> "set" volume.
> Is this normal with these boxes or is there something that needs
> adjusting/replacing?

It sounds like an AVC (Automatic Volume Control) issue.  Early 45-rpm 
pressings varied quite a bit in volume.  Jukebox manufacturers built in 
a circuit to automatically turn down the volume on "loud" records and 
turn it up on "quiet" ones so that the location wouldn't alternatively 
get blasted with loud music and then have a record that couldn't be heard.

During the mute interval while the juke is cycling, the AVC is set to 
reduce the volume by the maximum amount, so that the needle drop and any 
noise in the lead-in groove is suppressed.  This often results in the 
record "fading in" during the first few seconds.  Circuit modifications 
to reduce the range of the AVC action may help, as well as reducing the 
time constant.  You could also try adjusting the tonearm set-down 
towards the outside edge of the record for a longer time on the lead-in 
groove.  This is kind of delicate, with too much time before the music 
start the AVC detects a very quiet record and cranks it up, resulting in 
a loud blast at the beginning.

You can also disable the AVC entirely if most of your records are at 
about the same relative volume, which will be the case for most pop 
singles.  EPs and longer recordings are often recorded quieter in order 
to accommodate more grooves per inch.

Am I correct in assuming that the amplifier has been re-capped and gone 
through?

--
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
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