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Old 23rd February 2013, 08:02 PM   #1
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Default Rauland W-835A amplifier, choke field coil output?

Hi!

This is my first post on this forum so bare with me... :-)

The reason for me posting here is that I have a Rauland W-835A, said to be fully functional but I recently realized that it requires field coil speakers.

I play in a band were we already have a pair of suiting 15 Ohms speakers but with permanent magnets. If possible we would like to use them since they are perfect for us in many aspects (even though we would like to find field coil speakers in the future since we are all about authenticity).

I found some threads here on the forum about putting a choke on the field coil output but since I have the schematics and the user manual I figured it would better to talk specifically about this amp and the target at hand - to avoid confusion from my behalf and so that others may generalize from this specific example.

So, how do I do? :-)

Thanks in advance!
Rasmus, Joe and the Hornets
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Old 23rd February 2013, 08:49 PM   #2
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Quote:
Originally Posted by rasmusgrip View Post
The reason for me posting here is that I have a Rauland W-835A, said to be fully functional but I recently realized that it requires field coil speakers.
Looking at the schematic and reading the instructions, you do not need field coil speakers. The amplifier is designed to work ok without them. What they are saying is that AC mains power is supplied to the speaker output plug so you could use them provided they have their own built-in DC power supply. They are simply giving you that option.

Here in America field coil speakers never come with built-in power supplies for the coil. At least none that I have ever seen. Perhaps Rauland did make some that way. Or maybe it is something one would make themselves.

Some people think that field coil speakers sound good or even better then PM speakers. I do not. They always have a little background hum, even with hum-bucking coils built in.

I am thinking the reading you have done is about replacing field coil speakers with PM speakers and using a choke in place of the speaker coil to maintain good power supply operation. But this does not apply to you situation and this amplifier.

In any event, there is AC mains power at pins 6 & 7 of the speaker plug. Be very carful if you ever use that plug. Personally, I would disconnect that AC power to the plug because it is dangerous.
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Last edited by HollowState; 23rd February 2013 at 09:02 PM.
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Old 23rd February 2013, 10:11 PM   #3
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Many thanks!

I tried to hook up my two 15 ohms speakers (see the attached picture) in parallel without success. I tapped in the GA75 25 watts Gibson amp and got a very "small" low volume sound from it.

Does this suggest that Rauland is broken or rather my electrical engineering skills? :-)

Thanks again! Rasmus
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