[Joe Bloggs]

After all my shenanigans with a pot, I just got reminded that all the HeadRoom amps from the Supreme on up have a 3-position gain switch. In a world populated with single-gain amps, these are like the only cars out there that have a gearbox. There's no competition.

The maximum gain of your amp can be compared to the maximum speed of a race car, and your pot position can be compared to the speed your engine is running at (in rpm). Your car can do up to 300 km/h but if you don't have a gearbox, you can hardly start moving and you have very poor torque and power (or tracking performance

) until you go up to at least 100km and your tachometer needle points to at least 3000rpm. (or, say, 10 o'clock on your volume pot

) The most power can be had just before the redline, say 8000-9000rpm...

It is hard to design an engine that has good power and torque at low rpm (it is hard to make a pot that has good tracking at low settings... channel imbalance

)

Enough with the car analogy

What headphones do you use on low gear? (

)Middle gear? High gear? (Any?)

Ever had any headphones that had your amp revving too low even in first gear?

Can someone clue me in on the exact gear ratios of the HeadRoom Roadsters? Err I mean the gains

 

[Joe Bloggs]

Hello?

 

[gaineso]

Joe, you're gettin' a little anal over this.

To my knowledge, no one has ever mentioned mistracking on these amps.

You might be able to measure something, a slight amount, but I doubt if it would be audible.

You could probably contact Headroom and get them to build an amp with a little less gain, but why. The pot on the Cosmic goes probably 320 degrees or maybe more. I turn it a 1/4 turn for KSC 35's and on medium about 3/8 turn for HD600's. Then again, I keep the volume low, around 70db or close to.

Even on medium with KSC35's, I can't HEAR any problems with balance.

Can't hear any problems with the new TAH either.

 

[Joe Bloggs]

sorry guys

as a matter of interest... say you crank the volume to full on low gain--what pot position would this be equivalent to on medium gain? Ditto for changing from medium to high gain

 

[gaineso]

Joe,

My KSC35's work extremely well on LOW gain on the Cosmic. My HD600's will go a HELL OF A LOT LOUDER than I intend to listen on LOW gain on the Cosmic. I generally run the 600's on MEDIUM, because I like to use the volume control in it's lower half.

BTW, my home sources are fairly "HOT". Fairly high voltage output. Haven't tried it with portables.

Just get one and if you don't like it send it back. Ypu're right there in Joe Lau territory. Get him to build something custom.

 

[Joe Bloggs]

You like to use the volume control in the lower half huh?

May I ask why?

 

[JMT]

Why not just go with a stepped attenuator?

 

[tangent]

If you want multiple gain settings, any of the DIY amps will allow this, and any of the DBSE'ers (DIY By Someone Else) will be able to set this up for you. It would just require a 3PDT switch plus the extra resistors and bit of hookup wiring. Those switches are common among DIYers, since they're used for the Meier crossfeed on the Hansen board.

This does sound like a resonable way to attack your mistracking problem; you can pick the combination of gain and volume setting that work best for you. Personally I've never had a major problem with this, but hey, if it's what you want, there are ways to get it.

You could even hack up your PortaCorda to get the same effect, for what that's worth...

 

[Joe Bloggs]

Wow, where would I put the switch?

 

[tangent]

You'd know better than I, but I'd try for one of the sides. A DPDT mini toggle is about 0.5" square.