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

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

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

In article . com,
says...
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





Hmm, never heard this before about the 515 filters. My almost 25 year
old 515 works great, just needs a little alignment in the PBT circuit.
A friend's 20 year old one is fine and dandy too..

BDK

The radio itself was pretty good.................I knew a fellow back in
Iowa that had Collins filters installed and he was pretty happy with the
result. I was going to match the impedance of the new filters to the '515
but I lost track of him. It is still my favorite of the JRCs.

wrote in message
ups.com...
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

"Pete KE9OA" ) writes:
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.

Of course, one pays quite a bit for Collins mechanical filters, and
that's always been the case. Those Japanese mechanical filters were
significantly cheaper, at least back then. Reading the old magazines,
I've sometimes wondered if at least some times people were calling
ceramic filters the wrong thing.

Your description of the insides reminds me that some guy wrote about
a homebrew receiver in the early sixties, I think it was in CQ, and
he made his own mechanical filter. No, I don't have it handy and
can't specify the issue, but every so often I come across the article,
and wonder how practical it was to do. It seems like we'd have
read more about doing it if it was something easily doable.

Michael