Mono block Preamp

Krell made one years ago, I think maybe (?) Lamm made one too, and Line Magnetic makes one now.

PassLab

Gryphon

Constellation Audio

Audio GD  

‘The list goes on. Same advantages?  Yes. I know your next inquiry.  Mono phono stage?  Why not?

I believe Nucleosis also made a mono, but it's nothing you'd want.

Mono pres were a forerunner to Differentially/true balanced preamps/amps, where both channels share nothing in come, aside from the power supply

I hate dual volume controls......  I will pass on true dual mono preamps

Mark Levinson made the first one back around 1980. It was the ML6 and sold for $6K the pair. Outrageous price then, now pocket change for today’s moneyphiles (who dominate the High End).

Lamm LL1 Signature is a true mono block preamp. completely separate left and right dual chassis. no remote volume control.

https://positive-feedback.com/reviews/hardware-reviews/lamm-ll1-1-signature-dual-mono-preamplifier/

Gryphon Commander likely comes next closest, as it even has two power cords....and a separate power supply connection for the control processes. 

https://gryphon-audio.dk/shop/preamplifiers/commander

when you consider the switching and gain functions there is a need for a common control chassis. the Lamm is a bit too ’hair shirt’ for many with no remote volume control. a non-starter for most people.

YBA signature preamp. As i can remember in 6 chassis, even had separate power supplies for phono stage.

Coincident Statement linestage is true dual mono, to get all those parts into one chassis would require it to be quite large and affect performance, what with emi/rfi. Two chassis, one control unit, signal path only, other for power supply. I think this better configuration vs power supplies in both chassis, just for the emi/rfi alone.  The two mono volume selectors can be a pain, and no remote available.

There are several mono phono stages.

I believe Conrad Johnson offered a complete dual mono preamp which came in 4 cases.

Typically a two box solution will be separating the power supply and amplifier section. Since a preamp is amplifying at such low levels I think designers felt they got more bang for the buck by getting the high voltage stuff away from the low voltage stuff.

Esoteric makes one-dual power cords need

Seems like I vaguely remember an early Sutherland, 5000 maybe?

Most of the advantage of going monobloc is to reduces cross-talk (channel separation).  Monobloc is of more advantage when there are big voltages running around, like in a power amp.

The volume control requirement in a pre-amp is an inconvenience that will put of many aspirants.

Monobloc phono amps make some sense.

I had a mono Gryphon phono stage back in the 90's.  I think it was simply called The Gryphon.  Four-piece unit  Separate left and right units with a wooden knob on the front of each unit and two separate power supplies  It was a great sounding phono stage. Only one I have ever seen.

Preamp use small voltages and thier purpose is volume control and input selection and maybe a phono stage. 

Crosstalk would be the only purpose of monobloc pre.

Two volume controls would be the disadvantage. 

Two chassis and double the price.  

Maybe a dual mono in one box and a balance control?  That would be more my speed.

Canary makes a four box preamp, also First Sound makes 2,3, and 4 box preamps I believe.

Lejonklou offers an excellent mono preamp: Lejonklou Sagatun Mono

Stepped attenuators make the separate volume controls more manageable. My question would be, couldn't a remote move the attenuators in tandem?