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Thunderbird Club
- Thread starter TBird1958
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- club thunderbird
Sweet. Do I get a higher ranking if I get more likes?
Well, sure. True counterfeiters? Nail them to the wall and take every cent they have. But in that case, why telegraph anything? Get PIs involved, take it to the feds, and have them raided and shut down where possible, and tie them up in court otherwise. The video won't make any difference to such people.
MMmmmmm, Lemme think about that.
It's a tube head. Should be safe at 4 ohms. Going to a higher impedance gets riskier with tubes; they're backwards to transistors that way. With tubes, exact match is ideal, but half is normally fine unless they're running everything on the hairy edge (especially the OT).
Disclaimer: I have never looked inside a Tiny Terror to check its build quality, voltages, etc. If only we had someone here with experience to address this. If only... (weeps inconsolably)
No non working amps in the corner. The place is gonna be filled with bass players. I'm going to need amps that work.
And more basses.
no need for tears...
recently worked on a Dark Terror (post 115817) which although a little more involved is similar to the Tiny.
The plate of an EL-84 will start to melt around 9 Watts. If you look at the below schem;
you'll notice the output is operated in Class A (red circle on cathode self biasing components) and a blue circle on the power output (7 or 15 W) rating switch.
driving 4 Ohms should not be a problem with the switch in the 7 Watt setting. At 15 Watts all that's going to happen is the thing will get hotter. At 15 Watts and full volume the OT winding ratings may be exceeded resulting in funny smells and possibly smoke....as long as the volume is not set to max on the 15 Watt setting, one should be ok. All that would happen is earlier OT core saturation that (when not excessive) is characterized by the OT starting to bandpass the signal....some like this...
I have liked this post also. I suppose until @BklynKen starts looking at his likes, we will have to post to let him know we "liked" his post.
no need for tears...
recently worked on a Dark Terror (post 115817) which although a little more involved is similar to the Tiny.
That was sarcasm, because I had just seen your post. 8^)
....AND you're suppose to like my post...
no need for tears...
recently worked on a Dark Terror (post 115817) which although a little more involved is similar to the Tiny.
The plate of an EL-84 will start to melt around 9 Watts. If you look at the below schem;
View attachment 3451460
you'll notice the output is operated in Class A (red circle on cathode self biasing components) and a blue circle on the power output (7 or 15 W) rating switch.
driving 4 Ohms should not be a problem with the switch in the 7 Watt setting. At 15 Watts all that's going to happen is the thing will get hotter. At 15 Watts and full volume the OT winding ratings may be exceeded resulting in funny smells and possibly smoke....as long as the volume is not set to max on the 15 Watt setting, one should be ok. All that would happen is earlier OT core saturation that (when not excessive) is characterized by the OT starting to bandpass the signal....some like this...
Cathode bias isn't necessarily class A. And if they're truly getting 15W from the amp, they'd really be pushing it with class A. Well, depending on the tube brand. Did you measure voltages and current in the output stage?
I designed a clean 7W single EL84 amp; I spent hours and hours testing tubes. I forget now what I settled on, but there were only 2 or 3 brands that would handle the abuse and sound good. I was working on ways to switch between a baby Twin clean sound and a more Kalamazoo Model One dirt but never came up with anything I was happy with. I did mate an Orange preamp with both a VOX AC-15 output stage and a Fender Deluxe output stage. Loved both of those.
Is it a common problem, or are they just random JDs?
no need for tears...
recently worked on a Dark Terror (post 115817) which although a little more involved is similar to the Tiny.
The plate of an EL-84 will start to melt around 9 Watts. If you look at the below schem;
View attachment 3451460
you'll notice the output is operated in Class A (red circle on cathode self biasing components) and a blue circle on the power output (7 or 15 W) rating switch.
driving 4 Ohms should not be a problem with the switch in the 7 Watt setting. At 15 Watts all that's going to happen is the thing will get hotter. At 15 Watts and full volume the OT winding ratings may be exceeded resulting in funny smells and possibly smoke....as long as the volume is not set to max on the 15 Watt setting, one should be ok. All that would happen is earlier OT core saturation that (when not excessive) is characterized by the OT starting to bandpass the signal....some like this...
It has been a while since I have analyzed such things, but the configuration of the output transformer look to me like a push pull arrangement, not class A. Then again, the second gain stage does not look like it is inverting the signal. Colour me confused.
As far as running at 4 Ohms, unless there is a 4 ohm tap, I am unlikely to do it. What I can't understand is that output transformers with a 4 ohm tap are commercially available and do not meaningfully change the BoM cost.
BYOTB, A, &C - Thunderbird, Amp, and Cab.
You can do 15W Class A by running 2 EL34s parallel. Push pull can be done too, but requires a different O/T configuration. Amps such as the SVT run push pull with 3 6L6 parallel on either side of the phases.
