[doggie]

I am using US made Amperex 7062's(12AT7) and now a fresh pair of 12SN7 Tungsol black glass round plates. Previously I was using some Kenrad VT-231's which I liked a lot. The jury is still out regarding the TSRP's because they only have a couple of hours on them. Dynamics and soundstage are remarkable as is realism for instruments. For vocals so far I prefer the Kenrad's but I will allow a bit more time to decide.

[sabocat]

OK so after several days with the MZ2 preamp, I decided to move the microzotl back out into the main system. Right away I noticed how dark it sounded, so I switched out the amperex/sylvania combo and put in all GE. i also switched to all GE for the phase splitter and 2 driver tubes in my JWN EL34/6CA7/KT-77 amp. That created a more balanced tonal effect, a better soundstage, and more than adequate bass. In the meantime I hooked up the CJ preamp to the JWN amp in the bedroom, and the Omegas sound just great with the CJ. I'm using the nice CJ phono stage with a Lounge Audio head amp, fed by a thorens td-125mkii and a denon 301mkii cart. As expected, the gain needed for decent volume from the Omegas had decreased a notch with the CJ. Now I can sit back and enjoy both systems without any fuss.

[sabocat]

So after spending some more time with the CJ preamp running the Omegas, I have come to the regrettable conclusion that I have to sell it. I had hoped to have it modded by Bob Backert but he said that because of the internal phono stage there was not enough room for the gain stage mod so I might as well sell it. Bob offered me a deal on his own model, a previous incarnation. The CJ linestage is just too lean to match well with the omegas.

[sunnydaze]

..... The CJ linestage is just too lean to match well with the omegas.

Lean?!  First time I've ever heard CJ described that way!     

[danabunner]

Lean?!  First time I've ever heard CJ described that way!     

First for me too.  I own 4 preamps, and when I want my system to sound its warmest, that's  when I put my CJ preamp into it.  Warmest, "classic" tube sound I've ever owned.  Even their SS stuff is known for its warmer sound.   However I have read that the PV15 has less warmth than a typical CJ.  Does that one use 6DJ8/6922 line stage tubes?  Those are more neutral.  Mine has 12AU7s.

[sabocat]

It uses a pair of m8080 tubes. I would call it just on the lean side of neutral.

[danabunner]

You've been running these speakers for a few weeks now, with some very good front end equipment.   Are they keepers? 

[sabocat]

You've been running these speakers for a few weeks now, with some very good front end equipment.   Are they keepers?

Most definitely. I set the CJ aside and went back to the Microzotl2 preamp. I wanted to try the new production EH 6SN7 tubes, as they have gotten really good reviews and are only $20 each matched and balanced from upscale audio.  I think they may actually have more bass than the syl 6SN7 gtb's. In any event, this particular preamp strikes a good tonal balance with the omegas. I will continue to listen for another month or so, and then try the CJ one more time before making a final decision on whether or not to keep it. The Omegas, however, are staying. It is of course difficult to make sweeping judgements about speakers that are still opening up, but the only caveat i would have is that the Omegas are very revealing and not too friendly with shoddily recorded or pressed source material. On high quality pressings they really shine.  I was just listening to an OJC recording of Sonny Rollins and it really captures his big sound. I saw Sonny live at Carnegie Hall with Branford Marsalis and he blew Branford off the stage. The Omegas do not present like a live performance at Carnegie hall, but they throw out a big Sonny-like sound when called upon.

the Microzotl is sort of like sonny rollins, the cj like branford.

[EVOLVIST]

A super newbie question, I know, but is there a reason that the high output speakers cannot be 8ohms?  I'm guessing that the 4-6ohms is what makes it "high output," yes?

[borism]

Hi Evolves, I believe the "high output" refers to having two drivers as opposed to only one. The single driver speakers by Omega are 8 ohms and when you have two 8 ohm drivers in parallel you get a 4 ohm impedance. You would basically need two 16 ohm drivers in parallel for a combined 8 ohms.

[roscoe65]

A super newbie question, I know, but is there a reason that the high output speakers cannot be 8ohms?  I'm guessing that the 4-6ohms is what makes it "high output," yes?

Short answer:  Physics.

Longer answer:  The two drivers are in parallel below 500hz.  Since the drivers themselves are nominally 12 ohms in this range, their paralleled impedance will be six ohms.  The combined output of both drivers is what makes them "High Output".  If the individual drivers were of 10 or 11 ohm nominal impedance, then the combined impedance would be 8 ohms.

[EVOLVIST]

Thanks for the clarification, guys! 

So the manufacturer of my "amp" reads to only use 8ohms; then I guess the only way I could drive these is by using two of these guys, but damn they are expensive.

http://www.zeroimpedance.com/box.html

[WC]

Thanks for the clarification, guys! 

So the manufacturer of my "amp" reads to only use 8ohms; then I guess the only way I could drive these is by using two of these guys, but damn they are expensive.

http://www.zeroimpedance.com/box.html

What is your amp?

[EVOLVIST]

What is your amp?

The explanation might be a little too lengthy... Well, screw it, I've ordered the CAMs from Louis... The latest craze among a few Chord DAVE owners is going ampless into 8ohm Omega speakers of all varieties except for the High Output models. Chord came back and said only go into 8ohms.

Yeah, so the max output via RCA from the Chord DAVE is 3.35 Watts per channel before clipping. The volume produced at 1m with the Omega speakers has been clocked at 90 SPL, again, without clipping. But, in every case, going ampless from the DAVE preamp to the Omegas, it's been said, requires a sub, specifically a JL Fantom 110, via DAVE's 12vRMS XLRs, to keep up with the Omega speed.

The idea?  Ampless = ultimate transparency.  Not may DACs can do this. So, yeah, a max of 3.35 WPC,  8ohm load,  2vRMS to 6.7vRMS @.5 amps. If my math is correct this is what we're looking at. Regardless, people are reporting back killer results. Louis told me that he's already gotten more phone calls in this very amp/speaker combo. I mean, at a max of 1m that's plenty of gain for nearfield listening. I'm not sure of what the tradeoffs are, because I don't have my CAMs yet; still, depending in the results, my mind naturally gravitated toward how to make the High Output models work with very little in the path.

EDIT: P.S. - A buddy of mine made me two RCA to dual-banana Mogami cables, and for a lark we tested the DAVE going straight to these desktops speakers he had, some 89ds, 8ohm clunkers that require 15watts. Well, the DAVE drove the hell out of these speakers, whereupon my buddy remarked that he had never heard these speakers sound that good. So, it bolstered my hope that the Omegas will really shine in this setup.

[roscoe65]

The explanation might be a little too lengthy... Well, screw it, I've ordered the CAMs from Louis... The latest craze among a few Chord DAVE owners is going ampless into 8ohm Omega speakers of all varieties except for the High Output models. Chord came back and said only go into 8ohms.

Yeah, so the max output via RCA from the Chord DAVE is 3.35 Watts per channel before clipping. The volume produced at 1m with the Omega speakers has been clocked at 90 SPL, again, without clipping. But, in every case, going ampless from the DAVE preamp to the Omegas, it's been said, requires a sub, specifically a JL Fantom 110, via DAVE's 12vRMS XLRs, to keep up with the Omega speed.

The idea?  Ampless = ultimate transparency.  Not may DACs can do this. So, yeah, a max of 3.35 WPC,  8ohm load,  2vRMS to 6.7vRMS @.5 amps. If my math is correct this is what we're looking at. Regardless, people are reporting back killer results. Louis told me that he's already gotten more phone calls in this very amp/speaker combo. I mean, at a max of 1m that's plenty of gain for nearfield listening. I'm not sure of what the tradeoffs are, because I don't have my CAMs yet; still, depending in the results, my mind naturally gravitated toward how to make the High Output models work with very little in the path.

EDIT: P.S. - A buddy of mine made me two RCA to dual-banana Mogami cables, and for a lark we tested the DAVE going straight to these desktops speakers he had, some 89ds, 8ohm clunkers that require 15watts. Well, the DAVE drove the hell out of these speakers, whereupon my buddy remarked that he had never heard these speakers sound that good. So, it bolstered my hope that the Omegas will really shine in this setup.

Running the Chord Dave directly into a pair of CAM's is not going ampless; you are using the amplification stage of the Chord (I'm not sure of the topography, perhaps a high quality OP Amp).  It is effectively a headphone amp being used as a speaker amp.

A few points:

1.  You say that a subwoofer is needed, specifically a JL Audio sub.  I will argue that there are other subs that will be at least as fast as the JL Audio, specifically Omega's own sub or those from Rhythmik.

2.  90dB at 1m into a pair of CAM's implies a power of about 0.5wpc at most.  Again, we are talking about the level you will get from a headphone amp.

Can the Dave drive a pair of CAM's, even in the nearfield?  Sure, but rather than "transparency" I would expect that it would run out of steam.  Most music has some significant dynamic passages that create momentary current demands on the amplification stage.

You owe it to yourself to see how they sound with just the Dave and then with a high quality single ended amp, either SEP or SET.  Unless you have some very specific sonic preferences, the tube amp will vastly improve the drive to the speaker and make you rethink the "need" for a subwoofer.

[EVOLVIST]

Running the Chord Dave directly into a pair of CAM's is not going ampless; you are using the amplification stage of the Chord (I'm not sure of the topography, perhaps a high quality OP Amp).  It is effectively a headphone amp being used as a speaker amp.

A few points:

1.  You say that a subwoofer is needed, specifically a JL Audio sub.  I will argue that there are other subs that will be at least as fast as the JL Audio, specifically Omega's own sub or those from Rhythmik.

2.  90dB at 1m into a pair of CAM's implies a power of about 0.5wpc at most.  Again, we are talking about the level you will get from a headphone amp.

Can the Dave drive a pair of CAM's, even in the nearfield?  Sure, but rather than "transparency" I would expect that it would run out of steam.  Most music has some significant dynamic passages that create momentary current demands on the amplification stage.

You owe it to yourself to see how they sound with just the Dave and then with a high quality single ended amp, either SEP or SET.  Unless you have some very specific sonic preferences, the tube amp will vastly improve the drive to the speaker and make you rethink the "need" for a subwoofer.

Well, to quote Rob Watts, the Creator of DAVE regarding the output of the DAVE:

"So with Dave we have 20 elements that are resistors and flip-flops. So we can have them all on, and in voltage mode the OP would be +5v (the reference voltage) and all off and it would be 0v. With half on and half off we have 2.5v. Now actually I don't use voltage mode as it creates too much distortion - the switching activity propagation delay gets gets modulated by the actual OP voltage - so the resistors go into the single I to V converter. In this case the other input of the I to V is set to 2.5v, so now when they are all on it pushes current (5 mA) into the I to V node, when all off it sucks current (5 mA) out of the node. When current is fed into the node, this is balanced by an equal and opposite current from the OP stage - and due to the feedback resistor, we get an output voltage. Now this will be a noise shaped analogue output, which just needs some gentle filtering to get you analogue that can then drive HP or power amps directly. And the filtering is done by a couple of capacitors in the feedback path.
 
Simple really.
 
But getting the I to V node so it was exactly 2.5v under all conditions without RF noise ain't easy. And getting the reference voltage so that that was noise free and never changing was also not easy. Remember that only a 10 nV change in reference voltage that is signal related will create measurable distortion...
 
Rob"

So, not as a point of contention, but by means of explanation, that's a very sophisticated single OP that's identical from the headphone output at line level to the RCA output. In fact, not to pad the spec sheet, that's nearly an unmeasurable distortions profile of -150db, with noise floor modulation creeping below -180db, which is the furthest an APX555 can measure.

Granted, some of this is me regurgitating what I've learned over time, but a great deal of it has been the proof in the pudding. So, transparent? Yes, I could safely say about as transparent as one could get.

As far as my math, yeah, it could be wildly off. At 3.35 WPC maybe the DAVE can drive the CAMs better than I think. I'm really not into tubes, so that's pretty much out.

But, we will see how it does,  won't we?  I'm only going off of reports from people driving CAMs and SAMs with DAVE. They gush over it. I don't think I'll be able to reproduce Mahler's 5the with these boxes, but then again, I probably wouldn't want to. Thus the reason I question about the High Output speakers.

[EVOLVIST]

But anyway, don't mind me. I'm just riffing. It's difficult to wait for my CAMs to come in, but at the same time I'm simply daydreaming about the future. I tend to get ahead of myself. 

[roscoe65]

Well, to quote Rob Watts, the Creator of DAVE regarding the output of the DAVE:

"So with Dave we have 20 elements that are resistors and flip-flops. So we can have them all on, and in voltage mode the OP would be +5v (the reference voltage) and all off and it would be 0v. With half on and half off we have 2.5v. Now actually I don't use voltage mode as it creates too much distortion - the switching activity propagation delay gets gets modulated by the actual OP voltage - so the resistors go into the single I to V converter. In this case the other input of the I to V is set to 2.5v, so now when they are all on it pushes current (5 mA) into the I to V node, when all off it sucks current (5 mA) out of the node. When current is fed into the node, this is balanced by an equal and opposite current from the OP stage - and due to the feedback resistor, we get an output voltage. Now this will be a noise shaped analogue output, which just needs some gentle filtering to get you analogue that can then drive HP or power amps directly. And the filtering is done by a couple of capacitors in the feedback path.
 
Simple really.
 
But getting the I to V node so it was exactly 2.5v under all conditions without RF noise ain't easy. And getting the reference voltage so that that was noise free and never changing was also not easy. Remember that only a 10 nV change in reference voltage that is signal related will create measurable distortion...
 
Rob"

So, not as a point of contention, but by means of explanation, that's a very sophisticated single OP that's identical from the headphone output at line level to the RCA output. In fact, not to pad the spec sheet, that's nearly an unmeasurable distortions profile of -150db, with noise floor modulation creeping below -180db, which is the furthest an APX555 can measure.

Granted, some of this is me regurgitating what I've learned over time, but a great deal of it has been the proof in the pudding. So, transparent? Yes, I could safely say about as transparent as one could get.

As far as my math, yeah, it could be wildly off. At 3.35 WPC maybe the DAVE can drive the CAMs better than I think. I'm really not into tubes, so that's pretty much out.

But, we will see how it does,  won't we?  I'm only going off of reports from people driving CAMs and SAMs with DAVE. They gush over it. I don't think I'll be able to reproduce Mahler's 5the with these boxes, but then again, I probably wouldn't want to. Thus the reason I question about the High Output speakers.

That is a statement without proof.  No doubt the DAVE has a robust headphone output stage that can drive some efficient speakers under the right circumstances.  "Transparency" is a nonspecific audiophile term that has no real meaning. 

[sabocat]

Speaking of the infinite search for transparency, I discovered that the MZ2 does not like fancy interconnects at all. In fact, I'm running everything in the bedroom with Lounge Audio interconnects courtesy of Mr. Morin, 25 bucks a pair. I've also found that the Omegas really like the new production EH 6SN7 tubes, which is also great, as they run 20 bucks each.

[sabocat]

Just scored an audible illusions Modulus 3 preamp on audiokarma for a song. This is gonna get interesting.