... again talking to myself
I'll need one pcb.Hello ... just completed the main head phone amplifier PCB preparation .. nice and clean etc.
just a few pics before construction
I would like to point out that I am happy to sell these PCB's at pure cost plus postage .. as it takes me a long time to develop the modern gerber files. so I make no profit .. I can pass on savings as I can order a few hundred at a time from the manufacturer and pass on the savings to fellow members. I am more interested in making completed tested units, to improve my construction skills.
You can't find TIP3055s? These are super generic, the TO-220 version of the trusty 2N3055. FWIW, the original JLH headphone amp circuit actually used BC182 and 2N4922 (I think 2N1711 and TIP3055 were from the speaker version - do you need it to be that powerful?). Modern-day clones often seem to be using 2N2222 and TIP41 instead. This circuit likes oldschool slow output devices.
Oops, it does seem to be TO-218 indeed. Makes sense considering that this package, much like TO-247, would have better heat transfer than TO-220, and as such would have seemed the more appropriate TO-3 replacement at the time. (In this case it's 1.39 K/W for TIP vs. 1.67 K/W for MJE. ON Semi's 2N3055 is spec'd with 1.52 K/W, neither the best nor the worst TO-3.)
Over the years I have built numerous JLH class A headphone amplifiers (The Chiara example)
and the TIP41 transistor just works and is cheap and readily available in the UK .. but I am sure other transistors for Q1 and Q2 can be used so more then happy to receive any recommendations on this front.
The main area of improvement is the opamp choice I have tried lots over the years and have settled on the OPA627 but do accept currently very expensive, so will revisit and try a more budget oriented example
and the TIP41 transistor just works and is cheap and readily available in the UK .. but I am sure other transistors for Q1 and Q2 can be used so more then happy to receive any recommendations on this front.
The main area of improvement is the opamp choice I have tried lots over the years and have settled on the OPA627 but do accept currently very expensive, so will revisit and try a more budget oriented example
these are the list of op amps that I have used over the years for this design
LF 353 (Dual) even this chip gives a good account for it self in this design
Burr Brown OPA 2604 (Dual)
Burr Brown OPA 2132P (Dual)
Burr Brown OPA 2227P (Dual)
Burr Brown OPA 2228p (Dual)
AD712 JN (Dual)
AD823 AN (Dual)
OPA 62P BP (Single on brown dog adaptors)
LF 353 (Dual) even this chip gives a good account for it self in this design
Burr Brown OPA 2604 (Dual)
Burr Brown OPA 2132P (Dual)
Burr Brown OPA 2227P (Dual)
Burr Brown OPA 2228p (Dual)
AD712 JN (Dual)
AD823 AN (Dual)
OPA 62P BP (Single on brown dog adaptors)
Last edited: