SET on JBL Everests - Mouse breeding an elephant?

Don’t know whether named amps have variable gain (or how they otherwise match here as a fixed value), but you could use the SET(‘s) for the HF/MF horns and the bridged 275’s for the 15” units? Or else I imagine a pair of stand-alone SET’s would do well up to moderate volumes.

The real treat it seems would be running the DD67000’s actively - have you considered that?

https://positive-feedback.com/interviews/greg-timbers-jbl/

Wow the active system sure looks complex. I wonder why TWO bass amps.. and 4 amps per speaker.

A pair would be fine.

Mac 275s aren't at their best when stacked like that. Series or Paralleled, the SQ suffers.

I'd use one Mac 275 get a couple of good NOS Telefunken signal valves and a pair of good SS bass amps. 

Honestly for 1000.00 USD I could tear the pants off the set up you currently have. No SET involved. Those 275 sound a LOT better unbridged. You could use one for the mids and one for the highs or one for both.

THEN serious high watt cool running class d amps for the bass. Me I'm not into looks when it comes to BASS amps.. I'm looking for reliability, sound quality, big clean power supplies and enough dampening.. period!! I like circuit breakers in my bass amps too..

I use 12k Behringers on everything now.. 1000hz down nothing better..
and good to 1 ohm. ONE would bounce those JBLs all over in the BASS section, TWO one per side and 2 MC275s.. for the lows and highs..

You'll think 22 X 40 with vaulted ceilings.. You'll think Amphitheater!!

BTW they are 3-500.00 each.. I do a little fan mod and they are completely silent.. 3500 + watts per channel at 2 ohms 1750 @ 8 ohms

MC275 bridged.. ?? I remember VERY well. I did MC240 twice, bridged, it took a lot of work to make them sound right.. 275s were just LOUD..

VOT speakers.. 80s... They were used for square dancing 150 x 150.

I loved that job... Russco record players too..

Regards

+1 phusis - Always bi-amp at least. They will sound so much better even at low volumes and with all types of music.

I have to apologize for posting such a confusing question.  Let me start over.  I am using one bridged 275 to power the left speaker and a second bridged 275 to power the other speaker.  No biamping.  I’m using the internal crossovers.  A buddy has built an Elekit TU 8600s SET for his Valencias and the result is VERY impressive.  I have been wondering how it would sound on my Everests.  I know it could never handle four 15”s when playing music with any significant bass signal, but what about music that has an almost exclusively mid/tweeter signal - jazz ensembles, classical or jazz piano, acoustic guitar and such?  Perhaps the Elekit could work then?
 I’d have to put some sort of switching system into the mix to go from one amplification system (the 2 bridged 275s) to the other amplification system (the SET), depending on the type of music.  Complicated, yes, but man o man, the thing is really magic on my friend’s Valencias.  And my Everests are almost as efficient.  
Probably too much trouble to fool with.  I’m already tired of it, just trying to explain what I was thinking….

   ''Always bi-amp at least.''
I agree, my JBL 4435 monitors sound better active then passive.

The DD67000's are bi-AMP capable using the internal crossovers! You could use the SET's on the high end and bridged Mac's on the low end. Or you could un-bridge the Mac's and use one amp to power the right and the other for the left speaker. Believe me when I say bi-amping would sound much better than the bridge Mac configuration. Very easy to try.

I did try it when I first set them up, using 275 on top and Mac MC7270 on the bottom.  For some reason, they sounded horrible.  So bad that I had to verify every setting.  Swapped in a Luxman M6000 amp, no joy, so I gave up and went back to using the internals.  I think I need to retry that approach and invest more time in getting the biamping right.  Heckuva lot easier than the nutty idea I had come up with. 

You would be better off unbridging the amps and using one for bass and one for mids and highs.. That would sound better than bridged MC275s believe me.. 50 years with Macs, you don't bridge any of the 225, 240, or 275s without some serious reworks for SQ.. They just don't cut it for me.. or anyone I know.. Loud yes quality no.. Either way vertical or horizontal, The horizontal is better.  The channel load is more equal.

Still better off with SS for bass management.. JBLs use to be wired different to.. because of the JBL driver phase shift.. I like um... one of my all time favorites.. JBLs, Especially the Everest series.

Regards

“Still better off with SS for bass management.“


I got rid of my old 7270 but I have a 452 that I could use for the bottoms, a single 275 for the tops, then put the other 275s on the block.  I have an idle 4350 that got displaced by the Everests, and I had managed to get it dialed in when I first set it up.  Hopefully, I can manage to do it again.  Anyone have experience with biamping the 67000?

Impedance phase angles are large at low frequencies, though, so the EPDR (equivalent peak dissipation resistance) drops to a minimum of 2.0ohm at 72Hz, and at the other end of the audible spectrum to 2.1ohm at 18.6kHz. So the DD67000 is far from being a testing amplifier load, but it isn’t a pussy cat.

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You want a serious amp. 2.1 ohm load will heat up an amp in a heart beat.. The question is how much of your music is at either end of the scale. 72 hz or 18.6khz, answer not much.

That MC452 and a single MC275. You’ll like that a WHOLE lot more than the current set up.. Maybe not quite the eye candy, but SQ wise a lot better. Get a good set of Mid/High frequency cables for the MC275, maybe OCC/Silver clad ribbons with PTFE covers. Good heavy OCC or OFC copper with PTFE covers for the bass.. 150-250.00 maybe for both pairs.. 3 meter

You already have a good set of amps..... Xtra cables ..

Invest in some good Telefunken signal valves.. 2-300.00 you're WAY better off SQ wise.. Mac and Telefunken valves go together like milk and cookies..

Enjoy..

I agree with the above post. Use the 452 for the woofers and a single 275 for mids and highs. But get an active cross-over (2 - way) to split the signal from your preamp. That way each amp is not having to see a full - range signal and will work better! I have done this myself with a bi - amp system using four speakers.

Set the active cross-over to 200 -300 hz.  Feed the lower frequencies to the 452 and connect it to the woofers via the built-in cross-over. Feed the upper frequencies to the 275 and connect it to the mids/highs via the built-in cross - over.

No need to worry about wire quality. Any good quality wire will work just fine!

Use the gain controls on the active cross-over to set the sound levels between low and high frequencies.

@doodle6,
Make sure you remove the jumpers on the back of the crossover, before you bi-amp the Everest. Also, look at the McIntosh Mc 2301's tube mono blocks, they will best the Mc 452 amp. IMO

https://blog.projectryu.com/jbl-everest-dd66000-bi-amped-with-accuphase/

I totally agree with jasonbourne52 on the active crossover method. Jasonbourne52 - The second woofer in the 67000 operates up to 850 Hz., so crossover for bi-amping should be around there. I was under the impression that OP didn't want to hassle with it, so I didn't suggest that. Again I agree that limiting the frequency range to the input of the amplifiers is the most ideal (that's what I'm doing), but even if you don't do that, there will be a major improvement. The high frequency amps will not need to deliver the current in the output stage, same for the low frequency amps not needing to supply the current. The saving in output current is a significant overall load savings. 

ok, thanks!  I’m going to follow the overall plan that you guys have come up with:  single 275 for mids and tweeters, single 452 for woofers.  Active crossover with signal split around 850.  That last thing is probably what I did wrong when I tried biamping when I first bought them - IIRC, I set crossover frequency at about 250 instead of 850.  

I kinda like the idea of 2301s, mostly because of the looks. That’s a pretty hefty outlay, though.  Thanks for the good guidance!

best regards

A couple 9V batteries in crossover? I just read the D67000 manual and it says the internal crossover has a couple 9V batteries to keep the crossover energized. Has anyone heard of this approach before and does any other speaker manufacturer do this?

The 9 volt batteries keep a constant charge on capacitors in the crossover. Similar to a class A amp were the transistors are always on.

Vandersteen have been doing this for two decades. The amps use 128 v on the IC and speaker cables. Keeping a cap fully formed is important to sonics, including in delicate small signal electronics. There the approach is proprietary..

Thanks for the info, much appreciated. I just recently started upgrading and had never heard of this approach.