The following discrete and hybrid op amps reportedly meet these requirements.
Component designations J1, C3, R9, etc. refer to the DIY500 schematic, and are printed on the PCB surface.
Short means short circuit. Use zero ohm jumper resistors, or straight wire, such as clipped resistor leads.
N/A means not applicable. Leave that component out.
| Photo | Brand | Model | J1 | C3 (µF) | R9 (Ω) | R9a (Ω) | C4 (pF) | R13 (Ω) | R12 (Ω) | C7 (pF) | R14 (Ω) | J2 | Can drive an output transformer? | Tested? | Price (1 piece) | Purchase From | INFO |
![]() | ADK | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | yes | NO | ? | call(?) | |
![]() | Automated Processes (API) | 2520 | short | N/A | 100 | 1M | N/A | 47 | 10k | 100 | 47 | short | yes (75Ω min. load) | YES | ? | used market | |
![]() | Avedis Audio | 1122 | short | N/A | short (0) | N/A | N/A | 27 | 10k | 100 | 47 | short | yes (75Ω min. load) | YES | $80 USD | direct | |
![]() | BTI | OA400 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | YES | ? | used market | |
![]() | Fax Audio | FA-100 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | YES | ? | used market | |
| not pictured | Forssell Technologies | JFET-992 | short | N/A | short (0) | N/A | N/A | 68 | 10k | 33 | 51 | N/A | no, short J4 and J5 | YES | $65 USD | direct | |
![]() | Forssell Technologies | JFET-993 | short | N/A | short (0) | N/A | N/A | 68 | 10k | 22 | 51 | N/A | no, short J4 and J5 | NO | $80 USD | direct | |
![]() | Inward Connections | SPA690 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | NO | N/A | not for sale | |
![]() | JLM Audio | Hybrid Opamp (kit) | short | N/A | short (0) | N/A | 220 | 27 | 10k | 47 | 51 | N/A | yes | YES | ~$20 USD | direct | |
![]() | JLM Audio | 99V (+/-16V version only!) | short | N/A | short (0) | N/A | 220 | 68 | 10k | 47 | 51 | N/A | yes | YES | $54 USD | direct | |
![]() | John Hardy Company | 990C | short | N/A | short (0) | N/A | N/A | 27 | 10k | 91 | 39 | N/A | yes (75Ω min. load) | YES | $50 USD | direct | |
| Photo | Brand | Model | J1 | C3 (µF) | R9 (Ω) | R9a (Ω) | C4 (pF) | R13 (Ω) | R12 (Ω) | C7 (pF) | R14 (Ω) | J2 | Can drive an output transformer? | Tested? | Price (1 piece) | Purchase From | INFO |
| not pictured | Little Labs | The Discreet Opamp | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | NO | ? | call(?) | |
![]() | Modular Audio Products (MAP) | 5002 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | NO | ? | used market | |
![]() | Modular Audio Products (MAP) | 5003 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | YES | ? | used market | |
![]() | Melcor Electronics | 1731 | short | N/A | 100 | N/A | N/A | 47 | 10k | 100 | 47 | short | yes | YES | ? | used market | |
| not pictured | Millennia Media | MM-99 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | no, short J4 and J5 | NO | $75 USD | dealers or direct | |
![]() | Millennia Media | MM-990 | short | N/A | short (0) | N/A | N/A | 68 | 10k | 33 | 51 | N/A | no, short J4 and J5 | YES | ? | used market | |
![]() | Old School Audio | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | yes | NO | N/A | not for sale | |
![]() | ProTech Audio | Model 1000 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | YES | ? | call(?) | |
![]() | Purple Audio | KDJ 3 | N/A | 4.7 | 100 | 100k | N/A | 30 | 10k | 68 | 51 | N/A | no, short J4 and J5 | YES | $45 USD | direct | |
![]() | Purple Audio | KDJ 4 | N/A | 1 | 100 | 100k | N/A | 30 | 13k | 68 | 68 | N/A | yes | YES | $65 USD | direct | |
![]() | RCA | Operational Amplifier | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | yes | YES | ? | used market | |
![]() | Seventh Circle Audio | SC25 | short | N/A | short (0) | N/A | N/A | 27 | 10k | 100 | 47 | short | yes | YES | $75 USD | direct | |
![]() | Scott Liebers' | SL-2520 | short | N/A | 100 | N/A | N/A | 47 | 10k | 100 | 47 | short | yes | NO | $70 USD | Tangible Technology | |
![]() | Sound Skulptor | SK25 | short | N/A | 100 | N/A | N/A | 47 | 10k | 100 | 47 | N/A | yes | NO | $74 USD | direct | |
![]() | Sound Skulptor | SK99 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | NO | $74 USD | direct | |
![]() | Sound Skulptor | SK47 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | NO | $74 USD | direct | |
![]() | TOA | PC-2011 | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | ? | NO | ? | used market | |
![]() | Yamaha | NE-80100 | short? | N/A? | short | 100k | N/A | 51 | 10k | 100 | 51 | N/A | yes | YES | ? | used market | |
![]() | Yamaha | NE-80200 | short? | N/A? | 100 | 100k | N/A | 51 | 10k | 100 | 51 | N/A | yes | YES | ? | used market | |
| Photo | Brand | Model | J1 | C3 (µF) | R9 (Ω) | R9a (Ω) | C4 (pF) | R13 (Ω) | R12 (Ω) | C7 (pF) | R14 (Ω) | J2 | Can drive an output transformer? | Tested? | Price (1 piece) | Purchase From | INFO |
Specifications subject to change without notice. GMT