A big "Thank you!" to the High Efficiency Speaker forum.

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Posted on November 8, 2015 at 10:35:13

Todd A.

I placed a post back in the middle of October requesting information about Fostex back-wave horns, and there were many responses from which I learned a good deal about horns in general, crossovers, and general high efficiency issues. As luck would have it, however, a pair of speakers that Morricab had said he was very impressed with (Odeon La Bohemes) became available not too far from me, so I went to hear them. The seller was moving into a smaller home and had been trying to sell them for quite a while, with the end result was that he took an amp that I no longer had use for in trade, and I got a smokin' deal on a world class set of loudspeakers. I'm quite certain that these are the last speakers I will ever buy, at least for my main system.

I never would have known enough to bother to go look at these if not for the information I gained here in the High-Eff forum, so I'd like to thank everyone that contributed information on my first post. I'd especially like to thank Morricab and Tubeguy, since they were the ones that provided the specific mention that led me to go to see the La Bohemes in the first place.

Hmmm. They're 98 dB efficient, so there may be an SET in my future...

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SET? Some alternatives of lower cost.

Timbo in Oz

15:59:27 11/11/15

RE: SET? Some alternatives of lower cost.

morricab

08:37:15 11/12/15

RE: SET? Some alternatives of lower cost.

Todd A.

06:52:35 11/12/15

...

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SET? Some alternatives of lower cost.

Timbo in Oz

15:59:27 11/11/15

RE: SET? Some alternatives of lower cost.

morricab

08:37:15 11/12/15

RE: SET? Some alternatives of lower cost.

Todd A.

06:52:35 11/12/15

RE: SET? Some alternatives of lower cost.

morricab

08:46:57 11/12/15

OT: L10

jusbe

22:53:53 11/16/15

RE: OT: L10

morricab

08:09:58 11/17/15

Interesting.

jusbe

16:39:42 11/20/15

RE: Interesting.

morricab

08:55:10 11/23/15

RE: Was thinking about a passive.

Todd A.

08:59:03 11/12/15

RE: Was thinking about a passive.

morricab

14:13:04 11/13/15

PICTURES!... Please

lokie

05:22:44 11/09/15

But of course...

Todd A.

14:39:12 11/09/15

RE: But of course...

Mike in NJ

17:14:53 11/10/15

Those are the ones.

Todd A.

18:14:53 11/10/15

PICTURES!... Please, posted on November 9, 2015 at 05:22:44
lokie Audiophile Posts: 1989 Location: Georgia, USA Joined: January 28, 2003	.

But of course..., posted on November 9, 2015 at 14:39:12
Todd A.	They're a little big for this room, and it will take a while to get everything dialed in, but they already sound glorious to my ears.

RE: But of course..., posted on November 10, 2015 at 17:14:53
Mike in NJ Audiophile Posts: 596 Location: Paramus, NJ Joined: September 5, 2002	There was a seller on the Asylum trader selling a pair - did you happen to get that pair? They look awesome, and would love to hear a pair myself. Mike

Those are the ones., posted on November 10, 2015 at 18:14:53
Todd A.	He had them advertised in several places. I'm a little mystified as to why they didn't sell before I got them.

SET? Some alternatives of lower cost. , posted on November 11, 2015 at 15:59:27

Timbo in Oz
Audiophile

Posts: 23221
Location: Canberra - in the ACT - SE Australia
Joined: January 30, 2002

If they have similar impedance issues to the Odeon Traviata tested by Stereophile, you might need an amp that has a lower output impedance than typical SETs. To cope with dips and phase angles.

So, if it were me I'd be keeping your VAC mono-blocks (100wpc?) but have them connected in triode mode. But before that - see below - I'd try them on the 4ohm and 8 ohm taps tap and choose. It is likely that they will be less coloured off the 4 ohm tap. Do try it.

If you have the owners manual - the one for the MKII is on line - read up about using the taps. You may find that you should use two of the taps. To damp the lowest impedance dip.

Triode mode will have even better damping factor off either tap. On the MKIIs it gives 57 watts, not 30 watts. About 60% of UL (part triode) is typical.

How much less travel on the volume knob (pot) are you using than with the previous speakers. If it is a lot less you may not be in the pot's cleanest range. Have you yet tried them on large loud pieces of music, like say Mahler?

If they are out of warranty get a local techie to set them up in triode mode / put in a switch so that you still have the option / if you wanted to sell them. They can also adjust the gain down - if needed.

LBNL I think you will find that the bass cabinet is more akin to a reflex box.

Warmest

Tim Bailey

Skeptical Measurer & Audio Scrounger

RE: SET? Some alternatives of lower cost. , posted on November 12, 2015 at 06:52:35

Todd A.

Hey, Timbo!

Where to start...the factory says it's a backloaded horn. When setting them up, I looked at the bottom of the cabinet and it's completely open. It appears to be the mouth of a labyrinth that the woofer backwave fires into, so the horn fires downward rather than to the front or back. That would seem to be the reason for the bases and standoffs.

I've detected no coloration issues whatsoever. They're the most natural sounding speakers I've ever heard. I used to think my Martin Logans had a holographic soundstage, and they did to a large degree, but in retrospect, everything was larger than life, and they weren't remotely close to the Odeons on any other front. Instruments just sound real to me, so I don't feel that I'm listening to my stereo any more. I'm just listening to music.

I've had some communication with the factory, and they recommend +/- 10 WPCH. In triode mode the VACs produce 30 WPCH, so they're a bit much for these.

Incidentally, I had heard these were 98 dB efficient. The factory says 96. Crossover at 1.8 KHz.

I'll certainly try the 4 ohm taps on the VACS. It costs nothing to do so, and who knows? I've tried the VACs on the 8 ohm taps, and the gain is excessive. That could also be the preamp, of course, but it's obvious that some changes are afoot. It will be worth it, although it's going to take a while. I'm currently using the Wave 8s, and they sound better than they have a right to, although I'm looking forward to improvements in transparency down the road with different amplification.

RE: SET? Some alternatives of lower cost. , posted on November 12, 2015 at 08:37:15
morricab Distributor or Rep Posts: 9180 Location: switzerland Joined: April 1, 2005	I do not know what the impedance curve looks like for the La Boheme; however, both of my SET amps and my one push/pull tube amp strongly prefer the 8 ohm tap to the 4 ohm tap.

RE: SET? Some alternatives of lower cost. , posted on November 12, 2015 at 08:46:57

morricab
Distributor or Rep

Posts: 9180
Location: switzerland
Joined: April 1, 2005

I am also struggling a bit with gain...as in having too much becuase they are several db more sensitive than my previous speakers. Only 96 and not 98 db? Oh well...not a big difference really.

I am driving mine with the following amps:
Wall Audio Opus 50 PSET amps (2 x 6C33C per monoblock): about 35 watts
JJ 322 PSET (2 x 300B per channel): about 20 watts
PureSound A30 (2 X 6550 per channel): about 18 watts in triode mode

The gain of the two SETs are too high when I connect with an active preamp so I barely crack the volume control most of the time. With some preamps I had big trouble with noise and hum.

At the moment I am playing with the Wall Audio Opus 88 preamp as a "final" preamp. I will be considering others as well before I decide. I also have a PureSound L10 preamp that I am not terribly happy with but I think putting in new output transformers could make it a winner.

RE: Was thinking about a passive., posted on November 12, 2015 at 08:59:03

Todd A.

For a long-term game plan, perhaps a passive TVC with dual preamp outs into something like a pair of Decware SETs. Rather than bridging them, I'd be inclined to try using one on the woofers and the other on the spherical horns. The problem there is needing a third set of preamp outs to feed the subs.

This is obviously down the road. The VACs might work significantly better if I had a preamp with no gain, but that's not available right now.

RE: Was thinking about a passive., posted on November 13, 2015 at 14:13:04
morricab Distributor or Rep Posts: 9180 Location: switzerland Joined: April 1, 2005	I haven't found a passive yet that really outperforms a good active tube preamp...but I guess it is possible...

OT: L10, posted on November 16, 2015 at 22:53:53
jusbe Audiophile Posts: 5950 Location: North Island Joined: April 4, 2000	Morricab, forgive me for asking, but what happened to the L10? Has it broken down in some way? Or have you fallen out of love with it? I thought it was supposed to be a good performer? Big J "... only a very few individuals understand as yet that personal* salvation is a contradiction in terms."*

RE: OT: L10, posted on November 17, 2015 at 08:09:58

morricab
Distributor or Rep

Posts: 9180
Location: switzerland
Joined: April 1, 2005

Good question...I have mixed feelings about this preamp. One the one hand it is dynamic and quite palpable for solo instruments. Reasonably transparent with good rich bass. BUT, the soundstage was not so clear and instruments in the background get somewhat smudged together. I upgraded all the caps in the power supply and that helped a tiny bit but what i think is really holding it back are the output transformers. SO, I will be upgrading them with some Lundahl units to see where that gets me. If that works then it could be totally killer...or not.

I have been playing around now with a Wall Audio Opus 88 (matches with my Wall Audio Opus 50 monos) and it has a truly great linestage in it. Totally transparent, dynamic soundstage. bass etc. All valve rectified and regualted. The phonostage is where I am less sure about the preamp. It is very clear and explicit...especially for a tube phonostage. However, my Silvaweld phono is an amazing machine and it is giving the phono built into the Wall preamp a tough time. It seems to have more inner spark than the Wall. A bit less explicit but seemingly wider dynamic range overall.

I will hopefully be trying some others to see if I can better the Wall for my budget, which won't be easy, but I really don't want to sell off my Silvaweld unless I am sure the other preamp's phono can equal it.

If the lundahl transformer upgrade "transforms" the L10 then it is a moot point and I have my preamp.

Interesting. , posted on November 20, 2015 at 16:39:42

jusbe
Audiophile

Posts: 5950
Location: North Island
Joined: April 4, 2000

I think your tastes in preamps aren't too dissimilar to mine, so it's useful to now your experience with the L10. I had my eye on the L300, bought direct from the OEM through a friend in Asia, but was aware that it is hard to be certain what quality of transformer one would be ordering. This is the whole Bewitch/OEM issue at play, perhaps.

Do you think the Opus 88 phono stage could be tuned with tube rolling? It reminds me of some of the design ideas in my present Audio Innovations L2 and P2.

Big J

"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."

RE: Interesting. , posted on November 23, 2015 at 08:55:10

morricab
Distributor or Rep

Posts: 9180
Location: switzerland
Joined: April 1, 2005

It can be tuned by rolling. I replaced some new JJ tubes in one stage of it with some other new tubes (ElectroHarmonix) and it was a distinct improvement. One might think then that good NOS will bring it even further.

At least from the pictures the output transformer looks the same in the L10 and L300; however, the measurements I have seen of both indicate that the L300 has a wider bandwidth...the output tubes are different so perhaps if it is the same trafo the matching with the tube is better.

I will do a more in-depth investigation with the Wall next year for a review I am planning.

High Efficiency Speaker Asylum

A big "Thank you!" to the High Efficiency Speaker forum.

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