Let me say right up front that I think Brian Purdy at Harpgear makes excellent harp amps. For years I have recommended to my students and others that they buy the Harpgear HG2, a 5-watt tweed Champ clone with outstanding tone and build quality.
I’d heard and played the HG35 amp on several occasions, and at a blues jam last night I had the opportunity to play both it and my Mission Chicago amp and do a close comparison.
The two amps are similar: The HG35 claims 35 watts of power, while the Mission amp claims 32. They are both built in tweed cabinets of roughly the same size, with the Harpgear amp using two 10-inch speakers and the Mission amp using a single 12-inch speaker.
The basic circuits are similar, with twin 6L6 tubes providing the power in each amp. These tubes are cathode biased in the Harpgear amp, and that presents one of the biggest contrasts between the two: The Mission amp is switchable from cathode bias to fixed bias, and I prefer to play it in the fixed bias mode.
I have been curious about the Harpgear HG35 for this reason: Claiming 35 watts from a cathode biased 2x6L6 amp is unusual. Using the standard method of measuring output wattage, it is tough to get more than about 25 watts from this configuration in a harp amp.
This difference was evident last night when I played the two amps on stage at a blues jam. The 32-watt Mission amp is substantially louder than the 35-watt Harpgear HG35. In fact, the Mission amp has a remarkably fuller tone at half volume than the Harpgear has at three quarters volume.
Both amps produce good tone, but the Mission amp produces a bigger tone with noticeably more crunch and bottom end. I switched back to the Mission amp because I was concerned I would not be heard in the loud jam setting.
The Harpgear amp has a cleaner sound, and I am sure that is a feature that Brian designed into the amp. His amps are known for this. The amp sounded brighter and more directional. It was a bit more prone to feedback.
When I switched the Mission amp to cathode biased mode its volume dropped to a level similar to the Harpgear amp, but the tone retained more of a vintage-style warmth. Overall, the Mission amp breaks up more readily than the Harpgear amp.
For those who prefer a cleaner tone and always play in situations with low-to-moderate stage volume, the Harpgear HG35 could be a good choice. For players looking for a bigger crunchier tone, the Mission Chicago 32-20 amp might be a better choice.