Sonic Advantage of no Preamp / line-stage

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Big Dog RJ
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Sonic Advantage of no Preamp / line-stage

Post by Big Dog RJ » Sat Oct 21, 2017 10:35 am

G'day maties! gents & sheila's...

Just hurt my back overdoing things at work, out for the count for few days...
On a positive note, and before I could even hardly walk, let alone get out of bed, there was something I wanted to post but just didn't quite have the time, until now!

About two weekends ago, I tried several pre-power combinations on my Ethos, just to see where things are at before I get to the Melbourne HiFi show;

Preamps: CJ ET5, ET3SE, Arc LS28 & GS Pre
Power amps: CJ Classic 60SE, LM125M (mono's), ARC Ref75, GS150 (awaiting to try the new VT80- not out as yet for home demo).

As a rule I wanted to keep the power output in similar areas, between 60w to 100w, and use only SE connections. I was very keen to home demo the new VT80 but my ARC dealer is not ready to give this unit out for home demo's just as yet. It's a matter of time... This is one very interesting power amp, as I think it competes with CJ's 50 to 60 watters, and ARC refers to this amp as their "foundation series."

Anyway, to cut a long story short, as I suppose I can go on all day about every attribute with either of these combinations, which I must say was simply superb driving the Ethos, the one huge factor that I realized was the total lack of noise- absolute zero with the CAV45, hence being a control amplifier.

Nearly all the preamps had tube hiss, and this hiss was very apparent on the CJ's. I also clearly remember when I had the ACT2 and eventually upgraded to the series, even then there was significant tube hiss, and mostly from one channel (left ch).
The ET5 and ET3SE were wonderful sounding musical instruments and very accomplished in their own right. The ARC pre's were equally good and had an effortless sort of drive and control over the Ethos. Not all the ARC pre's had the hiss though, the one with the least hiss was the LS28. The GS pre and almost a similar amount of hiss and would actually attenuate whiles levels were adjusted. This would obviously go unnoticed once music played but was quite apparent when changing tracks...

I remember a good mate of mine, Mr. Ed D from CJ once told me- that a good designed preamp should be neutral sounding and should not add or subtract anything from the source. Be able to convey from the source directly to the power amp and is mostly used for switching. Since this cannot be accomplished, we might as well arrive at the conclusion that the best would be to eliminate the preamp altogether.

And this is exactly what I have experienced with the CAV45. Although rated at only 45w/ch, it was the lowest powered compared to the others, the musicality, the tonal accuracy, the lush timbres and palpable midrange, including the extraordinary resolution, just sounded perfect! Now I am not saying that this little bugger beat the mighty LP125M's (which I liked very much) or the REF75, which was another superb power amp but for the money and value, the CAV45 cannot be ignored.

I am on the quest (on low key) just to see what I could do for pre-power keeping the budget under 15 grand. For around 11 grand, the ET3 & LP125M's are on offer, since these units are being phased off. The ARC gear was costing much more but not the demo units and matching with CJ pre's there is a combination available with the Ref75, not the GS150.

I didn't quite get to use a ARC reference line stage at home, since they wouldn't release any Ref units for such demo's. Only these two ARC pre's were available. Perhaps a REF series ARC pre would not have that significant tube hiss, I wouldn't know.

All I can say is that the simplicity of the CAV45 meets all my expectations for sonic purity at it's best. It will not certainly drive anything out there nor would a pair of EL34's per channel be adequate to drive larger stats full range. However, with a high efficiency stat, having built in DSP and powered bass drives, this to me seems the perfect match so far. I don't see the point in the extra spend at all.

Therefore, I have come to the conclusion that if I am to achieve so called better sound, a significant upgrade would be required and that would involve a complete overhaul in the system. That would probably be either the REN15A driven with any of these pre-power combinations or the CLX's driven in full range with perhaps the GS150 and ET5. For the time being, I have yet to come across a pre-power for 10 grand that can out perform the CAV45.

I was not sure whether this post should go to the CJ Amplifier forum or not... but what I was trying to point out is that the preamp / line stage is not required in a well matched system using high efficiency speakers in a proper set up. The extra gain in the line stage can actually cause not only extra noise but also a mis-match in gain settings with efficient speakers. This can be an annoying problem with horn systems and similar dynamic types that do not require the extra gain from line stages. Then again, the line stage may be required in certain systems where the extra gain is required to adequately amplify the signal prior to routing to the power amp. My only concern is after living with the CAV45 for just over a year now, the overall performance beats every pre-power I tried since and owned to date. Again, unless I was doing a complete overall in the system, as I have mentioned above...

Cheers to integrated's, I sincerely think whether SS or tube, exceptional designs do offer purer music, and CJ and ARC's newest arrivals have just hit that spot!
All the best, RJ

Big Dog RJ
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Posts: 301
Joined: Sun Sep 07, 2014 6:30 am
Location: Melbourne, Australia

Re: Sonic Advantage of no Preamp / line-stage

Post by Big Dog RJ » Thu Oct 26, 2017 11:44 pm

G'day cj fellow enthusiasts;

Well the time has come! I just had to make a move- got the Classic 60se and a wonderful PV15.

Before I went this route, I tried a few pre's in there. The ET5, ET3se, Classic 2, ARC GSpre and previously the ARC LS28. All of these pre's were extremely good, top quality in sonics but that annoying hiss...
Then tucked away in a corner, in pristine condition, a PV15 was waiting for take off. I know the sound of this beauty very well and have sold many during my dealership days... I hooked up all sources, fired up a signal because the Martin Logan Ethos takes a few secs to get going on the panels and vola! no hiss! nothing, dead silent at all levels, hooray! And so the deal was infact down-grading towards a PV15 but the combination with the Classic 60se is just superb!

Overall, I still do miss that midrange magic of EL34's on the Cav45. It has a very sdeuctive tone in midrange musicality, and the rest falls into place nicely, nothing overblown. Hence, with a high efficiency system and the right gear, the CAV45 would be all you would ever need.

The Classic60se having KT120's are remarkable indeed. The upper-mid bass is a vast improvement in terms of transparency, speed and weight, and the lower bass is tighter and fuller, extends well into the depths of bass strings and dynamic extensions on low notes, capturing all the variations in bass. The mids are open and natural with plenty of slam, the extended airy highs are all there, very similar to the Cav45. The most significant improvement is with the dynamics and drive of transient control. This is a real treat to experience and it takes the Ethos to another level altogether.

In terms of power, plenty of headroom therefore I settled for the Classic60se mainly due to room dimensions, and in our new place this amount of amplification will be just right. I believe it won't overpower the room as for the musicality is a very important factor for me. I will miss the Cav45 no doubt, and the wifey wasn't too pleased to know BUT after she actually listened, it was not just doof doof and louder but very smooth and musical all the way. The Cav45 is very good within limits, however when it is pushed to deliver that extra depth or weight, although it gets louder, the presentation remains somewhat the same. It is more to do with the vocals/midrange that increases in level. I guess this is a typical trait if the EL34.

With the KT120's, that level is increased across the full frequency spectrum, giving you more added depth, weight, speed, agility, articulation, and full control of transients, without over-blowing the affects of typical "hi-fi" sound. It is very palpable and gives you a true sense of proper scale and realism. The PV15 added into that mix controls and shapes that incoming signal just beautifully, without any added graininess. The main thing I do miss on the CAV45 is the ability to listen to music at very low levels with all the details present. With the pre-power combination, it requires a bit more cranking up on the level to present what it can, and boy does it do that very well!

I plan to have my usual late night session today again, this will be the real test for all things quiet. I must say I am very impressed with the added depth in soundstage. I am not sure whether the preamp is a contributing factor, the soundstage has expanded and is more open in many ways. Comparing it to the Cav45 was more intimate and something I was very pleased with. However, since this was a great deal for a trade-in plus a brand new Classic60se and a mint condition cj pre, I guess this was in the making.

So cheers to integrateds once again, and a definite big cheers to well designed pre-power combinations.
big woof! RJ

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