London Power Scaling - DIY Monarch

[CanadianDave]

Yo,

After finishing my DIY Benson Monarch, the only real issue was how loud the amp was. I was using a Weber attenuator but wasn’t happy with it. I rolled the dice on installing a power scaling unit from London Power.

The “Could be Better”
- The PCB layout. Maybe personal preference, but I’m too accustomed to PedalPCB layouts and PCBs with contrast and clear labeling. I also understand that it’s designed for a small footprint, but I found it cramped.
- breakout boards on the pots. I found these to be a pain and unnecessary. They made wire twisting more difficult (that’s why the dual gang pot has that rats nest).

The Good
- Customer Service. I emailed London Power with my schematic and layout. When they shipped the kit, it included hand written diagrams and notes specifically for my amp. They also suggested bleeder resistors, and included them at no extra charge.
- the noise level. My DIY amp is still quieter and has less noise than my production amp.
- The drive control. There are two controls (which are now hidden on the bottom of the chassis.) One controls output, while the “drive compensation” is more like a “headroom control.” I have the amp dialed in where it doesn’t get louder after 4 on the volume, but just adds dirt from 5-10. Depending on pickup output and personal preference, I have that control now.
- Cost. It cost about the same as a mediocre attenuator, but much better performance.
- the sound. Time to sell the attenuator. I’m sure there’s a loss in tone, but I certainly can’t hear it, and it’s way better than any attenuator. No mud, no darkness, and at low volume it sounds outstanding. The dynamic range and touch sensitivity is challenging me to play better.


As it stands, I’m a little frustrated that the build isn’t as clean as it was. I think about going back in and cleaning it up, but it’s fully functional, low noise, and I’m super happy. If I need to test a pedal at 2am and not wake anyone up, I can do that.

 

[lowpitch]

This is still very clean looking. Nice work!

 

[Zanshin]

Awesome you found a solution that works for you. Is there a schematic somewhere? I don’t understand what it’s doing.

I agree with @lowpitch .

 

[jwin615]

Just read up on their website on this tech. Kinda non-descript on the technical side but seems interesting. Seems it starvws the screen and plate voltages to decrease output while keeping the ratio between them constant?
What's the I put jack inside the chassis? Seems like it could shift around and short something.

 

[ThatDude]

Good sir, awesome stuff as always. Does the power scaling unit lower the available output volume permanently in anyway, or with the two output controls all the way open do you still get the full volume you would without the power scaling unit in place? Comparing the tone between the Weber mini mass and the London power scaling unit for attenuation, is it a noticeable difference?

 

[CanadianDave]

Good sir, awesome stuff as always. Does the power scaling unit lower the available output volume permanently in anyway, or with the two output controls all the way open do you still get the full volume you would without the power scaling unit in place? Comparing the tone between the Weber mini mass and the London power scaling unit for attenuation, is it a noticeable difference?

Compared to the Weber mini mass, it is a huge difference. With the mini mass, there was less usable range and the sweep of attenuation meant that it was hard to get it where I wanted it.

The Weber also darkened the tone a lot. Even with the treble booster in the Weber, the EQ felt way off. I would compare it to turning down the tone control on my guitar and then trying to compensate with an EQ pedal.

Currently, the volume I’m getting out of this thing is comparable, or less than, a 5 watt amp. At that setting, it feels plenty bright enough and any change to the tone is slight if any.

As for the volume being permanently effected, there may be a slight difference if the power scaling is wide open, but it’s difficult to tell. I almost never had that amp wide open without attenuation.

 

[ThatDude]

Compared to the Weber mini mass, it is a huge difference. With the mini mass, there was less usable range and the sweep of attenuation meant that it was hard to get it where I wanted it.

The Weber also darkened the tone a lot. Even with the treble booster in the Weber, the EQ felt way off. I would compare it to turning down the tone control on my guitar and then trying to compensate with an EQ pedal.

Currently, the volume I’m getting out of this thing is comparable, or less than, a 5 watt amp. At that setting, it feels plenty bright enough and any change to the tone is slight if any.

As for the volume being permanently effected, there may be a slight difference if the power scaling is wide open, but it’s difficult to tell. I almost never had that amp wide open without attenuation.

You’re like the neighbor who gets awesome new things like a car and a boat. Now I am over here looking at my 5 year old car thinking I should trade it in and maybe I could become a boat guy myself. Lol I am joking, but seriously, your projects are so interesting to me.