Anyone know what the "tiny terror" circuit is?

[SanoTerror]

oh, another thing i noticed is that the original tiny terror has a 3 way switch for 15w - stand by - 7w . This one doesnt. Now, the 3 way switch has 3 pins, 2 of them go to the circuit board for 15w or 7w mode. Where should the third pin go?

Also, he didnt install a fuse, which i dont think is safe for the amp. The original TT has a 250mA fuse. This should work fine with this, right?

[SanoTerror]

i correct myself. The 3 way switch is on the on/off switch like this: on - standby - off

[dummel]

oh, another thing i noticed is that the original tiny terror has a 3 way switch for 15w - stand by - 7w . This one doesnt. Now, the 3 way switch has 3 pins, 2 of them go to the circuit board for 15w or 7w mode. Where should the third pin go?

Also, he didnt install a fuse, which i dont think is safe for the amp. The original TT has a 250mA fuse. This should work fine with this, right?

Did you ever get this to work? if so how did you connect the 3way switch?

[J M Fahey]

*IF* his PT has dual voltage secondary, the center point goes to one AC corner of the diode bridge, each external lug to the different voltage taps, so it selects one or the other.

The other end of the HV winding goes to the opposite corner of the bridge rectifier.

What the original schematic shows.

If it does not have a dual voltage secondxary (a standard transformer), you can not use the 7/15W option.
You won't miss it.

Personal experience: the 15W setting barely matches a typical drummer, requires a very good cabinet (usually a Marshall 4x12"or similar) and has no clean headroom.

7W is WAY too much for a home setting and almost unusable besides a drummer.

Wire it for 15W and use that great PPIMV
Very good sound and you set it wherever you want. .... Even a bedroom

[Gingertube]

I built a 2 x ECL86 (6GW8) + 12AX7LPS(Sovtek) + 6CA4(EZ81) with the main B+ cap at 47uF (to suit the tube rectifier).
B+ = 330V. Individual cathode bias resistors of 280R (2 x 560R 2W in parallel) on ECL86 pentodes.
I built from this schemo:
http://www.diyitalia.eu/forum/downlo...4672&mode=view
My experience is that the 7/15W switch is a waste of time. The post PI master volume works so well that the amp can be dialled between bedroom levels and really really LOUD with little change in tone.
The 2 stage gain control allows dialling between clean and mean very easily. I was super impressed. So was the local guitar god who on trying it out bought it off me on the spot.
I used this output tranny: 86PP output transformer
I capped and stowed the Ultralinear taps.
This little amp is amazingly versatile and is highly recommended. I have already had a couple of the "if you build any more put me on the list for one" conversations with a couple of other local players.
Only other mods I made to the posted schematic were 22K grid stops on the PI and 2nd gain stage.
Also did the "Wiz" low noise mod with the 68K grid stop on the input stage reduced to 10K and a 470pF added from grid to 0V.
Slightly less power than if I used EL84 outputs - so what is smaller than a Tiny Terror? I called it the "Anklebiter".
Cheers,
Ian

[dummel]

Transformers

As i was searching for another layout, i found this amazing schematic with a really nice layout from a russian web. It works perfectly according to the comments so i wanna share it with you guys. It has the 7/15 watts switch, im planning on doing it without it and replace that switch with a standby switch. In that case i should use the admiral's schem, right?

[ATTACH=CONFIG]29505[/ATTACH]

[ATTACH=CONFIG]29506[/ATTACH]

[ATTACH=CONFIG]29507[/ATTACH]

Although, i could make it with that 7/15 w option...it doesnt seem to be much harder that way.

based on this build can you recommend some quality transformers?

[dummel]

based on this build can you recommend some quality transformers?

I have selected the;
261G6 power transformer
1650E audio transformer
But I see by the schematic that it will be looking for 295v but the 261G6 will provide 250v
I am running this one off of a recommendation earlier within this thread but am a bit confused here.
I have found a 272dx or 272fx that provide 300v, would this be more appropriate?

[PeanutNore]

If your transformer provides 250vac, if you use a full wave rectifier you will see much closer to 300vdc after it is rectified.

[dummel]

As i was searching for another layout, i found this amazing schematic with a really nice layout from a russian web. It works perfectly according to the comments so i wanna share it with you guys. It has the 7/15 watts switch, im planning on doing it without it and replace that switch with a standby switch. In that case i should use the admiral's schem, right?

[ATTACH=CONFIG]29505[/ATTACH]

[ATTACH=CONFIG]29506[/ATTACH]

[ATTACH=CONFIG]29507[/ATTACH]

Although, i could make it with that 7/15 w option...it doesnt seem to be much harder that way.

ok I finished it.
here are some thoughts after completing it.
I put my signal wire way to close to some of the other wires (lotsa noise). after some testing I found that it was the wire and moved it. I will need to think about a shielded wire to replace it with? not sure but I will try it and repost.
The overdrive/gain sounds more Marshall (gritty/crunchy), I was hoping for more of the clean fuzz that I had heard in youtube video.
Not nearly the amount of gain I expected.
I have no sound unless the gain knob is turned. if the gain knob is at zero and the volume is at 10 there will be no sound.
Bear in mind that I have JUST completed this thing and will need to begin my recheck, I was very methodical during the fabrication but a mistake is possible.

[dummel]

found that my cheap diodes were the issue. the voltages were all wrong. repaired that and this thing sings. I am working on adding a choke and making some other adjustments to it, I will be posting it all on www.davidummel.com within a blog post. I keep having trouble making it to these later pages in this thread, not sure why and I don't want the information to float away. this is my first amp build and I learned much, thanks everyone!

[jbefumo]

Sorry if I missed a post addressing this question, but -- what is the purpose/effect of the dual volume control pot?

[jbefumo]

So, I threw together a quick sim, and the results are shown below. I adjusted the levels until the overall volume was approximately the same, and it looks to me as if a), the dual controls attenuate more at very low (< 10Hz) and high (> 10k) frequencies, and give finer control at lower volumes. Is there anything else happening here?

[Jazz P Bass]

Cool sim.
If true, as it appears is so, that is good information to have on the dual control.
Thanks.

[chuckb]

tiny terror tranny?

You're right, I omitted the master from my drawing. It's a 500K dual-pot post-PI master with an extra set of .1uF caps.

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.

Hi, I have a set of tiny terror trannys that i'd like to use in a matchless spitfire build. I will use a full wave bridge rectifier but I'm unsure how to hook up the AC secondaries as they are not the same voltage? one is 173vac and the other is 238vac? any help would be appreciated.

Chuck.

[Chuck H]

AFAIK that is to facilitate the watts switching feature on the TT. You could emulate that or just choose the one you prefer (likely the 238VAC)