I was doing a comparison of a few old SS amps (use for practice mainly but work for small gig/party situations, too) and I noticed something that kinda surprised me. I had a Fender Frontman 25R & 65R side by side. For guitars, I used a Fender Standard AmSe Strat (2004), a Gibson LP Studio (2003), and a Gretsch Pro Jet (2015). My choice of guitars was mainly for comparing the amps with the different pickups of choice (Single vs HB vs FilterTron) The 65R (quite loud, BTW) was actually great on the clean channel with all my guitars. (Don't care about distortion channel... don't use it!) On the other hand, the clean sound with the smaller 25R was real good with the Strat & LP, but it didn't like the Gretsch (FilterTron PUs) as it was noticeably distorted. Thinking the 25R had a problem, I actually got a 2nd 25R and the same thing happened! OK.... it's possible the speakers in the 25R may be sub-standard so I disconnected the 10" speaker and connected it to the 12" in the 65R for comparison... same problem so it seems to be nothing related to a speaker difference. Would it be caused by a difference in input sensitivity between the two amps (25R vs 65R)? The only other thing of significance (maybe?) is that the FilterTron PUs ohm out at aprox 4.6k & 4.7K vs my other guitars that measure out greater than 5.8k each on any of their pickups. Doubting the pickups are the issue, I'm thinking more like the input circuit of the 25R is significantly different. Is it something that can be fixed or changed? Sensitivity? Impedence? Thinking both 25R & 65R amps are the Frontman series, I would think the circuitry would have somewhat similar specs? (please, no SS amp sarcasm... just looking for a more technical explaination as to what's going on).