Start from the beginning. Is your mains voltage stable? The Aikido won't reject slow line voltage shifts, so I regulated the B+ on mine. If you can beg/borrow a regulated HV supply, see if that makes the problem go away.
I have a line conditioner....Generally my mains power is pretty stable.
When I measure B+ for a while I never see more than a few tenths change.
When I measure B+ for a while I never see more than a few tenths change.
Try resoldering all the connections in and from the supply. Ditto the heater supply. If the cones are moving together, the cause must be common to both channels.
You may also want to double check the value of the caps for the HV and LV PSU...of course if you had a 16V cap in the HV section it would have failed in short order...
I have caught on more than one occasion an incorrect value cap in a baggy that was labeled correctly.
I have caught on more than one occasion an incorrect value cap in a baggy that was labeled correctly.
On first powerup I did hear a slight crackling sound from the preamp.
I thought it was just the capacitors forming.
Maybe I have some fried capacitors?
I will go back through and Triple-Check my polarities and capacitors for venting.
Any other thoughts?
I thought it was just the capacitors forming.
Maybe I have some fried capacitors?
I will go back through and Triple-Check my polarities and capacitors for venting.
Any other thoughts?
I am wondering if my grounding may be an issue.
On my I/O jacks I have tied all my grounds together and brought them to the GND point on the board.
The output pad grounds are connected to the shield on the board and not to the RCA's.
The input RCA's are connected directly to the ALPS without ground, the input pad grounds are connected to the shield but nothing on the other end.
The ALPS ground is connected to the ground point.
On my I/O jacks I have tied all my grounds together and brought them to the GND point on the board.
The output pad grounds are connected to the shield on the board and not to the RCA's.
The input RCA's are connected directly to the ALPS without ground, the input pad grounds are connected to the shield but nothing on the other end.
The ALPS ground is connected to the ground point.
Attachments
My capacitors look to be in good order and the values and polarities are proper.
The LV has 16V caps and the HV has 450V.
My solder joints are not the greatest but it doesn't appear that I have any cold joints.
I have excess solder on pads and rosin on the board still.
The LV has 16V caps and the HV has 450V.
My solder joints are not the greatest but it doesn't appear that I have any cold joints.
I have excess solder on pads and rosin on the board still.
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OK, just had another thought.
I am running 12.6VAC into the heater supply.
After rectification that is 17.8VDC.
My LV caps are only 16V.
I am pushing 1.8V more than they are rated at.
Would that cause the crackling sound I heard upon first power up?
Maybe I should head to the Rat Shack and pick up some 25v capacitors to replace them.
Any thoughts?
I am running 12.6VAC into the heater supply.
After rectification that is 17.8VDC.
My LV caps are only 16V.
I am pushing 1.8V more than they are rated at.
Would that cause the crackling sound I heard upon first power up?
Maybe I should head to the Rat Shack and pick up some 25v capacitors to replace them.
Any thoughts?
Just FYI, V1&V3 heaters glow a lot brighter.
V1 & V3 are the left channel that has the hissing sound in it.
V1 & V3 are the left channel that has the hissing sound in it.
Heater PS Misconfiguration
After the umteenth time reading the heater supply portion I think I have noticed a problem.
My filament jumper settings are for a12.6V PS with 6.3V heaters.
This is normally a correct configuration.
Problem is I have the Heater PS configured for 6.3V.
I need to change R21 from 499Ω to 1.13kΩ.
This will give me a 12.6V Heater PS with the jumpers to send 6.3V to each tube.
Also the Heater PS portion of the manual has a note that says your Heater PS capacitors need to be at least VAC*1.414 rated.
This confirms my earlier worry about the 16V heater capacitors.
I have some 10,000uF 50V TS-HA's in place temporarily while I wait for replacements.
After the umteenth time reading the heater supply portion I think I have noticed a problem.
My filament jumper settings are for a12.6V PS with 6.3V heaters.
This is normally a correct configuration.
Problem is I have the Heater PS configured for 6.3V.
I need to change R21 from 499Ω to 1.13kΩ.
This will give me a 12.6V Heater PS with the jumpers to send 6.3V to each tube.
Also the Heater PS portion of the manual has a note that says your Heater PS capacitors need to be at least VAC*1.414 rated.
This confirms my earlier worry about the 16V heater capacitors.
I have some 10,000uF 50V TS-HA's in place temporarily while I wait for replacements.
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OK, here is my thought about what I was experiencing.
I think that I was feeding the heater circuit with 6.3V regulated.
The jumper settings were set to split 12.6V down to 6.3 per tube.
That was supplying my heaters with 3.15V per tube heater.
I'm positive that low voltage would cause all sorts of problems.
Any thoughts?
I think that I was feeding the heater circuit with 6.3V regulated.
The jumper settings were set to split 12.6V down to 6.3 per tube.
That was supplying my heaters with 3.15V per tube heater.
I'm positive that low voltage would cause all sorts of problems.
Any thoughts?
Attachments
I have the preamp hooked up now.
There is still a little hiss (I'm not concerned).
The thing that concerns me is that I turn the amp on then the preamp then the source (my blackberry).
The system makes a pretty loud buzz for a half second and the woofers get pushed to suspension max.
Once the buzz is finished they return to neutral.
During music playback the system functions flawlessly.
When I stop the source and turn off the preamp the woofers push to suspension max again and hold there.
Then when I turn the amp off the woofers return to neutral.
After dinner I am thinking of bringing my CD changer out to the shop and see what it does with a real source.
What's Up?
There is still a little hiss (I'm not concerned).
The thing that concerns me is that I turn the amp on then the preamp then the source (my blackberry).
The system makes a pretty loud buzz for a half second and the woofers get pushed to suspension max.
Once the buzz is finished they return to neutral.
During music playback the system functions flawlessly.
When I stop the source and turn off the preamp the woofers push to suspension max again and hold there.
Then when I turn the amp off the woofers return to neutral.
After dinner I am thinking of bringing my CD changer out to the shop and see what it does with a real source.
What's Up?
Correction......when the preamp powers up one woofer is pushed to max and the other is pulled to max.
They are held for about a half second and then both return to slightly (.5mm) negative of neutral.
During playback I can notice the woofer returning to neutral in a passage and then I notice the .5mm of negative excursion immediately after.
I notice no ill effects during playback.
The hiss is strongest at initial power up then as the tubes warm up (I guess) the hiss reduces to almost inaudible.
I don't hear the hiss until the buzz and excursion has finished.
Should I cut the output grounds?
Maybe I'm creating a ground loop between the amp and preamp???
They are held for about a half second and then both return to slightly (.5mm) negative of neutral.
During playback I can notice the woofer returning to neutral in a passage and then I notice the .5mm of negative excursion immediately after.
I notice no ill effects during playback.
The hiss is strongest at initial power up then as the tubes warm up (I guess) the hiss reduces to almost inaudible.
I don't hear the hiss until the buzz and excursion has finished.
Should I cut the output grounds?
Maybe I'm creating a ground loop between the amp and preamp???
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somehow I think you are getting a lot of DC on the speaker outputs. Do you have output caps on your power amp? Might try larger ones if you do maybe 5-10uF if you have any that large.
As far as grounding the aikido in/out...try - input RCA ground(s) to board. Run another set of wires from the input ground on the board to the pot. Board output ground(s) to RCA output ground(s). Then Aikido main board ground to star ground.
I typically turn on the aikido before the power amp and wait a few seconds to turn on the power amp...it has a tube stage so it takes about 30 seconds to equalize.
Channel hiss is typical while the heaters warm up.
Have you taken a DMM reading in DCMV on the speaker outputs from a cold turn on?
As far as grounding the aikido in/out...try - input RCA ground(s) to board. Run another set of wires from the input ground on the board to the pot. Board output ground(s) to RCA output ground(s). Then Aikido main board ground to star ground.
I typically turn on the aikido before the power amp and wait a few seconds to turn on the power amp...it has a tube stage so it takes about 30 seconds to equalize.
Channel hiss is typical while the heaters warm up.
Have you taken a DMM reading in DCMV on the speaker outputs from a cold turn on?
Also power amp speaker output ground should be taken from the negative or "0" strap of the PSU capacitor bank - not sure if you are running a bipolar psu or not.
I am running Peter Daniels LM4780 stock kit.
I do not have any output capacitors on the amp.
How large should I use?
I have 2.0uf MPP, 4.0uf MPP & 250uf NPE's.
I will try revamping my grounding procedure.
I will also take the DC readings you ask.
Thanks,
Richard
I do not have any output capacitors on the amp.
How large should I use?
I have 2.0uf MPP, 4.0uf MPP & 250uf NPE's.
I will try revamping my grounding procedure.
I will also take the DC readings you ask.
Thanks,
Richard
I would put the largest film caps in series directly on the outputs you have.
did you get the heaters sorted out? your best bet for 6.3V tubes is using a 12.6V circuit wired in pairs in series - it ends up using half the current. The key is to take readings on the pins at each tube...especially since they are referenced to B+/4 so taking a reading from one of the heater pins to ground will give you a reading of like 70V or so...right?
did you get the heaters sorted out? your best bet for 6.3V tubes is using a 12.6V circuit wired in pairs in series - it ends up using half the current. The key is to take readings on the pins at each tube...especially since they are referenced to B+/4 so taking a reading from one of the heater pins to ground will give you a reading of like 70V or so...right?
Won't my 250uf NPE's form a high pass crossover?
Is this just a troubleshooting step?
I can order some 2200uf NPE's from digikey if this is a permanent solution.
I have sorted out the heater issue, the heater PS is regulated at 12.6 and the heater setting jumpers are set to 6.3 per tube in the pair.
Yes, my B+/4 reading is like 93V if I remember correctly.
The bit about two of my tubes glowing brighter is just a function of the tube.
The two in question glow the same brightness no matter what socket I place them in.
So...I ended up putting the two bright ones in the driver stage and the two dimmer ones in the follower.
Is this just a troubleshooting step?
I can order some 2200uf NPE's from digikey if this is a permanent solution.
I have sorted out the heater issue, the heater PS is regulated at 12.6 and the heater setting jumpers are set to 6.3 per tube in the pair.
Yes, my B+/4 reading is like 93V if I remember correctly.
The bit about two of my tubes glowing brighter is just a function of the tube.
The two in question glow the same brightness no matter what socket I place them in.
So...I ended up putting the two bright ones in the driver stage and the two dimmer ones in the follower.
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