Date   

Lies, Damned Lies, and 10B specs

Charles Peterson <charlesp@...>
 

The specs for the Marantz 10b tuner now shown on the classic-audio site
list the alternate channel selectivity as 150dB and the adjacent channel
selectivity as 42dB. These specs (which I believe are from the manufacturer)
can't possible be correct, can they? What is the actual measured selectivity
of the 10b?

I've never heard of any other tuner having 150dB alternate channel selectivity.
Not even close. And while there are a handful (MR78 for one) that can beat
42dB adjacent channel selectivity, it's hard to believe that the 10B does.

Hoping it would address this void, I dug up the Stereo Review of the Marantz
10B (December 1965). This has to be one of the most worthless reviews ever
penned by Julian Hirsch. It's little more than a puff piece, full of
descriptions like "in a class by itself," at least one important factual
error ("Butterworth-filter i.f."), and excuses ("I could do no more than
ascertain the limits of my own test instruments"). And NOT ONE WORD about
the actual measured selectivity or capture ratio. (The IHF useable selectivity
was measured as 2.1 microvolts. That doesn't say much. The manufacturers
spec for "RF Sensitivity" is 2.0 microvolts.)

Here the one thing Julian said relating to selectivity, which doesn't answer
anything:

"The Butterworth-filter i.f. section never needs alignment, and is unaffected
by tube changes. It has a flat, phase-linear 200-kc pass band, with skirt
slopes of 108dB per octave. This far exceeds the performance obtained with
ordinary i.f. transformers, and makes adjacent-channel interference a most
unlikely occurance."

What does "108dB per octave" tell us about the selectivity? Does anyone know?

As far as adjacent-channel interference being unlikely, that is definitely a
lie. The Butterworth thing is inaccurate. Julian should have known that
"Butterworth" doesn't go along with "phase-linear." A suitable translation of
the comments about alignment might be:

"You'll have to hope and pray it never needs alignment, because when it does,
you'll have to send it to one of the few people in the world who can do it
properly, and pay them all the money you've got to do it right."

As I understand it, the 10B was DESIGNED not to require much alignment
(because of how difficult it is) with a relatively simple capacitance
compensation for each IF tube. If someone messes with the actual alignment,
which was purposefully made hard to get to, you might be in deep trouble.
Of course, after 40 years, even the actual IF alignment might need some work.

I wonder if Julian actually measured the 10B selectivity, but simply didn't have
the nerve to report it. He certainly measured the selectivity of later tuners,
such as measuring the Sansui TU-9900 as having 100dB alternate channel
selectivity, which very well supports the manufacturer's spec of >90dB.


Short rant on Muting

fades@...
 

I forgot to agree wholeheartedly with the Muting point. And perhaps
my #1 pet peeve: muting and mono/stereo on the same switch, making it
impossible to choose to listen to stations in weak stereo. Amazing
how many "good" tuners (like some top Pioneers) did that. -Eric


Re: Where's the MR77 IF switch?

fades@...
 

We hang our collective heads in shame... I'm not sure where I got
that bad info, but it's gone now.
http://www.geocities.com/tunerinfo/#mcintosh

Thanks, guys. -Eric

(--- In FMtuners@y..., Charles Peterson <charlesp@d...> wrote:
The Tunerinfo site must be wrong, then, because it says "Not quite
an MR 78
(two IF settings rather than 3, for one thing..."

With only one IF setting, the MR77 has a most incredible compromise
IF,
giving 90dB/47dB alt/adj selectivity with 0.2% distortion. While a
fair
number of tuners achieve the same alt selectivity in their "narrow"
mode, maybe a handful can achieve the same adj selectivity in any
mode
without modification.

It is, in fact, narrower than the MR78's middle IF mode, but gives
the same
rated distortion nonetheless.

I see also the MR77 was introduced in 1970 and the MR78 was
introduced in
1972, which is also pretty amazing.


There is no IF selectivity switch on the MR-77, that's what the
MR-78
is all about! The MR-78 is an MR-77 with some added bells and
whistles, the switchable IF selectivity is the most important one,
and
the only one I can remember.


Re: Accuphase T-107 - Resolution

Gary Aigen
 

Well, I went and heard this tuner this evening and did a fairly good
comparison with my NAD 4155 which I brought with me. The difference
was surprising to me: the Accuphase was more open, revealing, with
better soundstage as well as better bass and top-end. You probably
can guess that I came home with it. The best part is that my wife
heard the difference as soon as I set it up and was pleased that I
bought it. Now if I could only compare it to a Sansui 9900 or an MR-
78.
Gary


--- In FMtuners@y..., aigenga@y... wrote:
Does anyone have any knowledge of this tuner - how does it sound in
comparison with some of the fine tuners discussed in this forum?

I have an opportunity to buy this tuner for $595 in mint
condition.
I will be auditioning it on Teusday and hopefully get to compare it
to a Magnum Dynalabs model, but it will be a limited listening
opportunity.

Thanks for any info or leads on info (reviews, etc,).
Gary


Re: Where's the MR77 IF switch?

John <jbyrns@...>
 

You can't always believe everything you read, just because it's in
print! The numbers you quote for the MR-77 are the same ones that
are
on Roger Russell's page, but I suspect they are wrong. I am pretty
sure that the MR-74, MR-77, and MR-78 all used the same basic "RIMO"
filter for the normal selectivity setting, and they should all have
similar selectivity figures when set for "normal" selectivity.

John

--- In FMtuners@y..., Charles Peterson <charlesp@d...> wrote:
The Tunerinfo site must be wrong, then, because it says "Not quite
an MR 78
(two IF settings rather than 3, for one thing..."

With only one IF setting, the MR77 has a most incredible compromise
IF,
giving 90dB/47dB alt/adj selectivity with 0.2% distortion. While a
fair
number of tuners achieve the same alt selectivity in their "narrow"
mode, maybe a handful can achieve the same adj selectivity in any
mode
without modification.

It is, in fact, narrower than the MR78's middle IF mode, but gives
the same
rated distortion nonetheless.

I see also the MR77 was introduced in 1970 and the MR78 was
introduced in
1972, which is also pretty amazing.


There is no IF selectivity switch on the MR-77, that's what the
MR-78
is all about! The MR-78 is an MR-77 with some added bells and
whistles, the switchable IF selectivity is the most important one,
and
the only one I can remember.


Re: Sherwood Micro CPU-100 Tuner Literature

gfredsen@...
 

yes, according to the CPI the buying power of US$1000 in 1978 would
have to be equal to $2750 today. Somebody just paid $2025 for that
TUX1 (?) Sansui tuner on Ebay and there is another one on there now.
it will be fun to see how much it brings. Have you compared the
Sherwood to other tuners as to sensitivity and fidelty? A very
interesting tuner, but can it be repaired if something goes wrong.


--- In FMtuners@y..., gentry@i... wrote:
About a year ago I acquired a Sherwood Micro-CPU 100 FM tuner. This
was advertised as the first computer controlled FM tuner. It's
still
performing well coupled with a Sherwood HP2000 integrated amp. The
seller sent the original owner's manual and some advertising
literature with the tuner. I've scanned and uploaded the Stereo
Review of the tuner and a Sherwood brochure.

I like the sound and enjoy it a lot. Does anyone else have and
additional information on this tuner. I can scan and send the
owner's
manual if there's any interest.

I also got a copy of the original bill of sale and cashier's check
used for the purchase in 1978. The original price was $1000 a chunk
of change today, but really a lot in 1978 for an FM only tuner.


Re: Where's the MR77 IF switch?

Charles Peterson <charlesp@...>
 

The Tunerinfo site must be wrong, then, because it says "Not quite an MR 78
(two IF settings rather than 3, for one thing..."

With only one IF setting, the MR77 has a most incredible compromise IF,
giving 90dB/47dB alt/adj selectivity with 0.2% distortion. While a fair
number of tuners achieve the same alt selectivity in their "narrow"
mode, maybe a handful can achieve the same adj selectivity in any mode
without modification.

It is, in fact, narrower than the MR78's middle IF mode, but gives the same
rated distortion nonetheless.

I see also the MR77 was introduced in 1970 and the MR78 was introduced in
1972, which is also pretty amazing.

There is no IF selectivity switch on the MR-77, that's what the MR-78
is all about! The MR-78 is an MR-77 with some added bells and
whistles, the switchable IF selectivity is the most important one,
and
the only one I can remember.


Re: Where's the MR77 IF switch? Short rant on Mut

John <jbyrns@...>
 

There is no IF selectivity switch on the MR-77, that's what the MR-78
is all about! The MR-78 is an MR-77 with some added bells and
whistles, the switchable IF selectivity is the most important one,
and
the only one I can remember.

John

--- In FMtuners@y..., Charles Peterson <charlesp@d...> wrote:
Now that the MR78 trades for a small fortune on eBay, the lesser
MR77 is
getting attention as a near-equal substitute. When I get around to
buying
costlier tuners, this model is near the top of my list.

I see one closing out today on eBay, in fact, currently at $400.

But where oh where is the IF selectivity switch? There doesn't
appear to
be such a switch on the front panel, only mode selector, stereo
filter,
muting, volume, and tuning.

If it's tied to the muting switch, I hope you get the narrow
bandwith in the
"Muting Off" position. In most cases, I think the proper selection
for muting
is OFF, if not REMOVED FROM UNIT.

I note that the ultimate selectivity is significantly (if not
substantially)
better on the MR78. MR78 maximum adjacent channel selectivity is
55dB while
MR77 adjacent channel selectivity is "only" 47dB, a full 8dB
difference. Of
course, even 47dB is pretty incredible adjacent channel
selectivity, with even
other "supertuners" like my Sansui TU-9900 only specing at 22dB.


Where's the MR77 IF switch? Short rant on Mut

Charles Peterson <charlesp@...>
 

Now that the MR78 trades for a small fortune on eBay, the lesser MR77 is
getting attention as a near-equal substitute. When I get around to buying
costlier tuners, this model is near the top of my list.

I see one closing out today on eBay, in fact, currently at $400.

But where oh where is the IF selectivity switch? There doesn't appear to
be such a switch on the front panel, only mode selector, stereo filter,
muting, volume, and tuning.

If it's tied to the muting switch, I hope you get the narrow bandwith in the
"Muting Off" position. In most cases, I think the proper selection for muting
is OFF, if not REMOVED FROM UNIT.

I note that the ultimate selectivity is significantly (if not substantially)
better on the MR78. MR78 maximum adjacent channel selectivity is 55dB while
MR77 adjacent channel selectivity is "only" 47dB, a full 8dB difference. Of
course, even 47dB is pretty incredible adjacent channel selectivity, with even
other "supertuners" like my Sansui TU-9900 only specing at 22dB.


Sherwood Micro CPU-100 Tuner Literature

gentry@...
 

About a year ago I acquired a Sherwood Micro-CPU 100 FM tuner. This
was advertised as the first computer controlled FM tuner. It's still
performing well coupled with a Sherwood HP2000 integrated amp. The
seller sent the original owner's manual and some advertising
literature with the tuner. I've scanned and uploaded the Stereo
Review of the tuner and a Sherwood brochure.

I like the sound and enjoy it a lot. Does anyone else have and
additional information on this tuner. I can scan and send the owner's
manual if there's any interest.

I also got a copy of the original bill of sale and cashier's check
used for the purchase in 1978. The original price was $1000 a chunk
of change today, but really a lot in 1978 for an FM only tuner.


Re: 70s Yamaha

James Yerkes swbell <yerkesj@...>
 

Speaking of the Yamaha CR2020 receiver, there is one now currently available for sale beautifully resored at austin  stereo in austin, Texas, beautifully restored price also of 600.00. web site is as follows:  www.austinstereo.com  lots of other really nice vintage hifi gear.

jim Yerkes, st louis, MO

Scott Guthrie wrote:

Thanks! For 20 years, I've wondered what the NFB stood
for. (you'd think I would've figured it out by now)
I think the CR-2020 used it also.

Yamaha refers to the circuitry as "PLL NFB."  The
"NFB" stands for "Negative
Feedback," something which doesn't generate a lot of
ad copy these days.
Somehow, Yamaha applies NFB around the PLL chip
through the discrete
transistors. I'm a believer in using as little NFB
as possible (or none),
but this circuit does seem to work in generating a
good sound.





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Re: 70s Yamaha

Scott Guthrie <scottallwave@...>
 

Thanks! For 20 years, I've wondered what the NFB stood
for. (you'd think I would've figured it out by now)
I think the CR-2020 used it also.

Yamaha refers to the circuitry as "PLL NFB." The
"NFB" stands for "Negative
Feedback," something which doesn't generate a lot of
ad copy these days.
Somehow, Yamaha applies NFB around the PLL chip
through the discrete
transistors. I'm a believer in using as little NFB
as possible (or none),
but this circuit does seem to work in generating a
good sound.



__________________________________________________
Do You Yahoo!?
Yahoo! GeoCities - quick and easy web site hosting, just $8.95/month.
http://geocities.yahoo.com/ps/info1


Re: 70s Yamaha

Charles Peterson <charlesp@...>
 

Does anyone own a 70s Yamaha? Like a CT 600 or 800 series? I'm
curious to know if they used discreet transistors or op-amps in the
audio stage. The question is aimed at maybe improving the audio
stage, not DXing. Thanks. jim...........
I just purchased a CT-1010 on ebay about a month ago to add to my collection of
tuners. It is a very nice sounding tuner, almost on par with my Sansui TU-9900
in audio quality (neither are as nice sounding as my tubed tuners however).
Tuning performance is OK but not quite as good as Kenwood KT-7500 (which
itself is not as good as TU-9900).

The output stage features discrete transistors AND a PLL chip. Ultimately,
the audio is buffered by discrete transistors, not op amps.

Yamaha refers to the circuitry as "PLL NFB." The "NFB" stands for "Negative
Feedback," something which doesn't generate a lot of ad copy these days.
Somehow, Yamaha applies NFB around the PLL chip through the discrete
transistors. I'm a believer in using as little NFB as possible (or none),
but this circuit does seem to work in generating a good sound.


Onkyo T-4055

gfredsen@...
 

Anyone have any experiance with this tuner? I remember that it was
reviewed very favorably in a comparative test in Absolute Sound (for
what thats worth)in the mid '70s. It seems very sensitive and
rejects the powerful transmitter that is about one mile from where I
live. It does not sound as good, to my ears, as my valved Sherwood
S3000V. The Onk has a noise filter and muting and I just wonder if
the fidelity could be made a great deal better by new caps and the
other mods mentioned on the Tuner Info site. It has fixed or
variable volume and scope outputs.
Thank you for providing this site,
Greg


new photos added

mburnste@...
 

Goldmund Mimemis 4 tuner
McIntosh MR-78 and MIP-4 Scope
Marantz 2120 and 2130 tuners


Re: FM and radio information/reception/antennas

newaag
 

Excellent Site - really good links to explore here. Thanks

--- In FMtuners@y..., Scott Guthrie <scottallwave@y...> wrote:
Here's a website with lots of useful info.
http://www.mindspring.com/~brucec/dx.htm

__________________________________________________
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Find the one for you at Yahoo! Personals
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70s Yamaha

jimrivers3@...
 

Does anyone own a 70s Yamaha? Like a CT 600 or 800 series? I'm
curious to know if they used discreet transistors or op-amps in the
audio stage. The question is aimed at maybe improving the audio
stage, not DXing. Thanks. jim...........


Re: FM and radio information/reception/antennas

Scott Guthrie <scottallwave@...>
 

Here's a website with lots of useful info.
http://www.mindspring.com/~brucec/dx.htm

__________________________________________________
Do You Yahoo!?
Find the one for you at Yahoo! Personals
http://personals.yahoo.com


Re: Accuphase T-107

James Yerkes swbell <yerkesj@...>
 

Gary

List price on the T-10t accuphase tuner was 1800.00

Jim

James Yerkes swbell wrote:

Gary

don't know much about this tuner however, it has to be one of their
latest ones, they had an T-108 thta lloks very similiar to the current
model T-109, if you don';t buy this tunere please let me know, where do
you live, I presume its digital and what consider it fairly rare I have
not seem this tuner listed very rarely on e-bay.

Thankx, jim, st louis, mo

aigenga@... wrote:

Does anyone have any knowledge of this tuner - how does it sound in 
comparison with some of the fine tuners discussed in this forum?

I have an opportunity to buy this tuner for $595 in mint condition.
I will be auditioning it on Teusday and hopefully get to compare it
to a Magnum Dynalabs model, but it will be a limited listening
opportunity.

Thanks for any info or leads on info (reviews, etc,).
Gary



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Re: Accuphase T-107

James Yerkes swbell <yerkesj@...>
 

Gary

don't know much about this tuner however, it has to be one of their latest ones, they had an T-108 thta lloks very similiar to the current model T-109, if you don';t buy this tunere please let me know, where do you live, I presume its digital and what consider it fairly rare I have not seem this tuner listed very rarely on e-bay.

Thankx, jim, st louis, mo

aigenga@yahoo.com wrote:

Does anyone have any knowledge of this tuner - how does it sound in comparison with some of the fine tuners discussed in this forum?

I have an opportunity to buy this tuner for $595 in mint condition. I will be auditioning it on Teusday and hopefully get to compare it to a Magnum Dynalabs model, but it will be a limited listening opportunity.

Thanks for any info or leads on info (reviews, etc,).
Gary



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