Used Divas - Did I beat the odds?

[BrianBeck]

Hello all,
My first post here. Please allow me to introduce myself. I'm a long-time audiophile, but an Apogee Diva owner only for a few days now. Over the years I've owned many speakers, but for most of my adult life I have settled in blissfully with good old Quad ESL-63s. I've always loved them despite their obvious limitations. I've nearly always preferred tube amps with them, having had several generations of ARC amps plus a few DIY tube amps. Over these many years, I was only tempted by a few other mistresses: the big MBL Radialstrahers, the Sound-labs, and the big Apogees. But in the end, staying with the Quads always seemed right. However, I do still remember the exhilarating feeling I had back in the eighties hearing a pair of Duettas singing for the first time. At that time, I had toyed with the idea of buying a pair of Divas when they first came out, but I ended up with the much cheaper and easier-to-accommodate Quads. It was an easy decision at the time and I have never looked back.

I had pretty much forgotten about Apogees over the past few decades, when, in the past month while on a business trip, I had a chance encounter with a used pair of Divas at a San Diego audio dealer. They appeared nearly mint, not a scratch or mar on their lovely anthracite covers. Ribbons looked perfect. They were set-up for bi-amping; a DAX 3 was included along with the simplified passive crossover boxes. Serial numbers were 6711L/R, which I learned later are more recent units. Unfortunately, they weren't set up for a listen at that moment and I was in a rush to catch a plane back to Florida. I wistfully ran my hands across them as one might stroke the fender of a vintage Ferrari if the owner weren't looking. On the way out, I chatted briefly with the sales guys. They told me that they had not ever seen a used pair of Apogees in such good condition. They belonged to a long-deceased audiophile and had been crated in dry storage for years. These guys had recently unpacked and played them and they claimed they sounded "fabulous" and that the "foam" was still in great shape. I didn't know what the "foam" thing was that they were talking about. As I flew back home, I thought about those Divas. How many more times in my life would I bump into such a pretty pair? I researched the "foam" issue and learned about the dreaded "buzz". I learned about the Graz replacement ribbons and I spoke to both the US installers to learn more. I figured that these Divas, despite the sales guys' claims to the contrary, would surely need serious and expensive repairs, but I thought if I could get them at a low starting price, why not have some fun? The store and I settled on a very decent price and I ordered a freight pick using the original crates. They arrived a few days ago. I set them up with some trepidation using nondescript receiver amps since I didn't have matching hi-end amps ready for the bi-amping. I heard only music - no buzz - to my delight and amazement. I cranked them up loud and drove heavy bass with no problems. Loud male voices sound clean. I haven't run sine tones through the woofers yet, but I'm not tempting fate either. There is no crumbled foam dust on the bottom edge, as I had read about, and the foam midrange ribbon bumpers seem resilient and supple, as can be felt from the back side. The sound quality revealed the obvious limitations in the temporary supporting gear, and I am hard at work at that now - but I did hear potential greatness, and I'm very excited about the prospects ahead. I feel I've cheated on my Quads and so I put them into a spare bedroom so that I wouldn't have to look at them eye-to-eye with these new ladies in the room.

So, how do you suppose this good condition is possible? I would guess that these units were made in the early nineties judging by carbon-dating those 6711 serial numbers. The audio shop guys claim these probably never had the ribbons replaced, that they just had been stored unused for years in ideal conditions. Well, I don't know how long I have before the inevitable aging problems do set in, but for now at least, they seem to be as new.

Next I am getting the supporting cast in place. I will report on progress and, no doubt, ask questions here and there along the way. Just a hint: my set-up will involve some very powerful tube amps.

Wish me luck...

[Vansloneker]

Congratulations! You did good work up front of purchasing them. Since your Diva's are singing, enjoy them. You might want to change sometime just because Graz' ribbons are even more revealing. Show us some pictures!

[JarreYuri]

Interesting story!
Yes, up with some pictures of them.

[BrianBeck]

Thanks guys. Yes, I will post some pics when I have the proper amps in place. Right now my family room floor is strewn with temporary gear, wires and generally a mess. My sweet wife is so patient! BTW, when she first saw the Divas set up she remarked "Oh, beautiful!". I immediately felt relief because I feared she'd think them ugly. I think the entire Apogee line is beautiful, especially the tall and graceful Diva (the most perfect name for this speaker I can imagine). Besides the Quads I have a pair of massive Fultons that had preconditioned her to the concept of big speakers. Compared to the Divas and Fultons my Quads look positively diminutive.

My room is fairly large and very reverberant with tile floor covering. I think the line source ought to work best in this environment (my wife doesn't want carpeting in there). Still, early listening with the Divas reveal excess reverberations that I will have to tame. "Been there, done that" many times before in other homes.

Lastly, I forgot to mention that I am ordering the parts for upgrading the DAX ,which, especially for a tube guy, really needs help.

[willcycle]

Brian,

What kind of mods do you have planned for your DAX?

Will

[artm]

Brian,

Congratulations on your find. If I may make two pints:

1. More than one member here would tell you that Apogees of this age DO suffer from foam rot, among other issues, whether you know it or not. Ignore them and just enjoy your speakers.

2. If I recall, the DAX was a serious compromise to this speaker's capability. I would consider looking into a DSP crossover solution as I believe a couple of members here have done. These offer control over just about any parameter you can imagine and are software driven so on the fly changes are easy.

I read up on this long ago and this site was useful: digmoda.com

[BrianBeck]

Willcycle,

I'm glad you responded. I have read your older posts about replacing the opamps in the DAX with great interest. To start, I will do something along the lines of what you did with the LME49710 chips. I still don't know why your attempts to replace the OPA404 sections didn't work. Perhaps oscillations. Perhaps some added lead-lag compensation across the input terminals would solve that. I will probably hot-wire the unit into single-ended mode since my preamp and amps are single-ended and I can then bypass switches, etc. With opamp replacements in other projects, I like to add a 2mA current source pull-down in the output of each opamp to bias the NPN emitter-follower output stage into class A. The double LM317/337 regulators are OK, but I may add some local supply bypassing caps. I don't think that the LT1010 output buffers are necessary unless you like Krell amps' low input Zs (not for me). It may be better to directly drive the interconnect cable with the beefy output stage of the LME49710 through a 47 ohm resistor to maintain phase margin. At least I can compare the sound both with and without the buffers. I will allow some flexibility in setting the crossover frequencies. The DAX is set around 330 Hz. Actually I analyzed the circuit and it's slightly asymmetrical as part of the voicing. I believe the passive is around 550 Hz from what I recall. It would be interesting to compare 330, 440 and 550 Hz in the DAX to take some of the load off that poor midrange ribbon.

I still have not seen any scan of DAX 1 or 3 schematic except for that one incomplete page that was on the old forum. I can make out much of the circuit (it ain't rocket science, Krell or no Krell) by simply looking at the PCB, but a schematic would makes things so much easier. Surely someone has a complete set of the schematic who could scan the missing pages.

[BrianBeck]

If I may make two pints

Artm,

You certainly may, but will you share a pint with me?

Thanks for sharing your thoughts. I'm sure the foam has degraded in my Divas; hence the disbelieving nature of my first post. How can it not have, after 20 years? My experience with the dreaded foam surround rot on conventional woofers is that the decay will occur at differing rates depending on exposure to humidity (microbial growth), UV and/or ozone. But, for now, I witness no obvious foam problems in the Divas. I expect I will have to get the full Graz treatment at some point, probably sooner rather than later. I will have to decide if I will love them more than my Quads before I spend many more $K.

The DAX IS surely a compromise. I can hear the veiling even in my temporary set-up. I will do the best I can with the relatively easy changes I described earlier, and maybe, ... maybe, consider a proper vacuum tube DAX down the road. Or maybe passive... more on that later.

I appreciate your suggestion about DSP. DSP is very good at handling complex and variable algorithms. But, being mainly a tube and analog guy, you can imagine my thoughts about adding a DSP crossover into my system. It can work if you stay in the digital domain with digital sources. But going from a lovely turntable through a nice vacuum tube preamp into an added A/D conversion, DSP algorithms, and then a D/A conversion, even if the DSP part is totally well executed, seems like the worse compromise. Besides the basic DAX crossover functionality, ignoring "rakes" and such, is single-order, 6dB per octave filters which are necessary for accurate phase response (time alignment). This is one reason we like Apogees - the first-order slopes on many models. We want good square waves, don't we? So - an analog implementation of first-order slopes (and the other functions too) can be pretty simple, even if the existing DAX is a bit busy inside.

This is not to say that an improved DAX will necessarily be better than than passive. In the case of the Diva, I simply don't know yet. I don't want to inflame the passive-versus-active arguments that I've seen here, and elsewhere. It depends on so many variables, that I don't think there is one hard answer for all cases.

[artm]

Pints..what an idiot!

I also have a pair of Quad ESL-63's, which I use with a Contrad Johnson Premiere 11A tube amp. If more bass is needed then subwoofers kick in or I use my Caliper Signatures. Besides the great sound I also appreciate the option to rebuild these at reasonable cost - and by myself.

As for passive Diva, yep, I'd prefer that to the basic DAX, although I'd imagine upgrading internal components on the DAX will do wonders.

[BrianBeck]

Artm,

Any man willing to share his ale with me is no idiot!

Yes, there is something so right about the Quads. I too use a subwoofer, of my own design, crossed over quite low. You have to sit in just the right sweet spot. I've listened to many of the big boys this year: YG Acoustics, Magico, Wilson, Wisdom, Maggie 20.x, Adam, MBL Extremes, JM Labs, Sonus Faber, and so on. I spent hours at CES going back and forth between suites with my disks and I've spent time at several audio salons. Of course there were aspects of some of these monster systems that I liked, but overall, nothing to make me want to sell my Quads. Not a one was as focused and free of coloration as the Quads.That was both discouraging and encouraging at the same time. The Quads are like putting an exquisite and very clean lens on a fine camera and then carefully turning the focus ring until the image snaps.

So the Divas are getting their chance now. They don't quite focus like the Quads do yet in my temporary set up, but they evince a projected, living, breathing, expansive presence, and of course they can play much louder. I have a lot of work ahead of me to wring the best out of them. As I said earlier, they definitely show real promise (like you people need me to tell you that).

I think a lot of the differences in otherwise comparable speakers has to do with radiation patterns. The line source is a completely different approach to wave launch than point-source dipoles (Quads) or the point-source monopoles (most cone speakers).

[EldRick]

"As for passive Diva, yep, I'd prefer that to the basic DAX, although I'd imagine upgrading internal components on the DAX will do wonders."

Upgrading the passive internal XO would also work wonders, what with 20-year-old caps, loosely-wound un-potted inductors, and crimped connectors.

BTW, No electronics sounds better than No Electronics - keep that component chain short! Mine is source, Placette Passive, Classe amp. No signal benders, no digital, no need for either.

[willcycle]

Brian,

I also only have the first page of the DAX schematic, however, I do have the Grand crossover schematic which is a similar design and I can send it to you if your interested.

My limited opamp swapping experiments resulted in my preferring the OPA627s (as opposed to the National Semis) in all five filter positions and the quad National semi. part for the input buffer. I also increased the input impedance to 47.5K to better match my preamp. (Unfortunately, the OPA627 is no longer available as a dip.)

Let us know how your mods work out.

Will

[BrianBeck]

Will,

Yes, I came across a website just yesterday where an ex-Apogee employee had posted those Grand schematics. There are portions that are DAX-like. I think I saw a section that did the rake part. I emailed that person and asked if he had the DAX schematics. He didn't, but gave me another ex-employee's email address. This person didn't have it either but forwarded my email to yet a third ex-employee. If I can stir up a proper set of DAX schematics I will surely share it here.

I have experience with the OPA627 opamp more than the LME series in other projects. The OPA is smooth, maybe too smooth. I thought I'd read that you started with the OPAs but switched to the LME opamps and preferred the latter. I gave the last of my OPA DIPs to a friend. The LME49710 were only $1.29 so I bought a gaggle of those to try. Eventually, I will expunge all opamps from my otherwise-all-tube analog chain. Didn't realize that the OPA is no longer offered in DIP format. And, damn, they are pricey. Probably paying for laser trimming of DC parameters that we really don't need here.

I too will increase the input resistance. All that switching seems excessively complicated. I will keep you posted on my results but I am so busy with my work that my audio projects tend to move slowly.

[User211]

Hi Brian - thought you might like to see this - spent foam in my Duettas - made in 1989. It really DOES go. No idea of their storage or use history, though.

[willcycle]

I initially thought I preferred the LMEs but found them fatiguing over time so changed back to the '627s which are definitely smoother. Perhaps in your all tube chain the LMEs will work out better. I have all solid state, though I did dabble a bit with a tube preamp which I enjoyed.

[BrianBeck]

User111,

That's a good picture of a bad thing. Thanks. I never doubted that the foam will eventually go. I think my Divas must have been stored for a long time in their dark crates in a dry area east of San Diego, which slowed the inevitable foam rot a bit. I'm sure I'll face a full replacement a some point in the near future.

As I said in another post, I was able to squeeze the same type of foam dampers on the back of the Divas' midrange ribbons and they are still flexible and springy. This foam looks to be made of another material than the foam used around the woofer. The bumpers are charcoal colored (anthracite ) while the woofer foam, which I can't touch without removing the front cover, is a light brown.

[BrianBeck]

I initially thought I preferred the LMEs but found them fatiguing over time so changed back to the '627s which are definitely smoother. Perhaps in your all tube chain the LMEs will work out better. I have all solid state, though I did dabble a bit with a tube preamp which I enjoyed.

Will,

I'm not surprised. I've been pleased with the silky smooth OPA627. While I haven't used the LME series in my own projects, a buddy of mine did in his phono and line stage preamp. He's not entirely happy with the results for the same reason you weren't.

Are you saying that you used the OPA627 in all the filter locations, but you placed the LME49740 where the OPA404 quad was? Also, did you end up putting the OPA627 in the rake circuit?

[willcycle]

Yes. The rake circuit uses the 404 and as I stated in an earlier post the LME was noisy as a replacement so it did not work.

[BrianBeck]

(I continued this DAX circuit discussion under the DAX Schematics thread)

[Soloist1]

That foam's characteristic is time dependent and will be breaking down even if you can't see loose particles or hear it on most music. My Scintillas were like that. The foam just got hard and the foil would rattle against it. Bass wasn't an issue, but with the right harmonics they'd sound real bad. Try some Eva Cassidy, Stacey Kent, Dianna Krall or a variety of piano, even Joe Satriani Sleepwalk would really get them excited.
If not then you found a rarity and may well have a some time yet to enjoy them in a perfect state!