Looking for ideas - new mono blocks for stereo music

Further comment on bigddesign3's speakers.  The Martin Logan Montis is an active woofer design, meaning that frequencies under the 340hz crossover point are sent to the internal Class D amplifier.  This means that the main Krell amp does not need to carry the load of the woofer impedances.  Bigddesign3's comment that he may not necessarily need a huge amp power supply can be true here.

The JBL 1400 has a big 14" woofer.  It only drops down to about 5 ohm around 100hz, which is not too bad, but this speaker will still benefit from a huge amp power supply - to support bass strength/heft.

Bryston 7b3

Okay, here’s the low down.  The amp is actually smaller than the Parasounc JC1. It is lighter as well.  It does have a sizable transformer, but the JC1 transformer is bigger.  However, it has a larger capacitance bank in the power supply sections (16 x 10,000uf = 160,000uf!!).  Initial assumptions that it works only off a circuit breaker are incorrect.  There is actually a small 12.5A fuse on the board close to the IEC plug input.  It is covered by a rubber grommet that is easy to remove with pliers.

Stock – initial listening showed this amp as very clean.  It is definitely cleaner and faster than the Parasound.  I thought that it sounded somewhat thin, but it might sound different in other systems.  Extended initial thoughts seemed that this amp sounded a bit clinical and just a tiny bit sterile in presentation.

With Furutech fuses.  I had one 10A and one 5A that I put in these two 7b3.  The 5A is undersized, but I am not going to consume more than 600 watts of A/C for my tests, especially since these will drive my bookshelves, which are crossed over at 80hz.  With the Furutech fuses, it definitely filled in more of the midbass body.  Made things better and just a little bit more natural over all.  However, extended listening told me that this was still too clean and fast.  There was too much attack and it pushed it over the edge into the “too solid state” characteristics.  Bass was extremely clean and clear, but just bordering on a tiny bit harsh.

Isoclean 5A fuses (5A was the biggest I had).  Isoclean uses gold-plated endcaps and conductor wire.  Much much better!  The amp sounds more neutral now.  The upper mids and highs are not so push hard and it gives you a sense of tonality.  This is great because it tells us this amp can be tamed if it is too bright and hard edged.  The bass was very good here.  Overall, this was the best this amp sounded.  It does not have the slam and bass punch that the Parasound has.  I would describe this as a very gentle and delicate sound – extreme amounts of resolution and detail.  Even with the Isoclean fuses, this amp was extremely clean and resolving.

Here’s a note on others that have had extreme success with the new Bryston cubed amp series:

https://forum.audiogon.com/discussions/finally-took-the-bryston-4b-cubed-plunge

That being said, the Bryston in my system was very good, but it was still just slightly thin.  It was very clean and clear, but did not have the organic life that the Parasound JC1 had.  Since the Parasound had more body, the overall sound was fuller and, as a result, louder.  I could hear more of dialogue and voices in movies.  I think that my system is just way too high resolution for the Bryston amp.  I have rhodium plated everything.  Audioquest Rocket 44 with Furutech rhodium spades. Rhodium XLR connectors and power cord connectors.  The Krell S1200 is definitely not a warm preamp/processor.

I suspect the Bryston 7b3 would excel in a system that had a warm tube amp or something like a NAD or B&K preamp.  My Krell and cabling is just not warm enough to transfer to the Bryston.  With your Marantz processor, it might just be warm enough to give the Bryston a fully rounded signal.  However, with the Esoteric preamp, the Bryston might come out being too thin.  You’ll have to wait and see.  I will say that the Bryston is just about the highest resolution and highest resolving amp I have heard.  That being said, it will not add anything (which could be bad if you need something added into the signal).

Okay, just for the heck of it, I re-loaded my Parasound JC1 with all Furutech fuses. However, I had 4 small 10A Hi-Fi Tuning Silverstar fuses that I put in the post regulator power supply for the input stage. They are severely oversized, but enough for me to get an idea. These Silverstar are extremely fast and bright fuses, so much that they are way too bright in most systems.

What I got was an interesting wake up call. It added just enough attack so that it took the JC1 out of the “too warm” area. I got detail and resolution and excitement added to the mix. However, extended listening told me that the sound was just a tiny bit tilted towards the upper mids (making things sound just a bit high) and it gave me somewhat of a “click” sound in the high frequencies. However, it provided the detail and resolution, but still kept the fullness of body and the organic life and texture.

Based on this test, I’m going to be ordering a few Hi-Fi Tuning Supreme fuses to add into the mix, so I’ll have a combination of Furutech and Supreme. The Hi-Fi Tuning Supreme are faster than Furutech, but much more natural and less bright sounding than the Silverstars.

So, it turns out that I just needed a pinch more attack/resolution to bring the JC1s into perfect balance within my system. With all Furutech/stock fuses, the Parasound was just a bit too warm/slow in my system. System synergy is an important thing and you may have to work on tuning your scenario.

I will most likely be putting these 7b3 up for sale, but I won’t be able to do that until this weekend.