Other Amps

1954 Fender Tweed Twin

1

Working on my buddy’s Tweed Twin this morning. Early version, cathode biased, octal preamp. A little dirty, but pretty much original circuit.

2

Still has all but one of the original Astrons.

5

Offset speakers like the kool 2-10 tweed Super

6

SWEET!! I bet those octal preamp tubes rattle when you crank it up! I've got silicone rings on my 50 Deluxe.

7

All of the tube sockets, including the power and rectifier tubes are mounted using rubber o-rings. Still pretty pliable.

8

These are so fantastic. I’m so lucky to have a low powered twin . Is that an original cabinet?Looks super clean.

9

when you say a little dirty what are you talking about haha

10

Afraid not. My buddy came into the chassis only, no cabinet. I made this cab a few years ago for him. I think the originals came with Jensen P12Q’s. I put a mid-60’s C12N and P12N into this one for a little more headroom. The amp is cathode biased and puts out around 25 watts, so there’s plenty of crunch at the top.

11

when you say a little dirty what are you talking about haha

– powerjet

I mean filthy. I spent about an hour with a brush, q-tip and compressed air the first time I worked on it.

And a dust mask.

12

I mean filthy. I spent about an hour with a brush, q-tip and compressed air the first time I worked on it.

And a dust mask.

– Powdog

Yes! The asbestos heat shielding is always flaking off in thes old amps. Nice cabinet work as usual!

13

I had a Celestion Gold and a early 70s greenback in mine . I found a well broken in pair of Weber alnicos which are currently residing in the amp. Not sure which I prefer. They both have their merits.

14

The amp is cathode biased and puts out around 25 watts, so there’s plenty of crunch at the top.

I've yet to find the tweed amp that has the right amount of headroom for me. The biggest I've built was a Bandmaster, and it wasn't quite enough. It might be time to try a low powered Twin.

15

Magnificent. This is a dream amp for me.

16

The amp is cathode biased and puts out around 25 watts, so there’s plenty of crunch at the top.

I've yet to find the tweed amp that has the right amount of headroom for me. The biggest I've built was a Bandmaster, and it wasn't quite enough. It might be time to try a low powered Twin.

– Afire

I built a 5E7 Bandmaster in a 2x10 configuration. No one liked it cause it was “too clean”. Ended up giving it to Dave Creamer. Right up his alley.

17

Well.....this amp is nothing short of amazing. Bright and chimey with tons of headroom.

The owner was getting shocked when he played thru this. Wanted a grounded plug. It was still a little noisy. A lot of old Fenders that use a two prong power cord return the filament voltage thru the floating chassis. So I ran parallel filament wires, lifting them from the chassis, and then installed a grounded power cord so the chassis is grounded to earth.

18

Dang, I wish this were mine!

19

Any sharp eyes may have noticed that the socket wiring for the 6J5 gain stage between the Volume controls and Tone stack isn’t right. Another variant that doesn’t show up on schematics.......so Fender! It’s another 6SC7.

20

Parting shot. My older brother giving the Twin a run thru.

21

Yes! The asbestos heat shielding is always flaking off in thes old amps. Nice cabinet work as usual!

– GaryE

If the asbestos is already flaking off I would quickly start running if you care for your health. This stuff is highly dangerous if already a small amount of fibers is released into the air.

I am currently renovating a house and I had some materials tested before getting started. Here is a link from the Telecaster forum on that topic Link

22

A somewhat similar vintage amp (cathode biased, 2x12, 25 watts) is the Magnatone 260. You can snap them up for a lot less than 4K today. Typically around 1K. They also have a great vibrato built in.

23

It's good to find some tech buddies here. I have a 1980 Fender 75 Watt combo tube amp with a 15"speaker. I bought it from the original owner, in 1983, after beer had been spilled into the power tubes (6L6GC). One of the tube sockets and biasing resistor burned up, so did the filaments in every tube. It burned out the on/off switch, the High/Low power switch, the master volume pot and the speaker coil. I put it all back together with new tubes, and replaced the burned out components. It was a bit costly, but far less expensive than buying a new amplifier. It's worked fine all these years until one of the 6L6GC tubes lost vacuum about a month ago. I installed a matched pair last week, and much to my dismay, heard a loud hum riding on the audio signal. One of the 6L6GC tubes is getting way hotter than the other, I'm not sure exactly what happened but it's probably time to re-cap the set.

24

Which amp do you have? Some have the standard adjustable fixed bias circuit, but a lot of the Bassmans have a bias balance circuit.

25

Mine is a Fender 75 Watt Lead Combo Amp 15" speaker. It has a "Hum Balance" pot on the back of the amp, unfortunately this doesn't make much difference in the hum I'm getting. I'm getting a major hum, like a bad capacitor hum. This isn't a Bassman amp, it's a guitar amp with a footswitch actuated Lead Channel. It has a master volume pot a volume pot and a Lead volume pot. I stack it on a Fender 4x12" cabinet, it has a 1/4" Ext Cab jack on the back and a high power switch to be used when using jacked to the cabinet. I got a schematic in an email from Fender today, I've misplaced my paper copy. I'm not sure yet why one of the 6L6GC tubes is getting so hot. I'll put it on the bench this weekend. I'm fortunate that my Common Basic Electronics Training, in 1978 was heavy into tube theory, but that was a long time ago, some of the nuances have faded in my memory.


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