Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default United Transformer HA-100

Does anyone happen to have a data sheet or know the pinout of a UTC
HA-100 input transformer? It has 11 pins; 1 through 10 and a
ground. The particular unit I have was removed from something prior
to my owning it and has pins 8 & 9 shorted, 10 and ground shorted, and
3 & 4 shorted. No wire fragments or anything to go by. Wanting to
use is as an input transformer in a solid state NE5534 opamp circuit -
maybe barking up the wrong tree? Need something to take a line level
signal and match to the input of the 5534. Others have suggested
using an older transformer like this one for improved sound quality
but might not be right for the application. Could tell if I just had
info on the pinout. Anyone have access to this information? Thanks!
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Default United Transformer HA-100

On Sep 4, 2:33*pm, EricM wrote:
Does anyone happen to have a data sheet or know the pinout of a UTC
HA-100 input transformer? *It has 11 pins; *1 through 10 and a
ground. *The particular unit I have was removed from something prior
to my owning it and has pins 8 & 9 shorted, 10 and ground shorted, and
3 & 4 shorted. *No wire fragments or anything to go by. *Wanting to
use is as an input transformer in a solid state NE5534 opamp circuit -
maybe barking up the wrong tree? *Need something to take a line level
signal and match to the input of the 5534. *Others have suggested
using an older transformer like this one for improved sound quality
but might not be right for the application. *Could tell if I just had
info on the pinout. *Anyone have access to this information? *Thanks!


Hi
This may help somewhat, UTC catalog does not show pinouts..I gleaned
this
from image that was in picture in catalog.

HA-100 is a Microphone transformer 30 -20,000Hz +- 1dB You may want to
use a
600 ohm to 600 ohm transformer like an A-20.
'Line level', may be 47K in some apps.

There is some symmetry to the terminals. 2,3 means connected together
as is 4,6.
Then 50ohms is from the two sets, wire one to 2,3 and wire two to 4,6

INPUT
50Ohms 2,3 and 4,6
125/150 ohms 1,3 and 4,5
200/250 ohms 2 (join 3,4) 6
333ohms 1 (join 3,3) 5
500/600 ohms 1( join 3,4) 6

Output is 60,000 ohms overall split winding

kw
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Default United Transformer HA-100


EricM wrote in message ...
Does anyone happen to have a data sheet or know the pinout of a UTC
HA-100 input transformer? It has 11 pins; 1 through 10 and a
ground. The particular unit I have was removed from something prior
to my owning it and has pins 8 & 9 shorted, 10 and ground shorted, and
3 & 4 shorted. No wire fragments or anything to go by. Wanting to
use is as an input transformer in a solid state NE5534 opamp circuit -
maybe barking up the wrong tree? Need something to take a line level
signal and match to the input of the 5534. Others have suggested
using an older transformer like this one for improved sound quality
but might not be right for the application. Could tell if I just had
info on the pinout. Anyone have access to this information? Thanks!


I think this transformer was used for 600/250 ohm input to the grid of a
tube amp. It probably isn't going to be a good fit for a 5534.
Primary 1 -
pin 6 = hot side
pin 2 = ct
pin 4 = low side
Primary 2 -
pin 3 = hot side
pin 5 = ct
pin 1 = low side
Secondary 1 -
pin 7 = hot
pin 9 = low
Secondary 2 -
pin 8 = hot
pin 10 = low




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Default United Transformer HA-100

"bg" wrote in message ...

EricM wrote in message ...
Does anyone happen to have a data sheet or know the pinout of a UTC
HA-100 input transformer? It has 11 pins; 1 through 10 and a
ground. The particular unit I have was removed from something prior
to my owning it and has pins 8 & 9 shorted, 10 and ground shorted, and
3 & 4 shorted. No wire fragments or anything to go by. Wanting to
use is as an input transformer in a solid state NE5534 opamp circuit -
maybe barking up the wrong tree? Need something to take a line level
signal and match to the input of the 5534. Others have suggested
using an older transformer like this one for improved sound quality
but might not be right for the application. Could tell if I just had
info on the pinout. Anyone have access to this information? Thanks!


I think this transformer was used for 600/250 ohm input to the grid of a
tube amp. It probably isn't going to be a good fit for a 5534.
Primary 1 -
pin 6 = hot side
pin 2 = ct
pin 4 = low side
Primary 2 -
pin 3 = hot side
pin 5 = ct
pin 1 = low side
Secondary 1 -
pin 7 = hot
pin 9 = low
Secondary 2 -
pin 8 = hot
pin 10 = low


bg is correct in that this transformer is a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your primary line
level voltage is 1VAC, then the transformer's secondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's what
you're after.

Of course, you could always send the secondary into a resistive voltage divider
to get the level back down so the NE5534 input isn't overdriven. Better still,
connect the transformer in reverse; using the secondary as the input and the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 the input level. If you need to maintain the
frequency response characteristics of the transformer, then you need to
experiment with source and load impedances that the transformer sees.

A better choice would be a 1:1 ratio transformer; something like a 600:600 ohm
matching transformer.
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.


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Default United Transformer HA-100

DaveM wrote:
"bg" wrote in message news:g9uso7$2jt

...
bg is correct in that this transformer is a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your primary line
level voltage is 1VAC, then the transformer's secondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's what
you're after.

Of course, you could always send the secondary into a resistive voltage divider
to get the level back down so the NE5534 input isn't overdriven. Better still,
connect the transformer in reverse; using the secondary as the input and the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 the input level. If you need to maintain the
frequency response characteristics of the transformer, then you need to
experiment with source and load impedances that the transformer sees.

A better choice would be a 1:1 ratio transformer; something like a 600:600 ohm
matching transformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.




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Default United Transformer HA-100

The OP said he had line-level audio... not a mike.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.

wrote in message
...
DaveM wrote:
"bg" wrote in message news:g9uso7$2jt

...
bg is correct in that this transformer is a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your primary
line
level voltage is 1VAC, then the transformer's secondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's what
you're after.

Of course, you could always send the secondary into a resistive voltage
divider
to get the level back down so the NE5534 input isn't overdriven. Better
still,
connect the transformer in reverse; using the secondary as the input and the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 the input level. If you need to maintain the
frequency response characteristics of the transformer, then you need to
experiment with source and load impedances that the transformer sees.

A better choice would be a 1:1 ratio transformer; something like a 600:600 ohm
matching transformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.




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Default United Transformer HA-100

On Sep 7, 8:38 pm, "DaveM" wrote:
TheOPsaid he had line-level audio... not a mike.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.

wrote in message

wrote:

"bg" wrote in message news:g9uso7$2jt

...



bg is correct in that thistransformeris a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your primary
line
level voltage is 1VAC, then thetransformer'ssecondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's what
you're after.


Of course, you could always send the secondary into a resistive voltage
divider
to get the level back down so the NE5534inputisn't overdriven. Better
still,
connect thetransformerin reverse; using the secondary as theinputand the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 theinputlevel. If you need to maintain the
frequency response characteristics of thetransformer, then you need to
experiment with source and load impedances that thetransformersees.


A better choice would be a 1:1 ratiotransformer; something like a 600:600 ohm
matchingtransformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.



I was intending to use it as a line level input, however I tried it
and got nothing. Removed it and patched the line level input directly
to the R/C network at the input of the first opamp and I get a very
low level signal but adjusting the level pot doesn't seem to do
anything. Will try the 600:600.
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Default United Transformer HA-100

"EricM" wrote in message
...
On Sep 7, 8:38 pm, "DaveM" wrote:
TheOPsaid he had line-level audio... not a mike.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.

wrote in message


wrote:

"bg" wrote in message news:g9uso7$2jt

...



bg is correct in that thistransformeris a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your primary
line
level voltage is 1VAC, then thetransformer'ssecondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's what
you're after.


Of course, you could always send the secondary into a resistive voltage
divider
to get the level back down so the NE5534inputisn't overdriven. Better
still,
connect thetransformerin reverse; using the secondary as theinputand the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 theinputlevel. If you need to maintain the
frequency response characteristics of thetransformer, then you need to
experiment with source and load impedances that thetransformersees.


A better choice would be a 1:1 ratiotransformer; something like a 600:600
ohm
matchingtransformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.



I was intending to use it as a line level input, however I tried it
and got nothing. Removed it and patched the line level input directly
to the R/C network at the input of the first opamp and I get a very
low level signal but adjusting the level pot doesn't seem to do
anything. Will try the 600:600.


Sounds like your opamp circuit isn't working... or not wired correctly. Is it
possible for you to post a schematic of your circuit?
alt.binaries.schematics.electronic is a good place to post it. If you can do
ASCII art, just post it here.


--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.


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Default United Transformer HA-100

On Sep 8, 12:37 pm, "DaveM" wrote:
"EricM" wrote in message

...
On Sep 7, 8:38 pm, "DaveM" wrote:



TheOPsaid he had line-level audio... not a mike.


--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the
address)


Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.


wrote in message



wrote:


"bg" wrote in message news:g9uso7$2jt

...


bg is correct in that thistransformeris a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your primary
line
level voltage is 1VAC, then thetransformer'ssecondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's what
you're after.


Of course, you could always send the secondary into a resistive voltage
divider
to get the level back down so the NE5534inputisn't overdriven. Better
still,
connect thetransformerin reverse; using the secondary as theinputand the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 theinputlevel. If you need to maintain the
frequency response characteristics of thetransformer, then you need to
experiment with source and load impedances that thetransformersees.


A better choice would be a 1:1 ratiotransformer; something like a 600:600
ohm
matchingtransformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.




I was intending to use it as a line level input, however I tried it
and got nothing. Removed it and patched the line level input directly
to the R/C network at the input of the first opamp and I get a very
low level signal but adjusting the level pot doesn't seem to do
anything. Will try the 600:600.

Sounds like your opamp circuit isn't working... or not wired correctly. Is it
possible for you to post a schematic of your circuit?
alt.binaries.schematics.electronic is a good place to post it. If you can do
ASCII art, just post it here.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.


Actually I found part of the problem; was using a cutoff switch from
an old parts bin and it was bad. The circuit works fine. Don't
really need an input transformer at all, except the bass seems kind of
thin maybe the 600:600 would correct that. I'm going to be driving an
old tube amp with adjustable inputs at 50, 200 or 500 ohm - would it
be advisable to use a 600:600 on the output and go into the 500 ohm
tap of the tube amp's input? If I understand correctly op amps are
very high impedance on the input and output.
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bg bg is offline
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Posts: 41
Default United Transformer HA-100


EricM wrote in message ...
On Sep 8, 12:37 pm, "DaveM" wrote:
"EricM" wrote in message

...
On Sep 7, 8:38 pm, "DaveM" wrote:



TheOPsaid he had line-level audio... not a mike.


--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate

characters in
the
address)


Life is like a roll of toilet paper; the closer it gets to the end, the

faster
it goes.


wrote in message




veM
wrote:


"bg" wrote in message news:g9uso7$2jt

...


bg is correct in that thistransformeris a low impedance

microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your

primary
line
level voltage is 1VAC, then thetransformer'ssecondary level is going

to be
around 10VAC (assuming the impedances allow it). I don't think that's

what
you're after.


Of course, you could always send the secondary into a resistive

voltage
divider
to get the level back down so the NE5534inputisn't overdriven. Better
still,
connect thetransformerin reverse; using the secondary as theinputand

the
primary as the output. That would reverse the turns ratio to 10:1, so

the
output level would be 1/10 theinputlevel. If you need to maintain the
frequency response characteristics of thetransformer, then you need to
experiment with source and load impedances that thetransformersees.


A better choice would be a 1:1 ratiotransformer; something like a

600:600
ohm
matchingtransformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.




I was intending to use it as a line level input, however I tried it
and got nothing. Removed it and patched the line level input directly
to the R/C network at the input of the first opamp and I get a very
low level signal but adjusting the level pot doesn't seem to do
anything. Will try the 600:600.

Sounds like your opamp circuit isn't working... or not wired correctly.

Is it
possible for you to post a schematic of your circuit?
alt.binaries.schematics.electronic is a good place to post it. If you can

do
ASCII art, just post it here.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters

in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the

faster
it goes.


Actually I found part of the problem; was using a cutoff switch from
an old parts bin and it was bad. The circuit works fine. Don't
really need an input transformer at all, except the bass seems kind of
thin maybe the 600:600 would correct that. I'm going to be driving an
old tube amp with adjustable inputs at 50, 200 or 500 ohm - would it
be advisable to use a 600:600 on the output and go into the 500 ohm
tap of the tube amp's input? If I understand correctly op amps are
very high impedance on the input and output.

A 5534 can drive a 600 ohm load to about 10 volts peak, so it might do 500
ohms with a little less head room. Keep in mind that your transformer has
two identicle primaries, so you can use one as a primary and one as a
secondary to make a 1 to 1 transformer. You can also use your secondaries
the same way. If you make use of the center taps, you can make a 2 to 1
turns ratio. For example drive one primary with the 5534 and then use half
of the other primary to drive the amps 500 ohm input. This would put alot
less loading on the 5534's output providing the tube amp has enough gain.
You have quite a few options with that transformer but it's hard to say how
best to connect it without knowing the specifics of how much signal you need
into the tube amp. Then again you could also bypass the amps input
transformer???
bg




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Default United Transformer HA-100

"EricM" wrote in message
...
On Sep 8, 12:37 pm, "DaveM" wrote:
"EricM" wrote in message

...
On Sep 7, 8:38 pm, "DaveM" wrote:



TheOPsaid he had line-level audio... not a mike.


--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the
address)


Life is like a roll of toilet paper; the closer it gets to the end, the
faster
it goes.


wrote in message



wrote:


"bg" wrote in message news:g9uso7$2jt

...


bg is correct in that thistransformeris a low impedance microphone-to-grid
matching unit. Its turns ratio is about 1:10, meaning that if your
primary
line
level voltage is 1VAC, then thetransformer'ssecondary level is going to be
around 10VAC (assuming the impedances allow it). I don't think that's
what
you're after.


Of course, you could always send the secondary into a resistive voltage
divider
to get the level back down so the NE5534inputisn't overdriven. Better
still,
connect thetransformerin reverse; using the secondary as theinputand the
primary as the output. That would reverse the turns ratio to 10:1, so the
output level would be 1/10 theinputlevel. If you need to maintain the
frequency response characteristics of thetransformer, then you need to
experiment with source and load impedances that thetransformersees.


A better choice would be a 1:1 ratiotransformer; something like a 600:600
ohm
matchingtransformer.
--
Dave M


What microphone puts out 1 volt? Millivolts is more like it.




I was intending to use it as a line level input, however I tried it
and got nothing. Removed it and patched the line level input directly
to the R/C network at the input of the first opamp and I get a very
low level signal but adjusting the level pot doesn't seem to do
anything. Will try the 600:600.

Sounds like your opamp circuit isn't working... or not wired correctly. Is it
possible for you to post a schematic of your circuit?
alt.binaries.schematics.electronic is a good place to post it. If you can do
ASCII art, just post it here.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.


Actually I found part of the problem; was using a cutoff switch from
an old parts bin and it was bad. The circuit works fine. Don't
really need an input transformer at all, except the bass seems kind of
thin maybe the 600:600 would correct that. I'm going to be driving an
old tube amp with adjustable inputs at 50, 200 or 500 ohm - would it
be advisable to use a 600:600 on the output and go into the 500 ohm
tap of the tube amp's input? If I understand correctly op amps are
very high impedance on the input and output.


Actually, an opamp circuit's input impedance is largely dependent on the values
of the components around the opamp. The op-amp is basically a differential
amplifier having a large voltage gain, very high input impedance (megohms) and
low output impedance (ohms).

Consider the simple inverting amp below. The input impedance of this circuit
would be Ra in parallel with Rf. The output impedance is determined by the
opamp's internal characteristics. Most general purpose amps have output
impedance less than 100 ohms. To get the highest peak-to-peak signal swing at
the output, the opamp should be looking into 2k or more (again, highly dependent
on the opamp). Your NE5534 should be able to drive the 500 ohm input, but you
might not get full signal swing on the output (the NE5534 is spec'ed to drive
600 ohms).

Using a transformer interface between your opamp circuit and the tube amp's
input isn't necessary unless you have a ground loop or noise problem. The
transformer (600:600) should help eliminate that. That statement would apply to
the opamp's input also.

One thing to remember is that the transformer doesn't create the impedances; it
just transforms them. IOW, if you have a transformer with a 1:1 turns ratio
(such as the 600:600 ohm unit), then if you connect it to the opamp's output,
and drive the tube amp's 50 ohm input, the opamp will see 50 ohms at its output
(NOT 600 ohms). The turns ratio is the determining characteristic. The
impedance spec of a signal transformer is just an approximation of the circuit
impedances that it will work best in.
Following up on that , if you have a transformer with a 1:10 turns ratio, and
connect it between the opamp's output and the tube amp's 50 ohm input, the opamp
will see a reflected impedance of 5000 ohms.
Read more transformer theory at
http://books.google.com/books?id=PCo... #PRA1-PA92,M1


View in a fixed-width font such as Courier.



+------+
+--------+ Rf +-------+
| +------+ |
| |
| |
+-----+ | |\ |
------+ Ra +--+--------|-\ |

+-----+ | \ |
| \----------+-------
+------|+ /
| | /
| | /
--+-- |/
---
-


--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.


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