If it was the same one that I had, the push pull 811A's were in the modulator. The RF final was a 4-250. Of course I couldn't leave that alone, so in went a 4-400, and some SS rectifiers (both from a laser scrapped at work).
6146's got a bad rap in the audio world from their use in the first generation Ampeg SVT, a 300+ watt bass guitar amp. It used eight 10 inch speakers. The resonant impedance peak of the speakers was within the range of a bass guitar. The amp also fed the screens too much voltage. Combine these traits with the propensity of many users to set the volume knob on "KILL" and you get fireworks. One famous display was at a televised Rolling Stones concert in the late 1960's. Flames shot out of the amplifier for us all to see on TV.
The second generation SVT used 6550's and a bigger OPT. I personally saw one of these catch fire, and performed the autopsy after its death. The user had plugged a 300 watt amp into 100 watts worth of speakers, which lasted about 10 minutes. When the speakers went open at full throttle, bad stuff happened.
The 6146 does not make a good triode or UL amp due to the low screen voltage rating. My testing has shown that you can't violate that rating without inviting the glow of death. You could use it for a pentode mode amp and the previously mentioned Ampeg squeezed 300+ watts RMS from 6 tubes. If you ran 2 tubes in the 50 to 60 watt range they should be fine.
Yes... I agree with tubelab....
The 6146 is not happy when it sees over 250V on it's screens....
The old SVT amps that had 6146... i use to put a cheap quicky zener diode, resisitor and cap for each tube socket.... This way I locked in the 250V on the screen...
I was playing guitar one night and I was really close to my bass-player's SVT and I got sprayed with sparks when the 6146 tubes went off.... thats why I did that little mod .....
If you build a nice S.S. 250V regulator for the screen voltage, that would be good if you plan on using the 6146 in a safe and reasonable manner....
I believe if you tie it as a TRIODE, you may be able to apply 400V max....
Chris
The 6146 is not happy when it sees over 250V on it's screens....
The old SVT amps that had 6146... i use to put a cheap quicky zener diode, resisitor and cap for each tube socket.... This way I locked in the 250V on the screen...
I was playing guitar one night and I was really close to my bass-player's SVT and I got sprayed with sparks when the 6146 tubes went off.... thats why I did that little mod .....
If you build a nice S.S. 250V regulator for the screen voltage, that would be good if you plan on using the 6146 in a safe and reasonable manner....
I believe if you tie it as a TRIODE, you may be able to apply 400V max....
Chris
Dear all ! At the meantime, I have finished this amp. with 5842 Raytheon + 6146W Raytheon+ interstage transformer+3.5KOhms OT, triod-single- end connection. It sounds clear and detail at mid. freq. , but high freq. is not high enough ( I think ), low freq. is light and not deep enough , sound stage is not large enough too...Please let me know how to modify it.
Thank you.
Regards
Thank you.
Regards
I don't regard SE amps as being rich in bass at the best of times. It's not exactly the best amp for listening to heavy rock (or heavy anything, for that matter).
Also, it's tempting to blame the OPT when an SE amp is particularly light on bass. The OPT needs to be huge, heavy and suitably air-gapped for SE. Your speakers also need to be suitably sensitive.
Also, it's tempting to blame the OPT when an SE amp is particularly light on bass. The OPT needs to be huge, heavy and suitably air-gapped for SE. Your speakers also need to be suitably sensitive.
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