On the left is the Simple EL84 with just 4 EL84 tubes. On the right, sits the Simple 5687 preamp.
Note that after Waily has built the Simple 5687, he has gone to great lengths to tweak it. It's now using Lundahl output trans as output and no longer cap coupling.
Here's a closer look of the Simple EL84. Much better chassis work than mine... (what else is new?)
Here's what Waily has to say about the Simple EL84.
Date: Wed, 2 Jul 2003 07:04:04 -0700 (PDT)
OK, let me gives an official comments on this amp;-),
hopefully u can post it up and psycho more diy'ers to
try their hand in this project;-), find anything too
kuah cheong, do not hesitate to omit any line .:-)..
At first, never thought of taking up this project as I
found my setups is good enough, some sort of a hybrid
as using 5687 tube preamp driving a 60W SS amp Roksan
amp. After reading some articles on your site plus
your strong recommendations from you, I finally start
messing my place with drills, cutter, file, soldered
or whatever you name it DIY'ers life saving tools and
equipment:-), Got hold of a metal casing, Hammond
output transformer 1608, hammond choke 193L, all
metalfilm resistor at the grid leak and CCS section,
coffin resistor at power supply, 100u+100u LCR
leftover from 5687 project power supply caps, Tonsin
trans,JJ EL84 tubes, CCS components on a protoboard,
etc, built similar to the one listed in the website,
except the preamp section is ignored. As usual, the
chassis and spray painting takes the hell out from
me:-(...Finished it in about 4 days, I tend to slow
down nowadays as not as anxious as before:-)..,
followed by some minor troubleshooting during
power-up, miss a few wires connection :-), luckily the
tube and the CCS still survives. Once plugged into my
system after some voltage measurements, err...the rest
is history..
Anyway, initially the sound seems congested, a bit
distorted and somehow the music is missing a bit here
and there, of course it got me worried..Luckily with
Yeo kind advice, I am able to find the problem. The
biasing of the CCS is way out and too low. It is
running at only less than 60 mA per channel with 10mA+
difference between two tubes..After re-bias it, to now
about 80mA and with less than 4.5mA difference in both
tubes, it really gives me a good smack in my face.
This simple el84pp really has the oomph in a sense
that my SS power amp cannot match it. The fluidity,
smoothness and especially the low end(bass) will makes
you start to wonder how come there is so much lows
that your favourite song should have (due to the great
design of the CCS).That's to say, my SS amp can
produce hell of bass but unfortunately not as taut and
low as this el84 can gives, anyway I really prefer
this kind of bass as compare to my SS as it it much
realistic and goes lower. And when comes to the
detail, this is another area that my previous SS amp
loses flat out, you can hear much more of it as
previously in SS it is being muddied out or not as
defined as this tube can easily belts out. Another
veil is removes:-)...
For the power wise, do not belittle this 10W pp as I
believe with the cap-coupling output of a 5687 or
ECC99 preamp, it will sound loud enough until your
neighbor comes and knock your door:-)...As for my case
due to the design nature of Lundahl output transformer
in my 5687 preamp (some good reason why I implement
this OPT in place of the capacitor output:-)), I can
crank the volume pot to the max, it is still loud
enough for my bedroom...So for any preamp design that
is using cap-coupling output, rest assured that you
will be surprise with the power that this beast can
offer. (for your info. I am driving a paradigm
reference 20 with a sensitivity of 89db) For your
info. the OPT configuration will somehow reduce the
preamp gain due to the windings arrangement of the
Lundahl's as I'd experience a drop in output level
compared to cap-coupling output..
Anyway, the JJ el84 also needs to run in for tens of
hour as the sound will be blooming after that, it
seems getting better and better when listening to it.
The mids is sweet and I feel that it has improves
after some run in. So with proper biasing of the CCS,
and run-in of the tubes, the sound out from this
simple el84 pp will grows on you..Believe it or not,
I'd heard quite a number of setup, this combo will can
easily match or smoke the rest (IMHO), please do not
flame me!, The speed of this amp is comparable to a SS
amp as rectification is solid state as well. To cut it
short, let me extract an email from Yeo for this
simple el84 pp "the sound is just nice. quite polite.
and a tad sweet, it's like a very nice lady, with
grace and poise." and the thing I will add on
following his line is "accurate and produce
unimaginable bass, and lastly this amp will grows into
you:-)...in layman terms, the performance of a Porsche
with the cost of a Proton.... Well done, ONCE AGAIN
Yeo!
Regards,
Thanks for your great comments Waily.
Totally unrelated, but here's some other stuffs Waily has done. If you are terrified, don't worry. Very soon you'll be terrifying other diyers as well. This I assure you.
Clockwise from top left.
Way to go Waily!
What? You have never tried tube DIY before? Neither has Waily before the Simple 5687. Everyone has to start somewhere. The problem is, once you start, you can't stop. Just ask Waily...
From: waily
Subject: Re: Simple el84 pp
To: yeo
waily.
Congrats on a job well done!
Please note that it's YOU who built the amp. Not me. So all credit goes to YOU. By the way, you forgot to mention that you met this yeo guy before. And what a handsome chap! : )
Non-oversampling DAC. With just TDA1543 and a handful of components. This is implemented in the Marantz CD63. Waily prefers his original DAC's sound to this. Told you it's a taste thing.
An orgy of Black Gates!
Elna Cerafines and Black Gates
Audiocom Super Clock
Beefing up the power supply
