Running amp without speakers

That applied to amps with output transformers (back in the toob days).

speakers.

Some amplifier designs (poor ones, IMHO) have the current for the bias running thru the speakers. Some get around the disconnected speaker problem by putting a few hundred ohm resistor in parallel with the speaker terminals, so that there's still a path with no speaker. But in any case, these designs may have serious deficiencies without the speakers. If you want to be certain that things are kosher, put a ten ohm ten watt resistor across each speaker terminal.

What output from yout amp are you using to drive the input to your sound card. It seems strange to me that you are adjusting the speaker volume to get enough input signal to the sound card.

As for running an amp without speakers connected, It really depends on the desing of the output stage of the amp. What could happen is with no load connected to the output, the output voltage would be much higher than if you had a load (Speakers connected). this higher than normal voltages my damage componants if not the output amp itself. You can get around this by connecing some 8 ohm resistors to the speaker outputs. You must use resistor of the apropriate wattage. Use these 16 Ohm 50 Watt resistors in Parallel (that will give you 8 Ohm 100 Watt)

. (assuming you amp is no larger than 100W RMS) So, you would need two resistors per speaker output.

But really, I would like to know how you have things connected from your amp to your computer. You realy should not need to turn up the speakers to achieve good levels..

Pat Ziegler Wholesale Electronics Inc.

"Watson A.Name - "Watt Sun, the Dark Remover"" wrote in message news: snipped-for-privacy@corp.supernews.com...

I disagree, Tube Amps are much less suseptible to blowing outputs Vs. solid state.

A 10 watt resistor will smoke easily if his amp is say 100W RMS. Then he may have a fire to deal with.

Pat Ziegler Wholesale Electronics Inc.

When shorted or overloaded, yes. But the topic of the thread is open outputs. When compared with solid state amps, tube amps are more susceptible to blowing something in the output stage when run open. Solid state amps can typically be run open with impunity.

--
St. John

I can't argue with that. As I have never ran a tube amp without load.

However, I would still use a higher wattage dummy load.

Pat Ziegler Wholesale Electronics Inc

Assumes a single possible point of failure. . .

If you're lucky, the smoking resistor will be noticed and the system shut down. Components smoking inside the unit will be more difficult to detect. At any rate, it's preferable to an open load.

Here's a good explanation of what happens.

*-energy-in-this-magnetic-field-has-to-go-somewhere+Normally-it-would-be-dissipated-by-the-load+output-tubes-or+the-windings-of-*-transformer+high-flyback-voltage-generated+*-close-*-*-*+no-speaker-connected (My own experience, both times I have encountered this, was that the phenolic tube sockets burned.)