6G6B build done

[dcribbs1412]

Thank you Darin, here are the Koas:

http://www.mouser.com/ProductDetail/KOA ... 2bFWOGxedB

The 682 represents the value 6.8K for this specimen.

Also, I used FREDs, here:

http://www.mouser.com/ProductDetail/Vis ... lOJMUjHBOe

All the best!

Thanks for the info alvarezh...got some on order

I'm using the Speer/KOA SPR2CT.

TM

These are the small green ones right?

TM like to hear what you think of these resistors.
Have you used any in the signal path before

Darin

[ToneMerc]

Well, I've taken it as far as I can take it. I have every size strain relief but the one that fits this chassis. So, I pick up a strain relief and then drill a hole in the chassis for the mains ground and it will be ready for power.

TM

[Phil_S]

Horatio:
Actually, I generally twist a long length in the drill and then cut the sections to the proper length. I just never thought about knitting the sections together outside the amp and then putting them into the chassis. This is what happens when thinking inside the box! I will try this next time and thanks for explaining it.
Phil

[alvarezh]

@Mike
That was quick! I just plunked $50.00 for a strain relief plier, I love tools but $50.00! it better work on all sizes.

@Phil
I see nothing wrong with your procedure. Personally I don't like de look of the wire after untwisting it. It's a matter of taste. But for sure it's a lot less work and faster your way.

What confused me was the use of the word "plier", I thought you were twisting "in situ", now that's hard!

Good rest of the weekend gents.

[CHIP]

TM,
Curious. Are you happy with the results ,soundwise, of this build?

[ToneMerc]

TM,
Curious. Are you happy with the results ,soundwise, of this build?

Haven't lit it yet, I should get a chance to install the power cable this weekend.

TM

[CHIP]

Thanks, keep us updated. I've just about all the parts sourced for a 6G6B build in the next few months.

[Lindz]

Hey Fender builders - sorry to jump in this thread but I am sort of on topic

I was considering a 6g6b build but all the handwritten Fender Schems and layouts are pretty hard to read. Anyone have something a bit tidied up for folks with mediocre eyesight

thanks!

[ToneMerc]

TM,
Curious. Are you happy with the results ,soundwise, of this build?

Well Chip I'm done.........whew. First let me tell how I had orginally set it up.
Bass chan Vol - 500KA
Bass chan Bass -500KA w/ 1.8K tail
Bass TS stack - .02
Bass slope - 43K
TS cap - 390pf
PI= 750 and 8.2K tail
Bass cathodes - 4.7uf
Gridstoppers - 1.8K
no treble bleed on V2b

Powered it up with s/s rectifier plug with 448V on plates with 446V on the screens.

Yuk......motorboating on bass chan only with vol pass 4 and nasty parasitics.

Bass chan motorboating: circuit would excite itself with either 500K or 1M vol pot. Just before threshold of oscillation, I could take it over the edge by moving the lead to the bass pot wiper back forth as well.

Resolution: installed stock 250K vol pot value, verified condition 4 times.

Parasitics: increased gridstoppers from 1.8K to 3.9K which was better, jumped to 6.2K value and that negated them.

Leaking(20V) 390pf stack cap : replaced with 330pf

Did some searching around the internet and there's plenty of info regarding the 6G6B bass channel. I can see why the circuit was limited, it appears to be on the edge of stability. However, what a sleeper circuit though.

As built:

Installed GZ34 rectifier, 428V plates, 427V screens, biased at -31, with remaining preamp voltages almost dead on schematic.

Bass chan vol - 250KA stock value
Bass chan Bass pot - 100KA w/ 3.3K tail
Bass TS stack - .02, with all Bass chan couplers changed to .02
Bass slope - 43K
TS cap - 330pf
PI= 750 and 8.2K tail
Bass cathodes - 4.7uf
Gridstoppers - 6.2K
no treble bleed on V2b

Hmm, who needs the normal channel. The amp breaks up nicely at 4 with tons of gain, especially when the front end is driven hard and it cleans up nicely when you roll down the guitar vol knob. I can easily see why folks love this Bassman version.

TM

[CHIP]

TM, Thanks for the heads up on the bass channels vulnerabilities.
Did you give the normal channel a test drive yet?

[irv78]

Anyone have something a bit tidied up for folks with mediocre eyesight
thanks!

I've found very good quality 6g6-layout scans on this page:
http://www.gad.net/Blog/2011/06/07/how- ... zers-tone/

I used them to build mine.

I also have a small question regarding 6g6 bassmans - sorry for the slight high-jack. I think I have an issue with my presence knob. It only seems to work on the last quarter of its travel. Is this normal? Has anybody noticed the same?

[martin manning]

I also have a small question regarding 6g6 bassmans - sorry for the slight high-jack. I think I have an issue with my presence knob. It only seems to work on the last quarter of its travel. Is this normal? Has anybody noticed the same?

I think this is pretty typical. Some people, including me, prefer the sound and response of the older-style presence, as in the 5F6-A where a 5k pot replaces the 4k7 resistor and 25k pot, and the 0.1u runs from the pot wiper to ground. This configuration will produce some static noise when the pot is rotated, but it is not much of a problem, really.

That's a super clean scheme and layout; thanks for the link!

[irv78]

Ah, ok! Thanks for clearing that up. I also have a 6g7 Bandmaster with presence control - which is way more pronounced. So I assumed I made a wiring mistake.

[alvarezh]

@ Lindz, here is a PDF version you can expand.

All the best.

[Lindz]

Thanks! That schem/layout is great!