Good morning:
I have been going through my collection of salvaged output transformers trying to set up a new project. I came across a few of these transformers and am curious about them.
I did a turns ratio measurement and ended up at ~ 14k and 1.8k based on 8ohm speaker loads. These transformers came from a SE ell80 radio console.
My request is:
Can someone translate the wording on the attached diagram?
Can some help me determine what will be a reasonable tube to chose for these. The reflected load seems a bit high for most of the common tubes I am familiar with.
I suspect they are in the 2-3 watt range so Flea Power seems in order.
Thanks for the help
I have been going through my collection of salvaged output transformers trying to set up a new project. I came across a few of these transformers and am curious about them.
I did a turns ratio measurement and ended up at ~ 14k and 1.8k based on 8ohm speaker loads. These transformers came from a SE ell80 radio console.
My request is:
Can someone translate the wording on the attached diagram?
Can some help me determine what will be a reasonable tube to chose for these. The reflected load seems a bit high for most of the common tubes I am familiar with.
I suspect they are in the 2-3 watt range so Flea Power seems in order.
Thanks for the help
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The primary impedance will be (turns ratio)^2 × load impedance. Thus, having both pri and sec turns, you can match some loads to a primary impedane to some tubes you have or may get.
The 300T can be used for NFB depending on circuit topology. Having 0.1mm and 0.5mm the current capability is low (not more than 5W). Frequency depends on core size.
The 300T can be used for NFB depending on circuit topology. Having 0.1mm and 0.5mm the current capability is low (not more than 5W). Frequency depends on core size.
Thank you Osvaldo:
You caught me in the middle of an edit.
I am also wondering why the transformer would have two secondary windings. Is one for woofer one for tweeter?
You caught me in the middle of an edit.
I am also wondering why the transformer would have two secondary windings. Is one for woofer one for tweeter?
No. 0.5mm is for load. 0.1mm is for light load as a NFB loop.
I believe it is intersting for a EL84 or ECL82/85 pentode.
I believe it is intersting for a EL84 or ECL82/85 pentode.
Thank you
I take it then, that Cul. is German for millimeter? and refers to wire diameter
I got the wire colours figured out already.
Next what does 4220 Wdg. mean?
I take it then, that Cul. is German for millimeter? and refers to wire diameter
I got the wire colours figured out already.
Next what does 4220 Wdg. mean?
4220 turns of 0.1mm (diameter) copper wire. This wire size supports only small currents. With a current density of 4A/mm^2, a (0.1mm^2) x pi/4 gives .0078mm^2 or 31mA DC plus ACRMS. So very small transformer.
Stereo with one ELL80? Interesting. The ELL80 is closer to 2xEL95. An EL84 could tax the DC current capability of the transformer. E
I went thru a lot of Normended transformers.
The ones for the ELL80 made a nice little amp… one of the tubes is a rectifier.
dave
Thanks for the help.
Yes they are very small transformers.
Thanks Dave:
I remember that amp from some years ago. Your diagram does not have any voltages indicated. I will likely need to go with the recommended voltages from the data sheet. Do you think it will have enough power to drive my A10p Frugalhorn XL's to a reasonable listening level, or perhaps a more sensitive speaker is in order. Perhaps use it as a flea power mate to an F4 then the horns?
The quest continues
Yes they are very small transformers.
Thanks Dave:
I remember that amp from some years ago. Your diagram does not have any voltages indicated. I will likely need to go with the recommended voltages from the data sheet. Do you think it will have enough power to drive my A10p Frugalhorn XL's to a reasonable listening level, or perhaps a more sensitive speaker is in order. Perhaps use it as a flea power mate to an F4 then the horns?
The quest continues
An ELL80 will be good for 1.5-2 W IIRC.
Pictures of yours? Do they have any numbers on them.
dave
Pictures of yours? Do they have any numbers on them.
dave
Hello Dave:
the numbers on the transformers are in the first post. They came from an Ell80 Se radio. I think it was a Caruso console. I do not have high hopes for ELL80.
Mostly I was hoping there would be a Russian small tube that I might already have that would work with this impedance ratio. Or perhaps another TV pentode that likes such a high impedance. A couple or three watts output would likely be all these transformers can handle.
Any ideas?
the numbers on the transformers are in the first post. They came from an Ell80 Se radio. I think it was a Caruso console. I do not have high hopes for ELL80.
Mostly I was hoping there would be a Russian small tube that I might already have that would work with this impedance ratio. Or perhaps another TV pentode that likes such a high impedance. A couple or three watts output would likely be all these transformers can handle.
Any ideas?
I used to have tubes for these.
EL95 is a decent substitute… i did have one console where teh ELL80 was replaced with a daughter board with 2 x EL95.
dave
EL95 is a decent substitute… i did have one console where teh ELL80 was replaced with a daughter board with 2 x EL95.
dave
yes Dave:
I have 2 sets of those. It looks like the larger single one in the photo is a choke?
What does Gk on the transformer stand for?
I have 2 sets of those. It looks like the larger single one in the photo is a choke?
What does Gk on the transformer stand for?
Hello KeesB:
That is interesting.
Can it be used for local feed back or does it need to be global?
That is interesting.
Can it be used for local feed back or does it need to be global?