NFB values are a little different, the Gibson has more NFB?
You can't just look at resistor values, you have to look at the speaker load.
As DL said, less NFB might be what you'd think, cause the series feedback resistor is bigger, resulting in less feedback voltage with the same signal at the speaker.
But the Gibby circuit is using an 8Ω load and the Fender has 4Ω. Assuming same output power, there's less voltage across the Fender speaker load. 35w output across 8Ω implies 16.7vRMS, and 11.8vRMS across 4Ω.
Gibson used double the series resistance, and you might think that's because the speaker impedance is doubled. But I just showed the resulting voltage at the speaker isn't double (it's x 1.414), so the feedback divider in the Gibson will result in less NFB than Fender's circuit.
PP 5881/6L6GB with grid bias, 417dcv on the plates/screen. Looks like plenty of small bottle signal to put out more wattage? Schemo says -45dcv for bias, on the cold side?
It sounds cold compared to the 5E8 Twin with 395v plate, 385v screen and -32v bias. It doesn't sound cold compared to the 5F8A Twin with 395v plate and screen and -41v bias.
I'll tell you the Standel I built is so clean due to the 12AX7->12AT7->12AU7 (and probably the JBL) that I now hear how fuzzy Fender clean really is.
Now that's funny. New zero line. (One mans ceiling is another mans floor.)
If Dave Funk was more willing to schmooze guitar mag reviewers who made technically-incorrect statements in their reviews, Thunderfunk amps might be a widely-available and sought-after boutique brand today. He
did after all build some of the Trainwreck amps to Fischer's specs when Ken was too ill to build them himself (and they're still legit Trainwreck amps).
I had Dave work on one of my amps when I and he lived in Nashville, and when I was first trying to learn anything about tube amps. Thunderfunk amps were used by some of the heavyweight session and touring guys there. Mid-late 90's country had plenty of places with ultra-clean guitar parts, and the amps were prized for maintaining clarity and cut even at high volumes (though they could get distortion tones too).
But when Dave's amp was reviewed in one of the mags, the writer seemed to want what other boutique makers were doing then, which was cloning tweed Fender amps (blackface amps weren't ridiculously expensive like they are now). The writer said, "the clean sounds are Fendery-enough" but pretty much only had something positive to say about the reverb sound (the "12 Spring" reverb) which was acknowledged as vastly superior to other amps.
Well, Dave's articles in Vintage Guitar at the time often ripped on the inaccuracies of their other columnist, Gerald Weber, as he also did in his book (although in a veiled way). Dave wrote in a letter the following issue that said the statement about the cleans being 'Fendery enough' "... proves you're not qualified to do listening tests."
Anyway, his amps could do clear and clean even with complex chords, in the same way some pedal steel sounds are incredibly clean. It seems informative to point out the Standel 25L15 was probably first intended as a steel amp (that's who Chet bought his Standel from, a steel player).
Anyway, it seems like Dave just wasn't into selling people on an idea or hype. He was more into the technical side and removing mystery, and wasn't afraid to call people on their B.S. It's unfortunate, but it seems his distaste for marketing prevented technically superior amps from becoming sought-after.
That said, "fuzzy clean" is a sound I fell in love with in my first tube amp (a '67 Princeton Reverb), and set it apart from a good solid state amp.
Sorry for the thread hijack.
Topic: Thinking of building Gibson GA77 (Read 46933 times)