Anyone know what the "tiny terror" circuit is?

[chuckb]

hey chuck, thanks for the reply. if i eliminate the lower voltage secondary,do i just connect the higher voltage to the one side and leave the other side disconnected?

[Chuck H]

hey chuck, thanks for the reply. if i eliminate the lower voltage secondary,do i just connect the higher voltage to the one side and leave the other side disconnected?

Yup. Cap it with a wire nut or clip it flush and shrink tube it or (best) solder it to a fixed point that doesn't go anywhere like Marshall did with unused PT taps.

[chuckb]

hey chuck, i have a green 0v wire on the secondary of the power tranny grounded to the chassis. When i connect the ground of the rectifier the amp blows a fuse. when i disconnect any one of these grounds the amp stays on but no sound, any suggestions?

[Chuck H]

Is this 0V wire a center tap on the HV wind? If yes then it isn't used with a bridge rectifier unless you are connecting it to the junction of two filter caps in series as the first filter.

With the 0V of the bridge lifted the rectifier operates as a typical full wave rectifier that would need a 0V CT secondary. Not sure why there's no sound. We need to correct for the power supply first.

[chuckb]

hey chuck, a question about the 120v ac on the power supply. i have two 120v ac wires on the primary and 2 0v windings , I have the two 120vac wires (red and brown) conected to my on/off switch and i have the two 0v (black and blue) wires connected to the N on the power cord?
i'm also using a 500ohm/10w resistor in place of the choke. still have no sound.

[chuckb]

hey chuck, thanks for all your help, very much appreciated. I have sound now although it is low. I was wondering what size of resistor can i use in place of a chock in the spitfire build?

[Chuck H]

The site isn't allowing me to load the image for a better look right now so I can't say about which wire colors you've chosen. It sounds like your primary is a 120/240 depending on how you use the two 120 primary winds. It would help to have a schematic of what your doing with the power supply. There are ways one should wire filament and HV secondary winds. The use of CT in either is dependent on design.

It would also help to know the story as it's unfolding. Why do you have sound now? You didn't say how that was accomplished.

500R/10W seems fine to me. Most guys use 1k as a matter of course (probably because that's what the TrainWreck Liverpool and Rocket use) but most manufacturers seem to use 470R or 500R.

[g1]

The site isn't allowing me to load the image for a better look right now so I can't say about which wire colors you've chosen.

Try this one Chuck, it does not have a CT :

[chuckb]

hey chuck, i got sound when i used the ov green secondary to one side of the rectifier oppisite the purple ac238v secondary as you suggested. i believe it might be the primary thats causing me the trouble. I have the two primary 120v (brown and red wires) twisted together and going to a leg on the power switch. the 0v primary wires(black and blue ) are twisted together and soldered on the mains "N". I've checked all my connections throughout the board and went over every solder joint as well. I changed out the ot tranny for another new one and still the same results. G1 below has a good pic of the power tranny I'm using.I will post the schematic as soon as i can get a good pic of it. it seems to always come out blurry when i take a pic of it. oh ya the schematic i'm using calls for a GZ34 rectifier tube but where the tranny has no 5v winding i decided to go with the full wave rectifier instead.

[Chuck H]

Well, to be sure I didn't suggest any wire colors. It's interesting designations on those windings. 0V is somewhat a misnomer. I think it has to do with a language barrier

And speaking of language barriers (see what I did there?), can you please be more specific as to the type of rectifier you are using? Some people call a bridge rectifier a "full eave bridge". And correctly. But then there's the "full wave" which isn't bridged. To avoid confusion in threads I use the terms "bridge rectifier" or "full wave rectifier" to keep them distinct. Now, I don't suppose you are actually using a "full wave" rectifier as your HV secondary doesn't have a center tap that a full wave rectifier needs. If you are wired as a full wave, but without a center tap, you may be half wave rectified. I suspect you have low voltages.

I do think the parallel primaries is correct. It usually is but I can't be certain. You should show a schematic of what you actually have. The only reason I haven't asked for voltage readings is that I suspect your rectifier still isn't even wired correctly. I suppose voltage readings could confirm this and maybe give a some clues too though.

[chris07011985]

Hi,

I would like to install a FX-Loop (Kit Tube FX-Loop 6112 - Tube-Town GmbH) into my Tiny Terror. Because of the additional Valve I need additional 300mA for the filament.
Does anybody know the spec of the power transformer regarding the the filaments? I though I somewhere read something about 6,3V / 3A, is that correct?

Thanks
Christian

[Chuck H]

Why not build a transistor circuit for the FX loop and avoid taxing the filament winding entirely? Since anything in the effects loop is likely to be transistors or op amps, what tonal advantage is there to using a tube in the loop???

That said...

Just build it with the consideration that you may need an auxiliary 6.3V transformer. Leave a space for it just in case. I couldn't find specs for a stock TT PT. So what I would do is measure filament voltage, build it and recheck filament voltage. Also check power transformer temperature after a long burn in. If the voltage doesn't drop below spec and the PT doesn't get really hot, you're fine. If the filament voltage drops below spec and/or the transformer gets too hot you'll need to add the extra transformer. And that's ok because we accounted for that possibility.

[J M Fahey]

And anyway what's the point?

In a TT , loop is *always* before the distorting stage so you are not preserving delicate effects as reverb, chorus, flanger, delay, etc., they still get clipped when you clip.

You might as well use your effects between guitar and amp, for basically the same result.

[Chuck H]

Excellent point. So... Another option might be to add a line out circuit to the amp. This could even be done in a separate box. Then you could steal some signal of the final amp tone, send it to the effects and then to another amp or the PA. I know this involves another amp of some kind. But no added amplifiers in the main amps circuit and theres just no practical way to do it well in the TT anyhow.

[ivan.mangialenti]

New amp builder and love for TT

Hey there! I'm new, and ready to start in this world of amp making. After some months in studying and modifying existing amps I decided to build my first: a TT.
I've been starting from a schematic (find above in this thread) realized by AdmiralB and modified by Thomeeque (see attachment 1).
My first question: can you confirm that the schematic is correct? Is there a more updated version?

Looking to some thread in this site and around the web I built a Bill of Material (see attachment 2, sorry it's a pdf but the site doesn't accept Excel file - I can send it by mail)
with all the reference to the schematic and some comments collected here and there.
My second question: can you give a look to the BOM and correct/add your comment/fulfill the blanks?
Mainly I need suggestion about the Caps type and the choice of trannies.
I think when the BOM is completed may be a good help to all new amps builder like me!

Many thanks in advance!
Ivan