Developing the DIY "Champ" for first time builders

[xtian]

Let me know when I can order!

[mcrracer]

Looks good,
You could get away with only two diodes if your looking to cut costs a tiny bit.

At a penny a piece two wont break the budget.

[TheGimp]

Another output tube you might want to look at is the 6P1P-EV (Very inexpensive). This is supposed to be a 6V6 equivalent in a 9 pin envelope.

It has the same 12W plate dissipation limit as the 6V6, but 250V plate and screen limit. I think the screen limit should be observed as X-Ray images of the tube show it moderatly close to the cathode.

That said, I'm driving them with 325V on the plate and 250V on the screen without any problems. I plan on stepping B+ up to 350 on the next build.

I've built three Guitar amps with 6N2P-EV for the front end, and 6P1P-EV output tubes and all three sound great. One is a modified 5F1 design with a 5K OPT that puts out almost 4W. With a 4K transformer it should put out more.

I've also built stereo amps with the 6P1P-EV, but used 6N1P-EV for the front end instead of 6N2P-EV.

I beat the snot out of a pair of 6P1P-EVs when developing the stereo amp, and they are quite tough.

The only problem I've seen with them was one tube that I believe had a bad cahtode coating or possibly was gassy. It went Blue Flash and fried a catohde resistor. Luckly it did not dammage the PT or OPT.

This is a pair pumping out 13W with 13W plate dissipation (253Vk-a at 55ma Ia). I could not see the red plate with the lights on, but could see it with them off.

[Travst]

I'd be in for the group buy. This sounds like a fun project.

[ChrisM]

Looks good,
You could get away with only two diodes if your looking to cut costs a tiny bit.

At a penny a piece two wont break the budget.

Hence the tiny bit.
Could have board space too.

[RJ Guitars]

I'd be in for the group buy. This sounds like a fun project.

Cool... there have been a few inquiries and I'll follow through and post a notice when everything is in the house and ready to ship.

I am currently on the road and will have a weekend home this Saturday and Sunday before I leave again. Right now most of the parts have arrived at my house except for the transformers from Edcor. I am expecting those to arrive around the middle of Feb and that will be my predicted shipping date for parts packages. I won't start to collect any funds until I can start shipping them out.

thanks,

rj

[RJ Guitars]

Another output tube you might want to look at is the 6P1P-EV (Very inexpensive). This is supposed to be a 6V6 equivalent in a 9 pin envelope.

It has the same 12W plate dissipation limit as the 6V6, but 250V plate and screen limit. I think the screen limit should be observed as X-Ray images of the tube show it moderatly close to the cathode.

That said, I'm driving them with 325V on the plate and 250V on the screen without any problems. I plan on stepping B+ up to 350 on the next build...

I have often heard that the Russian tubes will take a little more voltage than than the rating, but I have no experience with them myself. I do have a few of the 6P1P-EV tubes around, just never had the right project to try one.

The 6AQ5 has also been mentioned as a good low budget output tube for these amps. Again they are a small bottle version of the 6V6 tube.

I will be hand punching the holes in the pre-punched chassis so if somebody wants a 9 pin version, that is way easy to do. I won't be offering to move the location of the holes but going undersize is fine.

rj

[texstrat]

I would be in for one of the kit, with the chassis punched. This has been a very interesting thread to read.

[M Fowler]

rj stay safe and I am looking forward to building with you this will be a great project.

I hope some newbies join us for discussion and fun.

Mark

[ToneMerc]

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

TM

[M Fowler]

ToneMerc,

What PT and OT are you using there? At first I though they looked large but comparing to the choke I guess not

Mark

[ToneMerc]

ToneMerc,

What PT and OT are you using there? At first I though they looked large but comparing to the choke I guess not

Mark

Mark,
The PT is a Heyboer HY022772 (Champ) w/upright mounting. A few months back I asked Heyboer to make me a couple of upright trannies for a harp amp project. I wanted something with a tiny footprint and I didn't want the hassle of cutting a square opening in the chassis for a laydown PT. However, I wound up using an upright PT on a bigger frame, so this one was left over.

Around the same time I ran across the OT on eBay. At the time the seller's price was $6 cheaper than what it is now so I took a chance on it.

http://cgi.ebay.com/Fender-5F1-Champ-Tr ... 3f06bbe38b

TM

[Travst]

The Reason Bambino use the 6AQ5 and it's one the best sounding amps I've owned. I still have a couple of NOS tubes, so that'd be a good choice... for me.

[RJ Guitars]

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

TM

Excellent looking work there. I am hopeful that there will be a few who are able to create or source parts from various sources. Helping others get the DIY experience is really what this is about for me and it's a no profit venture either way... There is an added bonus for every builder even if it's just for the education and experience. - A decent Champ style amp is an excellent amp to add to the arsenal.

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

[M Fowler]

Thanks guys we are getting closer to making this happen, I am looking forward to building one.

Mark