ANyone else done on of these ...
runoff Groove's 'umble' pedal preamp implementation of classic tube amp 'pre' section ...
http://www.olcircuits.com/olc_umble.html
I got my pcb going properly today and wow!zer - did it knock my socks off.
Biased it up quite basic like, the four fets are common unmatched .. j201 ... the Vp is reasonably similar across the set and the bias up quite close, at the 'source' pin .. +0.82V to +0.90V. No probs 'centre biasing' the 'drain' pin with 100K trimmers.
ANyway - yep, it's all there ... huge dynamic range, even with a standard 9V battery supply.
I was playing it into my 'tube bass amp' head and '15" pine box' and it was huge.
The tube amp is single ended and I like to run it at low power quite clean .. it's a big sound that you don;t mess with! It can be a little-bit light on the delicate 'treble' .. I think it 'takes' boosting pedals quite well, taking a lot to ruffle it's gravitas.
But this modest circuit transformed it into a raging beast ...
Fairly quiet, schmutz wise, with maximum on the 'touch sensitivity' tweaky-tweaky thing, like I've never known before.
....
ANyway, I'm just putting it in an alu box .. but again, I'm amazed at what 4 fets and some thoughtful approaches to historical circuits can achieve ... for quite low cost.
I'm really interested to hear how it will sound with some solid state power amps, like those tiny modern types
I'm ordering another similar pcb, just to see how it integrates into my rack of 'franken-modules' .. I think it's worthy of inclusion!
Thinking to add a line amp for recording and some small amp module ..
runoff Groove's 'umble' pedal preamp implementation of classic tube amp 'pre' section ...
http://www.olcircuits.com/olc_umble.html
I got my pcb going properly today and wow!zer - did it knock my socks off.
Biased it up quite basic like, the four fets are common unmatched .. j201 ... the Vp is reasonably similar across the set and the bias up quite close, at the 'source' pin .. +0.82V to +0.90V. No probs 'centre biasing' the 'drain' pin with 100K trimmers.
ANyway - yep, it's all there ... huge dynamic range, even with a standard 9V battery supply.
I was playing it into my 'tube bass amp' head and '15" pine box' and it was huge.
The tube amp is single ended and I like to run it at low power quite clean .. it's a big sound that you don;t mess with! It can be a little-bit light on the delicate 'treble' .. I think it 'takes' boosting pedals quite well, taking a lot to ruffle it's gravitas.
But this modest circuit transformed it into a raging beast ...
Fairly quiet, schmutz wise, with maximum on the 'touch sensitivity' tweaky-tweaky thing, like I've never known before.
....
ANyway, I'm just putting it in an alu box .. but again, I'm amazed at what 4 fets and some thoughtful approaches to historical circuits can achieve ... for quite low cost.
I'm really interested to hear how it will sound with some solid state power amps, like those tiny modern types
I'm ordering another similar pcb, just to see how it integrates into my rack of 'franken-modules' .. I think it's worthy of inclusion!
Thinking to add a line amp for recording and some small amp module ..