300 FM STEREO RECEIVER
In the review below I observed that the strongest asset
of the Advent 300 receiver is its tuner. While I have
not revised my opinion of the tuner's ability to pull
in stations well, it was a direct comparison to a Scott
330C/335 duo that opened my ears to its deficiencies.
An occasional observation that the sound of the Advent
tuner was a bit thin and acerbic was borne out when
a DX test with the 330C/335 revealed that the latter
had a top end that was vastly more musical and midbass
hump notwithstanding, was the tuner to listen to, even
in noisier stereo.
My option, elected frequently, is to turn the treble
down to about 10 o'clock while listening to FM, something
that I am loath to do, but have been doing of late when
I listen to the radio. The preamplifier and tone stage
went unnoticed in my review below, and I am happy to
note that the circuits still warrant little attention,
and it is perhaps for this reason that I am unenthusiastic
about inserting two more components into my electronic
mess (a suitable tuner and, while I'm at it, a preamplifier
that should sound better). As I am using the 300's power
amplifier to drive the Gradient SW57 subwoofers, the
upshot would be two additional components with the 300
still in use as an amplifier only.
Since the preamplifier has some merit (surprise!),
I have elected to retain the 300 as a tuner-preamp and
power amplifier. My only other option would be to replace
the 300 with my Scott
R74S which I modified to permit separate operation
as a tuner-preamp/amp. I may do so, but since I feel
no great desire to pull it out of storage, things will
be status-quo for a while.
I should note that the 300 performed well with the
Wharfedale W3's with (as noted below) some judicious
treble adjustment, and even attempted to kick at the
can of worms that the Quad ELS sometimes presents to
solid state amplifiers.
The original review...
Flexi-Boy of Audio that you can use in any
way, but at this point in thyme, as an FM
The Advent 300's most distinctive
attribute is that it looks like a miniature 311 series
Scott tuner, or perhaps it is what a Scott 310F might
have looked like, had Scott retained a vernier tuning
dial on its designs beyond 1963. Similar to most,
but not all vernier dial units, it offers FM only.
For a person who wants to listen to all of the CBC
broadcasts in Toronto, an AM radio is essential. The
Radio-Canada service that remains on the AM band is
an indispensable source of music, and yes, with a
high resolution tuner, the AM band can be a thrill
for reasons best explained in a separate article.
Okay, here's a bit: With notch filters, the useful
audio bandwidth can be extended beyond 11KHz, plus,
and this is a biggie: the band self mutes, since minus
a signal, there is only static and natural phenomena
that, with notch filters, are inaudible.
My description of the Advent
300 as a flexible receiver is no exaggeration: It has
the one important option that only a handful of receivers
and integrated amplifiers will make available to you
and that is the point at which pre and amp join up in
a system. With its inclusion, you have four ways of
using the receiver in a basic sense:
1. as designed, by amplifying
2. as designed, by amplifying headsets or a line
3. as designed, by supplying an unamplified signal
to a line
or, 4. As available by supplying an equalized and
a gain adjustable signal to a line, or, to an amplifier.
Most of the unit's charm stems
from its usefulness as a stepping stone to something
better, which in most instances would be a power amplifier
capable of demonstrating the capabilities of the receiver's
tuner, and to a lesser extent, its phono stage.
Allow me to say at the outset
that I treated the Advent 300 as an integrated receiver,
and I compared it to a Scott component that had a similarly
sized power transformer with the same stack density
and dissipation, etc. This turned out to be the 2502,
a model that Scott built for their least expensive combination
systems - you know, the kind of things with a Dual rim
drive turntable slapped on the top.
The 2502 is a good comparison
unit in this instance in a rough sense. It is superior
in that it offers an AM tuner, has a phono stage that
is truly exceptional, and has an amplifier that sounds
better. The FM tuner in the 2502 is compromised by Scott's
least involving multiplex adapter, and even with close
attention, the 2502 won't get near the Advent, despite
having an alignable front end and i.f.
There is bound to be some similarity
between the 300's best feature (its radio) and other
vernier dial units from Advent. Certainly the tuning
capacitors are bound to be the same, and since front
ends are critical, I expect that the Advent 400 (its
contemporary, a table model) is as good as the 300.
Considering the puny parts cost, I would be surprised
That aside, it is a very pretty
little tuner with a four fet front end with a classic
layout that passes off to a three i.c. intermediate
frequency stage that employs ceramic filters. The detector
appears to be a peculiar feature of the tuner (that
may be a theme of the design...), using two filter-sized
traps that are cross-connected to permit each trap to
impinge the other, just as they would in a more conventional,
full size detector can.
The multiplex adapter appears
to be on a chip, and it offers no 38KHz adjustment point
for time switching, or oscillation between channels,
nor for the 67KHz trap.. The 19KHz pilot can be adjusted.
The i.c. offers no information about the method employed
to place the time-switched signals upon the detected
signal. There is no threshold adjustment, and the separation
control is a bandwidth limiter which suggests that the
tuner may be teased into performance levels that permit
the separation threshold to be raised.
The 300's squelch point is a
tolerable compromise between overreach (which I prefer)
and a light touch which tends to let noise through as
the muting declutches. Since I tend to listen to a small
number of stations, including some that come from a
distance of about 100 miles, (my Buffalo coterie), I
tend to tune with interstation muting off and I for
the most part prefer to avoid muting circuits that cannot
distinguish between a legitimate signal and a multipath,
or other FM noise on the band.
One of the nicest compliments
that can be bestowed upon what is just a thing in a
box is that it does some things well that are important.
Stereo radios had better sound good in stereo and the
Advent 300 manages to do just that. Distant stations
hang in nicely with a smooth crossover into mono which
suggests some sort of automatic stereo circuit. Distant
signals hold stereo well, once tuned in.
The 300 holds onto a weak multipath
signal and it provides freedom from noise and physical
disturbances (this might be something as simple as moving
in front of the antenna) with no less success than any
of the tuners that I have aligned recently, and considering
how unadjustable the Advent 300's tuner is, perhaps
this is a good thing.
300 did not provide sufficient isolation to
permit me to spend any time listening to the
phono preamp. What I heard suggests that it
works best with a high output moving coil
cartridge, is sweet and certainly more pleasant,
say, over your average cascade amplifier.
obviously had an immediate urge to throw in
some mumbo circuitry to weird out people in
perpetuity, but my guess is the humpback transistor
is a semiconductor mu-follower. A Hunchback
of Notre Dame transistor.
As I noted;
a lack of power supply capacity prevented
the Holman preamp from being evaluated with
a medium to high output M.C. Regrettably,
when I used the phono with a typical high
impedance magnetic cartridge with an output
of 2 mv, the sound lost all of the allure
that it had demonstrated further into its
I always blind-date
magnetic phono preamps with an average output
moving coil cartridge because it is a litmus
of performance close to the noise floor, where
amplification is effortless and with low threshold
noise (the Holman design does well here) the
result can be near-stupefying. The Advent
was in this instance, a classic tragic pairing
of an upper-mid-fi-but-somewhat-mystical phono
stage (but no more so than, say, Scott's i.c.
phono preamplifier). That's where the similarity
ends, since the Scott phono circuit employs
a basic complementary circuit (and is very
quiet) and the Advent follower is complementary
with a more complex geometry. All noise floor
notwithstanding: The a/c. spikes were terrifying.
It was like listening to Sunshine On My Shoulder
at 3 a.m., while in the bathtub in a room
with tenement lighting.
Since the amplifier is
all that remains to be discussed, it is obvious
that it is the one portion of the circuit that
I found to be the least satisfying. I can point
to the obvious and say that the power supply is
small, but the unit swings 44 volts and that is
low for its rated output of 15 watts. While it
is more than the withering 5 watts per side to
twenty cycles that Flingpoo
made it out to be, it is a class b sweetie that
was designed to shake its bootie into a 1970's
style stuffy acoustic-suspension loudspeaker.
It draws itself out as far as far goes, toward
its optimal class b range, ultimately giving out
in a disintegrated class b wheeze and fry. Within
a more typical listening range, the amplifier
continued to unimpress me, but at no time did
it offend me.
I cannot account for the
amplifier and I won't try. Why should I? I'm not
Holman, eh? The Advent 300 delivered a constrained,
pinched, near fatally bright sound that was an
immediate and substantive move away from the sound
of the high impedance, high efficiency speakers
with the Scott 2502. My Comparison is far less
flattering when a Scott with a rated capacity
of twelve watts is used, such as the FM-only,
quasi-complementary TYPE 341. With a treble adjustment
while listening to the Wharfedale W3's, I was
able to derive some enjoyment from the circuit.
Jay Bee, a staffer who spent some time with the
Advent 300 believes that a treble adjustment that
corrects a deficiency in the component is unacceptable.
Correcting the treble problem
is easily accomplished due to the design of the
unit. Since a second loop (preamp out to amp in)
is supplied, it is easy to strip in a resistor
of a value that will provide simple resistance
sufficient to tame the treble. If I had to guess,
I would start at 270k. While I am talking about
tone deficiencies, I should mention that the bass
has problems that can't be solved. There is neither
weight nor detail to the bottom frequencies. Of
course, the champ
amp fared better up to its power limit.
the topology? The amplifier looks like a fireman's
ladder, and of all the circuits, it looks the
most simple. It is the first balanced circuit
in an amplifier that jumps all over the place
between unbalanced, floated, and truly complementary.
Admittedly I prefer single rails and I may be
getting annoyed about an utterly symmetrical design
for a symmetrical, ugh amplifier. On the other
hand, I have yet to listen to a symmetrical amplifier
that matches my view of what is the Audion sound
of solid state: Quasi-complementary.
I wish that
I could point to some redeeming factor of the
design, or at least an interesting one, but the
obvious factor isn't there. Each circuit stage
is terminated with a decoupling capacitor. It's
not even direct-coupled. What a disappointment.
I have chosen
to eschew what some call 'mods.', (but are only
substitutions) and have evaluated the amplifier
without any adjustments or tests. The Advent 300
was not designed to be adjusted, and it never
should need to be. Perhaps it would benefit from
service. There are an abundant number of 300 fans
who would have you believe this to be so. As I
have heard other complementary amplifiers that
leave me cold, I know that it is a -circuit-affair-
at the wires
The Advent 300 serves as a good example of what happens
when a bunch of designers get together and throw stuff
at a box, and then throw the power supply in, after
that. Indeed, the only circuit with an elegant implementation
with respect to power supply. is the tuner. This is
no surprise as the supply crowds the tuner.
It is easy to use the 300 as a standalone tuner. Lifting
the tuner signal off the record output will bypass all
other affected circuits, since the tuner's detected
stereo outputs are amplified separately. This is surprising
in one sense, since it makes sense to use the pre amplifier
to amplify the high impedance, low voltage signal from
the tuner. On the other hand, it speaks to the parts
bin approach to the design. There's no way for the tuner
to use Holman's phono stage because there was no dialogue
between Holman and the tuner designer who as rumor has
it, is also a chap named Holman. Perhaps he designed
one while he was in the bahamas, the other while he
was sitting on it.
Or... Leave the power supply stuff in and carefully
consider what it is about the 300 that motivates me
to comment on its tuner alone. It could be that I don't
like the sound of any of the other amplified stages,
or that all is great but the tuner is exceptional. In
answer, I did find the 300's tuner to be worthy, and
as hardly any tuners extant present themselves as worthy
or even listenable, this is a commendation enough. Considering
how expensive a capacitively tuned radio has become,
the 300 is a reasonably close glance at adequate tuner
performance. If it included an AM section of commensurate
quality (and here I would gladly enjoy the AM section
of the Scott 2502), the 300's tuner would be complete.
On the other hand, an FM only receiver has a lot of
cachet, especially in those cases where the tuner is
of exceptional quality, which for its price point, the
300 squeaks, 'flexy boy... I look like a TYPE 310F,'
and so on. Flexy adaptability helps too. The Advent
300 can be had for below $50.00 for a wreck to close
to $200.00 for one with the original factory carton
and Henry Kloss' personal okey dokey.