Hello

I am looking at

http://cgi.ebay.com/ws/eBayISAPI.dll...1151 681&rd=1

can I use the transformer as SE and what tube.

My gess are 45 or 2A3

Regards

Benny

"Benny Højvælde" wrote:

Hello

I am looking at

http://cgi.ebay.com/ws/eBayISAPI.dll...1151 681&rd=1

can I use the transformer as SE and what tube.

My gess are 45 or 2A3

Regards

Benny

The Hammond 365 has only a 3/4" x 3/4" core & no gap. Not suitable for SE.
Price in the 1960 Hammond Catalogue is $3.95 Canadian.

Interesting to collectors only. JLS

John Stewart wrote:

"Benny Højvælde" wrote:

Hello

I am looking at

http://cgi.ebay
com/ws/eBayISAPI.dll?ViewItem&category=67815&item=5771151 681&rd=1

can I use the transformer as SE and what tube.

My gess are 45 or 2A3

Regards

Benny

The Hammond 365 has only a 3/4" x 3/4" core & no gap. Not suitable for
SE.
Price in the 1960 Hammond Catalogue is $3.95 Canadian.

Interesting to collectors only.

Ah, the resident Hammond expert has spoken.

But he could use them in a parafeed amp with a choke for the DC to the
anode
of a 2A3 and then have the OPTs cap coupled from anode to
one end of the primary with the other end grounded.
They would surely handle 3 watts?

Patrick Turner.



JLS

Patrick Turner wrote:

John Stewart wrote:

"Benny H=F8jv=E6lde" wrote:

Hello

I am looking at

http://cgi.ebay
com/ws/eBayISAPI.dll?ViewItem&category=3D67815&item=3D577 1151681&rd=3D=
1

can I use the transformer as SE and what tube.

My gess are 45 or 2A3

Regards

Benny

The Hammond 365 has only a 3/4" x 3/4" core & no gap. Not suitable fo=
r
SE.
Price in the 1960 Hammond Catalogue is $3.95 Canadian.

Interesting to collectors only.

Ah, the resident Hammond expert has spoken.

But he could use them in a parafeed amp with a choke for the DC to the
anode
of a 2A3 and then have the OPTs cap coupled from anode to
one end of the primary with the other end grounded.
They would surely handle 3 watts?

Patrick Turner.

JLS

That would work, marginally. In those daze Hammond claimed only 80 to 700=
0
Hz for that transformer class. It might be OK for telephone work!! Well,
perhaps a little better than that!!

I used a Hammond 465 (next thing up) in a PP 6L6G amp. The driver was a
6SN7GT hooked up as a 'plain jane' triode voltage amp & split load phase
splitter. It had a whole 5 db NFB. DF was a nice round one. Ahead of that=

there was a 6SC7 mixer & a 6SJ7 mic amp on board as well. Used as a PA am=
p,
so OK in that application. The date on my early pencil drawing sez Octobe=
r,
1955.

The Hammond 400 Series transformers had a 1" x 1" core. So perhaps a litt=
le
better. But I guess core materials have got a lot better in the last 50
years.

Have Fun Anyway, John Stewart

John Stewart wrote:

Patrick Turner wrote:

John Stewart wrote:

"Benny Højvælde" wrote:

Hello

I am looking at

http://cgi.ebay
com/ws/eBayISAPI.dll?ViewItem&category=67815&item=5771151 681&rd=1

can I use the transformer as SE and what tube.

My gess are 45 or 2A3

Regards

Benny

The Hammond 365 has only a 3/4" x 3/4" core & no gap. Not suitable for
SE.
Price in the 1960 Hammond Catalogue is $3.95 Canadian.

Interesting to collectors only.

Ah, the resident Hammond expert has spoken.

But he could use them in a parafeed amp with a choke for the DC to the
anode
of a 2A3 and then have the OPTs cap coupled from anode to
one end of the primary with the other end grounded.
They would surely handle 3 watts?

Patrick Turner.

JLS

That would work, marginally. In those daze Hammond claimed only 80 to 7000
Hz for that transformer class. It might be OK for telephone work!! Well,
perhaps a little better than that!!

I used a Hammond 465 (next thing up) in a PP 6L6G amp. The driver was a
6SN7GT hooked up as a 'plain jane' triode voltage amp & split load phase
splitter. It had a whole 5 db NFB. DF was a nice round one. Ahead of that
there was a 6SC7 mixer & a 6SJ7 mic amp on board as well. Used as a PA amp,
so OK in that application. The date on my early pencil drawing sez October,
1955.

The Hammond 400 Series transformers had a 1" x 1" core. So perhaps a little
better. But I guess core materials have got a lot better in the last 50
years.

GOSS for E&I assembled cores had µ = about 5,000 max in 1953
when RDH4 was written.
It was quite good stuff and good enough for general use today with OPTs and
mains tranies.
But I now get E&I GOSS cores with assembled µ max = 17,000, so there
is more than 3 times the inductance for most winding apps.

But I still have to use the same amount of iron
for a given OPT because the Fsat for a given winding with
plain Lycore 150, µ = 2,700, is very near the same for the GOSS.
But the GOSS core will have 20DB+ less iron caused distortion at LF, until
it saturates, and then its like all iron, it saturates.

But its very easy to make an OPT with GOSS lams which will
contribute far less distortion to the signal than the tubes will.

Patrick Turner.






Have Fun Anyway, John Stewart

"Benny Højvælde" wrote:

Hello

I am looking at

http://cgi.ebay.com/ws/eBayISAPI.dll...1151 681&rd=1

can I use the transformer as SE and what tube.

My gess are 45 or 2A3

If it is not stated as being an SE transformer, it most likely isn't.
Since there is a CT mentioned, it is probably PP.
If it is PP, then it won't have an air gap.
Probably it is quite unsuitable for SET, unless
used in a para-feed circuit where it might be used ok without a gap.

And having been made in the late 1940s, these may not be all that wonderful
since hardly anyone had the concerns about bandwidth that a few
discerning people have today.

Have you phoned Hammond to ask them about these old models?

Sorry to be negative but most old OPTs I find are crap.

Patrick Turner



Regards

Benny

Most of the new ones are too... but even good ones can't make a good
amplifier out of single ended. For fullrange use SE is simply poor. And
no one will build limited bandpass SE transformers because no one smart
enough to use them well will fuool with SE.