Firefly owners/builders - fill me in...

11 Gauge · December 3rd, 2007, 04:10 PM

Well, the Champ is tweaked, the normal channel on my Vibrolux Reverb is sounding righteous, and my hacked Express preamp/5E3 power amp build is about 1/3 done...

I thought I was doing the neighbors a favor by leaning on the Champ pretty heavily lately, but my 5 year old daughter still proclaims that she can hear the amp when they are halfway down the street...

Needless to say, I've been infected with the Firefly bug...

What I'd like to know is what kind of parts have you cobbled up for your builds?

I can score a Hammond 269JX for about 40 bucks, but I'm wondering what other cheap iron you folks might have tried...

I also have a spare Champ OT, which some folks say will do double duty as a reverb driver, which kinda spawned the whole Firefly thing in the first place, AFAIK (Fender's tube reverb circuit puts out roughly ~1 watt).

Lastly, the pseudo "power tube" controversy. Some folks swear that it has to be a 12AU7, others have gotten good results with a 12AT7 (I've got a box of old Sylvania ECC81's kicking around).

I'm gonna go nutz reworking the preamp. The Sonic Deli Heavy Watter has given me some interesting ideas...Those guys are truly whacked out...

Please tell me about your Firefly experiences, specifically as far as tweaking and taking the "Fred G. Sanford approach" applies...

ruger9 · December 3rd, 2007, 08:22 PM

FYI, there is a source for Firefly PCBs... could make things easier...

If I had any freakin' TIME, I'd get one of these & build myself a Firefly:
http://web.mac.com/calhoun/PCB/Firefly_PCB.html

celeste · December 3rd, 2007, 10:44 PM

Champ OT is not going to do it, it is single ended, and a FF is push pull. I like mine with a 6SN7 output better then the 12AU7. I have not tried an 'AT7. The power supply is a little to noisy for me. The Cascode boost stage really needs clean power because it has very little power supply noise rejection.

it puts out about 2 watts if cranked, and can be a bit much for bedroom level.

JohnnyCrash · December 3rd, 2007, 11:06 PM

My girlfriend said she heard my Champ a half block away, through my closed window!

I just went up and dusted my Firefly off before I responded here...

It is an interesting amp to be sure. I love mine. I use it to record often and it gets great controlled feedback for tracks that need it but neighbors that don't.

I love high gain amp designs, so mine has a MV, a Gain, and then I modded it for a Cascade Boost and boost adjust switch/pot.

It can still be LOUD. Louder than you'd expect, so I'd downgrade even further from the Champ OT and use a little Hammond 125A 3watt (that's what I used and its still loud!).

I don't think it really needs any tweaking. I even love the cascade boost maxed and the gain maxed and then the MV to desired volume (or all three maxed) - as it is not like other cascade high gain amps and still sound full instead of thin and fizzy. Still, like I said I really dig high gain stuff.

This amp may be on the dark side to some folks, but it helps out when its at full tilt. The cascade switch helps brighten it up, but even then the amp still has this fat gruff voicing.

If volume is a concern and you need beefy crunch, I'd highly recommend building a Firefly.

Here's my Firefly head build I threw into a "ghetto" plywood cab I built for it:

JohnnyCrash · December 3rd, 2007, 11:09 PM

Quote:

Originally Posted by celeste

Champ OT is not going to do it, it is single ended, and a FF is push pull.

Good catch, I forgot about that :)

Quote:

Originally Posted by celeste

The power supply is a little to noisy for me. The Cascode boost stage really needs clean power because it has very little power supply noise rejection.

+1

That may be my next project (more filtering), given how I like to use it for recording.

Quote:

Originally Posted by celeste

it puts out about 2 watts if cranked, and can be a bit much for bedroom level.

This is exactly why I went back and added the cascaded gainstage. It is louder than you'd think 2 watts would be!

ruger9 · December 4th, 2007, 07:16 AM

I'd love to hear a demo of your Firefly, Johnny... if I was going to build one, that's exactly the "version" I would build. Sounds perfect.

11 Gauge · December 4th, 2007, 09:57 AM

Quote:

Originally Posted by celeste

Champ OT is not going to do it, it is single ended, and a FF is push pull.

It won't work for the Firefly, but it will work for the Sonic Deli Heavy Watter. They use a Fender reverb transformer for theirs, which is quite similar to the Champ OT.

I also have a Marshall reverb transformer that I pulled from my 4210 when I removed the split channel setup.

December 3rd, 2007, 04:10 PM	#1 (permalink)
11 Gauge Friend of Leo's Join Date: Mar 2003 Location: The East Coast Posts: 3,016 10 Photos	Firefly owners/builders - fill me in... Well, the Champ is tweaked, the normal channel on my Vibrolux Reverb is sounding righteous, and my hacked Express preamp/5E3 power amp build is about 1/3 done... I thought I was doing the neighbors a favor by leaning on the Champ pretty heavily lately, but my 5 year old daughter still proclaims that she can hear the amp when they are halfway down the street... Needless to say, I've been infected with the Firefly bug... What I'd like to know is what kind of parts have you cobbled up for your builds? I can score a Hammond 269JX for about 40 bucks, but I'm wondering what other cheap iron you folks might have tried... I also have a spare Champ OT, which some folks say will do double duty as a reverb driver, which kinda spawned the whole Firefly thing in the first place, AFAIK (Fender's tube reverb circuit puts out roughly ~1 watt). Lastly, the pseudo "power tube" controversy. Some folks swear that it has to be a 12AU7, others have gotten good results with a 12AT7 (I've got a box of old Sylvania ECC81's kicking around). I'm gonna go nutz reworking the preamp. The Sonic Deli Heavy Watter has given me some interesting ideas...Those guys are truly whacked out... Please tell me about your Firefly experiences, specifically as far as tweaking and taking the "Fred G. Sanford approach" applies... __________________

December 3rd, 2007, 08:22 PM	#2 (permalink)
ruger9 Tele-Afflicted Join Date: Dec 2004 Location: Hackettstown, NJ Posts: 1,662	FYI, there is a source for Firefly PCBs... could make things easier... If I had any freakin' TIME, I'd get one of these & build myself a Firefly: http://web.mac.com/calhoun/PCB/Firefly_PCB.html __________________ "I've got callouses, from all those nights, spent playin' a Telecaster, 'till my fingers bled Bud Light" - Travis Tritt

December 4th, 2007, 07:16 AM	#6 (permalink)
ruger9 Tele-Afflicted Join Date: Dec 2004 Location: Hackettstown, NJ Posts: 1,662	I'd love to hear a demo of your Firefly, Johnny... if I was going to build one, that's exactly the "version" I would build. Sounds perfect. __________________ "I've got callouses, from all those nights, spent playin' a Telecaster, 'till my fingers bled Bud Light" - Travis Tritt

December 3rd, 2007, 10:44 PM	#3 (permalink)
celeste Tele-Meister Join Date: Jun 2006 Location: Maryland Age: 47 Posts: 219 12 Photos	Champ OT is not going to do it, it is single ended, and a FF is push pull. I like mine with a 6SN7 output better then the 12AU7. I have not tried an 'AT7. The power supply is a little to noisy for me. The Cascode boost stage really needs clean power because it has very little power supply noise rejection. it puts out about 2 watts if cranked, and can be a bit much for bedroom level.

December 3rd, 2007, 11:06 PM	#4 (permalink)
JohnnyCrash Poster Extraordinaire Join Date: Mar 2005 Location: Lost Angeles and Orange County Posts: 7,128	My girlfriend said she heard my Champ a half block away, through my closed window! I just went up and dusted my Firefly off before I responded here... It is an interesting amp to be sure. I love mine. I use it to record often and it gets great controlled feedback for tracks that need it but neighbors that don't. I love high gain amp designs, so mine has a MV, a Gain, and then I modded it for a Cascade Boost and boost adjust switch/pot. It can still be LOUD. Louder than you'd expect, so I'd downgrade even further from the Champ OT and use a little Hammond 125A 3watt (that's what I used and its still loud!). I don't think it really needs any tweaking. I even love the cascade boost maxed and the gain maxed and then the MV to desired volume (or all three maxed) - as it is not like other cascade high gain amps and still sound full instead of thin and fizzy. Still, like I said I really dig high gain stuff. This amp may be on the dark side to some folks, but it helps out when its at full tilt. The cascade switch helps brighten it up, but even then the amp still has this fat gruff voicing. If volume is a concern and you need beefy crunch, I'd highly recommend building a Firefly. Here's my Firefly head build I threw into a "ghetto" plywood cab I built for it: