I have an OT from a Terryphone that is also marked cha 33. I found a schematic for bogen cha 33 and using that and the existing wire connections i was able to identify my 3 primary leads (blue brown and red) and i know the 4, 8, 16 and 150 ohm/75v taps. I also know the black is my common.
My problem is the two extra wires that aren't on the schematic either. There is a green wire. There is also another one that is green with a stripe. I forget the stripe color. It's either a white stripe or a black stripe.
Either way it seems that this OT is not following typical color conventions because one of my speaker connections is white and black and that should have been another common wire according to the book.
I hooked up 120 volts to the blue and brown wires on the primary and got voltages that coincided with the expected turns ratios and impendances for the amp. (Push-pull with 6l6 tubes)
I don't have the exact voltages but they were roughly:
3.5,
5,
6.5,
For the 4, 8 and 16 ohm tap. I state that just to put the turns ratios in perspective.
Now the reading that i got on my green striped lead was approximately 2.5 volts to common.
On the solid green it was approximately 40 volts to common.
Can anyone help me guess what those two green wires are for?
My problem is the two extra wires that aren't on the schematic either. There is a green wire. There is also another one that is green with a stripe. I forget the stripe color. It's either a white stripe or a black stripe.
Either way it seems that this OT is not following typical color conventions because one of my speaker connections is white and black and that should have been another common wire according to the book.
I hooked up 120 volts to the blue and brown wires on the primary and got voltages that coincided with the expected turns ratios and impendances for the amp. (Push-pull with 6l6 tubes)
I don't have the exact voltages but they were roughly:
3.5,
5,
6.5,
For the 4, 8 and 16 ohm tap. I state that just to put the turns ratios in perspective.
Now the reading that i got on my green striped lead was approximately 2.5 volts to common.
On the solid green it was approximately 40 volts to common.
Can anyone help me guess what those two green wires are for?
The 2.5V (green striped) is 2 Ohms . From 2.5/3.5 = 0.7, 0.7 squared = 0.5 so 4 x 0.5 = 2 Ohms.
The 40V - Um!! 40/6.5 = 6.15, 6.15 squared = 38'ish, 38 x 16 = 600 Ohms ??? Maybe a dedicated feedback winding else I have no idea either.
Cheers,
Ian
The 40V - Um!! 40/6.5 = 6.15, 6.15 squared = 38'ish, 38 x 16 = 600 Ohms ??? Maybe a dedicated feedback winding else I have no idea either.
Cheers,
Ian
This tranny might be be from a PA type amp. The 600 ohm is used to drive line type speakers for PA use. Just use the taps that you need and tape the ends of the unused taps so they don't short to chassis.
The amp was used as a PA, so that sounds logical. I've never heard of such a thing, but it sounds good.
PA amps often have 600 ohms outputs, or 70V (or 100V) too, meant to drive speakers far away (and I mean *far* , think the other end of a football field ) with less loss from wire resistance.
The speakers at the far end or along the line have individual matching transformers.
So those *weird* taps you found are actually quite normal.
The speakers at the far end or along the line have individual matching transformers.
So those *weird* taps you found are actually quite normal.
I have a similar issue. I have a Raphaelite OPT with the primary leads being Blue (P1), red (B+) and black (P2)...I can't seem to get a good fee for which of the following may be the common. Green w/yellow stripe, orange, violet & yellow.
I plan to put 24v to P1 & P2 and take some readings and see what I can come up with.
It was listed as 'OP5K60W 5K:4,8 ohm' - it's a PP Didn't get any other information with it.....yeah, I should have bought American so I could just call them....
I plan to put 24v to P1 & P2 and take some readings and see what I can come up with.
It was listed as 'OP5K60W 5K:4,8 ohm' - it's a PP Didn't get any other information with it.....yeah, I should have bought American so I could just call them....
Not sure if this helps at all, but I have a Bogen Challenger CHB-35A. It has the following taps:
Black - Common
Orange - 4 ohm
Yellow - 8 ohm
Green - 16 ohm
Black/Red - 25V
Grey - 70V
These are all connected to a terminal screw strip on the back, along with 2 lines coming off the mic preamp plates (about 110V, I believe)
No green striped, though.
Black - Common
Orange - 4 ohm
Yellow - 8 ohm
Green - 16 ohm
Black/Red - 25V
Grey - 70V
These are all connected to a terminal screw strip on the back, along with 2 lines coming off the mic preamp plates (about 110V, I believe)
No green striped, though.
After some low-AC voltage testing it seems the following:
PRI-winding:
Orange - center
Violet - P1 (think)
Yellow - P2 (think)
Green w/yellow (no idea - no cont with any wire or voltage)
SEC-winding:
Black - common
Red - 8ohm
Blue - 4 ohm
so , some definite movement but still a question or two....
PRI-winding:
Orange - center
Violet - P1 (think)
Yellow - P2 (think)
Green w/yellow (no idea - no cont with any wire or voltage)
SEC-winding:
Black - common
Red - 8ohm
Blue - 4 ohm
so , some definite movement but still a question or two....
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