Given the voltage on this amp, I am some 50v below what the Tweedle Dees are spec'd to. Could this amp take a conversion to the Tweedle Dee circuit? With these Transformers.
A
Tweedle Dee possible?
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Tweedle Dee possible?
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Stevem
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Re: Tweedle Dee possible?
If you simply just swap in a 5AR4 rectifier you will gain back a additional 30 volts of V+ since the internal impedance is less then a 5Y3 recto and that should be well in range of having a TD .
You will also have the added benefit of a slow warm up time with the 5AR4 so you do not even need a standby switch, this will also extend the life of the first filter node cap .
In terms of picking up even a few more volts of V+ the 5AR4 can handle having a total of 60 mfd of filtering at the first power supply node where as the 5Y3 can only deal with 40 mfd.
Be sure to get a real 5AR4 like a JJ brand!
The glass case of a real 5AR4 will be the same size as the black Octal bass, if it looks like a 5Y3 glass bulb which is smaller then base then that’s a tip off!
Also if you have the room you could add a small separate 6.3 volt filiment transformer to light up all the tubes other then the rectifier and this will ease the load on the power transformer.
This can get you another 3 volts of V+ plus power.
A 2 amp 6.3 volt transformer is all you would need.
A transformer such as a Hammond 166L6 would work fine, and it does not even cost 17 bucks.
You will also have the added benefit of a slow warm up time with the 5AR4 so you do not even need a standby switch, this will also extend the life of the first filter node cap .
In terms of picking up even a few more volts of V+ the 5AR4 can handle having a total of 60 mfd of filtering at the first power supply node where as the 5Y3 can only deal with 40 mfd.
Be sure to get a real 5AR4 like a JJ brand!
The glass case of a real 5AR4 will be the same size as the black Octal bass, if it looks like a 5Y3 glass bulb which is smaller then base then that’s a tip off!
Also if you have the room you could add a small separate 6.3 volt filiment transformer to light up all the tubes other then the rectifier and this will ease the load on the power transformer.
This can get you another 3 volts of V+ plus power.
A 2 amp 6.3 volt transformer is all you would need.
A transformer such as a Hammond 166L6 would work fine, and it does not even cost 17 bucks.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Tweedle Dee possible?
Thanks Steve, looks like its doable. I have some 5AR4's around here.
Best A
Best A
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Stevem
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- Joined: Fri Jan 24, 2014 3:01 pm
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Re: Tweedle Dee possible?
Is this amp your modding cathode biased?
If so note the idle voltage on pin 8 because once the amp is running on the higher voltage you will want to increase the ohmage of that cathode resistor to get that same idle voltage back.
Just use ohms law to figure out the ohms per volt you have now.
If so note the idle voltage on pin 8 because once the amp is running on the higher voltage you will want to increase the ohmage of that cathode resistor to get that same idle voltage back.
Just use ohms law to figure out the ohms per volt you have now.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Tweedle Dee possible?
Yes Cathode Biased, so I will run those numbers.
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Tweedle Dee possible?
Off the top of my head I would say that increasing the value of that resistor by 12% should get you well in the ball park and then you can fine tune it.
What amp is this that your modding to the TD?
What amp is this that your modding to the TD?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Tweedle Dee possible?
Its the Dukane I have been messing with.