[sachu]

I recently sold the CK2III as the CTH was above and beyond the better headphone amp.
The CK2III has a solid bottom end but the CTH blows it away in all other areas..

 

[smeggy]

Ok, just to keep you all apprised of it's performance with nasty cans..

I'm running one of the worlds hardest to drive phones on the CTH right now and it's doing a very nice job with them. The K1k is a known difficult load, the original Wharfedale isodynamic is like a K1k with a boat anchor attached. It's at 5oclock for decent levels... the knob only goes to 5:30.

Yeah, that kind of load!!
Impressive.

 

[sachu]

wow..you aare able to run the wharfedale isos with the CTH..nice..and the knob only goes to 5.30 eh?

 

[smeggy]

Mmm, quick question here... does the CTH have a thermal trip of any kind and it cut itself out for a little while and then popped itself back on again with a low ping sound. I thnk the woofeys may be more than the CTH is really comfortable with

 

[TimJo]

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif Mmm, quick question here... does the CTH have a thermal trip of any kind and it cut itself out for a little while and then popped itself back on again with a low ping sound. I thnk the woofeys may be more than the CTH is really comfortable with

Sounds like the e12 tripped. Were you just listening, or were you adjusting the volume when it happened?

 

[runeight]

Good job exercising this little amp.

It does not have any thermal protection, but it does have the e12 offset protection circuit. If you are running very high currents through the O/P devices and the phase splitter it may occasionally generate a transient offset that exceeds the detection limit. This should not happen for normal conditions and should be pretty rare even with what you are doing.

 

[smeggy]

Just listening and it suddenly cut out and came back a minute or so later. It's done it about 3 times now, only with these phones at max power. First two times I thought it was bad connections, apparently I found the CH limit

 

[cfcubed]

Quote:

Originally Posted by smeggy /img/forum/go_quote.gif Mmm, quick question here... does the CTH have a thermal trip of any kind and it cut itself out for a little while and then popped itself back on again with a low ping sound. I thnk the woofeys may be more than the CTH is really comfortable with

Right, it was an e12 trip. Things like line voltage flux may cause this too once in a while.

Even if he wasn't twirling the volume at the time, I'd suggest there may be a couple/few component adjustments we might want to make a CTH routinely driving "very difficult" loads. Removal/shorting of R18s (output resistors), e12 resistor tweaks from CTH tweak thread come to mind. Perhaps more, but if someone ends up habitually using a CTH this way we'd see. (E.g. If the difficult load phones don't sound as full/rich/fat as non-difficult cans - coupling caps, if TO92s get too hot little paddle HSs, etc.)

Edit WRT apparently I found the CH limit - Don't count the little tiger out yet for this sort of thing

 

[smeggy]

Cool, I'm gonna be making one soon hopefully so any thoughts of modifications to it you can suggest can be incorporated in the build and it can then act as a testbed for feedback.

Back to more reasonable loads it seems happy again.

 

[wiatrob]

Yup, as with many DIY projects, the design goals were addressed to the 'majority' of headphones in use (whatever they are

)

As CFCubed pointed out - there's room in the design to accommodate different operating conditions...

 

[holland]

Check the source for DC. DC coming in gets amplified. The volume knob attenuates all AC and DC, but with a difficult load the knob gets set higher. Try a quick test with an interconnect that has coupling caps, if you have bits on hand to make one.

Edit: When music plays DC will go up and down for direct coupled sources.

you can also try pulling the headphone from the jack and just max out the knob.

 

[smeggy]

heh, I have no idea what any of that means. I'm more of a 'paint by numbers' DIYer

I have the electronics knowledge of a gnat, besides, this isn't my amp so I won't be messing with this one

 

[holland]

Remove the headphones, max out the volume, and see if the relay trips (the click and the red light). Leave it for a bit and see if it flashes green and red (or some repeated clicking). Lower the volume knob and see if you can find the point where it doesn't. Make sure your track is on repeat. Different music will behave differently.

Source DC offset (from music) + amp gain can easily trip the e12. With a cap on the input of the amp, it shouldn't trip from source (that's the interconnect with the caps inline). From there, you can tell if it's the headphone load that's causing issues.

Just saying, because my source trips up other amps with the e12, and it goes away if I cap couple. I know my source is DC coupled (no output caps).

 

[smeggy]

Ah, gotcha. I like good explanations like that. Very helpful thanks. I'll try that tomorrow.

 

[Henmyr]

Quote:

Originally Posted by sachu /img/forum/go_quote.gif I recently sold the CK2III as the CTH was above and beyond the better headphone amp. The CK2III has a solid bottom end but the CTH blows it away in all other areas..

Thanks for the answer.

Do the CHT better the "large, deep 3D-like soundstage" that I've read that the CK2III has? What headphones did you test both with? Did you try both with your very hard to drive orthos? I would guess that the outcome COULD (as I really have no idea) be different as my current headphones are not that hard to drive in comparison.

thanks again.