1k variable resistor in ccs of original baby huey
I am building the baby huey as of page 1 of the thread. I dont want to make a stupid wiring mistake and burn anything, hence the post. Is this the correct way to attach the variable resistor pin out, used in the CCS, to the cathodes of the driver valve (see photo)? Thanks Alan
I am building the baby huey as of page 1 of the thread. I dont want to make a stupid wiring mistake and burn anything, hence the post. Is this the correct way to attach the variable resistor pin out, used in the CCS, to the cathodes of the driver valve (see photo)? Thanks Alan
Attachments
![IMG_0090[1].jpg](/community/data/attachments/495/495570-2733bb622600cd43cfc5f67b741eebed.jpg)
Also see Post #850
http://www.diyaudio.com/forums/tubes-valves/72536-el84-amp-baby-huey-85.html#post1984158
Cheers,
Ian
http://www.diyaudio.com/forums/tubes-valves/72536-el84-amp-baby-huey-85.html#post1984158
Cheers,
Ian
dont know if i have a problem or not. I have 160ma slow blows on the secondary ht leads of the power transformer and they keep blowing on start up, since I adjusted the voltage on the anodes of the ecc83. The transformer is rated to 160ma. Sound wise everything is fine, I put a hz sweep thru it and the 1650e gives 30 hz (phew). I checked the bias and ccs units before I installed. I have just swapped the units over (I am making mono blocks and this is the first), no joy. Dont know if I should chance a larger fuse. Is it just a start up surge I am experiencing ?
the amp is using 85ma and the ccs reads -7.73v the anodes in the ecc83 are using 203 v dv...does this sound right. Are my sums right a 250-0-250 transformer at 160va needs a 160ma fuse on each ht lead to protect it. I basically get one start up, then on the next it blows everything sounds fine, I cannot see a short anywhere. I have put the fuses on the secondaries before the diodes as the "valve wizard" website sites it as correct practice
Hi Dieter,
Yes, you will need a common signal ground to connect the sections. Otherwise it would be like trying to use one wire to connect a signal between components (like tuner to int amplifier). Isolate the chassis common with resistors between say 10 to 100 ohms. That will kill ground loops.
-Chris
Yes, you will need a common signal ground to connect the sections. Otherwise it would be like trying to use one wire to connect a signal between components (like tuner to int amplifier). Isolate the chassis common with resistors between say 10 to 100 ohms. That will kill ground loops.
-Chris
I have tried smaller caps to reduce surge but the problem still remains. I am using 200ma fuses and the amp even as a mono unit sounds great, but I am not happy that the power transformer is now unprotected. On start up the ccs voltage before it enters the adjustable resistor (between the cathodes of the ecc) starts at -7.73v BUT! I have just discovered it then goes to -1.13v after a few seconds and says there...Is this what we should expect? Alan
totally confused now...it is an ecc83s that is my driver....my transformer is 3.15v ct 3.15v, when I wire it as the data sheet that is 4 and 5 not joined , each connected to a 3,15 and the ct at pin 9 I get very dull heater and only can hear the feedback source in the speaker.....when i join pins 4 and 5 and connect to 3.15v then pin 9 to the other 3.15v and ground the ct and the ccs to the ground bus i get amplified rich sound but the ccs before the adjustable resistor now reads +1.2v which I am sure is wrong...I knew it was a mistake to by at ct heater winding but it was the only reasonably priced trannie I could buy.
Fwiw... With a 6.3V heater supply, the correct way to wire your ECC83 (12AX7) heater is with pins 4 and 5 shorted and one (3.15V) lead goes to that, while the other (3.15V) lead goes to pin 9.
For 12V operation, one (6V) lead goes to pin 4, the other (6V) lead goes to pin 5. Pin 9 is the heater center tap, which may or may not need to be connected to ground, depending on the situation. With a center tapped transformer, the transformer's center tap would be grounded, and pin 9 would be left disconnected. With single 12V winding, you could ground pin 9, or create a center tap with two resistors. 'Ground' has to be somewhere.
For 12V operation, one (6V) lead goes to pin 4, the other (6V) lead goes to pin 5. Pin 9 is the heater center tap, which may or may not need to be connected to ground, depending on the situation. With a center tapped transformer, the transformer's center tap would be grounded, and pin 9 would be left disconnected. With single 12V winding, you could ground pin 9, or create a center tap with two resistors. 'Ground' has to be somewhere.
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Hi Dieter,
You still should reference the supplies to a common potential. That will prevent some possibly really odd problems. It's also good engineering practice to do this.
Never give trouble a chance to slip into your design. Cover all your bases and just do everything right. Balanced connections should have good common mode rejection, and any voltage difference between reference grounds is a common mode voltage. You're better off eliminating the problem than depending on something else to solve it for you.
-Chris
You still should reference the supplies to a common potential. That will prevent some possibly really odd problems. It's also good engineering practice to do this.
Never give trouble a chance to slip into your design. Cover all your bases and just do everything right. Balanced connections should have good common mode rejection, and any voltage difference between reference grounds is a common mode voltage. You're better off eliminating the problem than depending on something else to solve it for you.
-Chris
Hi chokesrule,
I've seen things run for a few years that you would swear shouldn't even power up. Every technician knows that just because something runs for a day is no guarantee that it is problem-free.
317 VDC where? Your B+ with a capacitor input filter would sit at 353 VDC approx. You'll lose some voltage through any C-R-C-R-C type filters, and definitely some with a choke input filter at the input of your power supply.
Are you using a multi-turn potentiometer in the cathodes by chance? That probably isn't going to stand up to the current you are running through the wiper contact. Normally that position would use a wire-wound control. For a couple mA, you might get away with a more normal single turn control that can handle some current through the wiper.
-Chris
That is a poor assumption without actual fact to back it up.
I've seen things run for a few years that you would swear shouldn't even power up. Every technician knows that just because something runs for a day is no guarantee that it is problem-free.
317 VDC where? Your B+ with a capacitor input filter would sit at 353 VDC approx. You'll lose some voltage through any C-R-C-R-C type filters, and definitely some with a choke input filter at the input of your power supply.
Are you using a multi-turn potentiometer in the cathodes by chance? That probably isn't going to stand up to the current you are running through the wiper contact. Normally that position would use a wire-wound control. For a couple mA, you might get away with a more normal single turn control that can handle some current through the wiper.
-Chris