Looking for ideas - new mono blocks for stereo music

I have a pair of JBL 1400 Arrays.

I have tried a few different amps on them and have found that the Marantz MA9-S2 mono blocks as sounding superior.  I have them matching SC7-S2 pre and SA7-S1 sacdp as well.  I have not wanted to replace them.  As far as I am concerned, it would be ideal for you.

Resolution/detail/soundstage are (to me) fantastic.

Agreed on the Audio Sensibility. The Signature Silver interconnects (either XLR or RCA) from Audio Sensibility are probably the best you can do. That is if you want silver. I used to own these interconnects before I moved to OCC/Rhodium. My cousin still has a pair of the Signature Silver XLR and they are hard to beat.  Actually, I could build these cables myself if I wanted to, but it would cost just as much to get the wire/connectors, so it's a really awesome value for the money!!

However, I would suggest you avoid the lower end Impact and Statement series as they use stranded conductors. You’ll do much better with something like Wire World or Audioquest. Keep in mind that silver has it’s own double-edged sword and can sound too bright/sterile/harsh on a system that has too much resolution. It’s a fine line balancing act.

For power cords, I agree that getting $1,000 plus power cords is a total waste of money. Most of them use stranded conductors, which in my testing always results in sound that is not as good (phasing issues and solid-state sounding). I shy away from silver or silver-plated solutions as well.

If you are willing to DIY, I usually get a used Audioquest NRG-4 cable and chop the ends, then put on Furutech FI-28(R) rhodium connectors for IEC/Male. At the used prices today, it will come to $450-500 USD for a power cord that will beat the crap out of most other cords in the market. The Audioquest NRG-4 uses all solid-core OCC type solid-core copper conductors (4 x 19awg for hot, 5 x 21awg for neutral/ground).

What many people don’t realize is that the connector plug accounts for half of the sound quality of the cable. The stock NRG-4 cable sound nice and it has a very solid sound, but the gold-plated connectors will impart a warm sound with rolled-off/recessed highs. If you are budget constraint, you can even use the cheaper Furutech FI-11-N1(R) series or even go down to the Cardas 3455R connectors.

For interconnects, I hand make all mine using braided 20awg solid-core OCC conductors and Furutech rhodium XLRs. Speaker cable is usually a double-run of Rocket 44/88 with Furutech rhodium spades. (two runs of Rocket 44/88 would be a 10awg speaker cable).

eohtar OP
  Others that sound (no pun intended) interesting but will be a lot harder
to get a hold of in Canada:
Parasound Halo JC1 - around 6K USD

 Your amps, 600W@8 ohms, have twice the rated power necessary to run your speakers. Your amps are not being maximized to their fullest potential - they are not getting enough power.

I would like to directly challenge this statement, as I have used several extremely high power amps in my system and have never had problems with having an amp that has "too much power".  The fact that the amp has twice the rated power for a speaker should never be considered a negative thing.  In actuality, you want a huge reserve of power supply capacitance because any time the output circuits need to pull in voltage from the power supply in response to an input signal, the actual voltage from the power supply takes a dip.  Even if you can't measure this on a scope as "power supply ripple", it will still affect your sound quality and impact.

I also have 1,000 watt Emotiva XPR-1 monoblocks that include a massively huge 240,000uf power supply with a seriously heavy transformer (2.4kVA if I remember right).  With Furutech fuses loaded, these amps are amazingly detailed and nice for the price.  Never had a problem with "too much power for speakers", since I'm driving B&W 805, and they are specified at 120 watts.  In actuality, these speakers sounded better with a beefier larger amp.

NOTE: another disclaimer on Emotiva.  While they are very amazing amps for the money (if you load them with Furutech fuses), they are not the best amps out there.  There is an electrical resonance in the circuits that I can hear that makes the highs a little jangly and thin, as well as some grain in the general sound.  Other amps (JC1, 7b3, etc.) will be much cleaner and more refined sounding, but also significantly more expensive.

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Finally, if you really read what the OP was doing, you would see that he is in an apartment and doesn't want massive bass.  While the REL subs are awesome (I have heard one), the OP will have more than enough bass with good amps on his JBL 1400.

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.

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).

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.

Writing up my Parasound comments, since it is so lengthy.

Stock – JC1 has a very refined sound, midrange is very smooth and refined. Emphasis is tilted slightly towards the upper midrange which causes the audio to sound just a little bit thin in the midbass area. Sound is soft. Overall, sound to me is just a little bit low fidelity. It’s very smooth and refined, but just doesn’t sing or have that effect of sounding real.

Main A/C fuse (on back panel) replaced with Furutech 15A – This significantly improved things. The attack and resolution is much better and tonal qualities are much more real. Instruments and vocals ring out with more truth. Sound is no longer tilted so much towards the upper mids and it is fuller sounding. The high frequencies are just a little bit jangly sounding (best I can describe), but overall a significant improvement. Bass is a significant improvement. It is still somewhat soft sounding.

All internal fuses replaced with Furutech (there are 6 fuses inside each JC1 that affect audio) – This is the best and most natural sounding result so far. There is no grain or jangly resonance heard in any of the frequencies. Bass is just absolutely amazing – oh my god! I cannot stress how much tight deep and strong bass you get with this particular configuration. It’s a serious “punch you in the chest” type of bass – hits really hard, but sounds natural and deep. Resolution and attack are still soft here. I think the soft attack also extends into some of the high frequencies as well.

In actuality, I discovered my Emotiva XPR-1 amps (also loaded with Furutech fuses) just beat the crap out of the JC1 with regards to resolution and detail. However, the Emotiva is not the cleanest sounding amp and I can definitely hear a slight element of grain in the sound.

So what’s really going on here? I think it’s a combination of things. I have listened very closely this weekend and I think the main thing I am hearing is that the Parasound amps have a very soft attack on midrange and early high frequencies. I believe this is mostly due to the Class A biasing. Even though JC1 is not a pure Class A amp, it is still Class A biased into 10 watts (at low bias setting). This is still enough Class A biasing to soften the attack on the midrange waveforms by smoothing out the response to the waveforms themselves. Class A circuits will tend to have a very gradual curved response when it receives a waveform spike on the input. This is less sensitive with analog preamp circuits, but when you are working with speaker level voltage, the response curve is much more gradual (based on slew rate response). This has a result of making angular waveforms (like a snare hit) more rounded or curved. Again, it depends on the engineering of the Class A circuit and how it responds to spikes on the input.

A comment on the high bias (25 watt) configuration of the JC1. The only time in my system that the 25 watt high bias Class A setting sounded good was with the stock fuses. The High Bias actually provided a more engaging sound. However, with Furutech fuses, it just made things too slow and mushy.

Another possible reason is my speakers, which are B&W 805 D3 diamonds. They are not a very fast responding speaker (they are actually hard to drive from an amp standpoint), but they are very natural sounding (the reason I went with them). So the combination of a neutral responding speed and the difficulty of pushing the drivers and magnet engines could contribute to the slow attack on the midrange and highs.

Finally, it can also be from having too many Class A stages. I have found through extensive testing with DAC/preamp stages that if you have too many Class A stages in a row, the sound becomes too slow and soft. So, my configuration:

HT Processor – Krell S1200U discrete Class A analog stage

JC1 – discrete JFET Class A input stage, MOSFET driver stage

JC1 – high biased Class A output stage

In my case, I think all of the above items contribute to a soft attack on the mids/highs. It does sound very nice and pleasant. Music is nice and pleasant (such as with a tube amp), but just doesn’t have that extra bit of attack and resolution to make things stand out. For home theater purposes, I just don’t have enough attack/detail to make movies exciting and engaging. It’s definitely not an optimum amp choice for my system.

I think the Parasound amps would work very well with speakers that are extremely fast responding and no decay. The Martin Logan panels are one example as they definitely have a tendency to sound bright/thin/harsh. They require the waveforms to be further smoothed so that it fills out the sound. Other speakers that might excel are the Monitor Audio Platinums (with the very fast ribbon tweeters) or maybe the Focals with their extremely light and fast responding midrange/woofers. Or add a JC1 if you have a very thin/bright sounding preamp/source.

@bigddesign3 – this could also be the reason that the Krell Class A works so well with your Martin Logan panels. If you read Whitecamaross’s amp thread, he states that the JC1 does everything right from top to bottom. Reading further, he found that the huge Pass Labs 200 watt full Class A monoblocks were the best sound he heard (though I am suspicious of his continued “this is the best” posts). He also was listening with high end Martin Logan Panels with those two amps.

@bigddesig3 - I think you are pushing too hard on your sell. There’s many different opinions and actually many different configurations that would work great in different system synergies. There are elements of monoblock amplifiers that will be superior to stereo amplifiers (depending on size and design). One aspect is completely dedicated power supplies. Stereo amps will usually share a transformer and/or the actual power supply. The exceptions are stereo amplifiers that are built as "dual mono" amps (where each amp channel has a dedicated transformer and power supply).

Another aspect is size of power supply - which generally affects the ability to drive certain speakers. A larger power supply can give more muscle in the bass/midbass area. Granted, speakers with higher impedance (such as flat 8 ohms) or easy to drive speakers make it less critical for big power supply. But many woofers nowadays will actually drop down to 2-3 ohms at times. Some drivers are extremely hard to drive. Class A output can definitely smooth out an amp circuit that is usually bright/thin, but only a large power supply will give you that bass heft. I have compared multiple amps with different size power supplies.

Finally, monoblocks are usually a fully balanced differential design on the power output. I totally understand that there is much controversy in the industry as to whether or not balanced differential output is better than single ended, but I usually have found differential is better. There are some stereo amps that are fully differential (many Pass Labs stereo amps are balanced/differential output).

I’m not arguing against the idea that Krell Solo is a very good amp. We just need to keep an open mind and have a complete understanding on what to expect with each amp choice.

To this day.... a proper Class A design will be the best sound.

I actually disagree with this completely. Class A can be very good in some scenarios, but it will not provide the absolute best sound because of different system synergy and different personal tastes.

--More to come on this Class A thing - I’ve been listening to these Parasounds closely this weekend and I’ll write up more on this after I get a good listen to Bryston 7b3.