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The Hybrid Class A amplifier

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#121
Wavebourn said:


I did that. Tower-II project. Exactly 200W/Channel. It was during a winter. It sounded very nice, but I switched to 80W/Channel class AB tube amp.
Click to expand...

My main amplifier is 60W class AB, pp tube amplifier with 4 triode connected 6550. So it's sounds better than any of my ss, or hybrid amplifier.

But I'm curios about that 200W class A hybrid 🙂

Sajti
 
#124
Wavebourn said:
Mine too. Today I would use pentode driver. 😉
Click to expand...

I also try 6080. It can drive everything 🙂 One of my solution was the two half of the 6080 as connected parallel cathode follower, to drive double darlington output stage. It was really good, but I was bit shocked about the 5A of heaters current 🙂 (The sound was amazing, so mybe I will give a second chances for it)

I don't use DC servo, and I also try to avoid overall feedback as well

Sajti
 
#126
I had one idea, long time ago. To make triple darlington buffer, with single ended followers in the first two stages. Only the output stage would be push-pull.
This means high current for the second stage, and high current Vbe multiplier...

Sajti
 
#127
I would use the 6080/6AS7 over any tube for use in a hybrid amplifier, no matter the filament current, but by the sounds of what Wavebourn is describing.... I can't define the design that I plan on using as an hybrid amplifier because it is class "AB". 😀

If only I understood the circuit topology more, because to me it is quite complicated to understand the mixing of tubes and SS, all I really want to do is get rid of the unfindable FET input on the circuit I have, and replace it with a tube instead, if it was so simple to do so...

But because this thread is for the class "A" amplifier hybrid circuit I probably can't get much help, although, for me the ultimate hybrid would be one that will run in class "A" up to a cirtian output level then go into class "AB" mode but the only amplifier that I have ever read that actually does that is this one...
http://www.turneraudio.com.au/solidstateamps1mosfets.htm

Too bad it is full solid state overly massive and uses FET's :bawling:
 
#129
The only fets that I have large amounts of are IRF630's and 640's and one or two 9640's, what I am trying to acomplish is to use the stuff that I have to build a half decent amplifier, but all that I have are BJT's and not only that but they are more than sufficient to produce the power output I want ( 100 watts 8 ohms).

I have gathered much information about hybrid amplifiers just from reading this thread, but not enough to confidently design one myself without some help from others.

But I think I will stick with your idea of using a tube preamp at the input, but I really want to get rid of the fet chip at the LTP ( I think) on the input of the amplifier for the reason that I would never find a replacement.

The only hybrid circuit I could potentially build is the one I showed earlier using 6SN7's.
 
#131
Wow, that is the strangest design I have ever seen, how did you ever work it out? The circuit looks so unuasual to me that it doesn't look like it would even work, but it being class "D" would make it very efficient, too bad this thread is for class "A" hybrids but I'd sure like to try this circuit using the parts I have...

You tell us how it sounds, and take some pics of the setup as well Ja2, I am very much interested, although not too familiar with class "D" designs.
 
#132
CrazzyAbtTubes said:
this thread is for class "A" hybrids but I'd sure like to try this circuit using the parts I have...
Click to expand...

Yes, this thread is for Class-A, sorry bothered you. I will initiate another
thread when my amp will be completed. Now I have completed power
supply portion and PCB of amplifier portion as is shown in the below
URL.

http://ja1cty.servehttp.com/class-d/class-d1.html

Circuit simulation has been completed.

I will report in another thread hereafter.
 
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