So I have a bunch of MRF 458's and HG 2879's that I purchased long ago for $29 each around 16 or so of each. Most of them are matched pairs or matched quads.
I think in my youth I was taught that low gain bipolars where not a problem if drive with a high gain transistors. In my youth high gain American made transistors and Japanese made transistors where common and cheap so this was not a thing I really though about.
So I would like some input on this.
I was thinking about using a high gain American made or Japanese made transistor to drive lower gain American or Chinese made transistors.
I was thinking about using a high gain bipolar to drive say 6 lower gain American or Chinese transistors. It would be a B or AB biased not class C. I would probably make the driver switchable so I can use it with low drive old school radio's and modern high drive. Will likely do Manhattan style build since I only have 1, 2 and 4 transistors PCB's.
I have two MRF455's that depending on the current used to beta test them read high 90's to triple digits. I was have been saving them since the 1990's to service my 1998 President Lincoln should it pop it's final.
I was thinking about using one of them to drive either 6 MRF458 which are basickly low beta MRF454 or 6 HG 2879's. Motorola transistors need very little drive so maybe an all MRF box. Since the HG's are lower gain transistors I am not sure if 1 high gain MRF455 is enough drive.
I am rag chewing type not a com box type.
I know it makes more sense to use the HG's for a build like this since they are nothing special but part of me would like to do a all Motorola box as well for sentimental reasons.
I could skip the high gain MRF455's and use an HG as the driver or use a MRF454 or MRF458 as the driver but they are all lower gain.
In my youth I had fantastic results with 1 and 2 pill triple digit MRF455's purchased for like $9 per transistor in the early 1990's.
1 driving six is about all I want to power current wise any more than that and I might as well build a tube amp!
Thanks for advice, experience and opinions! I have plenty of MRF458's and HG2879's and
This would be the largest amp I have built in terms of transistor count. The MRF parts have all come from RF parts the HG's directly from HG.
I am really only trying to get hot TS667 power levels with out driving the tar out of my gear. I will likely use this for base operation with a combo of vintage CB's and mobil Ham radio's. It will initially be broad band with filtering on the output but if I like it I will build tuned input for each band.
Again Thanks!
I think in my youth I was taught that low gain bipolars where not a problem if drive with a high gain transistors. In my youth high gain American made transistors and Japanese made transistors where common and cheap so this was not a thing I really though about.
So I would like some input on this.
I was thinking about using a high gain American made or Japanese made transistor to drive lower gain American or Chinese made transistors.
I was thinking about using a high gain bipolar to drive say 6 lower gain American or Chinese transistors. It would be a B or AB biased not class C. I would probably make the driver switchable so I can use it with low drive old school radio's and modern high drive. Will likely do Manhattan style build since I only have 1, 2 and 4 transistors PCB's.
I have two MRF455's that depending on the current used to beta test them read high 90's to triple digits. I was have been saving them since the 1990's to service my 1998 President Lincoln should it pop it's final.
I was thinking about using one of them to drive either 6 MRF458 which are basickly low beta MRF454 or 6 HG 2879's. Motorola transistors need very little drive so maybe an all MRF box. Since the HG's are lower gain transistors I am not sure if 1 high gain MRF455 is enough drive.
I am rag chewing type not a com box type.
I know it makes more sense to use the HG's for a build like this since they are nothing special but part of me would like to do a all Motorola box as well for sentimental reasons.
I could skip the high gain MRF455's and use an HG as the driver or use a MRF454 or MRF458 as the driver but they are all lower gain.
In my youth I had fantastic results with 1 and 2 pill triple digit MRF455's purchased for like $9 per transistor in the early 1990's.
1 driving six is about all I want to power current wise any more than that and I might as well build a tube amp!
Thanks for advice, experience and opinions! I have plenty of MRF458's and HG2879's and
This would be the largest amp I have built in terms of transistor count. The MRF parts have all come from RF parts the HG's directly from HG.
I am really only trying to get hot TS667 power levels with out driving the tar out of my gear. I will likely use this for base operation with a combo of vintage CB's and mobil Ham radio's. It will initially be broad band with filtering on the output but if I like it I will build tuned input for each band.
Again Thanks!
