I don't think it is a good idea to mix the earthing with the ground lift.
The earth lead should be attached to the chassis via an M4 bolt and star washer next to where it enters, and that connection not used for anything else.
Regarding the ground lift, that could be from the negative of the PSU capacitor to whatever you are using for that, with the other end connected to the chassis. Then all the other grounds should end up going to the PSU capacitor via their normal routes.
I have restored a couple of these, and found that it was possible to have a neat solution with the power entry at the end by the power transformer, which saves the wires going the length of the amp. Also I discovered a laptop style IEC socket could be attached behind the large fuse holder, so I use a laptop lead with mine. The mains selector is no use with the voltages of today, so I removed that and put a new 35mm fuse holder in there, along with an illuminated toggle switch.
I fitted a ground lift too, but it was just a 5W 10R resistor. What are the two polystyrene capacitors in there for?
The earth lead should be attached to the chassis via an M4 bolt and star washer next to where it enters, and that connection not used for anything else.
Regarding the ground lift, that could be from the negative of the PSU capacitor to whatever you are using for that, with the other end connected to the chassis. Then all the other grounds should end up going to the PSU capacitor via their normal routes.
I have restored a couple of these, and found that it was possible to have a neat solution with the power entry at the end by the power transformer, which saves the wires going the length of the amp. Also I discovered a laptop style IEC socket could be attached behind the large fuse holder, so I use a laptop lead with mine. The mains selector is no use with the voltages of today, so I removed that and put a new 35mm fuse holder in there, along with an illuminated toggle switch.
I fitted a ground lift too, but it was just a 5W 10R resistor. What are the two polystyrene capacitors in there for?
I've got many different GE KT66s. I'm not sure what you mean about writing down numbers. I know what the spec readings should be and the issue is these monos aren't stable enough to get any sensible readings when under power
Not silver micas. they are 22pf polystyrene which are recommended for possible stability issues
I've explained the two polystyrene caps on previous reply. They made no difference. The earth lift is applied from the original connection to the chassis, so there's no mixing of earths and negatives. The original earthing scheme is intact with only the original chassis connection connected via earth lift to the chassis. I've used the safer implementation of diode bridge as well as resistor and 0.1uf capacitor
I used this reference when modifying my Quads ...
Patrick Turner: Quad IIs
I added screen grid resistor, the 'snubber' arrangment with 33pF capacitor, separate cathode resistors, larger screen grid electrolytic, DC blocking from the RCA input, and that was about it I think.
Patrick Turner: Quad IIs
I added screen grid resistor, the 'snubber' arrangment with 33pF capacitor, separate cathode resistors, larger screen grid electrolytic, DC blocking from the RCA input, and that was about it I think.
Using the wires that are specifically coloured for earthing for the grounding does make it hard to see that.
When looking at the picture in your post #34, I get the impression that the blank piece of wire going from the right-hand side 680K grid leak resistor to the tag where one side of the 2.7K resistor terminates is not soldered (properly).
Could of course again just be a matter of perspective. Only trying to help.
Could of course again just be a matter of perspective. Only trying to help.
Sovtek 6L6WXT are Russian tubes close to 6L6GC, New Sensor and others are the same tube as a 6L6GC. They are all good tubes.
I have rebuilt many Quad II amplifiers without ever having problems. Just watching. I'd make them stock, the biggest deviation I made was to replace the Jones plugs with a single RCA on a metal plate.
I have rebuilt many Quad II amplifiers without ever having problems. Just watching. I'd make them stock, the biggest deviation I made was to replace the Jones plugs with a single RCA on a metal plate.
It is actually perspective. That lug sheared off so they are correctly soldered but it does look a bit strange
As far as I know, it is not good practice to have a wire/connection wrapped around a lug/tag/etc. before the point of actual soldering.
But of course I can not know if this explains the problems that you are experiencing. To begin with, I do not know how the soldering on this lug looks like in your other Quad 2.
But again, just trying to help.
But of course I can not know if this explains the problems that you are experiencing. To begin with, I do not know how the soldering on this lug looks like in your other Quad 2.
But again, just trying to help.
Actually was baudouin0 onto something about the caps My eyes are not great but, I think I am seeing 1uF which does seem high for a valve amp. I havent got the quad schematic handy at the moment to check.
First of all, remove coupling capacitors from power tubes grid.
Check the static values shows in original Quad II schematic.
p.s.
0.1uF the original coupling cap value.
Check the static values shows in original Quad II schematic.
p.s.
0.1uF the original coupling cap value.
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'As far as I know, it is not good practice to have a wire/connection wrapped around a lug/tag/etc. before the soldering takes place.
But of course I can not know if this explains the problems that you are experiencing. To begin with, I do not know how the soldering on this lug looks like in your other Quad 2'
The lug on the other one is fine. Many say you should wirewrap the lug then solder so opinions clearly differ.
But of course I can not know if this explains the problems that you are experiencing. To begin with, I do not know how the soldering on this lug looks like in your other Quad 2'
The lug on the other one is fine. Many say you should wirewrap the lug then solder so opinions clearly differ.
Taken from V cap tech notes.
Some info to consider.
Some info to consider.
- The short lead indicates the outermost foil, and should be connected to the lowest impedance path to ground. Another way to identify outer foil is the writing on the label flows towards the outer foil.
- The ODAM, TONE, and OIMP series capacitors have metal bodies that are electrically conductive. Ensure that the body doesn't make electrical contact with any other portion of the circuit other components or electrically LIVE circuit traces. Heatshrink, 3M foam tape, or silicone tape around the body may be used to help insulate, and protect from electrical short. The TONE Cap series with values from .01 uF to .047 uF have a clear insulating sleeve over the brass canister and provides some isolation, but you should still safeguard against any laceration or puncture of this 'skin' to prevent any short...
- outer foil.
- The ODAM, TONE, and OIMP series capacitors have metal bodies that are electrically conductive. Ensure that the body doesn't make electrical contact with any other portion of the circuit other components or electrically LIVE circuit traces. Heatshrink, 3M foam tape, or silicone tape around the body may be used to help insulate, and protect from electrical short. The TONE Cap series with values from .01 uF to .047 uF have a clear insulating sleeve over the brass canister and provides some isolation, but you should still safeguard against any laceration or puncture of this 'skin' to prevent any short...
please With the amplifier off and the power capacitors discharged, measure the resistance of pin 5 of the kt 66 socket to the e ground.
Where does your mains supply come from? I see two brown wires is this from an autotransformer?
Also you have metal can coupling caps, are the 22pf caps redundant because the metal caps will have something similar 15-22pf to ground leakage?
The amps allegedly worked, did you check this before the rebuild.
The valves you have are 6L6G Russian equivalents, are they 100% pin compatible? has the amp been previously modded to run with different valves. I.e. was the wiring that you have replaced 100% correct?
Also you have metal can coupling caps, are the 22pf caps redundant because the metal caps will have something similar 15-22pf to ground leakage?
The amps allegedly worked, did you check this before the rebuild.
The valves you have are 6L6G Russian equivalents, are they 100% pin compatible? has the amp been previously modded to run with different valves. I.e. was the wiring that you have replaced 100% correct?