Question regarding adding a poweramp to an integrated amp

Well, one way to look at it is, if it can't be serviced anyway and you want to run an external amp, what would you be preserving the internal amp for?

Does the owners manual show anything about this?

@americafirst 

To answer your question, the amplifier portion will NOT turn off.  I believe it is class AB power, so it will still continue to continue to generate some heat, but not to the level of a class A unit.

What you don't mention is if you are using this for 2 channel or multi-channel/home theater.  If only just for 2 channel, you are better off just putting the money into a new (or new to you) integrated amp.  Most likely it will have a better preamp section than Lexicon's bottom line home theater receiver. 

Also, I seem to remember, but don't hold me to it, that Lexicon got criticized for the RV-5 because they just rebranded/borrowed the internals from someone elses home theater receiver, similar like they did with Oppo's blu-ray player.

I have a Cyrus integrated amp.   After buying new speakers 50 watts wasn't quite enough so I picked up an amp and ran it off the Cyrus Integrated amps RCA preouts 

The integrated amp runs my REL sub via it's speaker jacks and runs super cool.  The new amp drives the speakers , worked out great.   

Using pre-outs on integrated amps can be a mixed bag. Generally, the preamps in integrated amps are "tuned" electrically to mate best with the internal amplifier.   It's a crap shoot whether it will mate well with something else. 

In effect, most pre-outs are a convenience but the builders don't spend a lot on optimizing compatibility like one has to do with separate preamps.

Anything you do like this would be IMHO a temporary thing to bridge to something else.  I would replace the integrated or go separates. Not half of each. 

In my case a Cyrus amp was the best solution.     Same sonic signature just more power.  

Try an amp and see if there is a noticeable difference.    As the Lexicon is not "serviceable "  I would  just add an amp.    You could put a dummy 8 Ohm resistor across the speaker terminals if you are worried about an open load. 

Just get a new integrated. Time marches on and those times change.  There are a passel of integrated now that make the separates an expensive afterthought.  Also, then you'd still have the preamp outs for subs should you want them.

Wasn't Lexicon just rebranded Harman Kardon?

@devinplombier 

think LEXICON  audio amps as a joint venture with a rebranded BRYSTON

https://forum.audiogon.com/discussions/lexicon-nt-512-bryston-9b-thx

LEXICON 225 ( BRYSTON 4B-ST)

LEXICON NT412 ( BRYSTON 8BST ) 

LEXICON NT 212 rebranded Bryston 3B ST THX Certified Power Amplifier

Correct, the amps listed were straight out rebranded Bryston's.  I did a little further digging on the RV-5 Receiver (which is a home theater receiver, not a 2 channel integrated) and it appears that it was not a complete rebrand of a Harman Kardon.  It appears that the amp "modules" were sourced from a HK receiver, but a significant portion of the preamp/processor were Lexicon developed.

It was introduced in 2006, so it has some significant age on it, especially since it is an AV receiver.  And according to it's specs, HDMI is v1.1 and limited to 1080i (not 1080p), and 85W 2 channels driven, 8W for all channels driven.  Market value in 2025 is probably around $200 or less.  HiFishark is showing one listed in 2022 for $399.  So recapping, etc. is, IMO, is not worth the money.  (Unless it has sentimental value...)

So, @americafirst, how are you currently using yours? And what is the rest of your system?