passive attenuators

what are the best passive attenuator designs in your opinion ?

Again it is a matter of opininon and there are advantages as well as disadvantages.

What are the pros and cons ?

 

I am considering audio synthesis, welborne zephyr, django tx, placette, rothwell etc so its something I am pondering also.

 

I've been using a pair of Rothwell attenuators for quite some time now on my CD input to my pre.

I think they are very transparent in use, they don't seem to add or, take, anything away from the basic character of the sound, apart from lowering the volume. They look to be extremely well made, using good quality components, (basically they seem indestructable) !

I use the Rothwells to lower the volume on my CD input so that my CD and TT are better matched when switching between sources.

I bought the pair that i'm using at the moment second hand at far below the RRP, in this respect they were a good buy, i don't think they are worth 40 quid though.....

HTH.

 

I now have a passive attenuator, between cd and amp.

I have a question about it :

I noticed a tremendous change as far as the timing of the music was concerned but I don't understand why this is.

When I say timing, I mean for example the attack of a bass drum, as well as quieter percussive sounds.

Now, as I said, I don't understand why this change(which is in my case desireable and intended) has occurred and that is my question.

 

The way I look at it, is that its like making a copy of a copy of a copy... of a tape. Every active amplifier stage you have in the way is like making a copy of the music. Switching from an active pre-amp with lots of op-amps and transistors and valves to a passive one is like getting closer to the original copy.

I would guess your last pre-amp had poor slew-rate transistors/op-amps/valves.

 

today I have been trying out a prototype hificollective passive pre-amp.

It uses a stepped attenuator, silver wire leading to silver RCA sockets.

It has 2 outputs, record out (tape out) and six inputs.

The kit is going to retail at about £200. Details will appear here soon : www.hificollective.co.uk.

I've been really very impressed with it. Its a lot better (in my subjective opinion) than the WAD passive pre or the Creek passive pre.

At the price its going for it would be difficult to beat IMO.

It gives a very detailed sound with lots of treble energy. A very 'together' sort of sound which is easy to live with and makes listening to any recording a pleasure.

I believe hificollective will offer to build it for you for under £100 extra.

Im sure prices will all be confirmed.

 

How does it compare with the AS passion?

 

thorsten, could you shed some light on my question ?

 

Hi,

Not enough data. In broadest terms, the "attenuator" (am I right considering it to be something like the rothwell thing?) changes the systems transfer function due to capacitive loads etc, it may result in increased load on the source which may produce more distortion and so on.

Plus passive components do have their own sonic signatures, resistors are usually low in that regard, but poor choices can have a disproprtionate effects. Finally, you added more press-fit metal/metal connections with potential for thermomelemt voltage disturbances, possible forming of oxide layers which if copper is present may be semi-conducting and so on.

Finally, your volume control may very well form a further variable lowpass and a higher setting on the volume control may increase it's output impedance and thus roll off the treble more.

It is a complex system and you altered it, so it will behave differently.

If we had an exact description of the setup it may be possible to be a little more precise.

Ciao T

 

I thought that since i had replaced the preamp with a simple switched passive attenuator, that all the transients were sounding more snappy as there is less in the signal path.

Is this true ?

 

So are you saying there was an improvement? Your previous post didn't say if it was better or worse!

I found dynamics/transients improved switching from a valve (but very transparent) pre-amp to a transformer based pre. It also reviled or introduced a slight harshness. I have yet to find out which!

 

Hi,

Let me be clear. Your writing is not very clear on this point.

You previously had an active preamplifier and you replaced that with a so-called "passive" reamp, that is an adjustable, switched attenuator and the result to you makes transients snappier?

This is largely the polar opposite of what you appeared to be saying earlier.

Depends on your definition of truth.

I like that posed by Hassan Bin Sabbah - "All things are true, all things are lawful."

So, by that definition it is indeed true, as is of course the polar opposite.

Ciao T

 

why is it the opposite ?

I said that it sounded more snappy, eg the bass attack etc.

What are you not clear about ?

 

All you said before, is that you noticed huge differences.

 

Hello, I haven't heard the AS passion.

I will be comparing it to the Music First transformer based pre-amp as soon as possible.

Cheers
Chris

NB details here:

http://www.hificollective.co.uk/kits/glasshousehome.html

 

bbv, this old active vs. passive thread is interesting reading: http://www.audiocircle.com/circles/viewtopic.php?t=12676&postdays=0&postorder=asc&start=0
My Django is now in France. I can't wait to try it!