Simple hi-fi question

Nope. Anywhere from 10s of ohms to several Kohms, depending on design and vintage.

No such thing. Depends on the acoustic characteristics of the woofer and the enclosure.

Kal

For the tuning port, you need to know all the Thiele Small paramaters and you can plot the expected response curve. The port only works at the tuning frequency. You can actually buy adjustable ports, you can lengthen/shorten the tube and "tune" for ideal sound at low frequencies. (Fs, Qts, Qms, Qes, Vas, and you'll need the Vb (box volume)). It is easiest to plot this with software.

It is easier to make a sealed enclosure, but the problem is you loose the output you could have with a tuned port (at the lowest frequency).

I didn't understand what you meant in regards to output impedance for hi-fi speparates. You mean the output from the tuner (amplified? or just pre-amp signal?). Typically, line level is 600 ohms (-10dB) on a device such as a CD player/tuner, etc.. (recent electronics). The output of the amplifier is usually designed to run anything down to 4 ohms/channel (typically). I have a Bryston 3B, capable of 2ohms/channel.

Hope that sorta helps.

speparates.

Typically, line

Nope. Only in professional equipment. Consumer equipment has no such standard.

Again, your Bryston is quite competent (as is mine) but many (most?) consumer A/V receivers and amps cannot handle a 4 ohm load, let alone a 2ohm load.

Kal

On Tue, 18 May 2004 10:54:30 -0400, the world was enlightented by Kalman Rubinson, unto whom the words are attributed:

speparates.

Typically, line

Mmm, thanks for the feedback. The tuner is a 70's vintage Realistic tuner, of fairly compact size. I just supposed that since separates generally seem to work well together, there must be some kind of standard.

Thanks for the "speaker notes" - really wish I had my book on the subject now...

Monster

As long as the input impedance of the device it feeds is higher by an order of magnitude or more, there should be efficient voltage transfer.

Kal

On Thu, 20 May 2004 23:43:56 -0400, the world was enlightented by Kalman Rubinson, unto whom the words are attributed:

That is certainly the case, the device it feeds being a valve amp, the input is 1M ohm approx. However, the amp does not have volume or tone controls, so at the moment the tuner feeds across a 20k dual pot (completely guessed value), with the wiper connected to the amp. Trouble is, the volume goes up very steeply near the beginning of the track - I was hoping if the pot matched the tuner's output impedance a bit better, it might make a smoother change. Also, intend extending the simple volume pot with a baxandall circuit, and wondering about picking optimum values to start with - ie so the circuit has roughly the same impedance as the tuner output. Now I am thinking, perhaps what I need is a /higher/ value for the volume control, to match the amp's input...

Monster

The value is probably OK but you need an audio taper pot, not a linear one.

Kal

On Mon, 24 May 2004 17:48:36 -0400, the world was enlightented by Kalman Rubinson, unto whom the words are attributed:

It's log - isn't that pretty much the same?

Monster

Try wiring the other way around (anti-log). OTOH, if your amp's input impedance is 1M, you might also try a 100K pot in case your tuner has a very high output impedance.

Kal

On Thu, 27 May 2004 18:20:41 -0400, the world was enlightented by Kalman Rubinson, unto whom the words are attributed:

Thanks for all the input - must experiment now :-) Anti log sounds interesting!

Monster

Ideally, output impedance must be zero.

Little M> Anyone know what typical output impedance is with hi-fi separates? (A