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References: [ +from:barberaudio@gmail.com: 19 ]

Total 19 documents matching your query.

1. [Amps] 2x LDMOS design tweaks (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Mon, 9 Sep 2019 16:28:11 -0700
Since it's quiet out, here's my latest amp mod project... There's actually a question in the last paragraph. :-) Some time ago I bought a dual-package MRFE6VP61K25HS LDMOS amp from a OM, originally b
/archives//html/Amps/2019-09/msg00006.html (8,468 bytes)

2. Re: [Amps] 2x LDMOS design tweaks (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 10 Sep 2019 11:27:11 -0700
Hi Mike, Yep, a 9:1 it is. I most certainly will look at your latest output designs, thanks. The 9:1 isn't bad, though... After 2 minutes key down @ 1200W output it only runs around 7-8C over ambient
/archives//html/Amps/2019-09/msg00012.html (11,052 bytes)

3. [Amps] "Refurbished" BLF188XR's on eBay? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Thu, 12 Sep 2019 12:37:00 -0700
I'm seeing a good number o "refurbished" BLF188XR's up for sale on eBay. What does "refurbished" mean? They look like new NXP devices, but for $108 USD I doubt it - unless they're surplus or fall-out
/archives//html/Amps/2019-09/msg00014.html (6,567 bytes)

4. Re: [Amps] "Refurbished" BLF188XR's on eBay? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Thu, 12 Sep 2019 15:27:57 -0700
Thanks, Greg. Yes, it was just wishful thinking on my part. DigiKey's current price is $186.31, which is down quite a bit from 2 years ago. Compared to a 8877, it's quite a bargain. 73, Jim N7CXI ___
/archives//html/Amps/2019-09/msg00017.html (9,278 bytes)

5. [Amps] Coolant for liquid-cooled solid-state amp (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 8 Oct 2019 09:21:43 -0700
I'm laying out a 2-module MOSFET amp, and intend to use liquid cooling. The last time I visited the topic, ethylene glycol antifreeze diluted with the traditional 50% deionized water was the coolant
/archives//html/Amps/2019-10/msg00027.html (6,747 bytes)

6. Re: [Amps] Coolant for liquid-cooled solid-state amp (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 8 Oct 2019 10:26:30 -0700
Hi Bob, thanks for the reply. In this particular case, the electrical conductivity of the coolant doesn't matter as long as the cooling efficiency stays up and the corrosion doesn't become an issue f
/archives//html/Amps/2019-10/msg00029.html (9,260 bytes)

7. Re: [Amps] Distilled water in a dummy load ? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Mon, 22 Feb 2021 10:34:04 -0800
- or from Amazon. My wife buys it to fill snow globes and I use a little here and there: https://www.amazon.com/gp/product/B00VNI1JI0/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1 My MRFX1K80N amp
/archives//html/Amps/2021-02/msg00031.html (12,793 bytes)

8. Re: [Amps] HF 30 dB Coupler (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 15 Jun 2021 09:36:20 -0700
Seems I responded to the OP only. Oops. N4GA has an article on his site for a 50dB sampler: http://www.n4ga.com/50db-hf-rf-sampler/ This article goes takes a somewhat unusual path to get to the chees
/archives//html/Amps/2021-06/msg00007.html (9,112 bytes)

9. Re: [Amps] HF 30 dB Coupler (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 15 Jun 2021 10:27:26 -0700
My mistake then. I saw the work "coupler" but apparently ignored it. 73, Jim N7CXI _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/ma
/archives//html/Amps/2021-06/msg00009.html (8,862 bytes)

10. Re: [Amps] KPA1500 Efficiency vs. RF-Kit B26 (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 13 Jul 2021 12:42:46 -0700
If theyre measuring the case temp Ill buy 90C. If it was on the spreader the amp would be dead by now. 40C is a conservative limit for the spreader, 50C if youre taking chances. 90C is a reasonable t
/archives//html/Amps/2021-07/msg00050.html (8,066 bytes)

11. Re: [Amps] KPA1500 Efficiency vs. RF-Kit B26 (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 13 Jul 2021 22:03:39 -0700
Here's a liquid-cooled MRFX1K80N after soaking for 15 minutes at 1KW output from the LPF. It uses a commercial cold plate bolted to the 5x6x3/8" C114 spreader with top-grade thermal grease. The coola
/archives//html/Amps/2021-07/msg00061.html (10,110 bytes)

12. Re: [Amps] .01uf caps across diodes ? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 29 Nov 2022 12:07:19 -0800
I've never seen a HV bridge fail because of "switching transients". Do they exist? I don't know but if they do I have no evidence they're of critical concern. I have, however seen bridge diodes and e
/archives//html/Amps/2022-11/msg00090.html (8,374 bytes)

13. [Amps] 8877 - HV with heater, or later? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Mon, 23 Jan 2023 09:26:26 -0800
I'm overhauling a vintage 8877 amp, and it occurs to me that I've never seen a definitive answer to this question: Should HV be held off on a 8877 until the heater warm-up timer expires? Not that I c
/archives//html/Amps/2023-01/msg00017.html (7,698 bytes)

14. Re: [Amps] 8877 Warm-Up Period (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Mon, 23 Jan 2023 14:17:11 -0800
Interesting. I have a HV step-start because if I didn't it would trip the breaker. The xformer is a Dahl 2800V 1A with a 53 uF oil-filled cap and 200K bleeder resistance.The cap is on the large side,
/archives//html/Amps/2023-01/msg00027.html (9,048 bytes)

15. Re: [Amps] 8877 Warm-Up Period (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Mon, 23 Jan 2023 14:19:48 -0800
Correction: HEATER. Brian may be lurking with his trusty rapier in hand... Jim N7CXI _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/
/archives//html/Amps/2023-01/msg00028.html (9,257 bytes)

16. [Amps] MKS brand 8877 test (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Sun, 29 Jan 2023 09:32:01 -0800
I recently bought a mks branded medical pull. This is my first non-Eimac 8877, so Im interested in how it performs. For the sake of the curious, heres what Ive found so far: I gettered it overnight,
/archives//html/Amps/2023-01/msg00034.html (8,500 bytes)

17. [Amps] Cleaning/lubing vacuum caps? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Fri, 3 Feb 2023 14:17:48 -0800
I have an old glass Jennings vacuum cap that pulls harder than I think it should. I've cleaned and lubed the puller screw, as well as the plates and bearing in the end of the "puller housing". It hel
/archives//html/Amps/2023-02/msg00001.html (6,672 bytes)

18. Re: [Amps] 8877 - HV with heater, or later? (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Tue, 7 Feb 2023 09:29:16 -0800
Back on the original topic, I found what appears to be an updated 3CX1500A7/8877 data sheet on the CPII site. Updated, that is since the last time I looked there... (!) https://www.cpii.com/docs/data
/archives//html/Amps/2023-02/msg00002.html (8,231 bytes)

19. Re: [Amps] Triode Questions (score: 1)
Author: Jim Barber <barberaudio@gmail.com>
Date: Mon, 13 Mar 2023 21:12:03 -0700
Hi Alek, I dont have any comment about #1, not sure theres any reason to prefer one over the other. is to equalize the RF at both ends of the heater so that the heater isnt over-lit by the heater cur
/archives//html/Amps/2023-03/msg00016.html (8,798 bytes)

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