Samuel Groner
Well-known member
META - Discrete Operational Amplifiers
This is a meta-thread, made to allow you to keep track of the posts concerning this single issue. All should be contained in this first post - which is re-edited regularily. Everyone is welcome to reply with comments and pointers to things they consider relevant. This will be copy/pasted into the first post, if the meta-keeper finds it relevant. (We deeply dislike censorship, but here it seems necessary for the sake of overview). On a regular basis, a moderator will delete all posts but this first one, and bump the thread to the top.
BJT Input:
New Designs:
www.groupdiy.com/index.php?topic=775
B7 -- An attempt at making discrete opamp. There is lot to learn even from a simple circuit like this.
www.groupdiy.com/index.php?topic=4127
Playing with discrete class-A opamps on the simulator -- with comments by PRR
www.groupdiy.com/index.php?topic=5866
The GainBloak -- A Current Feedback Opamp using just five transistors.
www.groupdiy.com/index.php?topic=27102
Anyone have Tamas' "Bloke" series opamp diagrams? -- follow-up to the above thread.
www.groupdiy.com/index.php?topic=10868
Preview On New Discrete OpAmp -- Simple, yet high performance design.
www.groupdiy.com/index.php?topic=11105
Another "op-amp" to chew on
www.groupdiy.com/index.php?topic=14911
Another Bloak Hack... -- the FancyBloak.
www.groupdiy.com/index.php?topic=15297
www.groupdiy.com/index.php?topic=15297 -- a pretty unconventional desing.
www.groupdiy.com/index.php?topic=11369
Yamaha M916 Mixer Refurb Questions - schematic included -- Yamaha discrete opamp.
Jensen 990:
www.groupdiy.com/index.php?topic=1401
JE990 Lives! -- some attempts to make a PCB for the 990.
www.groupdiy.com/index.php?topic=8888
Some 990C Qs -- bcarso and PRR explain some clever bits of the 990C
www.groupdiy.com/index.php?topic=14422
DIY JE-990 DOA -- Gerbers for a 990.
www.groupdiy.com/index.php?topic=18409
long Opamp pins and 20µ inductors -- the secrets of the ferrite bead.
API 2520:
www.waltzingbear.com/Schematics/API/API_2520.htm
API2520 Discrete Opamp -- Datasheet.
www.groupdiy.com/index.php?topic=4903
Another Discrete Op-Amp (Pics) -- the modern 2520.
www.groupdiy.com/index.php?topic=25444
SMD Discrete Op Amp -- now with SMD parts.
www.groupdiy.com/index.php?topic=27705
HELP with blowing up 2520s -- why did they die?
Melcor 1731:
www.groupdiy.com/index.php?topic=44
Melcor 1731 PCBs.. Where we left off... -- Jay is making boards for this opamp
www.groupdiy.com/index.php?topic=89
Melcor Deconstructed -- Schematics and brief analysis of the opamp
www.groupdiy.com/index.php?topic=608
Melcor rev#1 board fix -- Instructions on how to fix rev#1 boards of the peterc-fallout enterprise
www.groupdiy.com/index.php?topic=16092
Melcor 1731 -- some pictures and price discussion of the real ones.
Jensen 918:
www.groupdiy.com/index.php?topic=8818
918 discrete opamp schemo request -- documentation for the 918, a antecessor of the 990 designed by Deane Jensen.
http://home.datacomm.ch/gronerfamily/DIY/918/918_documentation.pdf -- schematic and application notes from Deane Jensen.
NTP M100
www.gyraf.dk/schematics/NTP_M100_OPAMP.GIF
NTP M100 -- A discrete opamp recreated by Jakob. I have built this and it works very well.
www.groupdiy.com/index.php?topic=11943
Has anyone built an M100 NTP op-amp? -- discussion of this opamp.
www.silentarts.de/lab/studiotechnik/NTP/M100_Schematic.pdf
NTP M100/M100B -- Ancient looking schematics.
www.silentarts.de/lab/studiotechnik/NTP/M100_Data.pdf
NTP M100 data -- Invaluable datasheet for the M100 (German language)
Neumann OA10
www.silentarts.de/lab/studiotechnik/neumann/OA10_Schematic.pdf
Neumann OA10 -- The schematic. Did you know they made their own opamps?
www.silentarts.de/lab/studiotechnik/neumann/OA10_Data.pdf
Neumann OA10 Data
Other Designs:
www.bryston.ca/BrystonSite05/BrystonDocs.html -- lots of discrete opamps in the preamplifier schematic PDFs.
www.groupdiy.com/index.php?topic=169738
This DOA-33 thing from bryston
www.groupdiy.com/index.php?topic=14587
Quad Eight AM4 opamp.
www.groupdiy.com/index.php?topic=14794
Yamaha M1516/PM2000 Discrete op-amps? -- the name says it all.
www.groupdiy.com/index.php?topic=19710
cello OTA-1 -- the name says it all.
www.groupdiy.com/index.php?topic=19731
Cello VF-1 -- the name says it all.
www.groupdiy.com/index.php?topic=20458
LAWO 325 DOA schematic -- the name says it all.
www.groupdiy.com/index.php?topic=23648
Please help me analyze this circuit. -- an old design.
www.groupdiy.com/index.php?topic=23614
A few observations w.r.t. a discrete output-driver -- another design discussion.
www.groupdiy.com/index.php?topic=27143
Philbrick opamps P25a, P65a, P85a for preamp, etc? -- any use for audio?
www.groupdiy.com/index.php?topic=27746
A DOA from DDR -- another one.
www.groupdiy.com/index.php?topic=27743
Strange Opamps with API footprint ? -- any use for audio?
JFET Input:
New Designs:
www.groupdiy.com/index.php?topic=8708
Discrete JFET-NPN Cascode Input OPAMP -- a discrete opamp using the famous 2SK389.
www.groupdiy.com/index.php?topic=14911
Another Bloak Hack... -- a varition of the GainBloak.
www.groupdiy.com/index.php?topic=179746
DCBloak on the bench... -- follow-up to the above thread.
Other Designs:
www.groupdiy.com/index.php?topic=6573
Great River Opamp2.pdf
Great River OpAmp -- with comments by bcarso and PRR
Class A JFet Opamp.PDF
First generation JFET Opamp -- Nice and simple.
www.groupdiy.com/index.php?topic=20349
Some pics to study - HS2000 -- the name says it all.
Tube:
New Designs:
www.groupdiy.com/index.php?topic=18757
TOA-Tube Op-Amp -- the name says it all.
Other Designs:
www.forsselltech.com/schematics/VT%20Opamp.PDF
Tube Opamp -- Something for the tubularly inclined.
Pins & Sockets:
www.groupdiy.com/index.php?topic=3070
Where to find discrete op-amp pins and sockets?
www.groupdiy.com/index.php?topic=3909
Some MILL-MAX alternatives
www.groupdiy.com/index.php?topic=5104
Where in the UK can I get pins/sockets for MELCOR`s & 25
www.groupdiy.com/index.php?topic=7097
Discrete IC sockets and pins?
Mixed:
www.groupdiy.com/index.php?topic=8
Melcors and JLM pre pcb's -- Discussion on fitting the Melcor into Joe Malone's preamp board
www.groupdiy.com/index.php?topic=159
Api 2520 and MM990 how different do they sound? -- The title says it all. There is a comment at the from John Hardy the producer of the JH990 opamps.
www.groupdiy.com/index.php?topic=7645
Spin-off topic - Constant Current Sources -- all about CCSs.
www.groupdiy.com/index.php?topic=13164
Matching transitors, HfE and test sets......? -- why to or not to match transistors.
www.groupdiy.com/index.php?topic=13616
Transistor matching -- why to or not to match transistors.
www.groupdiy.com/index.php?topic=14146
What is the cleanest Discreet Opamp -- the name says it all.
www.groupdiy.com/index.php?topic=19688
Simplest discrete op-amps -- how simple does an opamp get?
www.groupdiy.com/index.php?topic=23336
Shockproof mounting of Discrete Op-Amps ? -- the name says it all.
www.groupdiy.com/index.php?topic=23345
Discrete Opamp potting -- the name says it all.
www.groupdiy.com/index.php?topic=27234
Ahuja-Compensation -- get the PSRR up.
www.groupdiy.com/index.php?topic=27761
DOA Potting Cans -- the name says it all.
www.groupdiy.com/index.php?topic=27884
buffering the VAS -- second stage design.
www.groupdiy.com/index.php?topic=28742
Clamping For Two-Stage Opamp -- overload troubles.
www.thelisteningsessions.com/session9.htm -- the listening session for ADK Custom Shop AP-1 Microphone Preamplifier with various 2520 style opamps and transformers.
www.utdallas.edu/~hellums/docs/JournalPapers/SmithCFBamp.pdf -- excellent overview on different opamp-topologies.
www.national.com/an/AN/AN-A.pdf -- good discussion of the standard 3-stage opamp architecture.
www.analog.com/library/analogDialogue/archives/39-05/Web_ChH_final.pdf -- Highly recommended and very interesting literature! Many examples and discussions of commercial discrete opamps.
External Links:
www.dself.dsl.pipex.com/ampins/dipa/dipa.htm
Douglas Self Amplifier Design -- Excellent pages on the internal workings of amplifiers. Even though the page is titled for power amplifiers everything there applies to their smaller cousins.
www.passdiy.com/pdf/diyopamp.pdf
Nelson Pass on Opamps -- Another great resource for design. It explores BJT, JFET and MOSFET operation amplifiers.
www.avensonaudio.com/tech.html
Quad Eight Opamps -- These quad eight discrete opamps at the Avenson Audio site.
www.borbelyaudio.com/adobe/borb502.pdf
Borbely buffer
Business Links:
www.johnhardyco.com
The John Hardy Company -- John makes the 990 discrete opamp and puts it into his preamps as well.
www.forsselltech.com
Forssell Technologies -- The home of JFET based opamps and nice audio equipment.
www.jlmaudio.com
Joe Malone Audio -- The maker of all sorts of pro-audio gear. The home of the JLM99V discrete opamp.
www.purpleaudio.com
Purple Audio
This is a meta-thread, made to allow you to keep track of the posts concerning this single issue. All should be contained in this first post - which is re-edited regularily. Everyone is welcome to reply with comments and pointers to things they consider relevant. This will be copy/pasted into the first post, if the meta-keeper finds it relevant. (We deeply dislike censorship, but here it seems necessary for the sake of overview). On a regular basis, a moderator will delete all posts but this first one, and bump the thread to the top.
BJT Input:
New Designs:
www.groupdiy.com/index.php?topic=775
B7 -- An attempt at making discrete opamp. There is lot to learn even from a simple circuit like this.
www.groupdiy.com/index.php?topic=4127
Playing with discrete class-A opamps on the simulator -- with comments by PRR
www.groupdiy.com/index.php?topic=5866
The GainBloak -- A Current Feedback Opamp using just five transistors.
www.groupdiy.com/index.php?topic=27102
Anyone have Tamas' "Bloke" series opamp diagrams? -- follow-up to the above thread.
www.groupdiy.com/index.php?topic=10868
Preview On New Discrete OpAmp -- Simple, yet high performance design.
www.groupdiy.com/index.php?topic=11105
Another "op-amp" to chew on
www.groupdiy.com/index.php?topic=14911
Another Bloak Hack... -- the FancyBloak.
www.groupdiy.com/index.php?topic=15297
www.groupdiy.com/index.php?topic=15297 -- a pretty unconventional desing.
www.groupdiy.com/index.php?topic=11369
Yamaha M916 Mixer Refurb Questions - schematic included -- Yamaha discrete opamp.
Jensen 990:
www.groupdiy.com/index.php?topic=1401
JE990 Lives! -- some attempts to make a PCB for the 990.
www.groupdiy.com/index.php?topic=8888
Some 990C Qs -- bcarso and PRR explain some clever bits of the 990C
www.groupdiy.com/index.php?topic=14422
DIY JE-990 DOA -- Gerbers for a 990.
www.groupdiy.com/index.php?topic=18409
long Opamp pins and 20µ inductors -- the secrets of the ferrite bead.
API 2520:
www.waltzingbear.com/Schematics/API/API_2520.htm
API2520 Discrete Opamp -- Datasheet.
www.groupdiy.com/index.php?topic=4903
Another Discrete Op-Amp (Pics) -- the modern 2520.
www.groupdiy.com/index.php?topic=25444
SMD Discrete Op Amp -- now with SMD parts.
www.groupdiy.com/index.php?topic=27705
HELP with blowing up 2520s -- why did they die?
Melcor 1731:
www.groupdiy.com/index.php?topic=44
Melcor 1731 PCBs.. Where we left off... -- Jay is making boards for this opamp
www.groupdiy.com/index.php?topic=89
Melcor Deconstructed -- Schematics and brief analysis of the opamp
www.groupdiy.com/index.php?topic=608
Melcor rev#1 board fix -- Instructions on how to fix rev#1 boards of the peterc-fallout enterprise
www.groupdiy.com/index.php?topic=16092
Melcor 1731 -- some pictures and price discussion of the real ones.
Jensen 918:
www.groupdiy.com/index.php?topic=8818
918 discrete opamp schemo request -- documentation for the 918, a antecessor of the 990 designed by Deane Jensen.
http://home.datacomm.ch/gronerfamily/DIY/918/918_documentation.pdf -- schematic and application notes from Deane Jensen.
NTP M100
www.gyraf.dk/schematics/NTP_M100_OPAMP.GIF
NTP M100 -- A discrete opamp recreated by Jakob. I have built this and it works very well.
www.groupdiy.com/index.php?topic=11943
Has anyone built an M100 NTP op-amp? -- discussion of this opamp.
www.silentarts.de/lab/studiotechnik/NTP/M100_Schematic.pdf
NTP M100/M100B -- Ancient looking schematics.
www.silentarts.de/lab/studiotechnik/NTP/M100_Data.pdf
NTP M100 data -- Invaluable datasheet for the M100 (German language)
Neumann OA10
www.silentarts.de/lab/studiotechnik/neumann/OA10_Schematic.pdf
Neumann OA10 -- The schematic. Did you know they made their own opamps?
www.silentarts.de/lab/studiotechnik/neumann/OA10_Data.pdf
Neumann OA10 Data
Other Designs:
www.bryston.ca/BrystonSite05/BrystonDocs.html -- lots of discrete opamps in the preamplifier schematic PDFs.
www.groupdiy.com/index.php?topic=169738
This DOA-33 thing from bryston
www.groupdiy.com/index.php?topic=14587
Quad Eight AM4 opamp.
www.groupdiy.com/index.php?topic=14794
Yamaha M1516/PM2000 Discrete op-amps? -- the name says it all.
www.groupdiy.com/index.php?topic=19710
cello OTA-1 -- the name says it all.
www.groupdiy.com/index.php?topic=19731
Cello VF-1 -- the name says it all.
www.groupdiy.com/index.php?topic=20458
LAWO 325 DOA schematic -- the name says it all.
www.groupdiy.com/index.php?topic=23648
Please help me analyze this circuit. -- an old design.
www.groupdiy.com/index.php?topic=23614
A few observations w.r.t. a discrete output-driver -- another design discussion.
www.groupdiy.com/index.php?topic=27143
Philbrick opamps P25a, P65a, P85a for preamp, etc? -- any use for audio?
www.groupdiy.com/index.php?topic=27746
A DOA from DDR -- another one.
www.groupdiy.com/index.php?topic=27743
Strange Opamps with API footprint ? -- any use for audio?
JFET Input:
New Designs:
www.groupdiy.com/index.php?topic=8708
Discrete JFET-NPN Cascode Input OPAMP -- a discrete opamp using the famous 2SK389.
www.groupdiy.com/index.php?topic=14911
Another Bloak Hack... -- a varition of the GainBloak.
www.groupdiy.com/index.php?topic=179746
DCBloak on the bench... -- follow-up to the above thread.
Other Designs:
www.groupdiy.com/index.php?topic=6573
Great River Opamp2.pdf
Great River OpAmp -- with comments by bcarso and PRR
Class A JFet Opamp.PDF
First generation JFET Opamp -- Nice and simple.
www.groupdiy.com/index.php?topic=20349
Some pics to study - HS2000 -- the name says it all.
Tube:
New Designs:
www.groupdiy.com/index.php?topic=18757
TOA-Tube Op-Amp -- the name says it all.
Other Designs:
www.forsselltech.com/schematics/VT%20Opamp.PDF
Tube Opamp -- Something for the tubularly inclined.
Pins & Sockets:
www.groupdiy.com/index.php?topic=3070
Where to find discrete op-amp pins and sockets?
www.groupdiy.com/index.php?topic=3909
Some MILL-MAX alternatives
www.groupdiy.com/index.php?topic=5104
Where in the UK can I get pins/sockets for MELCOR`s & 25
www.groupdiy.com/index.php?topic=7097
Discrete IC sockets and pins?
Mixed:
www.groupdiy.com/index.php?topic=8
Melcors and JLM pre pcb's -- Discussion on fitting the Melcor into Joe Malone's preamp board
www.groupdiy.com/index.php?topic=159
Api 2520 and MM990 how different do they sound? -- The title says it all. There is a comment at the from John Hardy the producer of the JH990 opamps.
www.groupdiy.com/index.php?topic=7645
Spin-off topic - Constant Current Sources -- all about CCSs.
www.groupdiy.com/index.php?topic=13164
Matching transitors, HfE and test sets......? -- why to or not to match transistors.
www.groupdiy.com/index.php?topic=13616
Transistor matching -- why to or not to match transistors.
www.groupdiy.com/index.php?topic=14146
What is the cleanest Discreet Opamp -- the name says it all.
www.groupdiy.com/index.php?topic=19688
Simplest discrete op-amps -- how simple does an opamp get?
www.groupdiy.com/index.php?topic=23336
Shockproof mounting of Discrete Op-Amps ? -- the name says it all.
www.groupdiy.com/index.php?topic=23345
Discrete Opamp potting -- the name says it all.
www.groupdiy.com/index.php?topic=27234
Ahuja-Compensation -- get the PSRR up.
www.groupdiy.com/index.php?topic=27761
DOA Potting Cans -- the name says it all.
www.groupdiy.com/index.php?topic=27884
buffering the VAS -- second stage design.
www.groupdiy.com/index.php?topic=28742
Clamping For Two-Stage Opamp -- overload troubles.
www.thelisteningsessions.com/session9.htm -- the listening session for ADK Custom Shop AP-1 Microphone Preamplifier with various 2520 style opamps and transformers.
www.utdallas.edu/~hellums/docs/JournalPapers/SmithCFBamp.pdf -- excellent overview on different opamp-topologies.
www.national.com/an/AN/AN-A.pdf -- good discussion of the standard 3-stage opamp architecture.
www.analog.com/library/analogDialogue/archives/39-05/Web_ChH_final.pdf -- Highly recommended and very interesting literature! Many examples and discussions of commercial discrete opamps.
External Links:
www.dself.dsl.pipex.com/ampins/dipa/dipa.htm
Douglas Self Amplifier Design -- Excellent pages on the internal workings of amplifiers. Even though the page is titled for power amplifiers everything there applies to their smaller cousins.
www.passdiy.com/pdf/diyopamp.pdf
Nelson Pass on Opamps -- Another great resource for design. It explores BJT, JFET and MOSFET operation amplifiers.
www.avensonaudio.com/tech.html
Quad Eight Opamps -- These quad eight discrete opamps at the Avenson Audio site.
www.borbelyaudio.com/adobe/borb502.pdf
Borbely buffer
Business Links:
www.johnhardyco.com
The John Hardy Company -- John makes the 990 discrete opamp and puts it into his preamps as well.
www.forsselltech.com
Forssell Technologies -- The home of JFET based opamps and nice audio equipment.
www.jlmaudio.com
Joe Malone Audio -- The maker of all sorts of pro-audio gear. The home of the JLM99V discrete opamp.
www.purpleaudio.com
Purple Audio
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