What preamp for ESP-950 (elecotrstatic headphones)

[Policar]

Going to try to keep this simple:

I have two sets of headphones I like, HD650s with a Bottlehead Crack amp with the speedball upgrade (sounds so much better with this amp than with a cheaper amp, I could not stand the HD650s before) and Koss ESP-950 electrostatic headphones with the included "energizer."

I can't afford a new amp for the Koss, but when I ran the Crack through the chain (DAC to Crack then headphone out to RCA to the Koss energizer amp to the ESP-950s) the bass filled out thicker and the tone was better. Sounded "tubier" and took away the electrostatic weightlessness and thinness.

But that seems like a waste of a good amp using it as a pre-amp. If I want a similar sound (or even thicker in the bass, I welcome even order distortion in the bass because the electrostats are too clean there) what are my best options for a similar piece of gear to put in the chain?

Should I get the quickie kit (seems affordable)? But no AC power...

Or I could get a Little Dot II or III, which have pre-amp capabilities.... would they sound good enough? I just need some thickness to the bass.

Or I could just cannibalize the Crack from the HD650, which will miss it so much I'll probably sell it. And I worry there's an impedence issue running the 1/4 out through two adapters to the Koss energizer's RCA in.


Thanks!

[Doc B.]

You could get another Crack if you want that exact sound. FWIW we considered rather seriously using the Crack circuit in a preamp when we were developing the BeePre. I'm not sure that you're "wasting" a circuit if it's doing the job you want. It may be that the relatively low output impedance of the Crack is what is getting you that sound you like. If it is, the Quickie's higher output impedance may not get you there. Or it might. You'd just have to smoke it and see.

[Paul Birkeland]

While the energizer for the ESP-950's lists a pretty high input impedance, it still looks like you're directly driving the primary of some step-up transformers.  Your observations aren't all that shocking, and if you're handy with a drill you can add a set of outputs on the back of your Crack that are activated when you unplug your HD-650's.

-PB

[Policar]

Thanks! I think I might just keep it in the ESP-950 chain, then. I'm an electrostat addict it turns out so that sum of components is my favorite for the price even more than with the HD650. (Though if you made an electrostatic amp I might be interested in switching to that instead...)

But I miss the HD650's thick, punchy bass. Is there a tube that camp give the bass some thickness and punch? I'm using stock tubes.... all tubes seem to measure about the same, which is why I'm confused by the wildly differing subjective opinions (even among tubes that should be identical and from the same OEM, making me suspect some of it is psychoacoustics/confirmation bias).

But I would like some nice thick bass.....

[Doc B.]

You're not going to fix an ES headphone's inherent lack of bass weight with a preamp. Might be time to try a different headphone. Maybe something magneplanar would be a suitable compromise for your taste.