Developing the DIY "Champ" for first time builders

[M Fowler]

rj green means go

The amp kit was sitting on a bar stool next to my bench begging me to complete it.

Benoit came over one day and said hey what is that neat looking amp with small tubes?

So the rest is history.

[surfsup]

Since there is some good interest in the "super" champ version (per RJ's email to me earlier this weekend), I decided to do a CAD layout of the proposed transformers with the chassis size he indicated he would likely use. I added all the main components (I think, as this is my first time doing this) to scale. My thought process is the super champ will likely get "tweaked" many times by me/us so I here's what I did:

1) Two novals - one preamp and a second for tremolo or reverb
2) Two octals - one for a tube rectifier and one for a 6v6/KT88/EL34
3) The Edcor trannys complete with drilling pattern in RED and BLUE
4) Input Jack
5) I filled the faceplate with pots and switches including indicator, standby and On/Off - these are spaced 1.25" (the pots). The switches are spaced a bit closer
6) I put the fuse and on/off, standby nearest the side wall so there would be no back-tracking of the leads
7) I spaced the two novals from the two octals a bit extra for clearance for the OT secondaries
8: If no tube recto is being used, perhaps the third socket can be used to add another effect, say one preamp tube V1, a tremolo, AND a reverb?
9) I am thinking of rotating the sockets to provide better access to the heaters and such so wires cross over less. Since it is a design still in progress perhaps RJ (if he was planning to punch em out) can use this design instead of supplying blank chassis - but that might be asking a lot!

Please let me know if the layout looks good, what considerations I am missing or should change, and I will re-do it. I hope I can inspire some comments with this work I've done and hope to give back more to this thread and community as time goes on!

Oh, and if anyone wants, I can kick out a DXF for the octal I drew up...

[img734]http://chicagocadcam.com/ChrisHahn/sche ... layout.jpg[/img]

[Cliff Schecht]

Damnit RJ! I got excited for a second when you said "super champ", I thought you were talking about the Super Champ!! I'd love to clone one of those..

[M Fowler]

The layout looks great.

The pots are just extra holes incase you want to add more additional tone shaping right?

[RJ Guitars]

Damnit RJ! I got excited for a second when you said "super champ", I thought you were talking about the Super Champ!! I'd love to clone one of those..

I eventually got around calling the the Supre Champ...

[surfsup]

Mark,

The layout looks great.

Really? Don't think it needs a longer circuitboard? Anything? I can't believe I got it all right first try...

The pots are just extra holes incase you want to add more additional tone shaping right?

Yea they would all be drilled out up front except now I'm thinking there's too many pots and maybe converting one more to a small switch. I am thinking, personally, maybe I would have that boost switch and also maybe a switch to change to different cathode bypass caps (three settings one for off, and the other two to add two different value Ck). What do you think? or maybe a mids bypass switch?

[surfsup]

Something like this perhaps? ...anyway, having an extra switch wouldn't hurt.

[img:889:542]http://chicagocadcam.com/ChrisHahn/sche ... bypass.jpg[/img]

[M Fowler]

I didn't get that detailed into my look

It just shows what a guy can cramp into a small chassis.

That cap switching is something Henry from Redplate amps does and sent me several of his schematics to work with. Running .68 and 10uf caps switched there can add bass or thin out the tone.

Having the holes drilled for 5/16 or 1/4 inch here can mean using either a mini switch or drill out later to 3/8 for pot.

[surfsup]

That cap switching is something Henry from Redplate amps does and sent me several of his schematics to work with. Running .68 and 10uf caps switched there can add bass or thin out the tone.

Thanks for the tip on the values. I'll have to check out Redplate amps sometime soon before I forget. I am in the "stoodio" workin up a new song with the ax84 I built. Doh!

Having the holes drilled for 5/16 or 1/4 inch here

Yea, but I was thinking of having 4 or 5 drilled for pots and the rest smaller. The one with the switch is def. a switch hole. But one or two others could prob. be switches too. (or on the back for that Ck bypass switch...there's plenty of room there. hmmmm....)

***EDIT: I added the two blue switches on the layout JPG in my earlier post...let me know what you think...a faceplate will cover any unused holes in front, too.

[Zippy]

Since there is some good interest in the "super" champ...

It thought the "Super" version was one with larger iron...

[surfsup]

I modeled up the PT/OT RJ was thinking of using. I didn't think a set had even been decided on yet. Which ones did you think were the ones needed?

[RJ Guitars]

I'll attach a drawing that generalizes what I had in mind for a Supre... or at least as far as I've taken those thoughts so far.

There is a lot of variation in the interests for this amp so it's not really clear that any one idea will capture the preferences for everyone. You'll see two things in the drawing that I find useful in putting together a layout.

1) Common parts and layout from previous designs. This is something I grasped from studying Trainwreck amps. Ken Fischer used the same general chassis layout, circuit boards, transformers, etc.. for all of his production amps. My thought for what I'm calling the "Eagle Supre" (I'll leave Champ out of the naming convention for various reasons) is that it is really part of a natural progression from the simplest of amp designs through phases of "improvement". As this happens I prefer to preserve some continued relationship to the original idea.

2) I also like to consider which direction the progression of events might take things in the future and consider that in the layout design as well. As you look at my drawing you might see that I am leaving a spot for another preamp tube and maybe even another output tube. I'm sure I'm not alone in believing that there will more layouts ahead...

There is a spot for a tube rectifier on my chassis, but this was one of the first things that most of you dismissed as a waste of space and transformer power... I tend to agree. However, I did leave a little space between the circuit board and the power transformer which I think is the best place for a 5Y3 if you wanted one in the layout.

The biggest disparity in requests for features on a Supre type of amp has been the different preferences for B+ voltage. For now I'm not committed to any transformer designations. We'll see if a consensus develops with time. I'll order anything available and have it shipped direct from Edcor if you want to save a few $$ over the street price from their web site.

I also added some tone controls and left room for a bright or boost switch. These are among the most common of requests.

I bought a dozen of the Supre Sized Chassis and had in mind to follow up on that idea after we worked through the simpler version... for those that are working ahead in the workbook keep going and if you don't mind, post up a thread on your work and share with us what you learned. Maybe you experience will help us avoid a few pitfalls that are waiting ahead.

rj

[RJ Guitars]

Damnit RJ! I got excited for a second when you said "super champ", I thought you were talking about the Super Champ!! I'd love to clone one of those..

No reason we couldn't do that ...right??

[M Fowler]

I was trying to stay away from a Super Champ because at some point I am going to build the Trainwreck DLM and don't need to have an army of SE amps sitting around

Mark

[RJ Guitars]

I was trying to stay away from a Super Champ because at some point I am going to build the Trainwreck DLM and don't need to have an army of SE amps sitting around

Mark

DLM - The ultimate Single Ended Amp in my book. I recently saw a note by Dana Hall where he mentions that what is known about these amps just isn't adequate to attempt that build (my paraphrase)... I can't add anything to that puzzle, but would trade a golden calf and two goats to know the details.

I suppose you noticed the KT-88 in my Supre... don't know if that is the right output for the DLM but that's my inclination.

rj