Balanced AND RCA


I am looking at adding a tube preamp in between my Bartok and Nagra MPA amp. Just because.

Some models (older Leben) only have RCA plugs. My amp is connected via XLR.
Can I do this or should I change the XLR’s for RCA’s?

Unsure exactly what you are asking:

Q. Can I add a preamp?
Q. Can I add a tube preamp?
A. Yes.
Q. Can I add a tube preamp with RCA connectors?
Q. should I change the XLR’s for RCA’s?
A. If the preamp only has RCA inputs, of course. Do not use an RCA/XLR adaptor. They completely screw up the sound.
Q. How do I connect the preamp to the power amp?
A. This question is really beyond the scope of this forum ( but see my comment about adaptors above. Yes I know that Nagra provide an RCA/XLR adaptor. That does not change my advice.).

However the above is basic stuff. Ensuring that the tube preamp is sonically compatible with both Bartok and power amp is another matter altogether. NB: I use a tube preamp, but one that is balanced ( not just XLR) in and out.

Let me clarify.
If preamp is connected with RCA, can the amp be XLR?
Or all RCA?
I would never get an adapter btw!

I am still unsure what the question is. Are you asking if the connection from Bartok to preamp input is RCA then the preamp output to amp input has to be RCA too? No, you can consider each interface separately. However as the Nagra MPA has only XLR inputs ( I am assuming they are balanced) and if you don’t want to use an adaptor then you either need a preamp with balanced outputs or, maybe, use a pair of custom made RCA/XLR cables from pre to power. However although the latter will not provide correct differential cancellation it is nevertheless a better compromise if compared to using adaptors for various reasons.

you can get pseudo-balanced cables made up

I used these between RCA-only preamp output and XLR-only inputs on active speakers

My amp has both XLR and RCA.
CAn I use RCA to preamp AND XLR from amp or all RCA.

Bernard, I have already answered this question :slight_smile::

So the answer is YES in principle . Whatever you like. However the Nagra website says that the MPA power amp only has XLR inputs. If yours is different and offers both RCA and XLR it is up to you what you use.

You cannot use XLR from the amp as the only output from the amp ( not preamp) is the speaker output.

Your original question concerns the use of a preamp with only RAC connectors. So you can only use RCA from Bartok to preamp. The output from such a preamp also has to be RCA. If your Nagra only has XLR inputs then you need to use a special RCA to XLR cable to connect the RCA only preamp to the XLR only power amp. This will not actually be balanced but will make a connection if the XLR pins are wired correctly. If your power amp also has RCA inputs then you can use RCA to RCA for that connection instead .

I hope that this makes things clearer.

Thank you for clearing this up for me.