Well, this one left us speechless.
On July 18, 2025, Guitar Pedal X published an in-depth hands-on feature of the Mosferatwo — and called it “the most beautifully balanced Original Harmonic Overdrive Circuit” they’ve tried.
A Conversation Turned Highlight
This review came after a long (and honestly inspiring) video call with Stefan Karlsson, the mind behind GPX. We talked tone, circuits, branding, and that weird little hippo origin story. Stefan asked where the name RhPf came from — and got the full scoop on our “Rheinpferd” roots.
But what matters most: he got the pedal.
From the very first paragraph, it was clear Stefan understood what makes the Mosferatwo tick — the harmonic bloom, the touch-sensitivity, the EQ logic, the control sweep, the MOSFET gain structure. He called out the sound, the design, even the hippo — and suggested we lean into it more.
“Effortless… Predictable… Harmonic… Expressive”
Here’s what Stefan said:
“It hit pretty instantly for me — which is always good news. Some pedals really make you work for it — this one is effortless.
You can so precisely shape its output — also with your guitar controls — for some really decent volume gain cleanup.
The pedal responds beautifully to your pick attack — you get a cool blooming of the overdrive when you dig in.”
He even detailed his favorite settings for each control, from Focus and Drive to Heart and Bite — backing up what we hoped all along: the Mosferatwo doesn’t just sound good, it feels good.
Bonus Points for the Nerd Lab
To top it off, he gave a full shoutout to the RhPf Nerd Lab, including both the interactive frequency plots and the diode curve visualizer — calling it:
“An essential resource for electronics engineers and pedal builders.”
We didn’t expect that. But we’re seriously grateful.
Why This Means the World
Guitar Pedal X is one of the most respected boutique pedal platforms out there. And Stefan doesn’t just review pedals — he understands them. For someone that thoughtful, experienced, and critical to call the Mosferatwo a “must-buy”… let’s just say, it lit a fire under us.
It’s one thing to build something from scratch. It’s another to see it resonate.
We can’t thank Stefan enough — for the kind words, the conversation, and the spotlight.
And to everyone who’s played, shared, or supported our pedals — this moment’s for you too.