I have been delayed a bit on my beta testing with another project. But I expect to get at this in a week or so.....
Folded Cascode CEN IV with fixed Rails
- Thread starter EUVL
- Start date
I felt a bit guilty as I was pretty slow at getting the beta build done - other things got in the way for a while. Over the last few evenings I built up a pair of these, verified basic functionality, and have them running now in the main system. They are sounding very good indeed - I don't think you would be sorry to have a pair of these at the end of your Miro DAC (or others) and it is certainly well worth the relatively low cost involved - a pair or valves could easily cost you more. The build is reasonably easy once you are comfortable with surface mount work (no really small stuff!). As usual, good soldering technique, patience and an organised workflow help a lot.
They are running now as I type this, using about 25mA per rail (15V rails) and while I have them running from a single supply, they really deserve their separate supplies. The sound is dynamic, very good transients/impacts, clean, very smooth, good deep and wide soundstage. I would say bass weight and impact deserves special mention - there is no lean sound here. I would consider this up there at the top of the pile in terms of the IV stages I've had.
There is still some testing on the cards which I hope to complete soon.
For reference:
Freshly serviced stacked Quad 57s
Solid state amplification
01a preamp based on Bartola valves recipe - gyrator anode supply, Coleman filament regs, source follower
Miro dac with SD card player source
They are running now as I type this, using about 25mA per rail (15V rails) and while I have them running from a single supply, they really deserve their separate supplies. The sound is dynamic, very good transients/impacts, clean, very smooth, good deep and wide soundstage. I would say bass weight and impact deserves special mention - there is no lean sound here. I would consider this up there at the top of the pile in terms of the IV stages I've had.
There is still some testing on the cards which I hope to complete soon.
For reference:
Freshly serviced stacked Quad 57s
Solid state amplification
01a preamp based on Bartola valves recipe - gyrator anode supply, Coleman filament regs, source follower
Miro dac with SD card player source
Attachments
All described in the pdf in post #1.
Patrick
Patrick
Its a mix of SMD and through hole Jim. The active devices are through hole, but the resistors etc are nearly all SMD. The vast majority are the bigger 0204 melf ones though, so easy enough to do.
Yep, probably..... I might have interpreted that incorrectly. Just to be clear (Patrick had laid this out above):
SMD version - its all SMD, still needing matched SMD components - I haven't built one of these, but I have a pair here that Patrick made.
TH version - the passives are still SMD, but transistors, fets, jfets are all TH (and matching is easier then). This is the pair in the photo above.
Fran
SMD version - its all SMD, still needing matched SMD components - I haven't built one of these, but I have a pair here that Patrick made.
TH version - the passives are still SMD, but transistors, fets, jfets are all TH (and matching is easier then). This is the pair in the photo above.
Fran
Schematic we can already see in the PDF in post #1 (i assume that is the complete one for both smd and TH version), but the BOM will be provided upon order, that's how it works right? 
I ask because i'd be courious to check what parts i can get before ordering.
I guess it is still in beta for now so nothing finalised yet.
I ask because i'd be courious to check what parts i can get before ordering.
I guess it is still in beta for now so nothing finalised yet.
I learned my lessons.
I do not publish BoM these days, except the circuit is from someone else.
The through hole version, for a stereo pair, needs a quad of 2SK170BL/2SJ74BL, plus a quad of 2SK170BL (or LSK170).
These are the cost driver. Rest are Mouser / DK standard parts.
The SMD version will be offered in a soon to come GB by Ripster as a limited-edition kit (max. 20 stereo pairs).
This includes all components, including all active devices prematched.
The 500+ transistors will take months to match, so patience required.
And you all owe this to Ripster. What a mammoth task.
Patrick
I do not publish BoM these days, except the circuit is from someone else.
The through hole version, for a stereo pair, needs a quad of 2SK170BL/2SJ74BL, plus a quad of 2SK170BL (or LSK170).
These are the cost driver. Rest are Mouser / DK standard parts.
The SMD version will be offered in a soon to come GB by Ripster as a limited-edition kit (max. 20 stereo pairs).
This includes all components, including all active devices prematched.
The 500+ transistors will take months to match, so patience required.
And you all owe this to Ripster. What a mammoth task.
Patrick
Ok, understood, and i see what you mean
It is a mammoth task indeed, i can see it maybe being meditative to him perhaps..either way good for DIY community and thanks to Ripster.
I was always wishing a 2sk209 complementary...this one in parallel (if matched) can already acceptably replace k170, if there is only similar j74 alternative, you could really do a lot with a crammed space in SMD form...
And now I guess you have solved that issue in the SMD version somehow...you posted nice image of complementary SMD jfet tracing above. Can we know which 3 legged critters these are or is it a secret?
It is a mammoth task indeed, i can see it maybe being meditative to him perhaps..either way good for DIY community and thanks to Ripster.
I was always wishing a 2sk209 complementary...this one in parallel (if matched) can already acceptably replace k170, if there is only similar j74 alternative, you could really do a lot with a crammed space in SMD form...
And now I guess you have solved that issue in the SMD version somehow...you posted nice image of complementary SMD jfet tracing above. Can we know which 3 legged critters these are or is it a secret?
Unobtanium.
Patrick
Patrick
Just a little update - testing is continuing and all is going well. Sound quality is really excellent but I will hold further comments until I have carried out some more listening.