Harley Benton PA-100 - Make a Cheap Attenuator Sound Better - HB PA-100 Mod

[Byrdman]

I picked up a Harley Benton PA-100 a few months ago for $60 and figured what the hell. Unfortunately, it made all my amps sound like they had their balls cut off.

Searching around, I saw the suggestion over at the Marshall Forum, so I decided to try it out. This puts a 10uf Cap (Non-Polarized 100v) with a switch between the middle L-Pad solder tab and whatever Ohm output from your amp to allow the higher frequencies to pass through. I use 8 Ohm on all my cabs so here are the pics to do it that way. Camera phone video at the end so you can hear the difference.

Black wire from switch to middle L-Pad solder tab right under the resister

Red Switch Wire to 8 Ohm Speaker out - That yellow wire is going to the 8 Ohm speaker jack

10uf Non-Polarized 100v Cap Ziptied out of the way to keep from grounding on anything. (Don't worry I did clip that tail off)

Switch installed on the front of the unit

Sound Clip to hear the difference with SC20H. Sounds much better to me!

 

[Frankencat]

Cool mod. It probably helps at lower volumes where the high frequencies can sound muffled. I think I would experiment with different cap values to land on something I liked.

 

[Byrdman]

Cool mod. It probably helps at lower volumes where the high frequencies can sound muffled. I think I would experiment with different cap values to land on something I liked.

Thanks! It does sound better, but it's still a cheap attenuator and all. I just ordered all the parts to make a 50w JohnH and I'll make a thread here in DIY as I'm building. Everyone says these are the absolute best without dropping a huge amount of money for a Power Station type attenuator.

I'll probably have about $170 or so with shipping. Parts List:

 

[Dave Lewis]

I seem to remember a few YouTubers years ago saying those Harley Benton attenuators we’re dangerous
I bought a Passive Bugera power soak PS1 a couple of years ago and it’s been very handy around the place when my TwoNotes Torpedo Captor X is in use on another setup.

 

[Byrdman]

I seem to remember a few YouTubers years ago saying those Harley Benton attenuators we’re dangerous
I bought a Passive Bugera power soak PS1 a couple of years ago and it’s been very handy around the place when my TwoNotes Torpedo Captor X is in use on another setup.

I read that too, but mine's been working fine so far. They are based on the same schematic done by quite a few manufacturers including your Bugera PS1. Very similar on the inside to yours.

Not sure, but since it's a PA-100, maybe some thought it would be fine on a 100w amp and it's definitely not since it's only rated for around 50w. IME, with any passive attenuator, you should always measure the Ohms in and out to make sure it's working right (Plus RTFM)