 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
198.144.203.126
In Reply to: RE: Their loss may be your gain. Or it may be... posted by viridian on August 10, 2019 at 14:37:22
One thing about this hobby is that personal taste and experience come into play heavily. When I acquired my obscure SET parts, some said I was nuts to pursue it. The eyes of my long suffering wife rolled back in her head, but survive she did (and enjoys the amp immensely now). I won't even mention what happened when I rolled some massive, gutted Altec Magnificent cabinets (with the requisite patina) into the garage.
I think the project would be very revealing. A design so far ahead of its time, which has spawned a small industry and cult following of OTL amplifiers, many current versions being highly sought after. Just what would that Futterman amp sound like if brought up to current standards using high quality components.
Just the impact of an IEC and high quality power cord might be significant. Good wire, quality resistors and capacitors - very interesting. Things that Mr. Futterman did not have access to.
I have already considered building the improvements somewhat in stages, both to see if each works in the amp, and to gauge what the impact is. Perhaps a bit more work, but it might also be educational and fun.
Key is to find the appropriate patient (Futterman H3) to perform the operation on. I also would like to have the final amp appearance relatively unchanged from the original.
Follow Ups:
I think the project would be very revealing. A design so far ahead of its time, which has spawned a small industry and cult following of OTL amplifiers, many current versions being highly sought after.
As a bit of an historical note, when I first invented my take on OTLs I had no idea who Futterman was or that OTLs were a thing. I was barely out of high school...
Nt
And studiously sidestepped a lot of the pitfalls in his design. That's why our OTL is unconditionally stable.
....there is an ad in it for an OTL amp with a matching very high impedance loudspeaker. I'm coming off the top of my head here but around 100 ohms. Have you heard of that Ralph? I should dig it out and post it here.
For the Beveridge models 2 and 2SW a direct-coupled amplifier is situated in the base of the gigantic speaker(s). No coupling capacitors OR transformer, driving a totally unique take on ESL, not really an ESL as we know it because the diaphragm does not carry a bias voltage; it's at ground reference. Which is maybe why after nearly 40s years my 2SWs still sound divine. (Knocking on wood.) I've owned the 2SWs for about 6-7 years now, but the amplifiers are dated inside, "1979".
Other later models of Beveridge speakers (models 3 and up) are much more like conventional ESL speakers and require an outboard amplifier.
Nt
I think I just wanted a chance to talk about Beveridge.
-
Nt
Stephens and Philips Norelco offered high impedance speakers with matching OTL amplifiers.I believe the high impedance Stephens TruSonic speakers were 500 ohms; while Philips Norelco had both 400 ohm and 800 ohm offerings.
As I recall, each of their OTL amplifiers were cap-coupled SRPP designs.
Edits: 08/13/19 08/13/19
Nt
Lots of interesting material here - scroll down for info on their OTL amplifier.
...I wouldn't mind a pair of those corner horns, and that mid-century modern house to listen to them in.
This combo (OTL + high impedance speaker) sounds interesting. I hope you can find it.
My Stax F83 speakers have a variable but overall very high impedance, around 160 ohms in the midrange. The NYAL Stax combination works very well. (But I now have a subwoofer to take
care fo the low frequency, where the speaker's impedance strangey goes back down to 4 ohms).
-
...in the Magnificents. I am quit jealous.
A friend of mine has a couple of Futterermans that he deploys with ESL57s and smaller Altecs. They were both rebuilt by local Portland OR tech Mat Kamna. I wish that I could give my impressions, but my friend has so much gear, and it changes so quickly, that I have a hard time nailing anything down.
I hope that you will share your project when it rolls around.
I actually converted them to 9cu ft Altec 604 enclosures (so a wee bit smaller, but by no means petite).If and when I get going, I will put something up and see if there is interest. Likely to need some conceptual help with the project as well, as I am no expert...
Edits: 08/10/19
Nt
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]