Bottlehead Forum
Bottlehead Kits => Kaiju Stereo 300B amp => Topic started by: Alonzo on May 14, 2019, 06:31:34 PM
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Thank you PB for a great build. It would've taken me a month of good days to get this done. Got 5 (5.1 and 5.7 mv) for hum. I will listen for awhile to see if the DC filaments are needed. Now realize I must retire some amps to the garage. Well, it's time I simplified my setup.
Now for burn in and speaker selection and tube swapping...
Alonzo
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I'm glad it made it safely! How did that expanding foam cradle work out?
I got pretty lucky with all those big caps, there's only about 1/16" of clearance left between the lowest hanging caps and the counter top.
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The expanding foam is a good idea, kept everything stable (along with the metric butt-ton of packing peanuts). I see what you mean by the chicken head knobs, I replaced them with the larger set but they still sit too high, will change to black knurled knobs.
I got a pair of GE 5 star 5670's, should I check the driver voltage (175v) at each tube swap?
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Pretty cool.
It looks like the plate chokes are mounted on standoffs - assuming this is the case, is this for ease of wire routing, or does it serve some other/additional purpose (e.g., additional distance from the OTs above)?
Thanks,
Derek
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If the driver plate voltage is off by a few volts, it isn't going to be particularly audible. If you plan to roll a lot of driver tubes, you could just set each cathode at about 4.2V and not worry about it till you have the pair you like.
The chokes are mounted on standoffs because the output transformers have been changed from our OT-5 to a pair of TFA-2004. In order to keep each TFA-2004 centered on each 300B, the transformer leads needed to pass right through the space now occupied by the plate choke, so I spaced them up off the chassis.
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What is the benefit of the TFA-2004 output transformer?
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What is the benefit of the TFA-2004 output transformer?
That particular pair is a one-off TFA-2004 with four different lamination materials and silver wire on the secondary. It's a different flavor.
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The Magnequest "Mexico"?
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Yep,
I was luckily going back and forth with Mike when these came out and ordered 2 of the three, I should've gotten them all. The other pair is in a Stereomour II.
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Sweet. The lamination pattern looks cool - imagine they sound very nice. I really like the brass end bells - did you keep the brass look for the SII? I'd love to know where Mike gets those.
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Mike paid a crap ton many, many years ago to have them custom made.
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The brass bells were painted for the Kaiju, the other pair is a basic black.
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What's the reason for 3 binding posts per side?
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Convenience, connection for 8 or 16 ohms.