The most common Premier Amp seems to be the Model 50. The earliest amp I've seen is a 1947 model and I have one dated 1965. The model changed over the years, so here are the pictures
1948
Premier Model 50.
I got these pictures off of Ebay.Original Rola 8" speaker, 285840. Tubes are
6SL7, 7C5, and 7Y4. The tubes are Automobile Radio tubes!

This Model 50 is just like one of mine. Notice that it assembled upside down from the way the 1948 was assembled.
Here's one off of
eBay that might be earlier than 1947. It uses a 7F7 tube, but the rest of the
tubes weren't listed.

I have three model
50's, all different. The oldest one is from the 1940's and has a low serial
number. I would guess that this is one of the earliest Premiers.
It also has the original amp cover. This is something that I've never seen anywhere
else!
Here's a Model 50
off of eBay (I cleaned up the images considerably). The gold woven grill cloth
is similar to a 1959 model that I saw. The 12AX7 tube visible in the chassis
shot pretty much precludes a 1940's model. I am guessing that this is a 1958-1961
model with replacement knobs. All premiers of this configuration had colored
knobs.



This is my Model 50
from the mid 1960's. It is square with the plastic letters.
Someone sketched out the Schematic
to the Model 50 above, but I have seen at least 5 configurations for
the amp. This combination uses a solid state power supply so it I guess it's
well into the sixties. pic I have one like this.
The 7591 tube provides as much or more power than the 6L6's in the earlier models.
The tubes are not easy to find at junk stores and flea markets, though.
My
best harp amp is a model 50 from the late 50's or early 60's. It has the 12AX7
tube and a 6V6 with a 5Y3 rectifier tube. This is the best sounding amp that
I have ever played through. It needs to be mic'ed through the PA. I am setting
up a rig so I can play through this amp with a mic from the speaker going to
my Blues Deluxe. This is way too much equipment, but at least I'll be heard.
The amp cost $35 at a garage sale. It has been partially repainted flesh tone
pink for some mysterious reason. The grill cloth was kicked in by a drunk, but
the speaker survived.