For any of you that know me by my posts here, you know I have a ‘73 vibro champ that I love. Last week I was asking some questions about tubes I pulled from an old Lowrey organ. The tubes turned out to be RCA’s that were branded as Lowrey.

There were two 6V6GT’s: On the side they say:

Made in USA
61-22
274

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and three 12AX7A’s also marked:
Made in USA
61-22
274

Anyhow, just for fun, I decided to try them in my Vibro Champ. To do the test I first played the VC with the stock tubes (yes mine still has the original tubes) I played for about 30 minutes on my tele using all three pup swtich settings. I then let the amp cool a bit and changed the preamp and power amp tubes to the "new-old" Lowrey stamped RCA’s. Once again, I fired up the amp and played with the exact same amp settings. The tele was full up on both volume and tone for both sets of tubes. Now mind you, I thought the amp sounded pretty darn good before - but I was blown away by the difference! The RCA’s from the organ sounded incredible! I think the orignal tubes were also RCA’s but all the writing was rubbed off and all I can see is what looks like some where letters once were, the same color ink I see on other old RCA tubes.

The new tone from the amp sounded even more open and alive. More clean headroom and even sweeter tone. Since the old tubes still work fine, I put them on the side in my tube box along with my new "spares" from what was left over from the organ, one 6V6GT and two 12AX7A’s. Not only did I find my tone, but I have extras of the tubes that made it happen.

Fender made the blackface bassman amp between 1964-1967. The bassman was designed as a bass amp but very quickly became a favorite of many guitar players. I’ve read that the original Marshall amps were designed based on the Fender Bassman circuit. The Blackface bassman was designed as a piggy back setup with a seperate head and speaker cabinet. Fender used three different circuits in the bassman depending on the year it was made, they are the AA864, AA165 and AB165.

Specifications:
Control Panel: Black forward facing w/ white labels
Front Conrol Layout:Bass: In, In, Deep Sw, Vol, Treb, Bass - Normal: In, In, Bright Sw, Vol, Treb, Bass - Pilot Lamp
Rear Conrol Layout: AC Outlet, Ground Sw, Fuse (2A), Power Sw, Standby Sw, Speaker, Ex. Speaker
Knobs: Black skirted w/ chrome center, numbered 1 - 10
Head: 8" x 22¼" x 9" (20.3 x 56.5 x 22.9 cm)
Head Hardware: Black strap handle, 4½" chassis straps, corner protectors, cab hooks
Cabinet: 64-67: 21" x 32" x 11½" (53.3 x 81.3 x 29.2 cm) Late 67: 40" x 29½" x 11½" (101.6 x 74.9 x 29.2 cm)
Cab Hardware: 64-67: Black strap handle, 16" tilt-back legs, corner protectors, knurled studs, glides. Late 67: 3 black strap handles, corner protectors, knurled studs, casters
Head/Cab Covering: Black Tolex
Head/Cab Grille: Silver sparkle grille cloth
Logo: Grille mounted, raised, chrome & black, script "Fender" (head and cab)
Weight: Head: 30 lbs. (14.5 Kg) Cab: 52 lbs. (23.6 Kg)
Speakers/Load: 2 x 12"/4 ohms total (8 ohms each in parallel)
Speaker Model: Jensen C12N, Oxford 12T6 or Utah ceramic 12"
Effects: None
Output: 50 Watts
Preamp: Bass: 2 x 7025, Normal: 7025
Power: 2 x 6L6GC
Bias: Fixed Bias, adjustment pot (AA864) or balance pot (AB165)
Rectifier:
Phase Inverter: 12AT7 (long tailed)
Comments: Fender bassmans are well known for incredible guitar tones. They overdrive perfectly for rock and blues and original blackface bassmans command top dollar even in poor condition.

The Fender Bassman has been a long time favorite for guitar players as well as bass players. It was designed as a bass amp but very soon guitar players realized that it was an even better guitar amp. The ‘59 Bassman reissue is an incredible sounding amp, best suited for rock and blues. The Fender ‘50 Bassman reissue is a combo style tube amp.

Specifications:
Control Panel: Chrome top facing w/ white screened labels, controls numbered 1-12
Conrol Layout: Ground Sw, Fuse (3A), Power Sw, Standby Sw, Pilot Lamp, Presense, Mid, Bass, Treb, Vol Bright, Vol Normal, Bright Hi-Gain In, Bright Lo-Gain In, Normal Hi-Gain In, Normal Lo-Gain In
Knobs: Black pointer
Cabinet: Narrow panel style, 22½" x 23½" x 10½" (57.2 x 59.7 x 26.7 cm)
Cab Covering: Diagonal tweed
Cab Hardware: Brown plastic "Fender" handle, glides
Grille: brown grille cloth
Logo:Cabinet mounted, Script "Fender Bassman" on rectangular tag
Weight: 53 lbs. (24 Kg)
Speakers/Load: 4 x 10"/2 ohms (8 ohms each in parallel)
Speaker Model: Eminence AlNiCo
Effects: None
Output: 45 Watts
Preamp: 2 x 12AX7
Power: 2 x 6L6GC
Bias: Fixed bias
Rectifier: SS (see comments)
Phase Inverter: 12AX7 (long-tailed)
Comments: The solid state rectifier is fitted into an octal socket to allow easy replacement with a tube rectifier. (5U4 or GZ34/5AR4)