Mono preamps

Moderator: JackD201

Mono preamps

Postby edgarryan » Tue May 15, 2012 9:12 pm

A noob question:

Supposing I have two identical mono preamps, would using them simultaneously, with one being the left channel and the other the right, produce a stereo sound? How would the imaging be affected? How different would this set-up be compared to using a single stereo preamp?
edgarryan
Citizen
Citizen
 
Posts: 488
Joined: Sat May 08, 2010 4:45 pm

Re: Mono preamps

Postby JackD201 » Tue May 15, 2012 10:53 pm

Hi edgar,

If fed L and R respectively from a stereo source, yes they will produce stereo. Theoretically if both channels are matched perfectly they will have an advantage in imaging over a stereo preamp whose two channels share a common power supply. It's the same principle as monoblock vs. stereo amps. There is one huge caveat however and that is, as mentioned, having both channels as closely matched as possible. By that they will have to have pretty much matching tolerances for all parts end to end. Mismatched gain can skew the soundstage and so can distortion. Timing differences will likely be perceived as mismatched gain, as in later will come across as softer with the image pulled toward the earlier or stronger channel. If the two mono preamps don't have stepped attenuators it will also be difficult to set the channel balance with the two independent volume controls. On the other hand two independent volume controls can serve as a substitute for a balance control. Personally I'm used to dual mono preamps and in time anybody that uses them will get used to them too. Just remember the caveat. :) ;)

HTH

Jack
User avatar
JackD201
Immortal
 
Posts: 10024
Joined: Sat Oct 09, 2004 12:10 am
Location: Bozania

Re: Mono preamps

Postby edgarryan » Wed May 16, 2012 12:37 am

Yup, that's what I thought. They should be identical in every way, except perhaps cosmetics, or else the sound would perhaps be like Capitol's Duophonic discs.
edgarryan
Citizen
Citizen
 
Posts: 488
Joined: Sat May 08, 2010 4:45 pm

Re: Mono preamps

Postby edgarryan » Wed May 16, 2012 4:38 pm

Follow-up question:

Would it be possible to add outboard volume and tone controls to a pair of mono preamps which don't have them? If it is possible, where should they be placed? Is it like

Source - Control - Preamp - Amp

or

Source - Preamp - Control - Amp?

If it is the second, wouldn't that decrease the "tubey" sound?
edgarryan
Citizen
Citizen
 
Posts: 488
Joined: Sat May 08, 2010 4:45 pm

Re: Mono preamps

Postby yaden » Wed May 16, 2012 9:11 pm

Sir you can add a passive pre amp so you can control two active pre amp
yaden
Newbie
Newbie
 
Posts: 14
Joined: Thu Nov 24, 2005 4:50 pm

Re: Mono preamps

Postby edgarryan » Wed May 16, 2012 9:43 pm

Stupid me. The amp I'll use has a treble, bass, and volume control nga pala. I could just use those.
edgarryan
Citizen
Citizen
 
Posts: 488
Joined: Sat May 08, 2010 4:45 pm

Re: Mono preamps

Postby Gau_Ban » Thu May 17, 2012 10:14 am

Uhhhhh.. I am puzzled. I don't understand why a preamp doesn't have a volume control. And it sounds like you are connecting the mono preamps to the input of an integrated amp.

Are those mono phono preamps by any chance?
Gau_Ban
Citizen
Citizen
 
Posts: 807
Joined: Fri Jan 24, 2003 1:33 pm

Re: Mono preamps

Postby edgarryan » Thu May 17, 2012 10:20 am

Yup, mono preamps. I am going to try a vintage tube set-up.
edgarryan
Citizen
Citizen
 
Posts: 488
Joined: Sat May 08, 2010 4:45 pm


Return to Technical Archives

Who is online

Users browsing this forum: No registered users and 4 guests

cron