5F6A Amp build help (Fender Bassman)

[RichBolduc]

I decided I was going to build an amp out of boredom. At first I was looking at Weber and Marsh kits but being a mechanical designer, I decided I really wanted something purely custom... So I grabbed the schematic off the Weber site and figured out what parts I would need. I plan on doing an exotic hard wood cabinet for the head and speakers cabinets (leaning towards Padauk with Jobillo accents). I'm going to do the whole thing up in Solidworks and document the build, so I can post plenty of design, in process and finished product pictures for you junkies. Here are links for the BOM I plan on using with links to the parts and also the schematic.

Google Docs

http://spreadsheets.google.com/ccc?k...ZUEcxYkE&hl=en

If you guys could go over the BOM and make any part suggestions for the blanks slots or parts that should be changed it would be greatly appreciated as I'd like to start ordering parts to do the design.

Things I would like to do for the schematic change is use a transformer that can do multiple impedances (already choose a multi-tap Heyboer, just not sure how to hook it up), a single 1/4" output jack (they currently have 4 RCA's) and adjustable Bias (for this I plan on using a 25K ohm pot in series with a 27K ohm resistor (so I can't short it out).

Any help on the schematics and parts is hugely appreciated.

Here is what the wood's look like too

Padauk


Jobillo



Thanks,
Rich

[OneyedK]

To make things easier:

Mojo Capacitor Kits 3330002 Tweed Bassman Capacitor Kit

[llwhtt]

Go to "Schematic Heaven" for almost any Fender amp, the layouts are there also.

Craig

[firechief]

Rich
Is this a pretty accurate schematic?? I ask because an example to get us started is quite helpfull. Looking forward to viewing your progress. Also I have delt with Mojo, and a kit will be a jump start.

[RichBolduc]

Originally Posted by firechief

Rich
Is this a pretty accurate schematic?? I ask because an example to get us started is quite helpfull. Looking forward to viewing your progress. Also I have delt with Mojo, and a kit will be a jump start.

Not sure why it's listed in the original post as "Google Docs" (maybe because that's where I stored the schematic?), but here's the schematic that I'm using as the base.

As I said, I'd like to swap to a single 1/4" output jack in stead of their 4 RCA's. I'm also using a multi tap Heyboer OT (2,4,8 ohm) that I'd like to hook up to a rotary switch to select the impedance. Lastly, where they have the adjustable bias circuit, instead of a straight 50k pot, I'm going to do a 25K pot in series with a 27K ohm resistor, that way I can't short anything out.

[RichBolduc]

Ohh yeah and thanks again in advance

[TheGimp]

One thing I've noticed on guitar amps, is that they all have cover plates of some sort to cover the open side of the chassis. This is to shield the wiring from emi (Noise Pick Up). Sometimes this cover is stapled to the inside of the CAB.

I've worked on five guitar amps in the last year, and all seem to be sensitive to hum pickup from ambient noise when the cover is not in place.

Shielding seems to be important in a guitar amp, although I've seen lots of audiophile amps made with minimal shielding so it may not be an issue.

People with more experience will hopefully chime in.

[RichBolduc]

Yeah the whole chassis is going to be a solid piece of sheet metal (probably 10 or 11 gauge aluminum). So the shielding part shouldn't be to bad. There tubes will be mounted on the top and you'll be able to see them glow through a glass window I plan on doing.

[RichBolduc]

Bump... still look for schematic help mainly

[OneyedK]

Originally Posted by RichBolduc

Bump... still look for schematic help mainly

What kind of help do you need? The 5F6-A is great as it is...