Thievin' Heathen
337 posts
Jul 19, 2014
9:49 PM
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I am pretty damn happy. I just finished up with my Weber 5F6A kit. A couple of minor setbacks. 1 of the 500V caps failed with a "pop" the 1st time I powered it up and then sizzled a resistor, so I had to go through a bunch of wire tracing and re-tracing, but then decided it was right and had to try again with another cap. It worked. Also, I had the Pwr. transformer wires backwards (schematic gave me a 50/50 chance) so there was a hum and a whistling in the presence circuit, but switched them around and now it's quiet as a mouse. Having an EE in the house was a big help.
I have an AT7 in V1, 5751 in V2 and, since I have a surplus of guitar amp tubes and a shortage of harp amp tubes, I had to leave the AX7 in V3. I can turn it up to 5 in my little shed here before I start to get the hint of oncoming feedback. I am using the SS rectifier it came with, but maybe I will experiment with a GZ34 sometime later.
Did I say I am pretty damn happy?
Last Edited by Thievin' Heathen on Jul 19, 2014 9:51 PM
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Barley Nectar
440 posts
Jul 20, 2014
10:56 AM
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Well, congratulations on the build. Weber has had trouble with caps in the past. I would like to try a build on their SS chassis. Rust on chassis bums me out. I doubt you will hear a difference with the GZ34. They are very efficient tubes and the voltage difference will be minimal. What speakers did you use?
If you want to antique it, see " Goose's Custom Shop Bassman" thread on page 3. Good Job Theivin ...BN
Last Edited by Barley Nectar on Jul 20, 2014 11:05 AM
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Thievin' Heathen
339 posts
Jul 20, 2014
1:00 PM
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At their advice, I went with the 10A-125-0 Vintage Series with H dust caps.
Paying homage to my childhood friends, and not wanting to have to answer a bunch of "is that a real Bassman?" questions, I went with snakeskin. Looks like water moccasin. Antiquing not necessary.
Last Edited by Thievin' Heathen on Jul 20, 2014 1:14 PM
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walterharp
1465 posts
Jul 20, 2014
7:38 PM
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Congrats. I did the same thing 5 years or so back and have been very happy. Did you go totally with what they put in or use some of the Mark Burness suggested mods?
you probably have a better amp than the current production bassmans... hand wired point to point, as long as you did a good job with the soldering, should last as long as you do.
i think the trouble with the caps was that some Chinese company put puny little things in the barrel caps. suspect that problem has been solved.
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Thievin' Heathen
340 posts
Jul 20, 2014
9:22 PM
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Everything I read advised building it by the schematic and making incremental modifications while carefully documenting the changes as you go along. I guess the philosophy is geared towards being able to backtrack to a known good condition. I was tempted to include all the harp mods but being my first build, I uncharacteristically stuck to the instructions. Too much money and potential heartache & frustration on the line. I was also being assisted by my 21 yr. old son who just finished his EE degree and I was having some difficulty enlisting his participation working on 70 yr. old electronic technology. Modifiying the antique technology was a hard sell. He wanted to design a PCB and outsource it to China.
I'm pretty certain I don't have any cold solder joints, but there are several I wish were prettier. I also wish the wiring layout was a little tidier. I will alter the assembly sequence a little bit if I build another one. Maybe I will make tidying things up a winter project and put some good caps in it.
Last Edited by Thievin' Heathen on Jul 20, 2014 9:23 PM
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HawkeyeKane
2570 posts
Jul 21, 2014
8:51 AM
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Heathen...was that you on the facebook Tube Guitar Amp Builders group asking about 5F6A kits last month?
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Hawkeye Kane - Hipbone Sam
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walterharp
1467 posts
Jul 21, 2014
9:59 AM
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that is where you are ahead of the game, most of the mods are easy once you have it down and have it all on the board, just replacing a resistor, clipping a cap or something.
I believe that Weber solved their cap issues and you probably would not gain much by replacing those.
More to be had figuring out the best tubes and how to bias them. I would say adjustable bias is probably the most important mod, and it allows you to dial in tone more than most any other, that and tube swaps and finding ones you like the sounds of,
mark might chime in here
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Thievin' Heathen
341 posts
Jul 21, 2014
8:23 PM
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No that wasn't me on facebook. The variable resistor on the bias circuit was the 1 mod I did include. I need to research biasing. I have to confess, it's in the plug & play mode right now. I have looked at some pin voltages but not measured any currents.
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