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Dear Everett et al, There are those that believe a Pi-Wound, or even a Solenoid-Wound inductor is the Saving Grace of QRO amplifiers. And there are those who think that monsters are really hiding in

I was told that the original RF-choke could cause oscillation. 73, Evert PA2KW <https://www.qrz.com/db/PA2KW> / 5T2KW <https://www.qrz.com/db/5T2KW> / <https://www.qrz.com/db/W8S> W8S Sent: Tuesday,

Thanks Dave. Always “good” to hear the issues! In the L7 the RFC3 was ok (no issues in 15 years) 73, Evert PA2KW <https://www.qrz.com/db/PA2KW> / 5T2KW <https://www.qrz.com/db/5T2KW> /

I've just bought 4 from W8JI at CTR Engineering. Installed one in my AL-1500 and one in my home brew 2 x 3-500Z 160 to 10 amp. No problems on any band with those chokes. 73, Alek VK6APK.

I found the RF-choke I used : https://www.rfparts.com/rfc3.html Thanks 225 ?H; that's a big value indeed. I thought you wound it yourself on the original mandrel. Why did you have to change this

From my own experience in blowing up two of those, is that RFC3 RF-choke purchased from RF-Parts is resonant on 30 meters when used in a 3-tube (8874) Alpha 76A amplifier. Use in other amplifiers may

I found the RF-choke I used : https://www.rfparts.com/rfc3.html 73, Evert <https://www.qrz.com/db/PA2KW> PA2KW / <https://www.qrz.com/db/5T2KW> 5T2KW / W8S <https://www.qrz.com/db/W8S> Sent: Monday,

Francois, ** Your capacitor 'A' went with your old RF choke. Yes, you are correct. 73, Evert <https://www.qrz.com/db/PA2KW> PA2KW / <https://www.qrz.com/db/5T2KW> 5T2KW / W8S

Hi All, I have a DTR-2000L that I'm trying to bring back to life.? It's the same one that I asked about last year.? What I'd like is IF someone that has one of these amps, that's working, would you

Hi Alek, I’ve seen some of the older units and worked on them. ?The real old ones had no grid trip circuit and so I made up a circuit board ?with a trip circuit and implement it on the old units.

Hello, ** No, I don't have the service manual for this amp. If you could share it with me, it would be appreciated. ** Your capacitor 'A' went with your old RF choke. A= 47 pF B= 307 pF Thanks for the

Fran?ois, here are the exact capacitors I used to replace C41 and C42 in my L7: https://www.rfparts.com/catalogsearch/result/?q=580050-7P https://www.rfparts.com/catalogsearch/result/?q=580300-7 **

Fran?ois, here are the exact capacitors I used to replace C41 and C42 in my L7: https://www.rfparts.com/catalogsearch/result/?q=580050-7P https://www.rfparts.com/catalogsearch/result/?q=580300-7 I

This is a real long shot. I have an old Commander HF-2500 which I love very much. It is Serial Number 186 and it conforms with the printed manual and schematic of June 1990. However, there is no

Hi Francois, I did not document my changes and sold the amp a few years ago. I remember the green capacitor (B) but not (A). That could easily be a memory leakage on my side but I couldn’t find it

Hello I am weak in technology (I am 75 years old). It seems to me that you are pointing out the two curious plate capacitors A = C41 (47 pF) and B = C42 (307 pF). Could you give me, precisely, the

The reason is in this message /g/ham-amplifiers/message/40898 -- F1AMM Fran?ois De la part de Evert Bakker via groups.io Envoyé : samedi 25 janvier 2025 19:38

I recently bought this L 7 (about $1000) from an OM who used it very little. It has the serial number 672. On this device, the air is sucked from the bottom of the case by a kind of scoop. It is a

Why do you want to see these tubes all the time? It is the most reliable amp I’ve had. You can push this amp to all its limits and beyond, it just won’t die. Even when it starts to stink like

It seems your lid or top sheet metal has been changed. Mine has holes and I can see the tubes.