Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Misc Schematics and Layouts => Topic started by: Johntb on September 10, 2017, 01:23:34 pm

Title: Looking for a proven ENGL Fireball
Post by: Johntb on September 10, 2017, 01:23:34 pm

I used one with obvious flaws that I worked through and got it to work somewhat on the overdrive channel. C!ean wa another story though. I spent over two months on it then just got frustrated and made something else.

Is there a proven schematic out there?

Title: Re: Looking for a proven ENGL Fireball
Post by: eldredjames on September 10, 2017, 09:15:35 pm

Have you checked the one on Tube Amp Schematics Library
http://el34world.com/charts/Schematics/files/engl/Engl_Schematics.htm (http://el34world.com/charts/Schematics/files/engl/Engl_Schematics.htm)?

 There's one there.



Jim

Title: Re: Looking for a proven ENGL Fireball
Post by: Johntb on September 10, 2017, 10:41:37 pm

Yup. That's what I started with. The first most obvious problem is V2 pin 7 goes straight to ground. Like that it won't work. I changed it to a 470k (and several other values and different caps in parallel). I ended up getting it to work in overdrive. Problem was everytime i got a good overdrive tone the clean was junk. I also had made several other changes i don't remember now. There are problems with the "depth" as well. The way it is it won't do anything and I worked past that too. Another issue was the "FX Loop" can't really remember that one right now.

I found this and was considering it but not sure. About 15 or so posts down Brutar posted on graph paper.

 http://guitar-gear.ru/forum/topic/402-%D1%81%D0%BE%D0%B1%D0%B8%D1%80%D0%B0%D0%B5%D0%BC-engl-e625-fireball/ (http://guitar-gear.ru/forum/topic/402-%D1%81%D0%BE%D0%B1%D0%B8%D1%80%D0%B0%D0%B5%D0%BC-engl-e625-fireball/)

I may just end up trying it.

But thanks for the reply.

Title: Re: Looking for a proven ENGL Fireball (Found)
Post by: Johntb on May 27, 2018, 05:00:35 pm

Well at least I like the sound I got. The preamp was a little further in the thread above (I tried to attach it). I used the amp section of the Superlite with 2 EL84's and an OT from and old Hammond organ.

I used the FX loop and it works fine but there is a very small amount of volume loss when fully "wet".

Still getting rid of some hum but it sounds great so far.

Title: Re: Looking for a proven ENGL Fireball better clip
Post by: Johntb on May 27, 2018, 11:03:28 pm

Added video.
Beginning hum can be heard. This is as quiet as I have been able to get it.

Some clipping distortion on clean from phone and using bridge pickup. Used neck only later to show depth and bright switches.

Not sure if I added link correctly.