Ceriatone Forum

Ceriatone => Overtone => Topic started by: fm4 on October 16, 2008, 10:33:57 PM



Title: Overtone100 half power mod
Post by: fm4 on October 16, 2008, 10:33:57 PM
Dear All,

That's my first thread to the Forum! I just finished my Overtone100 and it eventually runs after some minor problems with the wiring.

I start getting on the nerves of my neighbors. Awesome tone!!! ;D  I have some hum though, so I intend to have a closer look at the heater cables (in my previous amp glueing the cables to the chassis did the trick). Nik already mentioned that shielding of the head shell would help as well.

But now for topic of this thread: I prepared a layout for the 1/2 power mod for the Overtone100 and I thought before tweaking the amp maybe one of the gurus here in the Forum could have a quick look on the attached pdf file.

Looking forward to getting some feedback.

Thanks and cheers,
fm4


Title: Re: Overtone100 half power mod
Post by: hywelg on October 17, 2008, 02:43:58 PM

Looking forward to getting some feedback.


Just turn it up some more then !!! LOL


Title: Re: Overtone100 half power mod
Post by: ic-racer on October 21, 2008, 09:15:54 PM
Thats some pretty funky wiring.

Basically the Dumble way was to use a switch to break the path to ground for one tube on each 'side' of the phase inverter. As a bonus if you hook a LED and resistor to two of the tubes that will shut them off and make the LED light at the same time.



Title: Re: Overtone100 half power mod
Post by: fm4 on October 22, 2008, 05:48:54 PM
Thats some pretty funky wiring.
Thanks ic-racer......I guess it means rather on "crappy" side  :-\ ....sorry, folks, my strenghts might be in other subjects ;) I took the wiring from the general Ceriatone mod site and adapted it to the Overtone100. At least it makes sense to me and I works as I tried it out. However, I left out the initial connection from the 3k3 resistor to the power tube. The amp with the 1/2 switch on has less headroom (obviously).

Basically the Dumble way was to use a switch to break the path to ground for one tube on each 'side' of the phase inverter. As a bonus if you hook a LED and resistor to two of the tubes that will shut them off and make the LED light at the same time.

I will try this mod if the gurus believe this is a better solution.

Thanks for some feedback.... ;D

Cheers,
fm4



Title: Re: Overtone100 half power mod
Post by: fm4 on October 24, 2008, 07:23:59 AM
Following ic-racers suggestion, I tried to adapt the Overtone100 layout with the #124 schematics for the 1/2 power switch (see attached file).

As I am new to the tweaking business and still in the learning stage, I am of course glad about any hints and tips.

Thanks,
fm4


Title: Re: Overtone100 half power mod
Post by: ic-racer on November 20, 2008, 10:15:16 PM
Looks good!


Title: Re: Overtone100 half power mod
Post by: fm4 on November 30, 2008, 02:40:47 PM
Thanks, ic-racer!

I have built it in and it works well. I am switching to 4 Ohm (Ohm in the 100W mode) when activating the 1/2 power mod.

fm4