Project ST120R
Sitting on the couch last night, I was bumming out as I was thin on funds and not able to complete my chip amp project.. bummed to the point of selling it. Browsing ebay I came across a very COOL idea. A guy had gutted an old Dynaco St120 and replaced the parts with modern chip amps. Bingo! I had an St120 sitting on a shelf for years! This is perfect as the new monoblocks that I built "Peter Daniels LM4780 kits run in parellel" produce 60wpc just like the old dynaco. The goal is to totally refurb the old st120 with modern parts and dual monoblocks bringing it up to modern specifications which is why I named it "ST120R for Stereo 120 reconditioned"
In the spirit of the st120 which was one of the first modern high power transistor power amplifiers featuring capacitive output coupling and a regulated power supply "taken from notes found online about the st120" I figured I would do the 42 year old design justice. I would implement the most modern amplifier technology IMO which are gain clone "chip amps". IMO if Dynaco was building kits today, no doubt they would also choose chip amps keeping up with bang for the buck cutting edge technology that any joe can build and afford and sound fantastic.
Here are some photos of the original dirty dusty 42 year old solid state wonder......
Here are some photos of the chip amps themselves....
Tonight I gutted the st120 and layed out the new parts. One thing that 2008 parts have in common with 1966 parts is weight! The new torrids weight as much as all of the st120 guts if not more.
This photo shows 1966 solid state technology that produced 60wpc
This photo shows 2008 solid state technology that also produces 60wpc
Here are photos of the parts layed out inside the new chassis....
The chip amps parts list is as follows...
LM4780 kit with blue boards $68
Premium resistors upgrade (4 x 220R Caddock, 4 x 680R Riken, 8 x 22k
Caddock) $60
4 x BG N 100/50 $52
4 x BG STD 1000/50 $64
2 x Plitron 300VA toroids $160
Items needed to order and things to do....
- order in iec plug, fuse & switch
- order in binding posts
- order in RCA connectors
- order in new mounting feet
- order in heatsinks
- order in or build standoff's for boards
- order in all stainless steel hardware.
- Have a 1/4" aluminum plate cut to cover the entire bottom of the chassis. The chassis is flimsy and I want to give all the parts a solid mount
- Have bottom of chassis powdercoated... Still undecided on color but the bottom of the amp will be silver or black
- Have top cage powdercoated gloss or matt black & keep original dynaco logo & factory build serial number tag
Will keep this post updated on the progress..... Hopefully I have somthing to show in a week or so progress wise...
Sitting on the couch last night, I was bumming out as I was thin on funds and not able to complete my chip amp project.. bummed to the point of selling it. Browsing ebay I came across a very COOL idea. A guy had gutted an old Dynaco St120 and replaced the parts with modern chip amps. Bingo! I had an St120 sitting on a shelf for years! This is perfect as the new monoblocks that I built "Peter Daniels LM4780 kits run in parellel" produce 60wpc just like the old dynaco. The goal is to totally refurb the old st120 with modern parts and dual monoblocks bringing it up to modern specifications which is why I named it "ST120R for Stereo 120 reconditioned"
In the spirit of the st120 which was one of the first modern high power transistor power amplifiers featuring capacitive output coupling and a regulated power supply "taken from notes found online about the st120" I figured I would do the 42 year old design justice. I would implement the most modern amplifier technology IMO which are gain clone "chip amps". IMO if Dynaco was building kits today, no doubt they would also choose chip amps keeping up with bang for the buck cutting edge technology that any joe can build and afford and sound fantastic.
Here are some photos of the original dirty dusty 42 year old solid state wonder......
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here are some photos of the chip amps themselves....
An externally hosted image should be here but it was not working when we last tested it.
Tonight I gutted the st120 and layed out the new parts. One thing that 2008 parts have in common with 1966 parts is weight! The new torrids weight as much as all of the st120 guts if not more.
This photo shows 1966 solid state technology that produced 60wpc
An externally hosted image should be here but it was not working when we last tested it.
This photo shows 2008 solid state technology that also produces 60wpc
An externally hosted image should be here but it was not working when we last tested it.
Here are photos of the parts layed out inside the new chassis....
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The chip amps parts list is as follows...
LM4780 kit with blue boards $68
Premium resistors upgrade (4 x 220R Caddock, 4 x 680R Riken, 8 x 22k
Caddock) $60
4 x BG N 100/50 $52
4 x BG STD 1000/50 $64
2 x Plitron 300VA toroids $160
Items needed to order and things to do....
- order in iec plug, fuse & switch
- order in binding posts
- order in RCA connectors
- order in new mounting feet
- order in heatsinks
- order in or build standoff's for boards
- order in all stainless steel hardware.
- Have a 1/4" aluminum plate cut to cover the entire bottom of the chassis. The chassis is flimsy and I want to give all the parts a solid mount
- Have bottom of chassis powdercoated... Still undecided on color but the bottom of the amp will be silver or black
- Have top cage powdercoated gloss or matt black & keep original dynaco logo & factory build serial number tag
Will keep this post updated on the progress..... Hopefully I have somthing to show in a week or so progress wise...