Anyone know the difference between the 2515 and the 2515A?

I wonder who built this rcvr? Trio maybe?

Thanks

I believe that this was a Trio unit. It used one of the Toko ceramic
filter/I.F. transformer combinations in the 455kHz I.F. strip. It wasn't a
bad unit.

Pete

"Michael" wrote in message
...
Anyone know the difference between the 2515 and the 2515A?

I wonder who built this rcvr? Trio maybe?

Thanks

Michael wrote:

Anyone know the difference between the 2515 and the 2515A?

I wonder who built this rcvr? Trio maybe?

Thanks

The main difference is in the IF strip. The 2515 uses 4 of the
filters in the IF while the "A" only uses 2. I believe one stage IF amp
stage was dropped in the "A" model as well. Another minor difference is
in the RF amp. In the 2515 the bias on gate 2 of the dual gate MOSFET
is fixed with a voltage divider, while in the "A" a variable resistor is
added into the network, so as to be able to vary the bias over a small
range.
I remember using the 2515 as a SWL rx back in the late 60's and finding
the 4 IF filters to be too much selectivity for AM broadcasts, and not
quite enough for CW/SSB. The "A" model having fewer cans fared better
with AM.
Those cans were a mystery as well. I don't think they were Toko
products but I don't know for sure. I opened one up once and found what
appears to be a ceramic filter disk and an unusual arrangement of coils.

These radio were sold by Allied Radio. I have not been able to
determine who actually made them. I once corresponded with a Trio
employee who worked there about the time these units were being sold,
and he swore they were not one of theirs.

Bob

Those were Toko units................some of the CB radios such as the
Johnson 123 used them. Actually, I've even got a couple of them on hand for
upgrades with radios that use the Toko 10mm transformers.

Pete

"Bob Liesenfeld" wrote in message
...


Michael wrote:

Anyone know the difference between the 2515 and the 2515A?

I wonder who built this rcvr? Trio maybe?

Thanks

The main difference is in the IF strip. The 2515 uses 4 of the
filters in the IF while the "A" only uses 2. I believe one stage IF amp
stage was dropped in the "A" model as well. Another minor difference is
in the RF amp. In the 2515 the bias on gate 2 of the dual gate MOSFET
is fixed with a voltage divider, while in the "A" a variable resistor is
added into the network, so as to be able to vary the bias over a small
range.
I remember using the 2515 as a SWL rx back in the late 60's and finding
the 4 IF filters to be too much selectivity for AM broadcasts, and not
quite enough for CW/SSB. The "A" model having fewer cans fared better
with AM.
Those cans were a mystery as well. I don't think they were Toko
products but I don't know for sure. I opened one up once and found what
appears to be a ceramic filter disk and an unusual arrangement of coils.

These radio were sold by Allied Radio. I have not been able to
determine who actually made them. I once corresponded with a Trio
employee who worked there about the time these units were being sold,
and he swore they were not one of theirs.

Bob

What a horrid, miserable radio. I owned one brand new in 1971 as ordered
from Allied radio shortly before their demise.

The A-model has a bit more IF bandwidth due to one IF filter stage being
eliminated and replaced with a jumper wire on the circuit board. This spoke
volumes of the crappy design: imagine, the "improved" A-version actually
has less parts due to the fact that an entire stage in the IF was removed!

My 2515 model suffered from excessive drift, instability, bandswitch
glitching, microphonics, poor sensitivity above 20Megs, scratchy
pots.....and that was when the darned thing was NEW!

The A-model may be more desirable due to its selectivity being wider than
that of a razor blade. AM on my 2515 was absolutely miserable and devoid of
any detected audio above 1,500cps. It always sounded like you were
listening to a radio with a paper bag over your head.

No wonder Allied fizzled. This was the Company's last, dying attempt at
marketing a house-brand "communications" receiver. I can see why anyone at
TRIO would never admit to desingning the fool thing.




"Michael" wrote in message
...
Anyone know the difference between the 2515 and the 2515A?

I wonder who built this rcvr? Trio maybe?

Thanks

There was a Japanese company that made a smaller version
of the Collins Mechanical fitler and I htink it looked like your
discription. Poptronics ran an article int he mid 1960s about
how to add one to your existing SW receiver. I
Terry

Reminds me of a Lafayette HA-225 (KT-340) receiver I once owned. They
are fine examples of how far shortwave receivers have come!


patgkz wrote:
What a horrid, miserable radio. I owned one brand new in 1971 as
ordered
from Allied radio shortly before their demise.

The A-model has a bit more IF bandwidth due to one IF filter stage
being
eliminated and replaced with a jumper wire on the circuit board.
This spoke
volumes of the crappy design: imagine, the "improved" A-version
actually
has less parts due to the fact that an entire stage in the IF was
removed!

My 2515 model suffered from excessive drift, instability, bandswitch
glitching, microphonics, poor sensitivity above 20Megs, scratchy
pots.....and that was when the darned thing was NEW!

The A-model may be more desirable due to its selectivity being wider
than
that of a razor blade. AM on my 2515 was absolutely miserable and
devoid of
any detected audio above 1,500cps. It always sounded like you were
listening to a radio with a paper bag over your head.

No wonder Allied fizzled. This was the Company's last, dying attempt
at
marketing a house-brand "communications" receiver. I can see why
anyone at
TRIO would never admit to desingning the fool thing.




"Michael" wrote in message
...
Anyone know the difference between the 2515 and the 2515A?

I wonder who built this rcvr? Trio maybe?

Thanks

"patgkz" ) writes:
What a horrid, miserable radio. I owned one brand new in 1971 as ordered
from Allied radio shortly before their demise.

The A-model has a bit more IF bandwidth due to one IF filter stage being
eliminated and replaced with a jumper wire on the circuit board. This spoke
volumes of the crappy design: imagine, the "improved" A-version actually
has less parts due to the fact that an entire stage in the IF was removed!

My 2515 model suffered from excessive drift, instability, bandswitch
glitching, microphonics, poor sensitivity above 20Megs, scratchy
pots.....and that was when the darned thing was NEW!

The A-model may be more desirable due to its selectivity being wider than
that of a razor blade. AM on my 2515 was absolutely miserable and devoid of
any detected audio above 1,500cps. It always sounded like you were
listening to a radio with a paper bag over your head.

No wonder Allied fizzled. This was the Company's last, dying attempt at
marketing a house-brand "communications" receiver. I can see why anyone at
TRIO would never admit to desingning the fool thing.

I don't think it's unique to Allied. At that same period, a lot of
the old US companies and manufacturers went to solid state and Japan
for their receivers. The art hadn't developed much, and people wanted
cheap receivers. So you got a lot of junk, and in many cases it
wasn't made by the company, merely labelled with the company name.
I've heard it said that the companies were unable or unwilling to adapt
to solid state at the time, so rather than invest the needed research
and energy in solid state design, it was farmed out.

Virtually everyone had a low end solid state receiver at the time of
dubious quality. Something like the Hallicrafters S-38 was pretty bad,
but it was built with tubes and at least the designers knew tubes well.
It took more effort to make a good solid state receiver, and that wasn't
happening at the time, at least not at the low end.

My Hallicrafter's S-120A was horrible. I suspect that Ameco cheap
transistor receiver that tuned to 54MHz was likewise not very good, though
that's just a guess based on time an price. Lafayette, Radio Shack, probably
even Heathkit had similar receivers.

Of course, I'm less certain that such equipment killed the companies. I
suspect they were at the end of their long runs, and the fact that things
were changing and they didn't change with it helped.

Michael

Those filters were pretty awful................I don't remember the name of
the company name, but it started with the letter K.
They were used in the NRD-515 and in the Yaesu FRDX-400. They were filled
with some sort of foam substance that turns to a sticky jelly after many
years, causing the insertion loss of the filter to degrade. Peter Bertini
had an article in Popular Communications a few years ago on how to repair
them. I did just that for a friend's FRDX-400. You have to dismantle the
filter and clean out all of the goo with alcohol..........I used a product
called Flux-Off.
Afterwards, you have to replace the foam damping material. I used air
conditioner foam strip. Another thing about those filters....there is no
other mechanical support for the filter elements themselves. When you remove
the goo, you have the filter structure hanging by a few strands of Litz
wire. For years, I was looking for an NRD-515 until I discovered those
filter problems. I have never seen a Collins mechanical filter fail in that
manner, and I have had quite a few of those filters over the years. If any
of you ever have the problem with your JRC radios that use that filter, I
can give you advice on how to repair them.....................if you don't
feel comfortable repairing them yourself, I can repair them for you.
I did have one of those 2515 in for repair a couple of years ago, and the
unit that I repaired did not have any mechanical filters even though the
advertising hype stated that it did. It was definitely one of those slightly
oblong I.F. transformers that had the ceramic filter inside the same
structure.
For a cheap receiver, they weren't bad.
Anybody remember the transceiver that matched this unit in style? A friend
once told me that it was a Kenwood TS-510 with Allied's label.

Pete

wrote in message
ups.com...
There was a Japanese company that made a smaller version
of the Collins Mechanical fitler and I htink it looked like your
discription. Poptronics ran an article int he mid 1960s about
how to add one to your existing SW receiver. I
Terry

There is no excuse for a penny pinching move like that in an expensive
radio. My opinion of Japan Radio just went down a couple of notches.


Pete KE9OA wrote:
Those filters were pretty awful................I don't remember the
name of
the company name, but it started with the letter K.
They were used in the NRD-515 and in the Yaesu FRDX-400. They were
filled
with some sort of foam substance that turns to a sticky jelly after
many
years, causing the insertion loss of the filter to degrade. Peter
Bertini
had an article in Popular Communications a few years ago on how to
repair
them. I did just that for a friend's FRDX-400. You have to dismantle
the
filter and clean out all of the goo with alcohol..........I used a
product
called Flux-Off.
Afterwards, you have to replace the foam damping material. I used air

conditioner foam strip. Another thing about those filters....there is
no
other mechanical support for the filter elements themselves. When you
remove
the goo, you have the filter structure hanging by a few strands of
Litz
wire. For years, I was looking for an NRD-515 until I discovered
those
filter problems. I have never seen a Collins mechanical filter fail
in that
manner, and I have had quite a few of those filters over the years.
If any
of you ever have the problem with your JRC radios that use that
filter, I
can give you advice on how to repair them.....................if you
don't
feel comfortable repairing them yourself, I can repair them for you.
I did have one of those 2515 in for repair a couple of years ago, and
the
unit that I repaired did not have any mechanical filters even though
the
advertising hype stated that it did. It was definitely one of those
slightly
oblong I.F. transformers that had the ceramic filter inside the same
structure.
For a cheap receiver, they weren't bad.
Anybody remember the transceiver that matched this unit in style? A
friend
once told me that it was a Kenwood TS-510 with Allied's label.

Pete

wrote in message
ups.com...
There was a Japanese company that made a smaller version
of the Collins Mechanical fitler and I htink it looked like your
discription. Poptronics ran an article int he mid 1960s about
how to add one to your existing SW receiver. I
Terry