chiily
PFM Special Builder
I bought myself a model B, Quad FM1 (mono) tuner to keep me occupied through the long winter evenings, and obviously it needs a little work (that's why it was cheap). The previous owner told me that it sort of worked, but drifted off station and didn't have very clear audio.
Thanks to @martin clark for sending over a wedge of documentation...it took me a while to figure out that my FM1 was a B model...
PXL_20231211_190154239 by Garf Arf, on Flickr
It has previous had some work done, at least twice from what I can tell. The most recent was the previous owner replacing the resistor network of each valve's power. Here's a picture of the underside.
PXL_20231116_115428449 by Garf Arf, on Flickr
The Hunts capacitors are not in the best shape, cracked and turning quite waxy; due for replacement. A couple of other caps at the top of the above picture have been replaced in the life of the tuner, but I'll probably change those too.
And the FE:
PXL_20231116_115451968 by Garf Arf, on Flickr
For the moment I'm not going to touch the FE, though I've already measured some of the resistors' values and they are over the 20%/10% tolerance. I've emailed Quad and they have recommended to me a third party who is willing to update the FE and re-align the tuner if needs be.
I've put together a very simple PSU, looks very sparce in the box (Flatcap looks). I can't find the back of the front of the box atm! Yet to add the extra pair of 100uF/450V caps to the 47uF/450V ones already there. Choke courtesy of an old Radford amp I think.
PXL_20231228_145854882.MP by Garf Arf, on Flickr
Valve wise, all tested good apart from V5 the 6AU6, which was so very tired and V7, the ECC83, which tested good, but just a bit erratic on my CT160.
PXL_20231116_115523854 by Garf Arf, on Flickr
PXL_20231116_115543751 by Garf Arf, on Flickr
I did manage to service and calibrate my AVO CT160, and what fun and games that was! But the voltages are spot on now.
PXL_20231219_200308457.MP by Garf Arf, on Flickr
Next step is to replace the caps (all) and resistors (where out of tolerance), pop the valves back in (with a new 6AU6) and hook it up on a variac.
Thanks to @martin clark for sending over a wedge of documentation...it took me a while to figure out that my FM1 was a B model...
PXL_20231211_190154239 by Garf Arf, on FlickrIt has previous had some work done, at least twice from what I can tell. The most recent was the previous owner replacing the resistor network of each valve's power. Here's a picture of the underside.
PXL_20231116_115428449 by Garf Arf, on FlickrThe Hunts capacitors are not in the best shape, cracked and turning quite waxy; due for replacement. A couple of other caps at the top of the above picture have been replaced in the life of the tuner, but I'll probably change those too.
And the FE:
PXL_20231116_115451968 by Garf Arf, on FlickrFor the moment I'm not going to touch the FE, though I've already measured some of the resistors' values and they are over the 20%/10% tolerance. I've emailed Quad and they have recommended to me a third party who is willing to update the FE and re-align the tuner if needs be.
I've put together a very simple PSU, looks very sparce in the box (Flatcap looks). I can't find the back of the front of the box atm! Yet to add the extra pair of 100uF/450V caps to the 47uF/450V ones already there. Choke courtesy of an old Radford amp I think.
PXL_20231228_145854882.MP by Garf Arf, on FlickrValve wise, all tested good apart from V5 the 6AU6, which was so very tired and V7, the ECC83, which tested good, but just a bit erratic on my CT160.
PXL_20231116_115523854 by Garf Arf, on FlickrPXL_20231116_115543751 by Garf Arf, on FlickrI did manage to service and calibrate my AVO CT160, and what fun and games that was! But the voltages are spot on now.
PXL_20231219_200308457.MP by Garf Arf, on FlickrNext step is to replace the caps (all) and resistors (where out of tolerance), pop the valves back in (with a new 6AU6) and hook it up on a variac.
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