Eeek... Well I couldn't design an amp if my life depended on it but as I am a Laddy reading this post I do think if it has an opamp in it then make it an LM4562. This chip has turned my green solo into the most accurate detailed gorgeous sounding amp I've personally heard and it works miracles in my CMoy too. Mick prefers his Zigis CMoy to his Bravo amp and his Zigis hasn't even bedded in yet.
Also PSUs add a shed load of cash into the mix so why not contemplate using a battery pack like I use on my CMoy. It lasts weeks for a few hours a day on a set of 8 rechargables. There's nothing to stop us using a couple of maplins 8 or 10 AA battery holders to up the voltage. Cheap clean power... just a thought.
I hope that everybody realises that Robert started this topic in this area, as the intention was to create a Class A SE VALVE amplifier,or a variation on that theme where a valve is used. Designs that do not at least include a valve should not be discussed in this area. Alex
Ahhh... but this is NOT a valves only thread on my part.Anything goes... Valves included.Maybe even 2 or 3 final possible designs will roll out of the equation.Perhaps a universal design that will allow more than 1 topology depending on how a PCB is loaded with parts..Who knows.Maybe the whole thread will fall apart and no agreement can be made.In this case too bad... but at least we tried.
Frans There is already 7 pages of discussion in an existing thread, where Will is the moderator.Nothing has been ruled in or out in the existing thread. Alex
What do the 'LADDY's' think of this Bravo variation.
4 RCA's (2 in and 2 directly coupled through-outs 6.3 mm output (or 3 with different output Z's ?). Volume control. 2 heatsinks on the side. 1 tube as a voltage amp (Bravo topology but better CCS) so the typical Bravo 'sound' is there. an Opamp buffer with or without DC servo feedback. same class A output stage as Bravo BUT WITH feedback AND without an output capacitor.
Easy/cheap to build.
made so you can roll tubes and IC's easily
24 volt DC supply voltage
selectable OUTPUT impedance (10-56-120 Ohms)
a lesser gain as the original Bravo.
preferably lesser hiss when the vol pot is at zero.
Would anyone be interested ?
If not ... I'm not going to bother to spend time on it. If there is I will design something and everyone may shoot at it and come up with suggestions about parts used or change in topologies.
Also suggest housing appearance and specify board sizes even.
It looks good Frans. I suppose it all comes down to the cost and how that relates to the Bravo.
If it's a better version (or variation) then I'm sure people would love it because I really enjoy the full, fruity sound of the Bravo a great deal.
Being able to alter the output impedance is a nice touch.
Bravo doesn't hiss until you turn up to daft volumes so the gain is set too high. With lower gain, you would never be that aware of noise. It doesn't hiss at all at zero volume - it's more a case of at what level the hiss starts to appear. Mine is quiet until you just don't want it any louder.
Being able to use most of the volume pot travel range is also useful so that tracking is better. I use the Bravo at a very low setting only and it would be nice to have a little more finesse there.
I've just thought - you know how people rage about Chinese amps being clones? Is this a European clone now? In which case, I wonder if you could clone an Earmax? I could do with another one. And I'd be prepared to pay slightly more than a Bravo!!!
No, not SHOOT, SHIT ! In comparison with the other version with a decent CCS and a more reasonable HT voltage, that is. I can't help but feel that the opamp is going to alter the tonal characteristics a smidgin too. What is the BW of the 1st one Frans ? Alex
Need to cut the heatsink up one part for each end,..
Ok that didn't take much with the cutoff saw
Geez, Robert. Why didn't I think of that ? What better way to illustrate the difference between valve amps and a good SS design, than have a 12AT7 in one channel, and a 12AU7 in the other channel !!! ;D Alex