silvertone 1484 reverb pan repair notes:

[solderhead]

I apologize, but this will be a little long-winded.

It's impressive what a big difference there is in the physical size between the iron for a 50W Bassman and the iron for the 35-40W guitar amps -- the 35-40W amps have iron that is impressively smaller than the 50W amps.

I have one of those 40W guitar amps (a Bassman Ten) which was actually advertised as a 50W Bassman combo while the reality is that it's electrical performance is nowhere near the performance levels of a true 50W bass amp. Telltale signs are the PT and OT that are much smaller in size. The PT is an 022798 (late numbering scheme as the Bassman 10 didn't exist in the BF era). It is listed as a cross reference for the 125P5D which was used in the Bandmaster Reverb, Pro / Pro Reverb, Super / Super Reverb and Vibroverb. Those were all 40W guitar amps not 50W bass amps. Their PT are notably smaller than what you'd find in a real 50W BF/SF Bassman head. It may not be obvious why the difference in iron is so huge between a 35-40W guitar amp and a 50W bass amp, that is until you start comparing the iron requirements that are necessary to produce extended LF response on a bass amp. That extra LF and the extra 10W add up to a bigger PT b/c the amount of energy required to reproduce a sine wave is equal to the area underneath the curve, and that amount of energy gets a lot bigger at low frequencies. If you're making a guitar amp, cutting off that LF content below 80 Hz allows you to make the iron a lot smaller.

The same holds true for the OT -- when you're not trying to make LF response that's needed for the bass amp, and you've got a 40W spec instead of a 50W spec, the OT gets a LOT smaller. As testament to this, the 40W guitar amps have OTs that are a lot smaller than the 50W Bassman heads... with the exception that the Bassman 10, which was actually sold as a 50W Bassman, only carries the transformer set of the 40W-capable guitar amps. The dirty little secret that the Bassman 10 was really designed around 40W guitar amp iron instead of 50W bass amp iron helps to explain why it's not as highly revered as the the true 50W Bassman heads.

But an interesting little quirk about the B-10 is that it used a 4x10 speaker array where the speakers were 32R each, for a net impedance of 8 ohms. The B-10 carried a similarly sized OT as a Super Reverb, but the B-10 OT was rated for 8R instead of the SR OT that was rated at 2R. All of this is sort of a roundabout way of stating that if you need to replace the OT of a 1484, and you plan to use a single modern 8R speaker that can handle all of it's power, then you might find the B-10 OT useful if you can't find a genuine 1484 OT and you don't want to fight to squeeze a 4R 50W Bassman OT in the 1484's cramped chassis.

I don't have the B-10 apart right now, but my recollection is that the B-10 OT is a bit bigger than my original 1484 OT or my Mojo/Heyboer 1484 OT. That could be attributable to the fact that the 1484 is what I would call a 30W guitar amp and not the 60W guitar amp that Silvertone claimed it to be. It can afford to be smaller than the 40W iron referenced above b/c a 30W amp doesn't need it's OT to be as heavy as a 40W amp's OT.

I really wish we had the Fender OT measurements to work with. I honestly believe that the 1484 OT is meaningfully smaller than the series of OTs used in the Fender 40W amps, but then I could be wrong about that. An any rate, we have the 1484 measurements in Post # 166 as a reference. Hopefully somebody can come up with the Fender 40W OT dimensions to see if they'll make a good OT substitute for the 1484.

Oh -- I see that I'm taking us off on a tangent from the reverb pan topic of this thread. sorry about that.