Blackheart Killer Ant

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Blackheart killer ant Schematic

Postby quaternotetriplet » 30 Nov 2008, 03:32

Hi I'm interested to this amp. Any who have the schematic??
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Re: Blackheart killer ant Schematic

Postby GuitarLord5000 » 02 Dec 2008, 10:25

Don't know which one it is, but there's a schem for a blackheart amp here:
http://www.rowbi.myzen.co.uk/Blackheart/blackheart.htm
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Re: Blackheart killer ant Schematic

Postby qwixzh » 02 Dec 2008, 13:26

that's the little giant. :D

thanks!
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Re: Blackheart killer ant Schematic

Postby GuitarLord5000 » 02 Dec 2008, 13:48

qwixzh wrote:that's the little giant. :D


Hmmm....true.

Isn't the Killer Ant just a modified Epi Valve Junior?

Either way, I like the Little Giant better! :twisted:
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Re: Blackheart killer ant Schematic

Postby JiM » 03 Dec 2008, 01:02

It's the Little Giant who is a Valve Jr. derivative (it might even be made in the same factory, as the Harley Benton GA-5 is), with the following mods :
  • 1M input resistor (instead of 68k, already done on Valve Jr. V3)
  • 33k grid stopper on V1a (instead of 68k)
  • lower B+ for V1a
  • 1.5k cathode resistors on preamp stages (already done on Valve Jr. V3)
  • full tone stack after first stage
  • 1µF decoupling cap at V1B cathode (instead of 22µF)
  • pentode/triode switch, with screen resistor
  • different (better ?) transformers

The Killer Ant is a practice amp, using half of a 12AX7 as "power" tube, for a total power of 0.25W ! I'd love to see a schematic too ...
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Re: Blackheart killer ant Schematic

Postby quaternotetriplet » 03 Dec 2008, 01:08

Thanks for the Schematics.

But I just a small amp. that is easy to build. Anyone who has a schem of killer ant?
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Re: Blackheart killer ant Schematic

Postby GuitarLord5000 » 03 Dec 2008, 01:12

Hey Jim,

Thanks for the info!
I guess I'd like to see a schematic too!
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Re: Blackheart killer ant Schematic

Postby TragicTravisty » 03 Dec 2008, 02:51

that preamp tube as power tube thing is an excellent idea! and if the valve jr is a copy of a champ, shouldnt the credit go to the champ?
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Re: Blackheart killer ant Schematic

Postby Ronsonic » 03 Dec 2008, 06:50

The Epi Valve Jr is not a Champ copy. That would've sounded a hell of a lot better than a stock VJ.

For crazy, small amp experimentation, parallel both halves of a 12AU7 with a Fender Reverb transformer for an output. You'll get about 1.5 watts. Yep, that tranny has an 8 Ohm output.

I've got a one-tube practice amp using the reverb tranny and and a 12DW7 with the high mu side as a driver and the low mu driving the tranny. It lacks gain but takes pedals beautifully.
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Re: Blackheart killer ant Schematic

Postby TragicTravisty » 03 Dec 2008, 16:08

i thought that the vj was essentially a fender champ with a few different components and no tonestack?then again, im far from an expert
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Re: Blackheart killer ant Schematic

Postby JiM » 06 Dec 2008, 21:06

Ronsonic wrote:The Epi Valve Jr is not a Champ copy.

Yep, not directly. But it's more-or-less a reissue of the Gibson GA5 Skylark, which itself was very close to the Champ of that time ...
If you look at the 5E1 Champ and the Valve Jr. schematics, there are not much differences :
  • Attenuation resistors added after V1a on the VJ (R6 & R7)
  • Negative Feedback on the Champ : 22k from HP to V1b non-decoupled cathode
  • 1.5k grid resistor (R15) added on V2 for the VJ
  • the power tube is a 6V6 on the Champ, EL84 on the VJ
  • Power supply uses a tube rectivier and a choke on the Champ, and its voltages are a bit lower
Modding one into the other is not very difficult ...
http://www.tknives.com/classact/champ_5e1_schem.gif
http://www.muzique.com/news/images/Epi1.gif

About the Killer Ant, here is the bloc-diagram to be found in the manual. The first 12AX7 is used as two gain stages, the first half of the second one is a cathode follower driving a non-adjustable tone stack (!), then the second half is the (low)power tube.
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Re: Blackheart killer ant Schematic

Postby JiM » 06 Dec 2008, 21:26


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Re: Blackheart killer ant Schematic

Postby Ronsonic » 08 Dec 2008, 07:21

JiM wrote:
Ronsonic wrote:The Epi Valve Jr is not a Champ copy.

Yep, not directly. But it's more-or-less a reissue of the Gibson GA5 Skylark, which itself was very close to the Champ of that time ...
If you look at the 5E1 Champ and the Valve Jr. schematics, there are not much differences :
  • Attenuation resistors added after V1a on the VJ (R6 & R7)
  • Negative Feedback on the Champ : 22k from HP to V1b non-decoupled cathode
  • 1.5k grid resistor (R15) added on V2 for the VJ
  • the power tube is a 6V6 on the Champ, EL84 on the VJ
  • Power supply uses a tube rectivier and a choke on the Champ, and its voltages are a bit lower
Modding one into the other is not very difficult ...
http://www.tknives.com/classact/champ_5e1_schem.gif
http://www.muzique.com/news/images/Epi1.gif


I'm old and you had to go back to before I was born to find a Champ similar to the VJ. Fair enough I suppose - I didn't specify a year when I made that comment. I was thinking Champ = something more like: http://www.schematicheaven.com/fenderam ... _schem.pdf

Wait a minute, that Epi schematic is NOT what I found inside the two I've modded. Excuse me while I google a moment.

Here ya go: http://www.diycustomamps.com/images/sch ... _schem.pdf

That's a little more like it.
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Re: Blackheart killer ant Schematic

Postby JiM » 09 Dec 2008, 00:54

Ronsonic wrote:I was thinking Champ = something more like: http://www.schematicheaven.com/fenderam ... _schem.pdf
You're right, this version is a lot more common.
Still, the heritage is clear. The only differences i see between these two Champs are the tone stack, the NFB circuit, and the power supply (without choke).

Ronsonic wrote:Wait a minute, that Epi schematic is NOT what I found inside the two I've modded. Excuse me while I google a moment.
Here ya go: http://www.diycustomamps.com/images/sch ... _schem.pdf
This one is the second version (which is similar to my Harley Benton GA5, when it was stock :mrgreen: ), the link i've posted is the third and up-to-date version (easily recognisable to its black PCB). Only 3 resistors differ.

So, i'm not saying that they're identical, nor a copy, but that there are enough ressemblance in all these 5-watters to mod one into another. I find very interesting to understand the impact each difference has on the sound.

By the way, don't you think this Killer Ant schematic is inspiring ? i think the next mod i will do to my amp is adding a preamp tube, one half for a cathode follower driving a tone stack, and the other half for tremolo :thumbsup
Heck, where could i put 5 more knobs in it ?
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Re: Blackheart killer ant Schematic

Postby TragicTravisty » 09 Dec 2008, 01:10

so could you just replace the 6l6 in say a champ with a 12ax7? and everything would work out?
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Re: Blackheart killer ant Schematic

Postby JiM » 09 Dec 2008, 02:03

TragicTravisty wrote:so could you just replace the 6l6 in say a champ with a 12ax7? and everything would work out?
Hmm, no, it's not that simple.
In the Killer Ant, as said in the sewatt.com thread, the OT has 50 kOhm primary impedance (10 times the usual impedance for a EL84), because a preamp tube can not pass as much current as a power tube. It also has a different cathode resistor, and in this case no cathode decoupling cap.
Not quite a direct replacement !

gwtekman, from sewatt.com forum, wrote:Interesting little amp. PT has 250v secondary. OT is 50K ohm primary.

Looks like a scratch build could use a reverb driver transformer (typically around 25000 / 8 ) using a 16 ohm speaker?

Few other notes :
Wall voltage = 119V
Output at Power transformer 244V
+B to Output Transformer = 313V
V2B Plate = 307V
V2A P;ate = 274V
V1B Plate = 172V
V1A Plate = 170V

For other designs using low gain (but higher current) preamp tubes as power tubes you can look at the FireFly, and the 6n1p output tube option for the P1, both at AX84.com. There is also the Gilmore Jr. but i did not find a schematic for it.

I tried once a 6n1p (only one triode connected) in place of an EL84, it was humming a lot but the power was effectivey reduced by a fair amount. Maybe i should try again, with both triodes in parallel.
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Re: Blackheart killer ant Schematic

Postby TragicTravisty » 09 Dec 2008, 19:59

but you could use a 3pdt switch to run v2b at 240v (or whatever the other tubes are), put an el84 or whatever after v2b, and add the cap/resistors your talking about (im new to this, dont know too much about the OT impedance and stuff youre talking about)
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Blackheart Killer Ant

Postby Syrus1312 » 09 Aug 2011, 17:11

As some of you might have read, I am going to build a single tube 12ax7 amp.

This insperation came from owning a killer ant from blackheart, which is IMO a great sounding amp.
Simple and pure. Rock 'n Roll.

Are there any of you who own one of these Gems?

I want to exchange the tubes, but can't get the chassis to slide out of the case ?!? :scratch:
Rather troublesome. It seem like there are only 4 screws holding the chassis to the casing.
Am I missing something? If I remove all 4 and try pushing or pulling it doesn't move. What the?

I have some TAD 7025 "high-grade" tubes laying around, which makes me want to put them in this little sucker. Anybody have some experience with those tubes?

Any help is much obliged.

Btw, i canz put up some pictures of the inside if people are interested ;)
Some men see things as they are and say, "Why?" I dream of things that never were and say, "Why not?" - George Bernard Shaw
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Re: Blackheart Killer Ant

Postby D-Day » 09 Aug 2011, 18:24

I had one for awhile. Mine was stuck to the tolex and just needed some gentle prying to pop free.

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Re: Blackheart Killer Ant

Postby Syrus1312 » 09 Aug 2011, 19:38

Yep, that did the trick. I should have known from my fender C600, which had the backplate stuck with some glue.
But hey, better safe than sorry ;)
Some men see things as they are and say, "Why?" I dream of things that never were and say, "Why not?" - George Bernard Shaw
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