Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: crashtm1 on September 03, 2017, 04:38:42 pm

Title: H&K Rotosphere
Post by: crashtm1 on September 03, 2017, 04:38:42 pm

Definitely not an amp question..😉
  I've done a google search with no luck.
I'm wanting to have my Rotosphere gone through.
Cleaned and brought to spec. I've had it for 12 years
and don't plan on parting with it anytime soon.


   I need some recommendations for a good tech to take on the task.




THANKS..✌🏻✌🏻✌🏻

Title: Re: H&K Rotosphere
Post by: drgonzonm on September 03, 2017, 05:21:48 pm

Had no idea that this was an SS Leslie replacement,

I make a bet it is moved to effects.  (Actually a request, when completed, I will remove this post, thanks). 

These might be schematics for the effect

from this website, I able to find schematics,  http://www.diystompboxes.com/smfforum/index.php?topic=101190.0 (http://www.diystompboxes.com/smfforum/index.php?topic=101190.0)

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=48630&g2_GALLERYSID=3bef53a3853c15ba5cc071f2421f1d70 (http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=48630&g2_GALLERYSID=3bef53a3853c15ba5cc071f2421f1d70)
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=48627&g2_GALLERYSID=3bef53a3853c15ba5cc071f2421f1d70 (http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=48627&g2_GALLERYSID=3bef53a3853c15ba5cc071f2421f1d70)

These are bmp files, huge. I tried to import the drawings into my cad program with no luck.  I was however able to print as pdf's 

Title: Re: H&K Rotosphere
Post by: drgonzonm on September 03, 2017, 05:44:24 pm

whats wrong with the pedal? 

Title: Re: H&K Rotosphere
Post by: crashtm1 on September 06, 2017, 08:25:05 pm

It's been sitting for about 2 years. It has some noise. I know this was a fairly common problem, but would still like to have it gone through and checked. It could probably use a new tube too.

Title: Re: H&K Rotosphere
Post by: silverfox on September 08, 2017, 12:26:36 am

Not sure what year this is. I'm guessing late 80's, perhaps early 90's. It would be interesting to see who could actually fix something like this anymore short of mechanically related problems. There used to be lots of techs that would sit at a bench somewhere and fix stuff like this all day.

The noise may be solved by replacing the Op Amps with newer low noise versions.

silverfox.