Developing the DIY "Champ" for first time builders

[RJ Guitars]

I just punched out this BF Champ layout so all I need now is is a chassis.

TM

I see a pot for variable feedback... give us a report back on that. Simple idea but a good one for changing the amp behavior.

rj

[ToneMerc]

I just punched out this BF Champ layout so all I need now is is a chassis.

TM

I see a pot for variable feedback... give us a report back on that. Simple idea but a good one for changing the amp behavior.

rj

Yep, it's a 20K (thought I had a 25K or 50K thumbwheel, no dice). Also, there's a switch in between it and the 2.7K FB resistor to disable the NFB loop if I choose too. I also moved the 15K bass resistor from pot down to the board, the intent is install a p/p pot or a mini switch to lift the tone stack.

Mike

[ToneMerc]

I just punched out this BF Champ layout so all I need now is is a chassis.

TM

I am also curious about the transformer set you've got. Looks a bit like the BF Champ set from Triode EL. I've got the pairs coming from Edcor but no choke in my design. I did ask Edcor to wind them with a 120/240 primary so that we can include a bunch more places in the world to build along with us.

rj

Thanks RJ

PT: Heyboer Upright Champ
Choke: Mojotone small Fender, I'm pretty sure this one came from Marvel
OT: 8W, 5K, 4 & 8 ohm taps, no markings supposely USA made

TM

[rp]

OT: 8W, 5K, 4 & 8 ohm taps, no markings supposely USA made

I'm looking at the Triode Champ OT in front of me and it looks the same. I'm sure MC stuff is as good as everyone says but I found this OT to be really lame in an ax84p1. The Edcor 10W I sub'ed ate it's lunch and dinner.

I'd say build it with what you have but plan on getting an Edcor from RJ when they come in. Holes will all be different.

[angelodp]

Mike & RJ, this shaping up to be a fun project, sweet. I am in... all the way. Maybe the board can include some of these mods as an add on?

Ange

[ToneMerc]

OT: 8W, 5K, 4 & 8 ohm taps, no markings supposely USA made

I'm looking at the Triode Champ OT in front of me and it looks the same. I'm sure MC stuff is as good as everyone says but I found this OT to be really lame in an ax84p1. The Edcor 10W I sub'ed ate it's lunch and dinner.

I'd say build it with what you have but plan on getting an Edcor from RJ when they come in. Holes will all be different.

RP, I'm not sure what brand it is although the lack of frame markings and single input Z is closer to this one offered by Mojo.

http://www.mojotone.com/amp-parts/trans ... ransformer

TM

[rp]

RP, I'm not sure what brand it is although the lack of frame markings and single input Z is closer to this one offered by Mojo.

I was looking at the one in that ebay link. That one looks identical to the Triode one. I wasn't sure which you were using. I think mojo uses more than one supplier too so who knows. I normally go for originality no matter how dinky and the original Champ was dinky. But the Edcor 5K/8/10W I swapped into the P1 really shone, so I was giving you a heads up.

[surfsup]

RJ and tonemerc (or anyone else), since this is an amp for noobs, and I'm a noob, do you guys mind a coiuple questions?

1) The PT and PreT pinouts don't seem to exist on the web. I've checked Dr. Tube, and many other sites and can't seem to find which pins are which (I can tell which are the heaters but would like to figure out the schematic for this amp).

2) tonemerc's board is not the same as RJ's layout. What is that 20k component there in the middle/top?

3) Why the 16 and 8uF values on the smoothing caps? I seem to always see 47uF.

[xtian]

Edcor iron in yet?

[ToneMerc]

RJ and tonemerc (or anyone else), since this is an amp for noobs, and I'm a noob, do you guys mind a coiuple questions?

1) The PT and PreT pinouts don't seem to exist on the web. I've checked Dr. Tube, and many other sites and can't seem to find which pins are which (I can tell which are the heaters but would like to figure out the schematic for this amp).

2) tonemerc's board is not the same as RJ's layout. What is that 20k component there in the middle/top?

3) Why the 16 and 8uF values on the smoothing caps? I seem to always see 47uF.

1) See the attached links, this should closely mimic RJ's layout minus the tube rectifier and single input.

2) My layout is based on a Blackface (AA7 64) Champ. I couldn't leave well enough alone so I added a switch to disable the negative feedback circuit and also a 20k pot so that I can vary the FB resistance value from the original 22k down to the BF value of 2.7k.

3) Original 5F1 filtering values are 16, 8 & 8 , BF values are 20, 20, 20 and I think later values were 40, 20, 20. I'm using 22, 16, 16 and a choke.

https://taweber.powweb.com/store/5f1_layout.jpg

https://taweber.powweb.com/store/5f1_schem.jpg

Hopefully this helps

TM

[RJ Guitars]

Edcor iron in yet?

Usually it is me that drags things behind, but this time I actually have everything except the transformers here at the shop.

Edcor iron is expected around mid February. I'll be on the road until then so so it should all come together about the same time.

I'm not expecting a big run on these but I will start putting together a list over these next couple weeks to get an idea of what to expect. It looks like I should be able to ship to put packages together and ship during the 2nd half of this month.

rj

[RJ Guitars]

Tone Merc,

Those are great schematics... I was just about done with my own when you posted those up. You can see the they all have a lot in common. Somebody let me know if there are any major flaws in my drawing.

There are several things that can be done to modify the character of these amps. My schematic shows you the fundamental basics to build from with a minimum of options. Should be a lot of fun!

rj

I'll leave this schematic up but recommend you go to page 16 for the latest greatest

[Ian444]

Russian 6N6C, to find these on ebay search 6P6S. These tubes sound fantastic in hifi, I haven't tried them in a guitar amp yet, I doubt there will be any disappointment. They have a very wide freq response (very low lo's and high hi's), I have had no problem with Reflector brand tubes from the 1970's and 1980's. I bought 8 of these tubes a few months ago and got four reasonably well-matched pairs out of the unmatched untested 8, and all sound very good. They are stumpy, ugly, blacked out, and use 8-pin bases, but all is forgiven when you hear them The Russian datasheets are conservative on max ratings too. That schem should give plenty of gain to those who want it. What are we looking at, maybe 320V B+, maybe 17 or 18V on the grid (depending on screen voltage), it won't be hard to drive this amp into breakup and beyond

The only problem with buying Russian tubes is the postage, you can get 8 x 6P6S for around $4.20 ea delivered, but try to buy one or two, and its much more expensive, possibly not worthwhile. There are current production 6V6 also.

[surfsup]

Tonemerc, a few more noob questions if you don't mind:

2) My layout is based on a Blackface (AA7 64) Champ. I couldn't leave well enough alone so I added a switch to disable the negative feedback circuit and also a 20k pot so that I can vary the FB resistance value from the original 22k down to the BF value of 2.7k.

The NFB loop is R13 in the schematic you posted yes?

Your preamp layout vs. the soldered board seems to be reversed left to right?

If so, your 68k resistors don't match. Seems to be a 42R and a 240k Is that correct? The colors seem to be yellow red black and red yellow yellow on the two...

Is your 220k actually a 100k?

The orange line is going to run to pin5 of the 6v6 output tube?

The holes on the outside top/bottom of the board are to run connector leads underneath but have them come up to the top for possible repair convenience later?

[ToneMerc]

Tonemerc, a few more noob questions if you don't mind:

2) My layout is based on a Blackface (AA7 64) Champ. I couldn't leave well enough alone so I added a switch to disable the negative feedback circuit and also a 20k pot so that I can vary the FB resistance value from the original 22k down to the BF value of 2.7k.

The NFB loop is R13 in the schematic you posted yes?

Your preamp layout vs. the soldered board seems to be reversed left to right?

If so, your 68k resistors don't match. Seems to be a 42R and a 240k Is that correct? The colors seem to be yellow red black and red yellow yellow on the two...

Is your 220k actually a 100k?

The orange line is going to run to pin5 of the 6v6 output tube?

The holes on the outside top/bottom of the board are to run connector leads underneath but have them come up to the top for possible repair convenience later?

R13-yes

Controls-I'm mounting it a tubes upright chassis, input will be on right.

My board- it's not a clone of the 5F1. I posted circuit links that are relevant to the original spirit of the build, an 5F1 circuit.

Resistors- yes it's a 43 and a 240k. There are no 68k's on my board, since I'm only going to have one input type, the 68k grid stopper will be mounted at the V1 tube socket.

Org wire- goes to the treble pot.

Lead routing- for me it manages lead dress a bit better and it does have some benefit of a more secure connection.

Here's a board with tails that has the lead holes on the back side of the turrents.

Mike