Dampp-Chaser threads

[atonal@planet.eon.net]

Bob Anderson wrote:

> To David Pitsch: In my experience, the Dampp-Chaser system is too small
> to control the humidity in an entire room. If you think the system can
> affect the action in a grand, how does that work? It seems that the
> conditioned air would either have to travel from under the rim into the
> air of the room and from there finally into the action. Or it would have
> to travel through the holes in the soundboard and through the gap beween
> the SB and the pinblock. 
> 
> In my experience, I've noticed tighter tuning pins in a vertical piano
> after adding a Dampp-Chaser system. I've never noticed any improvement
> in a grand. Can anyone else add testimony pro or con?

I've installed many vertical and grand Dampp-Chaser systems, and both 
systems promote tuning stability by keeping the soundboard stable. I 
have seen enough systems in operation, over a period of years, to 
know that they make a significant difference in this respect. 
	However, I have never seen any evidence that they work to keep the 
action  regulation consistent, or keep the pinblock solid. Last week 
I worked on a two-year old 5'8" Samick with a 50 watt 
full Dampp-Chaser that has been installed for a year, in a large, dry 
theatre. Prior to installing the Dampp-Chaser, the pitch would vary 
considerably, sometimes dropping as much as 25 cents.  The hammer 
line correspondingly dropped, and much regulation was needed to bring 
back aftertouch and hammer letoff. This time, the pitch was within a 
few cents flat - barely noticeable, but the regulation had dropped 
again! This has also happened in verticals that are relatively stable 
in pitch, but are still new and settling in in the regulation 
department. Tuning pin tension remains fairly stable ie: tight, but I 
don't attribute this to the Dampp-Chaser. I've worked with 
enough Dampp-Chasers to know this isn't one of their attributes. 


just my .02

Rob Kiddell, 
Registered Piano Technician, PTG
atonal@planet.eon.net