I'm thinking of learning to design a circlotron type preamp. Which one will sound more musical and tube like?
Just curious. I haven't tried this topology and everyone say it's great.
I'm going to use 1632 like Juma did
I'm going to use 1632 like Juma did
what is usually meant as "tube like" is dominant 2nd harmonic, flavor of SE topology - as result of unequal amplification of sine halves - one is always going to be greater than the other
circlotron per se is symmetrical circuit, and you can only compare it with fully symmetrical tube circuits*** , when speaking about tube
saying that only to give you more details so you can clarify your own preferences ... it would be pitty building wanted circuit just to be disappointing on outcome, not with quality but with nature of sound
anyway, depending of your own objections, it's always possible to deliberately ruin symmetry of symmetrical circuits, thus invoking some 2nd
*** say push-pull all the way from input to output, having all stages symmetrical thus 3rd dominant; that ideally/in principle, and there are some amplifiers having PP OS, and SE FE, where FE is not having significant contribution to overall THD of amp, thus amp still being dominantly symmetric
circlotron per se is symmetrical circuit, and you can only compare it with fully symmetrical tube circuits*** , when speaking about tube
saying that only to give you more details so you can clarify your own preferences ... it would be pitty building wanted circuit just to be disappointing on outcome, not with quality but with nature of sound
anyway, depending of your own objections, it's always possible to deliberately ruin symmetry of symmetrical circuits, thus invoking some 2nd
*** say push-pull all the way from input to output, having all stages symmetrical thus 3rd dominant; that ideally/in principle, and there are some amplifiers having PP OS, and SE FE, where FE is not having significant contribution to overall THD of amp, thus amp still being dominantly symmetric
Depletion MOSFETS are tube like (electrically) because they are normally on and a negative voltage on the gate or a source resistor can be used to bias it... That's why I prefer them 🙂
That said, all of my preamps are vacuum state.
The LND150 can effectively replace a 12AX7 if you respect the max Pd.
I've also done some experiments with an ixtp08n100d2 using 300V B+, 33k drain resistor, 600R source resistor. 47k gate leak resistor.
Here's a look if anyone is interested. Bottom trace is input, upper trace is output from drain. Not useful in a preamp but would make a good driver for a low mu triode output stage (strapped sweep tubes).
That said, all of my preamps are vacuum state.
The LND150 can effectively replace a 12AX7 if you respect the max Pd.
I've also done some experiments with an ixtp08n100d2 using 300V B+, 33k drain resistor, 600R source resistor. 47k gate leak resistor.
Here's a look if anyone is interested. Bottom trace is input, upper trace is output from drain. Not useful in a preamp but would make a good driver for a low mu triode output stage (strapped sweep tubes).
Thank you all for informations
I had tried se. Pushpull, balanced In tubes and ss and experiment with output transformers. So I'm left with circlotron. Anyway zenmod. I heard 2 of the singing bushes they are awesome!
In fact lnd150 is one of the things on my mind to experiment.
I scribbled something.. Still alot of mistakes but this is a rough idea what I'm trying to do. Since my dac and output transformers are all balanced. If I fail. Nah it's all fun. I just started learning to use the program pardon me if it look bad
I had tried se. Pushpull, balanced In tubes and ss and experiment with output transformers. So I'm left with circlotron. Anyway zenmod. I heard 2 of the singing bushes they are awesome!
In fact lnd150 is one of the things on my mind to experiment.
I scribbled something.. Still alot of mistakes but this is a rough idea what I'm trying to do. Since my dac and output transformers are all balanced. If I fail. Nah it's all fun. I just started learning to use the program pardon me if it look bad
Attachments
A depletion mode mosfet will look more or less like a pentode, but without the advantages of the pentode's screen grid. Miller capacitance will be in full effect. Choose one that doesn't have a lot of gate capacitance - It'll be easier to drive.
Tube sound comes from plate feedback and vacuum state resistance changes which the LD150 do not duplicate.
If you want tube sound get a couple of 6922 or 12ax7 and buffer them with LD150 or DN2540.
If you want tube sound get a couple of 6922 or 12ax7 and buffer them with LD150 or DN2540.
Thank you Papa. I was jumping ahead of myself and got greedy . That's a good reminder
@Stocktrader thank u, I actually have tried Jim audio hybrid 12ax7 + jfet and korg b1. Aleph L and 5687 tubes . I wonder just lnd150n3 will sound like with a huge swing in voltage.
I had actually tried susy opa1632. Papa's license. That really surprised me. I didn't find anything I don't like. Quite genius simple put.