In Reply to: RE: From what I understand the Zero's... posted by Lew on May 15, 2017 at 16:14:39:
"Chris, You and a few others are the ones taking the purist stance."
Well, I am a theoretical physicist in my day job, always questioning, seeking to extract general principles, universalities, and precise definitions. I suppose I tend to apply a similar approach in the rest of life; automatically questioning, looking for inconsistencies or ambiguities, and so on. (Doesn't always go down too well, I have to admit!)
So in this case too I just like to have a clear, precise and robust definition of what OTL means. For me, it means one thing and one thing only; no inductive impedance-matching device between the output tubes and the loudspeaker. As far as I can see, any attempt to broaden this definition so as to allow some impedance-matching transformers but not others is just opening a can of worms, and it will end up with arbitrary criteria being introduced in order to try to justify something that really cannot be logically defended.
In any case I don't see any need for such a broadening of the concept of OTL; better just to stick to the simple yes/no criterion of whether there is any impedance-matching transformer between the output tubes and the speaker or not.
In a case where a Zero autotransformer is being used, it can perfectly well be described as an OTL amplifier supplemented with an impedance-matching transformer that connects to the loudspeaker.
I guess the thing that prompted me to comment in the first place was that for myself, I would feel it to be a bit of an admission of defeat if I had set out to build an OTL system and then ended up resorting to using impedance-matching autotransformers in order to do the job satisfactorily. Now, I'm sure it is true that certain speakers with especially low impedance might be quite challenging loads for some OTL amplifiers. If I had such speakers, and was determined to use them with an OTL amplifier, I think I would direct my attention to beefing up the OTL so that it could handle the load, rather than using transformers.
In the end this comes down to a matter of personal taste, I suppose. I built my OTL amplifiers because I was fascinated by the idea that tubes could drive ordinary loudspeakers directly. I wouldn't want to give up on that motivation, and if I had very low impedance speakers that provided a difficult load for the OTL amplifier, I would view that as challenge to overcome by improving the OTL amplifier itself.
Edits: 05/16/17This post is made possible by the generous support of people like you and our sponsors:
Topic - OTL amps and high impedance speakers. - Cougar 13:55:07 04/22/17 (44)
- RE: OTL amps and high impedance speakers. - firstname.lastname@example.org 15:52:17 05/05/17 (0)
- RE: OTL amps and high impedance speakers. - ozzyboy 10:31:10 04/29/17 (35)
- RE: OTL amps and high impedance speakers. - email@example.com 16:01:42 05/05/17 (34)
- Can you please list the system.... - Cougar 07:20:34 05/06/17 (33)
- RE: Can you please list the system.... - firstname.lastname@example.org 15:23:42 05/12/17 (0)
- RE: Can you please list the system.... - email@example.com 15:22:46 05/12/17 (0)
- RE: Can you please list the system.... - cpotl 09:15:01 05/06/17 (30)
- RE: Can you please list the system.... - firstname.lastname@example.org 09:14:10 05/13/17 (0)
- From what I understand the Zero's... - Cougar 11:09:20 05/06/17 (28)
- RE: From what I understand the Zero's... - email@example.com 15:12:08 05/12/17 (1)
- You might want to read... - Lew 12:00:26 05/16/17 (0)
- RE: From what I understand the Zero's... - cpotl 17:39:17 05/06/17 (10)
- RE: From what I understand the Zero's... - firstname.lastname@example.org 20:46:50 05/08/17 (9)
- RE: From what I understand the Zero's... - cpotl 05:42:05 05/10/17 (8)
- I never said it was.... - Cougar 15:41:48 05/20/17 (2)
- RE: From what I understand the Zero's... - Lew 13:05:16 05/15/17 (4)
- RE: From what I understand the Zero's... - cpotl 11:46:44 05/06/17 (14)
- One way to find out is to check.... - Cougar 13:13:34 05/06/17 (1)
- Paul Speltz, Zero maker, has done this.... - Lew 10:39:27 05/16/17 (0)
- RE: From what I understand the Zero's... - ozzyboy 13:08:17 05/06/17 (11)
- RE: From what I understand the Zero's... - email@example.com 20:49:52 05/08/17 (0)
- RE: From what I understand the Zero's... - cpotl 15:18:30 05/06/17 (8)
- You should go to their website.... - Cougar 16:24:23 05/06/17 (7)
- RE: You should go to their website.... - cpotl 16:34:40 05/06/17 (6)
- I have an idea... - Lew 07:49:36 05/16/17 (5)
- Thank You for clearing that up.... - Cougar 13:20:17 05/06/17 (0)
- The comment on Tubecad - Ralph 15:25:39 04/22/17 (6)
- The power droop at very high impedances... - Lew 07:24:32 04/27/17 (1)
- RE: The power droop at very high impedances... - Ralph 10:22:10 04/28/17 (0)
- I figured 8-16 ohms was the best range for speaker ohms. - Cougar 15:51:07 04/22/17 (3)Follow Ups
- RE: From what I understand the Zero's... - cpotl 02:00:00 05/16/17 (1)
- My thinking has a little more plasticity,.... - Lew 07:21:32 05/16/17 (0)