© Don Sachs, 2015
Vintage Tube Audio
Restoration and Repair
Other Tube Gear
I have repaired or restored all sorts of vintage tube gear
Over the years I have had the pleasure of working on all sorts of tube gear. I am going to keep
adding to the gallery page so you can see some completed projects, so check back and maybe
an example of your amp will be there. I don’t need a big amplifier collection because I
eventually get to hear an example of most amps and preamps that I would like to try! I just
have a Citation I, II, V, a Sherwood S8000 receiver and a few other small pieces. In my
experience, many pieces can be improved considerably with minor changes. I routinely add
cathode and screen resistors for safety and ease of bias adjustment. I often make bias supplies
adjustable or build a small regulated DC filament supply to drive phono and preamp tubes.
Often in the old amps they would use the bias supply or the cathode circuit of a cathode biased
amp to drive the DC filament supply of low level tubes. This was done to save parts and keep
costs down. Not because it was ever a great idea. Today we can take a small transformer and
separate the filament from the bias supply in many cathode biased amps. They sound much
better and it means that when you change output tubes you can adjust the bias on the amp
without changing the filament voltage to the phono and line stage tubes. In a lot of Scotts, and
other amps where the bias supply also drives the DC filament for tubes we can add a small pot
to be able to adjust the bias independently of the filament supply. Sometimes we can add a
constant current source tail to certain designs like the Citation II, Citation V, or the Eico HF-87.
This is inexpensive and improves the performance significantly. I have had to troubleshoot all
sorts of amps and can usually find any problem. Basically, I will rebuild most anything with
tubes in it. Or at least I will research it for you and tell you what it might cost or whether it is
worth doing. Every project is different and I would be happy to give you an estimate for
various levels of restoration for your gear. I would certainly never modify your gear in any way
without your approval. I will always suggest what might be done and you decide. It is your
gear!
Generally it takes 1 - 2 days to rebuild a vintage integrated amp like a Scott, Sherwood or
Fisher. That is $300-$500 labor. Parts will run $75-$200 depending on how many of the
expensive multi-section can caps there are in the power supply, whether you want the phono or
tone control sections rebuilt as well, whether you want a better power cord, or jacks replaced,
or if a volume pot needs replacement.... there are many factors. Certainly I can do less for you
such as only replacing some power and bias supply parts, and output coupling caps and
generally just make the amp safe to use. This will cost less and the amp will be fine, just not
sound as good as it can.
If you have a project in mind please feel free to contact me and I will be happy to discuss it
with you and provide a quote.