Pass X150 specs

[Sonance84]

Pass X150 input impedance

I just got an early version X150 with owners manual, but it doesn't state the unbalanced input impedance. It just shows the balanced input impedance as 22 kohms. No input sensitivity spec either.

But, when looking at the X250 owners manual, it shows 22 kohm balanced and 11 kohm unbalanced.

I'm mainly interested in the impedance of the unbalanced inputs on the X150. Should I assume 11 kohm, like the X250?

I appreciate any input, thanks in advance!

 

[Zen Mod]

if 22K balanced , then you can count on half of that unbalanced

 

[Sonance84]

Thanks for the quick reply.

So if I use the 20:1 rule of thumb for impedance matching, a preamp with output impedance of no more than 600 ohms (unbalanced) should give best results?

 

[moe29]

I can't imagine any preamp on the market today (or last 20 years) that wouldn't play with the X150 - it's a beast! 🙂

 

[Zen Mod]

oh yes

but nothing wrong with preamp having much lesser Rout

for more than 600R , forget it , those are not preamps but Tone Effects

 

[Sonance84]

Using an Adcom GFP-750 at the moment which sounds great, but it belongs to a friend, so I'll have to find a good matching preamp eventually.

Thanks again for the info.

 

[ludkokanta]

I have one. It can drive shoe boxes I think.

I tried 7 preamps/caps/concepts.

Now I run it with a b1 r2 with k75-10 caps.

I thought maybe it sounded best with my friends matisse tube preamp clone. 4k output impedance.
Involving sound with great imaging.

 

[adason]

What's the sound of one shoe box clapping...or clipping?

 

[Nelson Pass]

The input impedance of the amp is resistive, so a high source impedance
just lowers the gain of the amp a bit. The high impedance driving the
capacitance of long cables might be a different matter.