Hey all!
I am gonna make a Firefly rev. II amp in the very near future, but I was wondering how I could boost the wattage of the amp to about 10-20W, I like the sound of the amp (http://dhammond_1.tripod.com/sounds.htm) but was wondering if it would be 'big' enough for me. I usually play in my bedroom but sometimes I go jammin at a friend's place and my 10W SS amp barely gets me where I want, it just about makes it. Could I use a 'power tube' (I just made that up) that is also a 2-triode thingy but has a little more power.
Or can any of you point me to a beginner's tube amp project that can deliver 10-20W? Oh I probably have help though from a technician but I gotta ask him if he want's to help yet... :roll: ;)
Hi,
Sure someone else will have a really better explanation or sugestion for you, but...
In my experience tube amps are way more loud than SS amps...
I think my 50W JCM800 sounds way more louder than ANY 100W SS amp.
So, I guess the Firefly will give you MORE volume/power than your SS amp... I may be wrong anyway...
Sure probably the way the Firefly is, it would be hard to get another easy_build tube amp with the same tone quality level :P
Regards
Kleber AG
That's cool, I read something about tube amps sounding louder due to harmonics and stuff like that that I only hlaf-understand.
I saw the High-Octane at wwwax84.com and www.silvatone.bravepages.com and I think I've fallen in love with it. Hey with help from a guy that owns a tube amp/vintage shop, who sells his own amps, I guess I could tackle that one. :D I should think both ax84 and the local amp man know what they're doing, so ;)
I'm planning to build one of'em too...
I also wonder about the "HighOctane versus FireFly" tone, wich one would I like better? :D Yeah, a hard question?
From what I've heard (sound samples) I guess I woul like better the FireFly, the HO on some samples looks a little harsh...???
Does anyone have something more about tone to add between these two great amps?
Also, looks like the Firefly would be more stompbox pedal friendly???
I'm searching for one OT, here in Brazil :(
Regards
Kleber AG
Well I was thinking of making a high octane first and then once I'm addicted a firefly ;)
If you want more output, you could always use a Hammond 125C OT instead of the 125A and then replace the output 12AU7 with a pair of EL84s. That would boost the output to maybe 6 watts of sweet tube tone. :)
A switch to go between the 12AU7 and EL84s would be a nice trick.
Take care,
-Peter
Hmmm. I get the basic triode tube idea, and I'm busy reading up on pentodes, but what on earth is the output transformer for? Ansil mentioned that I could use a different output transformer but why is that?
Hey peter, I was actually thinking of using 2 EL84's but was also pondering noise issues. But a switch? Would I not need a 6-pole double throw switch? Or maybe I could use relays but what about the bang when switching? Worth thinking about though. Like a high/low power switch :mrgreen:
The High Octane amp uses a single-sided EL84 power stage.... hmmm :? Ah hell I might just build 'em both and use a signle cabinet and choose between the two :)
Quote from: smoguzbenjaminWould I not need a 6-pole double throw switch? Or maybe I could use relays but what about the bang when switching? Worth thinking about though. Like a high/low power switch :mrgreen:
The High Octane amp uses a single-sided EL84 power stage.... hmmm :? Ah hell I might just build 'em both and use a signle cabinet and choose between the two :)
Tubes (the vast majority of them) are fairly high impedance devices so you need a transformer to match them to the speaker which is very low impedance. This connects with your "where does current come into this" thread. You need a transformer that is matched to the load your tubes want, so don't substitute too far.
If you want an example of a self-split EL84 output stage, look at this: http://www.triodeel.com/compact.html
To switch between two different output configurations, you would need a high power 6 pole 2 throw switch. If you switch the transformer plate connections, the input to the first grid, the screen supply (only used with the EL84), one of the filament ocnnections, and the OT tap used, you could switch at will (be sure the amp is either off, or in standby). It might be better to just wire up sockets for both configurations and install the tubes you want to use at that moment. No HV switches that way and much safer as long as you don't install all the tubes at once. I would avoid using a relay because there's just too much potential for damage to the tubes.
Caution: If you think stompbox building is addicting... ;)
Take care,
-Peter
Before you jump into a tube amp project get some help from your tech friend and hang out at ax84 a while and ask questions. Google "randall aiken" and check out the tech section at his site. It is an excellent resource for learning about tube circuits.
I have experimented with the Hi Octane preamp with a single-ended 6L6 output section (around 10W). It's an excellent high gain preamp but it is not a good beginner project because it is prone to oscillation if you don't lay it out right. The Hi Octane is designed as a "preamp distorter" that is intended to be used with a master volume kind of amp. Depending on the output tube used and etc, you can get into metal territory with it if you crank the master volume far enough. I don't think the HO is really intended to be "pedal-friendly" and it doesn't really clean up well, but some people have wired in switching schemes to bypass one of the preamp stages for that sort of thing.
The Firefly is more of a "power tube distorter" kind of amp. There is no master volume and part of its tone comes from pushing the 12au7 output tubes pretty hard. It is purposely voiced to work well with pedals on the "normal channel" when the booster is bypassed. I think the triode output stage works well for this since they have a flatter EQ response than a typical pentode. The "clean" sound is kind of flat, not "chimey" or "sparkly", the point is for it to work well with pedals. When you switch on the booster you will get a good high-gain "amp" sound. This amp doesn't sound real good clean IMO, but with pedals or the booster I think it sounds pretty nice.
If you decide to try the Firefly, build rev 3, it is an improvement over rev 2. Oh, and it is pretty loud, to me anyway... :D :D
Doug
Thank you Doug.
I'm searching for a OT around here, as soon as I could find one I'll certainly have more questions :D
I like the way you designed the Firefly to be friendly with pedals...
Thanks for all
Kleber AG
aikenamps.com is offline - out of bandwidth :evil:
Doug, doesn't the HiOctane have two preamp gain pots? What if I kept those low? Wouldn't that make it better clean? Because I found some sound samples at www.silvatone.bravepages.com (//www.silvatone.bravepages.com/HO/MP3.htm) which sound pretty clean and cool.
Hmm. Anyway, what I want as a first amp build would be an amp that has about 10W of power, but isn't too costly to make, I'm not quite qualified to work yet (minimum age is 16, got a month to wait yet :D ) and so my income is low :lol: I can't do without a tone stack and I kinda like the idea of having a master volume thing and preamp volume knob. So I can play clean loud, and play with tube distortion more quietly... Sortof.
I'm getting some parts from ansil, they should arrive in about a week, but untill then I don't know what parts I have to play with, and what I'll have to buy myself. :?
Man, it's hard to decide what I want to make. Limited resources, know what I mean? ;)
I was just looking at the schemmo of some tube amps. I see most of them are rigged for US use. :? But in Holland, the only grounded wall plugs are in kitchens and laundry rooms... So where's all the elctricity gonna go?