In Reply to: Powering a tube amp without speakers posted by Byrd69 on November 4, 2017 at 16:08:07:
on the amplifier design. My Marantz 8B has a warning to not run with no load. In fact I tried using the 16 ohm tap a couple times with a speaker attached and the output tubes started to run away (not enough feedback?). I caught that quickly. The Marantz in ultra linear pentode operation is essentially a Williamson circuit and has a feedback winding on the output transformer - no feedback (i.e. no load) means the amp can go full on even with a very low noise signal on the input (that is the definition of unstable). Obviously, this does not apply to non feedback tube amps (most).
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Follow Ups
- It depends - mgbpuff 11/5/1706:10:07 11/5/17 (12)
- RE: It depends...apparently!... - Steve O 08:15:43 11/5/17 (9)
- I guess neither of us is 100% correct - - mgbpuff 03:40:46 11/6/17 (8)
- LOL...Get to know your 8B better... - Steve O 06:39:03 11/6/17 (7)
- The "Willy" reference came from a - mgbpuff 07:26:09 11/6/17 (6)
- Split load PI vs LTP PI alone is a significant distinguishing feature... - Steve O 08:27:25 11/6/17 (5)
- Significant distinguishing feature? - mgbpuff 09:21:41 11/6/17 (4)
- If PI topology isn't a significant distinguishing feature of an amp design... - Steve O 10:43:39 11/6/17 (3)
- Bah, you're just getting silly now - mgbpuff 11:03:52 11/6/17 (2)
- I own a pair of those amps... - Steve O 12:56:18 11/6/17 (1)
- Yes, I thought - mgbpuff 14:58:25 11/6/17 (0)
- RE: It depends - Caucasian Blackplate 07:35:28 11/5/17 (1)
- You may be correct - - mgbpuff 03:53:04 11/6/17 (0)