One set of bare printed circuit boards to suit the assembly of a stereo phono ("vinyl") RIAA preamplifier, built to the classic John Linsley-Hood K1450 design.
You will get two single-channel RIAA preamp PCBs, plus one power supply PCB as the basis of a 15-0-15V power supply to run the preamps.
As long as I have them available, I will include a pair of suitable heatsinks and one TO-220 insulator set for the PSU board.
The power supply may be assembled in various forms, from a basic regulated power supply to one with massive amounts of OTT filtering and smoothing, as in the photos.
Printed component lists and notes will be included with each purchase; these are also available to download from project page linked below.
The end result are totally dependant on the types and quality of the components used to assemble them; I include suggestions and/or part numbers in the parts list to aid identification and purchasing of the components.
These are the specifications claimed for the original JLH design:
Moving coil (mc) or moving magnet (mm) input - link selectable.
Frequency response: +/- 0.25dB to RIAA curve.
Signal to noise ratio: 26dB below record surface noise.
Sensitivity (for 500mV output): 37mV (mm), 340pV (mc).
Input impedance: 47K Ohms (mm), 100 Ohms (mc).
Gain: 134 (mm), 1460 (mc).
Overload: 670mV (mm), 60mV (mc).
[On these PCBs, fit links in both the J1 & J2 locations for the moving coil gain & input impedance selection].
The PCS are double sided, plated though hole with a top side ground plane, solder resist both sides and topside component identification overlay. The layouts are original and not copied from any other version of the K1450.
They are designed to take metal film resistors such as MRS25 throughout, with polystyrene capacitors in the RIAA equalisation network, plus good quality plastic film and electrolytic caps in other locations.
As the vertical polystyrene capacitors can be difficult to obtain, I am listing those separately. Normal axial lead caps can be used if preferred, with a lead folded down & optionally sleeved.
Note that the photos showing various assembled boards are provided purely for information, as examples of what these may look like once assembled.
The single board in the last photo uses the exact component types specified in the parts lists, the pair are prototypes and use the same values but some in different physical sizes.
Except as stated above, no other components are included in this sale. Bare PCBs & PSU heatsinks only.
More details of the PCBs and end result here, with a selection of audio samples:
k1450 RIAA preamp project page
Assembly videos here:
https://www.youtube.com/playlist?list=PLuzW8n0FM__Uwl_-lu6UojTfrGqvIoAiM
Postage not included; that depends on the total order and the destination.
PCBs are copyright (C) Robert Jenkins.