MOSFET vs. Bipolar Amps for 2ch. music

aaharvel

I have a pair of Rti-4's wired to an Adcom 5300 MOSFET amp, and an Adcom 7300 60x5 bi-polar amp wired to my center, side and rear surrounds, with a Harman Kardon 235 serving as the receiver, pre/pro. My question is regarding listening to music in 2ch. mode with just my rti-4's with subwoofer.

Adcom's midrange tonality is nice (the 5300 amp) - yet the high notes are kind of in your face. For home theater- the Adcom's bright/aggressive sound is of no consequence, but I listen to music first and foremost and prefer a warmer laid back sound that the Adcom isn't giving me. Is it because it's a Mosfet design instead of a bipolar one?

Question #1-
Which amp design is better for 2ch. music playback if you much prefer a warm/laid back sound from neutral speakers (rti-4)?

BI-AMP option- (Midrange to the Adcom, Tweeter to the H/K receiver)

Bi-Amp Scenario #1- I could wire the tweeter to the h/k and let the 2ch. mosfet adcom 5300 (80 wpc) play the 5 1/4 inch midrange- do you think that will improve the sound?

Bi-Amp Scenario #2- ... or should I instead hook up the 5ch. bi-polar 7300 (60wpc) to the rti-4's woofer while wiring the tweeter to the H/K?

The reason I'm thinking of hooking the tweeter up to the H/K is because Its widely accepted that H/K has a warmer sound in it's highs than Adcom does. I haven't tried either yet- cuz i'm afraid i'd blow the speaker.

Any feedback (specific) would be much appreciated.

heiney9

Bi-Polar vs. Mos-Fet that is a question that will get many varied responses. I myself have preferred Bi-Polars partly because of the detail and partly because I haven’t spent enough quality time with Mos-Fets. The first thing some will say is that Bp’s are grainy and in your face. I don’t think so. They are very detailed and on a very good system will definitely reveal weakness in source material. I do find the Bp’s can sometimes bit bright, for lack of a better term, but it always seems to come back to the source. Because I can always find another recording that isn’t “bright”. I love the decay characteristics and the aire around a good Bp design and Adcom, contrary to many opinions on this forum, have an exceptional design (especially the original 5xx series). Ever since adding an outboard DAC my GFA-545 has become very liquid and exceptionally revealing. Analytical is another word many use to describe Bp’s. Yes that goes along with getting the last bit of detail. Mosfet’s while still producing a great amount of detail are a little more rounded in their sound/ less analytical warmer sounding. Mosfet will also reveal weakness in source material. Overall there really is only a slight difference and it’s more about matching it with your system and source material rather than which one is better. Soon I hope to spend some time with an Adcom Mosfet amp and see if I would like it.

H9

RuSsMaN

Too bad all the answers you are getting will be spread out in 3 threads, instead of 1.

heiney9

Sorry, I didn’t really answer your question. I would try all the combination’s you have suggested in your scenario and see if YOU like one over the other. I know the popular thing for some people is to use their receiver as a pre-amp, IMO this is a pretty big limiting factor. You may get the sonic results you desire for 2 CH by adding a high quality dedicated pre. It’s true that 2 channel listening sometimes suffers when you have to combine both HT and 2 CH on the same budget. I really like Adcom products they provide a great amount of musicality at a reasonable cost. People who bash Adcom don’t always know what they are talking about. You know what sound you are looking for, getting that sound is part of the journey and part of the enjoyment of this hobby.

H9

sucks2beme

Some amps will help, so will a better source. But in the end, the RTI speakers will all sound bright. Time for LSI7/9's?

aaharvel

Heiney9- Glad to see someone besides me is familiar with the old Adcom bi-polar units. Your knowledge really helped me out on how i'll keep my amp/speaker configuration.

Suckstobeme- i think i'm going to go your route and just save up and get some lsi7's after i graduate. Also, this weekend I've noticed that after about 30 min. of moderate playing the 2ch. mosfet adcom really breaks in nicely and my rti-4's calm down quite abit. This was very refreshing to hear considering the Klipsch-like sound i was getting a few days ago.

thanks again and sorry again for the multiple threads. i learn something new on here everyday