Developing the DIY "Champ" for first time builders

[angelodp]

Devious Little Mongrel, nice name. What does it sound like.

A

[RJ Guitars]

Devious Little Mongrel, nice name. What does it sound like.

A

it's never been built (by me anyway) but this thread has some really cool stuff...

https://tubeamparchive.com/viewtopic.php?t=7995

rj

https://tubeamparchive.com/download/file.php?id=7893

[M Fowler]

Here is some info from past posts:

Trainwreck Experience #5

At some point after I got my Liverpool, Ken played the "original" Dirty Little Monster for me over the phone. As I remember, he mentioned the amp in his Trainwreck pages.
It was a little Fender (Champ?) that he totally "NUKED". Wow, what was that, he told me it's a amp called the Dirty Little Monster that he gave to his brother. The amp was in the shop for a little servicing. Raunchy Rock n Roll at it's finest. I believe he said that it was a rock n roll machine with no real clean sound, I didn't care, that amp sounded GREAT! I asked if his brother was interested in selling the amp, I'd like to be the 1st in line, he laughed and said that the amp was not for sale.
Later, he mentioned that he planning to design an amp for an nationally known amplifier company. This was after the Kendrick Climax (heartache) and before Komet got off the ground (story was an experience). He was calling it the Dirty Little Monster. It was designed to be a guitarist 1st real low powered true tube amp. I heard the Prototype DLM just after he built it. He told he had decided not to do the deal with the company and was planning to just keep the amp. I asked him that if he ever decided to sell the amp to give me the 1st call. As it was with my one of a kind Komet, he told that he wasn't going to sell the amp at this point, but agreed to give me the 1st call. And about a year later, he gave me the call. Interestingly, he sold the amp to me for the price of the parts. He was being a good friend and he knew I was a struggling musician. I ended up sending him twice the asking price. I know that he got lots of offers for that amp and could have made a fortune on a regular sale. But Ken was always true to his word.
INFO: Front Panel

Input
Gain
Treble
Bass
Master
Harmonics (Presence)
Slope (Midrange)
On Switch
Pilot Light


Back Panel

Power Cable
Fuse
Ext speaker
Main Speaker (8ohm)

2 ECC83 (GT Yugo)
1 EL 34 (Mullard xf2 )
1 GZ 34 (Mullard)

Single ended (EL34/6L6/6550) 8 to 10 watts
note: the original used a 6550
this Prototype sounded best with an EL34

The Prototype Dirty Little Monster that he built was very different from the Original. He described it as a Killer Plexi with Trainwreck clarity and voicing with the master disengaged. Using the master gave it a more JCM 800 flare. This Prototype wasn't as gained out as the Original. There was a trade off more tone and clarity less raw distortion. This would be a great recording amp and takes pedals really well (Menatone Blue Collar was killer combination). There is definite vintage plexi Marshall vibe to this amp. Great amp



Steve, Ken did the Dirty Little Monster for a big, well known amp manufacturer. There were several successfull prototypes made, but the project was eventually abandoned because the target price couldn't be met.

The DLM is a single ended amp using a 6550 output tube. It puts out about 12 watts. One prototype was made with a different output transformer for a single EL34 putting out 8 watts. That's the one wreckboy owns and aron played.

Ken and I discussed making the DLM under the Komet name. We decided not to because if you look at the work and parts involved, it really is about the same for a 60 watt amp as it is for a 12 watt amp (give or take a couple of tubes). Who would pay $2500 for an amp that's too loud for an apartment and not loud enough for a stage. Hogy

[telentubes]

No official cab yet but I like the Alnico speaker with this amp.
I've taken three different amps to low volume rehearsals for the past three weeks. A Spitfire, a 2XEL84 Stangray hybrid, and last night, the Champ. The Champ is the best so far, in terms of sitting in the mix.

I always leave the tranny leads WAY long until I decide an amp is a keeper or not. If I like it, I'll trim them back. They are left long just in case I will want to use the iron for another project.

I couldn't bring myself to run the AC ground all the way to the input jack, as it's drawn. I've always read that the ground should be as close to the receptacle as possible. Any comments on that?

This is a cool amp.

[M Fowler]

Do you have the PT wiring schematic?

I thought the yellow wires were 5v taps for tube rectifier.

Brown is the 6.3 no CT use two 100R resistor so ground.

Black 0-120v primary

Red secondary HV

White/yellow strip?

Black/red strip?

[xtian]

Mark, here's the label on the bottom of the Edcor PT:

Primary
Black pair = 120vac 60Hz

Secondary
Red pair = 460vac, black/red = CT
Yellow pair = 6.3vac, white/yellow = CT
Brown pair = 5vac

[telentubes]

You beat me to it. Ditto xtian

OT is...
Blue = plate
White/blue = screen (tie this off)
Red = B plus
Yellow = 8 ohms
White = common

Mark, These colors are for the "premium" version Champ, with the Edcor trannys, which I believe is the one you have. So there ARE CTs. The basic version Champ didn't have center taps (pretty sure) so used the 100s to ground.

[RJ Guitars]

Sorry guys, I thought i posted that power tranny info already. Hopefully this time tomorrow my taxes are done and I'll get back to some of the more important matters at hand and make fewer apologies for my inability to multi-task.

Let me know if this tranny diagram agrees with reality... You are all ahead of me now. I haven't built the premium yet.

rj

[M Fowler]

Thanks guys

I am surprized they went with yellow as the filament supply and not brown but that is Edcor they have their colors different.

Mark

[XgamerGt03]

Thanks guys

I am surprized they went with yellow as the filament supply and not brown but that is Edcor they have their colors different.

Mark

Edcor is interesting like that,

One transformer I have from them is brown as 6.3V and yellow as 5V and another is the exact opposite...

[M Fowler]

I think on my past orders I asked Brian to change the colors and add CT for the filament.

[RJ Guitars]

No official cab yet but I like the Alnico speaker with this amp.
I've taken three different amps to low volume rehearsals for the past three weeks. A Spitfire, a 2XEL84 Stangray hybrid, and last night, the Champ. The Champ is the best so far, in terms of sitting in the mix.

I always leave the tranny leads WAY long until I decide an amp is a keeper or not. If I like it, I'll trim them back. They are left long just in case I will want to use the iron for another project.

I couldn't bring myself to run the AC ground all the way to the input jack, as it's drawn. I've always read that the ground should be as close to the receptacle as possible. Any comments on that?

This is a cool amp.

Very cool looking work... I think it really has the right colors for a Blues amp. With that amp in a combo with a good alnico speaker you can actually choose your "Roadie" for attributes other than brute strength... or maybe save the Roadie fees altogether.

I think your band practice experience is going to be typical. This should be a great utility amp. I'm looking forward to the audio clips we'll get out of these.

I've since relented on running that ground wire over to the input jack... I think it's critical to run that ground to a well secured lug on the chassis first then go from there over to that input jack. I don't like the thought of having that input jack come loose and then your ground is lost. I think you do want to get a good ground on that input jack but this is not the complex high gain amp that inspired the idea anyway. I agree with your choices there.

rj

[M Fowler]

telentubes

Thanks,

Your amp looks good are you enjoying it through the 10 inch Alnico speaker?

I went cheap a Mojotone 10 inch but I have some other speakers sitting around I can try.

Mine are for my grandkids anyway not me rocking out.

Mark

[M Fowler]

Started on this one last night.

Volume 1M
Treble 250KA
Bass 250KA

[telentubes]

Mark, I like the clever way you wired in the diodes. Let us know how the bass and treble controls work out. I may want to add them to my rig. The premium Champ is balanced well as is, but I usually can't resist a little fine tuning when playing. Earlier in this thread, the tone controls were described as tone suckers, which scared me away from them at first, so I'll be interested in your first hand take. I also just wanted to build the kit as it was presented, just for the sake of that.

The Alnico is a 12" Celestion I had lying around. I'd love to try a 10" but need to cut back on buying more gear, for at least a little while. I have to finish my 2XEL84 Rocket first.