Help with a pre-amp

I guess the pre-out which is not the main preamp output (those are on the 1/4" TRS jacks) could be "subordinated" to a 3.5 jack on the rear?

(by the way, the TRS jacks can also be used "unbalanced" for single sided power amp inputs)

Also aux send and return (used to be tape loop but I guess nobody uses tape anymore?) seeing they're most likely going to be used with some form of computer/iPod could also be 3.5 jacks?

All the above being on the rear...

Duplicates on the front could be OK, but reliable break jacks in 3.5 size are a bit of a laughing matter and therefore I'd have to rely on the user not plugging both to front and rear at the same time? Maybe I ought to just stiock with 3.5 jacks on the rear for aux send and return, and one for pre-out. And round the front input 3 on a 3.5 jack and headphone out also on a 3.5 jack?

I think that may appease most everybody?

The question being can I fit 2 3.5 jacks, a mini volume control for headphones, input selector "toggle", tone gradient "toggle" aux send/return "toggle" and main volume control all on the front? I shall draw it on the computer and see.

(toggle refers to the 3 position up-down switches as seen on some of our other products -- the "nothing" position would only cut the feed to the main and pre-outs but the aux out would not be interupted)


Edited by Graham Slee - 19 Aug 2009 at 2:49am

mrarroyo wrote: How about instead of a rotary volume pot a digital one? It may add to much cost though.

Maybe on the headphone out?

Thank you for that answer -- it helps a lot.

I think we need a poll on DIN versus 3.5mm jacks.

Quite happy to do a cable/loom selection but some people have their favourite interconnect cable brands which most of the time are unfortunately not us.

A digital volume control is similar to the up-down buttons on a remote control. Except for the motorised volume controls you get on expensive gear, usually it's a voltage controlled amplifier stage similar to that used in cheap cassette recorders that did ALC -- automatic level control. They can be done pretty well these days and voltage controlled amplifiers (in effect a little sub-circuit) have been used for years in studios -- the expensive Penny and Giles sliders simply controlling a DC voltage.

However, I'm looking at a miniature Alps volume control instead to 1] keep the price reasonable and 2] make it all fit the drinks coaster sized/palm sized case footprint.

The smaller the parts, the more I can offer.