appeared in SOUND
issue 13 (written on February
"What would you like to achieve in life?" was an out
of the blue question my wife asked me two years ago. How
should a Turkish citizen, living in Istanbul, 43 years
old (41 at that time), mechanical engineer, representing
and distributing Carrier Air Conditioning equipment in
Turkey for many years, an Audiophile tube and Music lover
and the president (this year) of Istanbul Hi Fi
Club reply this question? Although not very uncommon, the
question struck me as if I was hearing it for the first
time - maybe I was hearing it for the first
"I want to design and build my own tube amplifier" was
my reply, "but unfortunately I have to wait my
retirement". She suggested that I should consider
starting it at that very moment (she is a
therapist!!). Her following arguments were
convincing enough and the idea so attractive: I
First I contacted my electronic guru friend (who
builds his own marble speakers) and asked him if he would
volunteer to teach me just enough electronics to
achieve my project. He gladly accepted, gave me several
books and suggested I subscribe to both Glass Audio and
Sound Practices [...but not necessarily in that order
-ed.] and buy all past issues, which I did.
After much reading, lessons from my friend, my
realization of the analogy between tube curves/load lines
and pump curves/system curves I'm used to working with in
my job, the inner workings of amplifiers eventually began
to make sense to me.
Thanks to the great influence of SP magazine I've
decided to build a single ended amp (the concept of SE or
PP was totally new to me). For a beginner SE amps were
easier to understand and to conceive, apparently had a
magical mid-range, were unheard of here in Turkey, in
other words it was a "Mystery Cafe". My intuition (which
played a major role throughout the project) also said:
The whole point of the project was to improve on the
sound of my existing push-pull ARC Classic 60 amp;
here again my intuition said that only a "cost-no-object"
SE amp would be able to achieve this goal. It had to be
as purist as possible (no parallel tubes) and capable of
driving a relatively wide range of speakers.
I chose to build a single 845 tube, driven by 300B
with a SRPP configured 6072A at the front end. Separate
power supply circuits for each tube and mono design would
be adopted. Gordon Rankin's article (A Single "807"
Amplifier, issue #2) was a great help for starting my
calculation and design.
After finishing my preliminary calculations and
circuit schematic, I contacted Allen Wright (author of
the The Tube Preamp Cookbook) for consultancy. He
suggested me to use "choke input" filters instead
of the originally drawn capacitor input ones. "As you aim
a cost-no-object amp you should have the best filtration,
and choke inputs will give you a much better result if
you have space and money to spend. Thus, you may as well
use solid state diodes as their switching noise will be
filtered by the chokes. It is also the solution adopted
by Cello" was his argument to defend the choke
He suggested to split the first choke to two and place
one to positive and one to negative leg after the bridge
in order to filter the whole of the mains trash.
Verifying what he had mentioned with the Radiotron
Designers Handbook and cross checking it with my
guru friend, I applied his suggestion to the point and
used three chokes per tube (in total 9 chokes per
The same purist philosophy and intuition was in use
when it came to selecting and ordering the components: I
used TANGO X-10S OPT (best of TANGO for 845 tubes), Gold
Aero tubes, Caddock, Vishay, Holco resistors, Hovland
Caps on the signal path and MIT bypassed SOLEN's
elsewhere, Kimber AG cable on all signal paths, SOWTER
mains transformers and inductors.
Since I had very good results (picking up more detail
and extention on the top end) when I tried bypassing the
250 uF electrolytic input capacitor of my Quad 63
speakers, I decided to bypass all capacitors. As a unique
touch, an LCD display hour meter is included. This would
be useful to indicate the burn-in times and give me an
exact statistical idea about tube life.
On paper everything looked fine but the most difficult
part started when I received all these HUGE components.
How on earth I was supposed to assemble them? It was
going to be monstrous!
After a few days of acute depression followed by a
heavy meditation period I decided to take everything to
our company's workshop and get the help of our
technicians for the chassis design and construction.
The chassis is constructed from aluminum profile.
Magnetic elements on my amp were banned like smokers in a
US domestic flight. For the finish only black painted
brass and wood are used. Soldered joints were made using
WBT Silver solder and ground lines are connected in star
fashion. Signal inputs are made from the sides in order
to shorten the signal cable runs inside the
The two mono blocks are built in mirror symmetrical
fashion to allow both signal inputs to face each other
and the hour meters to look to the exterior.
It took me two years to finish and test everything.
The test results came out wonderfully with a perfectly
symmetrical sinus at the output which gives approx. 25W
on 8 ohm fixed load before clipping.
I had also to find them a name. NUANCE came to my mind
as a very appropriate one: NUANCE is what gives the
emotion to Music and meaning to life. It was lucky and
surprising for me to discover that no such brand name was
used by anybody else. Its model designation would be
Op.65, 65 being my wife Eda's birth year. She was the one
who initiated, supported and encouraged me at every level
of the project.
The subjective listening results are also very
satisfactory: silky, full bodied midrange, trebles
detailed and free of harshness or edginess,
extended and fairly controlled bass (if not on par with
best solid state and/or push-pull gear). Nothing
seems tiring at any duration. Maybe as a result of this
(or because of the increased pleasure) I noticed that I
am now listening to Music for longer periods.
I can confortably declare that I achieved my goal of
bettering my ARC Classic 60 amp which sounds thin or lean
in the mids like a solid state compared to NUANCE.
Furthermore, the ARC seems to be less involving and less
musical. Subjective tests are carried out using ProAc 2.5
One of my "golden eared" friend declared that it was
the most musical amp he had heard to date and another one
(who builds kits) suggested I write about my project in
Sound Practices as he thought it was a success
So here I am. Its a pity I can only transmit the story
but not the sound but anybody who is willing to visit my
wonderful country, Turkey, is most welcome to my home for
an audition. For appointments kindly contact the