1967 "Fender" Double Bassmaster Custom Amp

[Synchu]

Looks in great condition despite the age. Sure it'll get even better.
Niki

[xtian]

Thx, Niki!

Hey, the bypass caps are "DUCATI" brand! Vroom!

[xtian]

Finished with the tune up. I replaced all electrolytics. You'll notice my custom reservoir cap made from eight 22uF Panasonic radial caps and a bit of strip board, making a 44uF/900v reservoir.

Also, I installed each node's filter caps nearer the plate resistors--see the radial caps between the pots and circuit board. Radials can be cool!

My observation about the OT secondaries was correct. Now that I'm using the right tap against the right load, I'm getting 72 watts, even with the 6P6S tubes that Steve warned were not equivalent to 6L6GC, and even biased cool, at about 40-50%.

Sounds great!

[Stevem]

Don't know if the speakers are original, but the 67 is the CTS manufacturer code, and the 7451 is the 51st week of 1974!
Those drivers are 2 steps down from what would have come in a real Fender, in fact I have only seen those square size magnet CTS drivers used in old console type home stereo's!

[Phil_S]

67 = Eminence. 7451 is 51st week of 1974.
Nice cab. Good catch on the wiring. Makes you wonder...
Steve, your hands must be going faster than your brain! I am sure you know 137 is CTS!

[vibratoking]

I have speakers with similar magnets and frames. Eminence 12" that came in a 65 Super Reverb that had been baffle hacked. Mine sound like ass. I removed them a long time ago. Still sitting on a shelf gathering dust. I should toss them. I hope yours sound better.

[xtian]

Thx guys. Yes, this cabinet sounds killer!

[tubeswell]

Might pay to replace those IC bias supply caps with something more reliable.

[Stevem]

Sorry, yes there Eminence!
Eminence speakers would have never had come stock in any 1965 amp as the person who started Eminence left CTS in 1969 to start Eminence!!!!

[xtian]

Might pay to replace those IC bias supply caps with something more reliable.

I thought paranoia about Illinois caps went out of style. I've been using new Illinois caps from cedist.com with no issues since I started building.

[tubeswell]

Might pay to replace those IC bias supply caps with something more reliable.

I thought paranoia about Illinois caps went out of style. I've been using new Illinois caps from cedist.com with no issues since I started building.

YMMV

[mhartman]

I've used a ton of Illinois caps over the last few years. I've had a better success rate than I've had with sprague atoms.

[Phil_S]

I remember a post from years ago at another forum. Someone very experienced ran a bunch of tests on IC, Atom, and some generic caps. IC came out on top and this was received as a bit of a surprise. I wish I could remember the particulars. Maybe it will come to me and I'll amend my post.

Found it: https://groups.google.com/forum/#!searc ... rC7tzuv8MJ
Look for Mike Schway 10/27/06

Memory of this post was not exactly right, but still on point.

[Stevem]

I have never seen as many young IC brand caps fail as I have in Fenders made in the last 15 years!
Seing as some folks love them and have had no issues with them, that leaves me to assume that when IC makes a big production run for Fender they cut the quality in some way, or maybe it's just that Fender runs them cranked up too close to there voltage rating?

[pompeiisneaks]

I have never seen as many young IC brand caps fail as I have in Fenders made in the last 15 years!
Seing as some folks love them and have had no issues with them, that leaves me to assume that when IC makes a big production run for Fender they cut the quality in some way, or maybe it's just that Fender runs them cranked up too close to there voltage rating?

I don't recall where, (maybe a FB group) I read that there was a particular batch of bad caps that IC ran and basically fender bought all of them in their mass purchasing, and just had the bad luck of getting that batch. Many people have said that it was a big blip on an otherwise solid reputation. I've used them in a few builds with no adverse problems, but my builds are all about a year old, so haven't had time to see issues. I'm more of a fan of JJ anyway, fits in the middle on price between the IC and Sprague cost and quality is solid.