In a very comprehensive and detailed article, published in Japan in 1999 and reproduced in Glass Audio the following year, Satoru Kobayahi described a 300B SE stereo amp that uses Plitron toroidal OP and power transformers.I was interested to see that he used a power MOSFET series regulator in place of the smoothing choke in what would have been a conventional CLC pi-filter.
Essentially, his PS consisted of: toroidal power transformer - SS bridge - 100uF smoothing cap - MOSFET series regulator - 100uF reservoir cap.
For regulation, he had well-bypassed stacked zeners (3 x 150 v) from the MOSFET gate to ground. According to the test voltages written on his schematic, he dropped 33 v across the MOSFET.
His initial objective, in replacing a choke with a MOSFET, was to save money and reduce weight. However, he also reported that the ripple was much less than he could have achieved with a 10H choke. In view of Satoru-san's reputation as a designer and builder, I'm inclined to think that if it's good enough for him then it's good enough for me!
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Topic - Low Hy? How about no Hy? - Ray Moth 16:16:00 05/05/07 (45)
- My experiments with high voltage regulators - John Swenson 14:41:42 05/07/07 (1)
- Re: My experiments with high voltage regulators - Ray Moth 00:58:34 05/08/07 (0)
- Wow, you copped a hiding on this one ... - Naz 07:26:30 05/07/07 (6)
- Thanks for your concern, but . . . - Ray Moth 00:45:42 05/08/07 (5)
- Re: Thanks for your concern, but . . . - Naz 00:30:30 05/09/07 (4)
- Re: Thanks for your concern, but . . . - Ray Moth 00:52:56 05/09/07 (3)
- Re: Thanks for your concern, but . . . - Naz 06:41:47 05/09/07 (2)
- Perhaps I meant the drain! - Ray Moth 14:43:44 05/09/07 (1)
- That's what I thought ... - Naz 15:56:59 05/09/07 (0)
- Anyone consider this as an alternative? - ahlgren11@telia.com 13:19:28 05/06/07 (0)
- Re: Low Hy? How about no Hy? - Dave Davenport 06:30:00 05/06/07 (1)
- Re: Low Hy? How about no Hy? - Ray Moth 20:30:50 05/06/07 (0)
- Ray, the whole point of using a choke input filter... - Allen Wright 03:18:51 05/06/07 (21)
- Re: Ray, the whole point of using a choke input filter... - Ray Moth 11:38:51 05/06/07 (7)
- "avoid the use of a heavy and expensive choke" - Allen Wright 05:06:23 05/07/07 (5)
- Re: "avoid the use of a heavy and expensive choke" - Ray Moth 06:35:11 05/07/07 (4)
- Compared to the cost, size and weight of using Plitrons for... - Allen Wright 14:47:57 05/07/07 (3)
- Re: Compared to the cost, size and weight of using Plitrons for... - Ray Moth 00:35:47 05/08/07 (2)
- "It seems a choke-input filter (a real one!) is a hard act to follow" - Allen Wright 01:34:53 05/08/07 (1)
- Re: "It seems a choke-input filter (a real one!) is a hard act to follow" - drlowmu 06:27:31 05/08/07 (0)
- Re: Ray, the whole point of using a choke input filter... - Eli Duttman 16:56:55 05/06/07 (0)
- Re: Ray, the whole point of using a choke input filter... - Tre' 09:58:58 05/06/07 (10)
- Re: Ray, the whole point of using a choke input filter... - Ray Moth 06:42:30 05/07/07 (0)
- EXACTLY!!! (nt) - Allen Wright 05:09:03 05/07/07 (0)
- dynamically incorrect (nt) - drlowmu 16:08:50 05/06/07 (1)
- Re: Ray, the whole point of using a choke input filter... - sorenj07 10:13:44 05/06/07 (6)
- Re: Critical Inductance.... - JimL 19:53:36 05/06/07 (3)
- And if some's good, and more's better... - Allen Wright 05:12:46 05/07/07 (2)
- Re: And if some's good, and more's better... - JimL 18:24:05 05/07/07 (0)
- In case you missed the memo - Russ57 08:15:33 05/07/07 (0)
- Re: Ray, the whole point of using a choke input filter... - Tre' 11:06:16 05/06/07 (0)
- Re: Ray, the whole point of using a choke input filter... - Eli Duttman 10:27:02 05/06/07 (0)
- Well put... - BBeck 06:03:20 05/06/07 (1)
- Yup! (nt) - Allen Wright 01:37:25 05/08/07 (0)
- I see a possibility for high-current tube amps - sorenj07 22:20:55 05/05/07 (3)
- Re: I see a possibility for high-current tube amps - Ray Moth 02:07:08 05/06/07 (2)
- Re: I see a possibility for high-current tube amps - sorenj07 09:32:11 05/06/07 (1)
- Re: I see a possibility for high-current tube amps - Ray Moth 20:35:07 05/06/07 (0)
- Re: Low Hy? How about no Hy? - Eli Duttman 20:29:11 05/05/07 (1)
- Re: Low Hy? How about no Hy? - Ray Moth 02:04:20 05/06/07 (0)
- Re: Low Hy? How about no Hy? - Triode_Kingdom 17:58:01 05/05/07 (1)
- Re: Low Hy? How about no Hy? - Eli Duttman 20:03:59 05/05/07 (0)
- Why not? - gluca 16:32:44 05/05/07 (1)
- Re: Why not? - zobsky 21:01:01 05/05/07 (0)
- Yes it would work - gluca 01:40:29 05/06/07 (0)