|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
165.21.154.14
In Reply to: Re: Critique this list of "rules of thumb" for SET/Speaker Interface posted by Paul Joppa on December 28, 2006 at 18:14:41:
Paul,Great info. I have a question. If I have a 16 ohm (nominal) speaker, would it be better to drive this with a 16 ohm tap or an 8 ohm tap from the amp.
Given that the speaker may actually have impedance below 16 ohm in its freq range, would it not be better to always have the amp at a lower output impedance than the speaker's impedance to meet rules #2 and #6 always. But then again having a 16ohm tap with a 16ohm speaker impedance gives better impedance matching. Your thoughts and commnets most appreciated.
Addicted to Tubes
Follow Ups:
Janos is right, it gets down to specifics.Some amps use a relatively low transformer impedance (relative to the tube's operating point) in order to get more power from the amp. This works as long as the speaker impedance does not drop much below nominal. Other amps may use a relatively high transformer impedance, which enables them to work well with speakers that have a more severe impedance dip. Also - a separate effect - using the higher primary impedance provides a larger damping factor, which may or may not be important for the speaker in question.
Putting a 16 ohm speaker on an 8 ohm tap will provide more damping, less distortion, and less power. Best to let your own ears choose among these. It won't hurt anything either way.
In this case it comes down to how the specific amp interacts with the specific speakers, and with the room acoustics. In one room the 8R tap would work better, and in a different room the 16R might be the optimal... it also depends on how much power the amp has, and how sensitive the speakers are.
The way the OPT is built (capacitances) also influences the selection.
Hi Janos,In my case, I have 8w 300B SET amps driving 16ohm EV12TRXB speakers which are 96-97dB.
A 300B should drive 96-7dB super easily, but I have no idea which tap will sound better. The 8R tap will probably have better highs, and the 16R tighter bass.
Hi Janos,In my case, I have 8w 300B SET amps driving 16ohm EV12TRXB speakers which are 96-97dB.
This post is made possible by the generous support of people like you and our sponsors: