Don’t sweat it, just post it when you can. I don’t read anything into projects that go dormant for 3 (or more) years. I understand there are things called JOBS and CHILDREN that sort of get in the way of completing projects.
Hmm a schematic. Guess i am not a bot after all.
Anyways enough of the nonsense. Came here to learn about audio circuits not be involved in drama.
Anyways enough of the nonsense. Came here to learn about audio circuits not be involved in drama.
You can easily develop over 100V of signal coming off that 6V6. You probably want some gate oxide protection on the Hexfet.
That looks pretty obvious to me. Get the gain right first. I would use a triode wired EL11 myself but that's not likely to happen.
Anything wrong with a 6J5 or 6SN7? True triodes and better sounding than a 6V6
Nothing wrong with a triode as an input tube. Would probably make it easier. If i used a 6SN7 would need to resistor load it.
You been here 20 yrs. So what is the max gain of a triode, in simple terms??
Where did you find that?? Just wondering if you have invested in any books on this subject at all. 😀
I have plenty of books. Morgan Jones tube book etc. Gain of 6V6 triode mode transformer or choke load is around 9.8. Less if its resistor loaded. Ignoring content by members is a good feature of this forum. I don't have to prove anything.
Should be good. I used a full SS amp to follow after the tone stack. Twin triode 6922's provide the amplification. Sounds fantastic.
The question asks for max triode gain, not a triode connected 6V6.
The answer is simply 'mu' of the tube.
Morgan Jones book is very good & used by many.
The really serious folks on this & other forums like RDH4.
And Fred E Terman,, Ed 4. And many others, all add to our knowledge.
Many people search but do not necessarily find, however their searches can help things move forward.
Isn't trial/error the basis of progression?
Yes, I agree that there are intangible bases, but if everyone looks in the same direction, we will never know if we could have done something else with it.
I do have a copy of the RDH4 too. Someone got rid of it at my job. I snatched it up in a second.
To be fair i do tend to jump around from one design to another, sometimes never building something i post and ask questions about. I like the positive interactions, being able to ask questions, and get informative replies from folks who have more experience than I.
To be fair i do tend to jump around from one design to another, sometimes never building something i post and ask questions about. I like the positive interactions, being able to ask questions, and get informative replies from folks who have more experience than I.
why would I do this for a voltage gain stage? I was using the 6V6 triode connection just based on what others have mentioned as extremely low distortion and a "45" type of sound. granted I could just put a DHT on the input instead. (gain maybe an issue?... will need to do some more digging into what DHT's would work). Or as said about just a reg triode. i.e. 6SN7
There are projects that were started a long time ago that have yet to see completed, finished hardware up and running in the field. Most notable is a “4000 watt” SS amp now in its 4th generation, where design began in 2006, and first articles on the bench came in 2009. It’s now just a bucket list project, but the end goal is now a production run of 8 of them. Still could be a ways off. In the meantime, my interest in tube amps has rekindled and actual working hardware produced. And now thinking about building tube amps at the maximum practical limits based on what parts I can get. Its a race to see whether me or George Tubelab get there first. Hard to say. I’m building a new house, or more correctly, a new RANCH at the moment. Until I have a house where something isn’t always BROKEN in need of fixing, the big projects will get pushed to the side. At least with everything new, built from scratch to standards where things won’t fall apart in my hands, there is at least a chance of having a year or two break in there somewhere.
If you are starving for gain as it is (got about 9x but looking for 20x) then a DHT is probably not the way to go. Mu is typically even lower. Unless you start looking at transformers for voltage gain. Designing that way does lead to more variables, and things can get expensive fast. Flat response in a transformer costs real money, and without measurements to back things up you are going to be chasing down a lot of things that can affect the sound. Going down a lot of subjective rabbit holes.
Parallel the two halves of an SN7 and you probably have enough drive power if your chokes have enough inductance. They are easier to drive at both ends of the band the lower the ra. Hexfet input capacitance is bootstrapped so it’s effective value is lower, but it can’t be ignored either. Eventually it will start eating into the high end.
yeah thats why I have not built anything yet. just thinking out aloud here... i may not need the full 20 gain. a paralleled 6SN7 should work fine. Maybe even resistor loaded.
The 6V6 in triode doesn't sound like a 45. It sounds like a triode strapped beam tetrode, which is what it is. A-B'd it against true triodes like 37, 76, 6P5, 6J5 and 26 and they were all audibly better. Currently using a 76 but 37 just as good, and of course the 26 better still. The round plate 6J5GTs sound very good - better than the flat ribbed plates. They sound like the 37 and 76, similar construction. I've been trying out all of these in my driver stage which drives an EL12 in SE, mu = 18 in triode. I spent some time on comparisons. These were all resistor loaded. You need 39K or more for the anode resistor but they don't need much current - say around 4mA.
The circuit is simple enough that if you have the tubes and coupling chokes on hand it’s time to put something on the bench and listen to what it sounds like. If it’s another 3 years till it’s finished and making music in your bedroom or living room that’s ok. Idle speculation can only go so far.