Holden and Fisher
Dear Sirs,
I have tried many small VA transformers in linear PSU's because of the secondary winding impedances, are critical to load, any amplifier will
produce harmonics of mains hum through any regulated PSU, "don't patch
a problem on your knee when its your elbow" good low frequency regulation
and impedance, is vital, also filtering and smoothing are critical as well
Holden and Fisher build to a high test and build standard, used in many audio
amplifiers, that have low output impedance, that need to deliver high current
and sustained low frequency signal demand, and to keep regulation within
tight tolerance otherwise distortion will result on fast paced Movie explosions
from films, SMPS is not as good as well as linear supplies, maybe less noise but current demand, and sustained power they fail.
I have designed a external Power Supply for the quad 33 preamp using
one and its quiet, and low noise when compared to a multiplate transformer,
with careful filtering grounding, and smoothing, with regulators with high grade Electrolytics, the improvement is quiet staggering since I have designed a MC amp for the quad as well, using an LP-12.
Dear Sirs,
I have tried many small VA transformers in linear PSU's because of the secondary winding impedances, are critical to load, any amplifier will
produce harmonics of mains hum through any regulated PSU, "don't patch
a problem on your knee when its your elbow" good low frequency regulation
and impedance, is vital, also filtering and smoothing are critical as well
Holden and Fisher build to a high test and build standard, used in many audio
amplifiers, that have low output impedance, that need to deliver high current
and sustained low frequency signal demand, and to keep regulation within
tight tolerance otherwise distortion will result on fast paced Movie explosions
from films, SMPS is not as good as well as linear supplies, maybe less noise but current demand, and sustained power they fail.
I have designed a external Power Supply for the quad 33 preamp using
one and its quiet, and low noise when compared to a multiplate transformer,
with careful filtering grounding, and smoothing, with regulators with high grade Electrolytics, the improvement is quiet staggering since I have designed a MC amp for the quad as well, using an LP-12.
Holden and fisher
Dear Andrew,
Here is the first version of my Quad 33, is this what your refering
to ? left side is the MC amp, mounted on the M12019 issue 4 Disc board as a daughter board all the original components have been removed on the Quad disc board it was drilled to mount daughter board with nylon screws and pillars, good attention to grounding was done, as pins 8 are +14V, pin 7 -14V
pin 5 is ground, pin 4 is Right input, pin 3 N/C, pin 2 Left O/P, pin 6 is Left I/P, and pin 1 is Right O/P this can be traced and confirmed with a meter
this is standard on a Quad 33 with the exception of pin 7.
The PSU board DRW M12032.3 has beed removed from the Quad transformer, reinstalled with LED's mounted on the original PSU board -14V and +14V supply, with current limit resistors. The Electrolytic Capacitors were upgraded. The external PSU is connected through the Disc DIN socket on Pins 1 and 4 these are unused normally, with tone arm input on 3 and 5 so you can use a cheap 5pin DIN to DIN cable, diodes and resistors were removed on the PSU M12032.3 board, I reused the quad board to keep the price down.
I will do a revised photo, as all the Resistors have been replaced with 1/2W or 1/4W, clearly 1/4W are less noisy I fitted metal film types on all the PC boards. The Tape adaptor board has been updated as well, the Output boards have been modified to run at +14V resistor changes R411/R412 and to improve the signal to noise ratio, by 8db and the higher supply voltage, since the Quad runs more stable at a slightly higher PSU voltage
Transistors are original, and the MC board has very high quality Burr-Brown Op amps, I have no CAD drawn circuit as yet, this was done on paper with calculations and the -14V is a small wiring change from the DIN socket
to the motherboard (pin 10) and pin 7 of the original Disc board, since with the S1 disc adaptor board slot used and links applied, S1A link, S1H, SID, and R115 is removed and linked, I do know how much knowledge you have of Quad circuits, RIAA is not used on the disc adaptor, this was done on the MC board, so the -14V was implemented, as no internal connection is used, when S1 slot is inserted. All components should be removed from the disc M.120021 adaptor for safety reasons, in case of a wrong insertion.
It will take a long time to document all, but i will show some photos, if you what a conversion to a QUAD 33 I can do it, I can refer you to circuit diagrams, as interfacing is total, no MM with a tape adaptor, I can redo the input circuit to reduce the gain and impedance matching, for MM with RIAA.
Dear Andrew,
Here is the first version of my Quad 33, is this what your refering
to ? left side is the MC amp, mounted on the M12019 issue 4 Disc board as a daughter board all the original components have been removed on the Quad disc board it was drilled to mount daughter board with nylon screws and pillars, good attention to grounding was done, as pins 8 are +14V, pin 7 -14V
pin 5 is ground, pin 4 is Right input, pin 3 N/C, pin 2 Left O/P, pin 6 is Left I/P, and pin 1 is Right O/P this can be traced and confirmed with a meter
this is standard on a Quad 33 with the exception of pin 7.
The PSU board DRW M12032.3 has beed removed from the Quad transformer, reinstalled with LED's mounted on the original PSU board -14V and +14V supply, with current limit resistors. The Electrolytic Capacitors were upgraded. The external PSU is connected through the Disc DIN socket on Pins 1 and 4 these are unused normally, with tone arm input on 3 and 5 so you can use a cheap 5pin DIN to DIN cable, diodes and resistors were removed on the PSU M12032.3 board, I reused the quad board to keep the price down.
I will do a revised photo, as all the Resistors have been replaced with 1/2W or 1/4W, clearly 1/4W are less noisy I fitted metal film types on all the PC boards. The Tape adaptor board has been updated as well, the Output boards have been modified to run at +14V resistor changes R411/R412 and to improve the signal to noise ratio, by 8db and the higher supply voltage, since the Quad runs more stable at a slightly higher PSU voltage
Transistors are original, and the MC board has very high quality Burr-Brown Op amps, I have no CAD drawn circuit as yet, this was done on paper with calculations and the -14V is a small wiring change from the DIN socket
to the motherboard (pin 10) and pin 7 of the original Disc board, since with the S1 disc adaptor board slot used and links applied, S1A link, S1H, SID, and R115 is removed and linked, I do know how much knowledge you have of Quad circuits, RIAA is not used on the disc adaptor, this was done on the MC board, so the -14V was implemented, as no internal connection is used, when S1 slot is inserted. All components should be removed from the disc M.120021 adaptor for safety reasons, in case of a wrong insertion.
It will take a long time to document all, but i will show some photos, if you what a conversion to a QUAD 33 I can do it, I can refer you to circuit diagrams, as interfacing is total, no MM with a tape adaptor, I can redo the input circuit to reduce the gain and impedance matching, for MM with RIAA.
Attachments
good morning.
I'm new to the forum.
I like to do a project for POWER ENTRY turntable Linn LP12.
I have a Holden & Fisher transformer (photo).
Can you give me the exact characteristics. Normally this is a 2x46v 640VA.
Can you also tell me What do the yellow cables yellow and black and white black and white.
Thank you to you.
I'm new to the forum.
I like to do a project for POWER ENTRY turntable Linn LP12.
I have a Holden & Fisher transformer (photo).
Can you give me the exact characteristics. Normally this is a 2x46v 640VA.
Can you also tell me What do the yellow cables yellow and black and white black and white.
Thank you to you.
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An externally hosted image should be here but it was not working when we last tested it.
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