Anyone thought of making an Orange Tiny Terror?
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I've had a quick read about the PPIMV mod on NMV amps. Theres a nice thread over at Metroamp talking indepth. However i dont see much mentioned about the mod on cathode biased amps. I'm not sure how that would work.
The Metroamp thread is here for reference:
http://forum.metroamp.com/viewtopic.php?t=4390
The Metroamp thread is here for reference:
http://forum.metroamp.com/viewtopic.php?t=4390
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In this case the post-PI MV is already part of the amp. And it makes no difference whether it's a cathode-biased or fixed bias amp. It works the same way in both cases. You just need to have a reasonable amount of gain in the preamp and PI, which is certainly the case with the Tiny Terror.
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Thanks Loy. After looking at a picture of the tiny terror I see its labeled 15 watts - 7 watts. I suppose one could use a power resistor to drop the B+ coming from the rectifiers to achieve the same result, or to place the resistor before the rectifiers.
With the PPIMV wouldn't you achieve similar results of low volume vs. tube distortion, or is there something to power scaling I'm missing?
btw Loy one of these days I'm gonna get to work on that 18 watt amp; I'm to the fun stage of wiring everything up.
With the PPIMV wouldn't you achieve similar results of low volume vs. tube distortion, or is there something to power scaling I'm missing?
btw Loy one of these days I'm gonna get to work on that 18 watt amp; I'm to the fun stage of wiring everything up.
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I'm working on the layout. The MK 1 version should be posted when i get it roughed out then put into electronic format. The half power switch is basically switching between two taps of the HT winding on the PT secondary. Barry Plows in the UK sells an 18 watt PT that can do just that. All you need is a two way switch (with three prongs on. The two PT taps go either side of the switch and the middle goes to the rectifer. That way you can switch between different B+s.
I'm thinking can caps might be easier with the hand-wired layout. A dual 50uF + 50uF and a single 100uF should do most of the filterign while the 22uF cap can be accomadated onboard.
It should be interesting to see whether i could build one from scratch cheaper than i could buy one. I intend to tear down by Ampmaker 18 watt lite for much of the bits and should just need to order a few pots and power resistors. I'm even going to have a go making my own chassis from a PC case...
I'm thinking can caps might be easier with the hand-wired layout. A dual 50uF + 50uF and a single 100uF should do most of the filterign while the 22uF cap can be accomadated onboard.
It should be interesting to see whether i could build one from scratch cheaper than i could buy one. I intend to tear down by Ampmaker 18 watt lite for much of the bits and should just need to order a few pots and power resistors. I'm even going to have a go making my own chassis from a PC case...
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What would happen by using a PT with 290/215 taps verses the 325/250 taps stated in another thread as the original voltages. Would this set of transformer work OK for the 7/15 watt drop?
http://www.brownnote.net/bntransformers.html
http://www.brownnote.net/bntransformers.html
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Cheers Stray Cat. I have a rough version of the layout which i'm going to tidy up and get in electronic format. I might have that up by tonight.
ing that thread, there is a suggestion about replacing the power selector switch with a double pole switch to also switch in another cathode resistor when going from 7 watts to 15 watts thus keeping the bias of the output tubes consistent at both power levels. Thats a really good idea. I might try and implement that later on...
ing that thread, there is a suggestion about replacing the power selector switch with a double pole switch to also switch in another cathode resistor when going from 7 watts to 15 watts thus keeping the bias of the output tubes consistent at both power levels. Thats a really good idea. I might try and implement that later on...
Last edited by Wicksy on Wed 05/16/07 7:20 am, edited 1 time in total.
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