I believe the Quads drop to 3.5 ohms or so in the bass and rise quite high in the treble.Actually, as with most electrostatics it is the opposite of that. The impedance of a capacitor decreases as frequency increases, and from an electrical standpoint an electrostatic panel is essentially a giant capacitor.
Here are impedance curves and other measurements for the ESL-63 and for one of the versions of the Snell Type A:
It appears that the Montrachet only provides a single output tap, and I wasn't able to find a spec on what nominal load impedance it is designed for. But if the answer is 16 ohms, as you mentioned, the fact that both speakers have impedances that are well under 4 ohms at certain frequencies in the treble region does not bode well with respect to sonics. Nor does the relatively low 86 db/2.83 volts/1 meter measured sensitivity of that version of the Snell Type A.
With the Snell, though, I don't see these measurements as being suggestive of any danger to the amp. The one possible danger to the amp that I can see in any of these measurements relates to the 2 ohm impedance of the Quad at 30 kHz. Even though that frequency is well above audibility and above any substantial frequency content the music may have, a low and highly capacitive impedance at high frequencies can cause some amplifiers to oscillate. Perhaps that was the possibility the dealer had in mind. Although in general I would expect that to be more likely to be an issue with a solid state amp than with a tube amp.
Good luck. Regards,
I have no information as to why, but my Ars Sonus Filarmonia SJ Integrated (EL34 PP) has 8 Ohm output taps (only) and there are cautionary notes in the owners manual warning that damage could occur to the amp if operated with speakers that drop below 4.3 ohms impedance.
I use the amp with Merlin TSM Black Magic speakers and a REL R305 (powered).
Thanks Al! The Snell A impedance data you sent is for the Type A Reference which is several generations from the original Type A. I think this is an entirely different speaker separated by 20 years and entirely different design. It is challenging to find data on the original.
I suppose what I am hoping to hear is what you hinted at ... That the 1970's snell is inherently less threatening to the shindo than is the Quad esl-63.
I found the following link, which indicates a nominal impedance of 4 ohms and sensitivity of 86db, similar to that for the more recent version of the speaker: http://www.snell.no/the_archives_type_A.htm.
The old Stereophile reviews don't have Atkinson's measurements, sadly. The reviewers did use very powerful amps in their reviews, mainly to take advantage of the Type A's bass capabilities. In Googling the speaker I found some forums where people seemed to be endorsing using lower-powered tube amps with them, but unfortunately no specs.
Yes I know those archives. I must have read elsewhere that the four ohm figure was the minimum impedance, not nominal. But now all I see is 4 ohm everywhere I read. You must be right. If this is the case I think it may be o good for the shindig. I have posts in a shindo forum and an email to the Snell servicing company and will see if I hear anything different.
If it is truly a 4 ohm minimum, then I doubt the amp will be hurt; sonically, though, as the manual also says and Al mentions above, you probably won't get the sonics that those speakers are capable of giving you (they remain one of my favorite speakers that I auditioned when first getting into the world of better audio).
Why don't you just call the Shindo distributor, Tone Audio, or a Shindo dealer and just ask?
Shindo is designed to work best with speakers 8 ohms or greater, that are high efficiency speakers. The low impedence (less than 4 ohms at certain frequencies) and low efficiency of the Snells is not a good match for Shindo amplifiers.
I confirmed that the Snells are a 4ohm nominal load so they just are not suitable for the Shindig. Too bad. Thanks very much for everyone's advice
Now I need to either find a new amp or other speakers ... But I do not like most speakers, so I may have to sell the beautiful Shindo so I can stick with my Quads. Ouch. (I did buy the Snell's just to have because they were a great deal and I love them).
I see you have the Shindo Montrachet EL34 amp for sale here on AG.
I was thinking that the Auto transformers sold by Anti-Wire may be a solution to matching your speakers to the Shindo, by increasing speaker impedance. I am sure you already have given this some thought, but hadn’t seen it come up in the conversation/post. Even though the autotransformer would make the amp load non detrimental, I am not sure what tonal/timber changes they may cause; something you would have look into . http://anticables.com/autoformers