Biggest impact: moving from integrated to separates

asp307 12-19-2017
I am not looking to upgrade both amp and line stage at this point, just one or the other with the next upgrade probably occurring next year. I can continue using the Cronus Magnum either as a line stage or amp so I have flexibility.

If I’m not mistaken none of the versions of the Cronus Magnum provide either an input to the amplifier section or a means of disabling the amplifier section.

Which means that if you were to use it as a line stage you would have to put load resistors having high power handling capability onto its speaker output terminals. As you may be aware, running a tube amp which has output transformers in an unloaded condition can cause damage to both the transformers and the output tubes, especially if the amp is processing a signal.

And if you were to use the CM as an amp, I believe you would have to have its line stage in series with the new line stage you would be purchasing. That would work, but it would probably negate the benefits of the upgrade. Although I realize it would only be a temporary arrangement.

Good luck. Regards,
-- Al

@almarg , very good points that I have not considered. I guess as I assumed I can use my XP-15 Phono pre, that I would be able to do this with other separates (line and amp) and ween myself off of my CM. This has given me pause and I’ll need to do some more homework. 

@trelja @mesch @missioncoonery @keithtexas @twoleftears @robd2 thanks for your feedback and I’ll keep you posted on how I get on..

Hi @almarg , just spoke with Rogue Audio. I figured I'd follow up.

Here's what they say:

  "You can use the version 1 Cronus just as an amplifier. The way to do this is to connect the outputs of your preamplifier to the variable output of the Cronus. I know this sounds wrong connecting an output to another output, but doing this will bypass the front end of the Cronus and feed the signal straight to the amplifier portion of the Cronus."

Cheers

Awesome! Thanks for letting us know.

I would suggest, though, that you follow up with him by asking what the output impedance of the variable output is. Assuming that the "variable output" is in fact an output, that output impedance will be seen as a load by whatever line stage you connect to it. Which in turn could very conceivably result in an impedance match with the line stage you end up choosing that is very non-optimal from a sonic standpoint. Especially if the line stage you choose has a coupling capacitor at its output, as most tube-based line stages and at least a few solid state line stages do.

Also, when and if you use this approach I would suggest having the CM’s input select switch set to something other than phono. And in addition it would probably be a good idea to put shorting plugs on the selected input, to avoid the possibility that RFI/EMI pickup might cause the CM’s line stage to sum a low level "signal" together with the intended signal. If you search at eBay for "RCA shorting plug" (without the quotes) you’ll find many such things at very low prices.

Good luck. Regards,
-- Al

@almarg great thanks! I'll follow up with Rogue on the points raised. I currently have the CM in the Aux 1 input as I am using an external phono pre.