I have one ECC808 that I will try with this phono stage. I have adapter aswel because of different pinout. ECC808 should be even better than any ECC83 mentioned.
What LED should be used Ollie, and why?
The BOM said any LED, I'm using red, and it seems to all work ok.
Would a different colour improve things?
Yellow..
Original BOM said any green IIRC, but it turned out the forward voltage (?) mattered.
I can't remember why. As @Vivant has gone on holiday for a week, we'll have to wait for the technical answer.
I've just looked at the original BOM that I ordered from (not necessarily the actual original you refer to, as I came in quite late) and it actually states red or yellow.
I think I got red simply because that was first on the Farnell listing.
Hopefully, when Alan returns, refreshed and raring to go, he can advise whether it'd be beneficial to change them.
It sounds superb, brilliant job by yourself, Alan and all concerned.
I think I got red simply because that was first on the Farnell listing.
Hopefully, when Alan returns, refreshed and raring to go, he can advise whether it'd be beneficial to change them.
It sounds superb, brilliant job by yourself, Alan and all concerned.
Finally. Powered up the LV supply and I think I have problems because the valves don't light up and some of the valve pin measurements look low or mad. I'm reluctant to go further without some guidance or reassurance
After 5-10 minutes the valves are warm, but nowhere near hot, and the VReg heatsink is warmer, but not so much that it's uncomfortable to touch. No smoke.
For my testing I've closed the mm/mc switch and can hear the relays tick over on power on/off, but nothing from the LEDs because no HV. The inputs and outputs aren't connected and the loading is just jumpered. I've got the multifet boards and have r7 as wire links.
The LV taps from the transformer are at 9.85v (10.3v unloaded) when valves are in, the output of the VReg is 4.86v (4.93v no valves) and there's 10.4v on C1P regardless of valves or not. So everything up to and including the vreg looks OK.
The valves are ECC83 and PCC88 and I've got the jumper set. Voltages for the heaters (pins 4&5?): V1: 4.79, -23mv, V2:4.19, 4.18, V3:4.9 -48mv. As I understand it I should be looking for 6.1 to 6.5v so they're probably 1.5-2v too low, and the pin 5 values are just plain wrong. With the valves out the measurements on the pins don't change much if at all. R2P, R3P are 4.9v.
ZD1p is 1n4615-1 2v 500mw, and FWIW the LEDs are bog standard yellow LEDs from mouser MCL034YD (20ma 2.1v) everything else was from the BB3 BOM.
I'd already had problems with the first Vreg not doing anything sensible (it's a right bugger to change it with those caps front and back), the second one seems to behaving itself but I'm beginning to wonder...
I've done the obvious things, like checking for dry joints, orientation and bridges. I think I've taken this about as far as I can without some help to point me at where to look next. I might wile away the time checking the resistors are where they should be...
After 5-10 minutes the valves are warm, but nowhere near hot, and the VReg heatsink is warmer, but not so much that it's uncomfortable to touch. No smoke.
For my testing I've closed the mm/mc switch and can hear the relays tick over on power on/off, but nothing from the LEDs because no HV. The inputs and outputs aren't connected and the loading is just jumpered. I've got the multifet boards and have r7 as wire links.
The LV taps from the transformer are at 9.85v (10.3v unloaded) when valves are in, the output of the VReg is 4.86v (4.93v no valves) and there's 10.4v on C1P regardless of valves or not. So everything up to and including the vreg looks OK.
The valves are ECC83 and PCC88 and I've got the jumper set. Voltages for the heaters (pins 4&5?): V1: 4.79, -23mv, V2:4.19, 4.18, V3:4.9 -48mv. As I understand it I should be looking for 6.1 to 6.5v so they're probably 1.5-2v too low, and the pin 5 values are just plain wrong. With the valves out the measurements on the pins don't change much if at all. R2P, R3P are 4.9v.
ZD1p is 1n4615-1 2v 500mw, and FWIW the LEDs are bog standard yellow LEDs from mouser MCL034YD (20ma 2.1v) everything else was from the BB3 BOM.
I'd already had problems with the first Vreg not doing anything sensible (it's a right bugger to change it with those caps front and back), the second one seems to behaving itself but I'm beginning to wonder...
I've done the obvious things, like checking for dry joints, orientation and bridges. I think I've taken this about as far as I can without some help to point me at where to look next. I might wile away the time checking the resistors are where they should be...
I wish. I replaced the Zener at the same time I replaced the Vreg.
Are all 2v 500mw Zeners created equal though? Which Zener are you using? I have another mouser order to go out soon, so...
C1P no valves is 13v (not what I said). So 1v below what Vivant was saying it should be in #759
Thing is, the heater voltages being low is one thing, but there's as good as nothing on the pin5 of both of the PCC88's, but not the ecc83? I'm sure it means something, but I've no clue what :|
Are all 2v 500mw Zeners created equal though? Which Zener are you using? I have another mouser order to go out soon, so...
C1P no valves is 13v (not what I said). So 1v below what Vivant was saying it should be in #759
Thing is, the heater voltages being low is one thing, but there's as good as nothing on the pin5 of both of the PCC88's, but not the ecc83? I'm sure it means something, but I've no clue what :|
Vreg is faulty. Good without tubes, but with tubes in no Voltage on heaters. I soldered a old 7805 and everything was fine.
Don't remember, came from Farnell. But increasing the voltage by 2v is what it's there for.
Heaters being 2v low is exactly what I had, and replacing zd1p cured it.
I did have lots of problems with the voltage regulator as well.
Got to be one or the other.
Heaters being 2v low is exactly what I had, and replacing zd1p cured it.
I did have lots of problems with the voltage regulator as well.
Got to be one or the other.
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@Flikoman. First one was definitely was, same as you. But this one they're the same regardless of valves being there or not. So it may be the Vreg, I'd like it to be the Vreg, but I'm not sure. Think I may have borked something else...
Perhaps I'll just pick a different Zener and another Vreg just to be sure...
Perhaps I'll just pick a different Zener and another Vreg just to be sure...
Forget zener, put green LED instead. It has to in reverse if you compare with zener. Led cathode on zener anode.
@Flikoman Thanks for reminding me, I'd read it in the thread somewhere but had forgotten it could be an alternative. But I have no green LEDs. Hohum.
What are you measuring voltage at pin 5 against? I imagine pin 5 on the PCC88's is the heater ground
You should have 7v across pin 4 and 5 on the pcc88's, and 6.3v across pin 4 and 9 and pin 5 and 9 on the ECC83.
If the jumper is in the 6N2P position, you should have 6.3v across 4 and 5 on V2
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Happy to confess to noob status in all of this. I think I've tied myself into a knot trying to understand too much before I started asking questions.
Been back and looked at ecc83 and I can see you're right about the parallel heater supply. All the measurements were against ground. I'll go back, measure again just to be sure.
@Flikoman Tried a yellow LED with a Vf of around 2.03v and now I have heater voltages of 6.9v so I should be good to go?
Yeah, everything is fine and within tolerances. Measure on ECC83, just to confirm. It think it will be a little low, but that is not a problem, it can be adjusted easily.
ecc83 pins 4&5 are at 6v at start but gradually drop to about 5.8 while being measured, pcc88's pin 4 stays at around 6.8v
Voltages should stay steady on the heaters. Seeing V1& V3 are steady, although a tad low, I would imagine there's a fault with whatever is being used to drop the voltage from 7v to 6.3, which I assume is a voltage divider using a couple of resistors, although I've no idea which ones.
I've not had any issues or experience with this part of the circuit, so I'm only surmising to give you starting point
Vivant would be best placed to answer, unfortunately he's on holiday.
I've not had any issues or experience with this part of the circuit, so I'm only surmising to give you starting point
Vivant would be best placed to answer, unfortunately he's on holiday.
If I remember correctly, R2P and R3P and in parallel and are dropping resistors for ECC83 heaters. What values do you have?