chassis and 5F1

Well, considering other than transformers, Ive about got enough parts and pieces kickin around to make a 5F1 Champ clone in a head version, something small and compact for jams.. I've been looking at Hammond Manufacturing Chassis and screen covers and have either a
4"X8"X2" or a 5"X9"X2" chassis to choose from and would like to install the tubes upright on the top side with the transformers and wondered if you guys think I can get away with the 4x8 chassis....the screen cover sits 5.2" overtop of the chassis and think it Should fit neatly overtop..

Also have been looking at the tubedepots cheaper BF princeton/champ tranformers as the OT is 4 and 8ohm multi tap and didn't think the prices were too bad, but wanted to see what you all thought, of my plan... Thanks in advance..

Hello,


Sounds like a cool project. A typical 5f1/5e1 chassis is 8 3/4 L x 4 1/2" W x 2 5/8" H. If it were me I'd go with the 5x9x2 but a lot of other factors come into play. Are you going to be doing this with just PTP wiring, or will you be using either an eyelet/turret board/Termnial Strips/etc? The layout will most likely determine which size of chassis you'll want to use although I am open to correction from the more experienced builders out there. :-)
The prices for the OT are pretty good, in my humble opinion. I'm using that one in my own champ amp build. Looking forward to seeing a build thread on it when you get the time. Best of luck. :-)

Dennis

I'm using a turret board and will make it as small and compact as I can. Using the hammond chassis either 4x8 or 5x9 which r both 2" high then the steel cover sitting on top will have an overall height of 7.2" which will be a tiny little sucker.

I think you're makin' your life more difficult. Read the adjacent "no filament voltage" thread. Scroll down to the point where the OP says "I'm never using a tweed chassis again!"

http://www.tdpri.com/forum/shock-brothers-diy-amps/315691-have-no-filament-voltage-my-champ-amp.html

The hassle with a 5F1 is it's very tight in there. Good thing it's a Fender design. Fender was a master industrial artist. Fender's stuff ain't industrial design, it's industrial art. How else can you explain 50+ y.o. designs that are still useful and relevant?

Any time you re- think an established design you're undertaking a prototyping process. When you go your own way it's a prototype. A prototyping process is usually a three step process at a minimum.

Step one, build a test mule. You are astonishingly skilled if you achieve perfection on the first try. The first try likely will have flaws no matter how well you planned it.

Step two, try to eliminate as many of the issues as you can identify and rectify.

Step three, now that you're gettin' comfortable with the design it's time to make it pretty.


Try the 13.5"x5"x2" chassis. Get the preamp as far away from the power supply as you can. It's still tiny.

The tighter the space the more you have to think about how one wire will interact with another. I built a small 5C1 type amp using a compactron, two pentodes in one tube. It worked but I did not like the sound and about 1W it was not too exciting. I originally had a tone control in it but found it not worth the trouble and took it out. I could have made the size a bit smaller but it would have taken more effort.

http://i406.photobucket.com/albums/pp142/printer2_photo/guitar%20amp/12AE1W-1.jpg

http://i406.photobucket.com/albums/pp142/printer2_photo/guitar%20amp/12AE1W-2.jpg

Another amp I built used strip board where I used every second strip in order to give some air gap between the conductors to prevent arcing. I only ran up to 270V on this one, if I went higher I would have cut out the unused strips. Made for a small size board.

http://i406.photobucket.com/albums/pp142/printer2_photo/Tabletopboard.jpg

Was this Dennis's first amp build?? Well the man gave it life

I;ve built 3 deluxes now and stuffed them inside the tweed chassis they came with and I feel that a 9"X4" chassis is slightly larger than the standard champ chassis therefore I wasn't terribly concerned that I couldn't do a neat job with it..

Is it possible or a consideration with you saying that fender hasn't done this design that building it within a steel chassis and cover that the chance for noise or hum issues is greater than done with wood ?? I like the ideea of a head over a combo because of the fact rahter than every build I need another speaker rather than have one or 2 speaker cabs with as many heads as I like plus it lighter with two pieces rather than one although the champ doesn't count... :)

Is it possible or a consideration with you saying that fender hasn't done this design that building it within a steel chassis and cover that the chance for noise or hum issues is greater than done with wood ??

Layouts aren't designed, they're evolved. Grown.

Like I said, something seems good until something better presents itself.

makes sense..at least I won't have too much tied up into it if it is a flop..

Yeah it was my first amp, and I made quite a lot of mistakes along the way. Having said that though, planning is always the first step in a great build. It keeps the problems at bay and it allows you to stretch what your needs might be in the design versus what has to be done. Heed Muchxs's advice, it is the best advice I can give you. :-) Also, let us know how the build comes along as it is a great confidence builder in us all.

Good stuff Dennis, and after considering what you guys have said, (even though it's a small build) I will go with a 12x8x3 chassis and that way I will not be pressed for space and it will still be look small enough...so with the perforated cover 5.2" high finished height will be 8.2" high, which should look good.. thanks for the advice..

Although it is a small layout, what do you guys think about components for this build, as I ordered 1/2watt metal oxide and 2watt carbon comp and my main concern is noise reduction...

i also went rather then the 16x8x8 E-caps, I decided from looking at other builds went with the 22x8x8..

with this 4 and 8 ohm multi tap OT, what type of selector switch will i need to install with that ??

Selector switch SPDT. Like this:

http://img836.imageshack.us/img836/592/spdtononswitch1.jpg
By boothillamps (http://profile.imageshack.us/user/boothillamps) at 2012-04-23

http://img252.imageshack.us/img252/7613/26478583.jpg
By boothillamps (http://profile.imageshack.us/user/boothillamps) at 2012-04-23

Center goes to hot tip on speaker jack. One outer lug gets the 4. The other gets an 8 ohm lead off OT. Black OT lead goes to Ground lug on jack.

That's easy enough Hack, thank you, and what do you think about the resistor selection I choose...

Also if going with either a 10x6 or 12x8 chassis I'd like to have the tubes standing up on top of chassis with the transformers to help keep it neat and compact....I was thinking of how the 5E3 are layed out and keep the rec tube right close to the PT, the power tube right close to E-caps and then the pre amp tube close to right end of the board, and have the transformers plates running opposite to each other,,,then with all leads as short and direct as possible and hopefully that will gice me a neat and quiet build...

Carbon Comps make more noise (hiss) than other types. Since they are 2 watt, they go to the plate node and the preamp node, right?. I cannot tell you whether they will induce perceptible noise here.

What the heck. You're going to have one percent THD in any case. A bit of extra noise from your resistors isn't a deal killer. (Perhaps if you were building two Champs to run a Hi Fi Stereo - you would use wirewound where possible).

The most sensitive area for amplifying resistor noise is in the Preamp Section.

http://www.aikenamps.com/ResistorNoise.htm

Yes, the two 2 watt resistors are off the hot side in between the E-caps....isn't that what most people use there are the CC ??

http://www.mouser.com/Search/ProductDetail.aspx?R=PR02000202202JR500virtualkey5 9420000virtualkey594-5083NW22K00J

ICBW, but Metal Film like this are typical in these positions.

could 1 watt resistors could be used in place of the 1/2 watt

Who do you guys feel has the best 5F1 layout out there these days ?? Reviews seem pretty good with the Ceriatone..