JPS said:
I respectfully disagree,
If he is running the heaters off the same power, he will pull 2.4A just for the heaters....I think it will blow the .5A fuse you suggest
A dimmer switch does not work the same way. Sorry, Look on FleaBay for a used Variac. I picked mine up for <$30 and it looks brand new. One of the best investments I ever made.....
.47 is a good place to start, measure the voltage (carefully) and add more capacitance as needed to raise the voltage to desired level.
Ron
Brit,
Here is a great explaination of the differing types of controllers and when to use which type.
http://www.fancollectors.org/info/speed.htm
Ron
Here is a great explaination of the differing types of controllers and when to use which type.
http://www.fancollectors.org/info/speed.htm
Ron
Put a light bulb in series with the line in, as you would a fuse, for testing. Maybe 25W or so. This adds a level of protection against a dead short somewhere. If the bulb lights to full brightness, something is wrong. If less then full brightness, go ahead and check your voltages. They will be low due to the presence of the bulb…John
Looks like the trace for pin 1 goes in close proximity to a ground trace - then there looks to be an provision for a jumper. I presume that this would be for using a rectifier that needed a ground for pin 1 ???
The 6X5 rectifier that I think most are using does not use anything for pin 1 so no worries.
The 6X5 rectifier that I think most are using does not use anything for pin 1 so no worries.
Some brands of 6X5 rectifiers have an internal shield, connected to pin 1, for grounding. Close the jumper if using valve with shield.
http://www.mif.pg.gda.pl/homepages/frank/short/064/6/6X5G.gif
Hum in my Aikido
May be to Bas (or anyone else)?
I do need some help to get rid of hum on my Aikido. I do have a feeling that it is the powerunit who is the “troublemaker”??
B+ is taken from a CT transformer with this specification: 2x110 V AC 50VA. I do not use the CT (0-220).
AC heather to 6x5 GT is taken from a separate 6,3 V AC transformer.
I have measured AC in on the power unit to 263 V with Aikido connected and playing music quite well (except for the hum).
C1 is 0,47 uF.
Instead of R1 I use 10H 195 ohm (I took what I had)
Still with the Aikido connected, I measure only 140 V DC on the Aikido board. I have also measured between BIAS from the power board and GND on Aikido: Result ca. 80 V.
BIAS is connected to CT on a separate 2x6,3 V 2,5 A transformer (Hammond 266 L12).
Heather on the Aikido board connected in series.
The BIAS I have measured is very far from what Broski recommend (reference voltage= one-fourth the B+ voltage, for example 75 V when using a 300 V power supply).
80 V BIAS from a 140 V supply must be far from what it should be?? I think this is the reason having the hum.
My intentions from the beginning was to go for 300 V power supply, but the voltage drop over C1 and DCR is obviously to much.
1.So what value do I choose for C1?
2. What do I do to have the correct BIAS?
May be my intention of having a 300 V power with a 263 V AC in is to optimistic?
Will 200 V be a better/realistic choice??
On the Aikido board I use 6N6P in both positions, driving the second tube a little harder than the first one 220 ohm versus 430 ohm. R 15 = 78 Kohm and R 16= 100 Kohm.
Regards
Eivind Stillingen, Norway
May be to Bas (or anyone else)?
I do need some help to get rid of hum on my Aikido. I do have a feeling that it is the powerunit who is the “troublemaker”??
B+ is taken from a CT transformer with this specification: 2x110 V AC 50VA. I do not use the CT (0-220).
AC heather to 6x5 GT is taken from a separate 6,3 V AC transformer.
I have measured AC in on the power unit to 263 V with Aikido connected and playing music quite well (except for the hum).
C1 is 0,47 uF.
Instead of R1 I use 10H 195 ohm (I took what I had)
Still with the Aikido connected, I measure only 140 V DC on the Aikido board. I have also measured between BIAS from the power board and GND on Aikido: Result ca. 80 V.
BIAS is connected to CT on a separate 2x6,3 V 2,5 A transformer (Hammond 266 L12).
Heather on the Aikido board connected in series.
The BIAS I have measured is very far from what Broski recommend (reference voltage= one-fourth the B+ voltage, for example 75 V when using a 300 V power supply).
80 V BIAS from a 140 V supply must be far from what it should be?? I think this is the reason having the hum.
My intentions from the beginning was to go for 300 V power supply, but the voltage drop over C1 and DCR is obviously to much.
1.So what value do I choose for C1?
2. What do I do to have the correct BIAS?
May be my intention of having a 300 V power with a 263 V AC in is to optimistic?
Will 200 V be a better/realistic choice??
On the Aikido board I use 6N6P in both positions, driving the second tube a little harder than the first one 220 ohm versus 430 ohm. R 15 = 78 Kohm and R 16= 100 Kohm.
Regards
Eivind Stillingen, Norway
Different 6x5 tubes like (must) have different rated capacitors directly after them. (first one in the power supply) Most are in the 5 - 30 uF size.
6x5 types
You must read up on this as it is not standardized!
I just looked into this myself.....
I ordered 4 from FleaBay for $10.00 all were used but they are tough sturdy tubes. They were used in automobile radios! Also used on the space station and shuttle! Sturdy tubes.
This was ripped straight from a thread on this forum. I love diyaudio.......
bournville
Jayal,
I can understand the confusion over reservoir caps - it is not helped by different manufacturers giving different specifications. I have the specs for several thousand valves by different manufacturers, and, for example, Mullard quote 16uf for the reservoir cap of a 6X5GT whilst Tungsram quote 4uf, Cossor quote 8uf and Brimar 32uf! Mullard quote 16uf for a 6X5, but Brimar quote 40uf!
To play it safe it might be wise to veer towards the lower values in your power supply. In the old valve sets I mentioned which used a 6X5(GT) a 8uf was common for a reservoir cap and 16uf for the smoothing cap after a choke.
Ron
6x5 types
You must read up on this as it is not standardized!
I just looked into this myself.....
I ordered 4 from FleaBay for $10.00 all were used but they are tough sturdy tubes. They were used in automobile radios! Also used on the space station and shuttle! Sturdy tubes.
This was ripped straight from a thread on this forum. I love diyaudio.......
bournville
Jayal,
I can understand the confusion over reservoir caps - it is not helped by different manufacturers giving different specifications. I have the specs for several thousand valves by different manufacturers, and, for example, Mullard quote 16uf for the reservoir cap of a 6X5GT whilst Tungsram quote 4uf, Cossor quote 8uf and Brimar 32uf! Mullard quote 16uf for a 6X5, but Brimar quote 40uf!
To play it safe it might be wise to veer towards the lower values in your power supply. In the old valve sets I mentioned which used a 6X5(GT) a 8uf was common for a reservoir cap and 16uf for the smoothing cap after a choke.
Ron