Anyone thought of making an Orange Tiny Terror?

[Wicksy]

I fancy giving it a go at some point. The circuit looks pretty simple so i figure i could knock one up on some turret strip. Barry sells the right PT to implement the half power switch and his OT will work nicely.

If i get something together would anyone be interested in a layout?

[joe6v6]

If i get something together would anyone be interested in a layout?

I would be very intrested, even though I havent seen the schematic (if there is one) Is this a single ended 6 watt 1xEL84 type thing?

JOE

[Bulatovic]

Nope, its a push pull 2xEL84, and yes, there is schematic on this lovely forum.

PS. I have copied this schematic from some thread which i can't find now, but anyway

[Wicksy]

I tried one and was pretty impressed. Whether it sounds much different to the 18 watt lite i have built is another thing. Even if it does you can never have enough 18 watters can you?

Bare with me though, this will be my first layout.

[populartsl]

Wicksy

I'd be interested in the little toaster

Ben

[jckid66]

there is a similar post over at the sloclone forum

[martinw]

Hey Wicksy, nice one, I might be interested.
It shouldn't sound like a Lite, as there's more gain going on in the preamp. I tried one at Sounds Great and was mightily impressed.

BTW you should come to one of our gigs, you can hear my 36W in action!

[zaphod_phil]

I tried one and was pretty impressed. Whether it sounds much different to the 18 watt lite i have built is another thing. Even if it does you can never have enough 18 watters can you?

I've checked the schematic. I can see several obvious things in the circuit which I think could be improved, so that the tone doesn't get mushy or fizzy when cranked, or suffer woofy low end. BTW, the Superlite TMB 18W is also a similar kind of an amp, but with TMB tone controls.

[Wicksy]

I tried one and was pretty impressed. Whether it sounds much different to the 18 watt lite i have built is another thing. Even if it does you can never have enough 18 watters can you?

I've checked the schematic. I can see several obvious things in the circuit which I think could be improved, so that the tone doesn't get mushy or fizzy when cranked, or suffer woofy low end. BTW, the Superlite TMB 18W is also a similar kind of an amp, but with TMB tone controls.

Cool! Its being laid out on turret strip (a spare bit hauled from an old Sound City chassis) for easy modding. I figured the Tiny Terror wouldnt escape the soldering irons of the guys here

I'll make a stock version then mod it I have all the parts i need but it does mean tearing apart my Ampmaker kit to do so...I suppose i could rebuild it afterwards.

Only thing i was thinking about was whether Barry's PT will deliver the correct HT voltage for the Tiny Terror. I could do with someone who has a Tiny Terror measuring the HT off the PT secondaries and the B+ off the rectifer. That way i can change the dropper ressitors as required or am i worrying too much?

[Wicksy]

Hey Wicksy, nice one, I might be interested.
It shouldn't sound like a Lite, as there's more gain going on in the preamp. I tried one at Sounds Great and was mightily impressed.

BTW you should come to one of our gigs, you can hear my 36W in action!

I'd love to but i've since moved back to Essex. I finished uni in Manchester. I guess i should update my profile. I'm angling for a job up around there so maybe some other time.

[conger]

Wicksy - This http://music-electronics-forum.com/show ... php?t=1477 is where the schematic came from. I seem to remember there was some discussion about the 2 PT voltages.

Very interested to hear how you get on with this.

[conger]

Anyone know how the AD15 and the Tiny Terror compare?

[zaphod_phil]

Cool! Its being laid out on turret strip (a spare bit hauled from an old Sound City chassis) for easy modding. I figured the Tiny Terror wouldnt escape the soldering irons of the guys here

Several cap values need to be reduced. Change the cathode bypass caps in the preamp to around 1uF or 2.2uF. You could also experiment with lifting the 2nd preamp stage's bypass cap for some NFB. Change the two 0.047uF coupling caps between the preamp and PI to 0.022uF or maybe 0.01uF. The two 0.1uF caps going to the grids of the EL84s also need to be reduced to 0.022uF or even 0.01uF.

A couple of resistor values could also do with being changed. The 1.2k resistor on the PI cathodes will tend to make the PI distort in a fizzy way, and needs to be reduced to 820 ohms (like an 18W) or 470 ohms for a bit more crunch. I would also suggest reducing the 2nd preamp stage's cathode resistor to something between 620 and 1k ohms. 820 ohms might be a good value to start with. Lower values will give earlier distortion, and vice versa.

These are just some fairly obvious fixes that need doing, with some room for tweaking to taste.

Only thing i was thinking about was whether Barry's PT will deliver the correct HT voltage for the Tiny Terror.

If it's for Barry's 18W kit, then the voltage should be in about the right ballpark.

[Wicksy]

Cheers Zaphod_Phil, just what i needed to know.

I have a couple of questions about the cicuit though:

I got confused by the two 500K audio pots either side of V1b. From the schematic it looked like they might be a dual ganged pot. I guess one is the gain and one is the tone control. Can anyone tell me which is which please? Also, there seems to be a 500K pot in series with a 2.2nF cap across the two 100nF power section coupling caps. What purpose does this serve? The tone stack seems a little confusing to me. Can anyone explain to me how that works please?

[zaphod_phil]

The ganged pots act together as a gain control. There's no tone control as such in the preamp. The only tone control is the one in the power amp, with the 500k pot and 0.0022uF cap between the EL84 grids. It provides a simple treble cut function, the same as you'll find in many Vox amps.

[peesinstew]

I got confused by the two 500K audio pots either side of V1b. From the schematic it looked like they might be a dual ganged pot.

This is a dual ganged pot which controls the gain by simultaneously attenuating the signal both going from V1a to V1b and from V1b to the PI.

Also, there seems to be a 500K pot in series with a 2.2nF cap across the two 100nF power section coupling caps.

This is the "Tone" control of the amp. It acts like the classic Vox "cut" control by allowing higher frequencies to cross between both sides of the post-PI circuit, where they get cancelled out. Adjusting the 500KL pot will change the cutoff freq.

At least this is my understanding of how this works. There may have been a better description in one of the other threads about the TT on this site.

Whoops! Sorry Phil! I take too long to type.

[Wicksy]

Nice one. Cheers guys for the clarification. However the Tiny Terror has three controls and there appears to be only two indicated in the schematic... I'm guessing theres a master volume in there somewhere?

[conger]

AdmiralB, who I believe drew the TT schematic said about the MV - "I omitted the master from my drawing. It's a 500K dual-pot post-PI master with an extra set of .1uF caps."

... and also about the PT:

"The power switch is on my drawing, it's on the HV secondary. It selects between two 'ends' of the winding - HV winds up with about 325V and LV about 250V."

[Wicksy]

AdmiralB, who I believe drew the TT schematic said about the MV - "I omitted the master from my drawing. It's a 500K dual-pot post-PI master with an extra set of .1uF caps."

... and also about the PT:

"The power switch is on my drawing, it's on the HV secondary. It selects between two 'ends' of the winding - HV winds up with about 325V and LV about 250V."

Cheers mate! Thats a typical PPIMV then. Brilliant!

[Boprikov]

I think the master volume pot is included in that schematic. "500 KA dual" between the PI and tone control.