Blackvibe 6v6 making noise at 3/4 or 75% volume to 100% .Not able to bias.

[silat]

I would appreciate help on figuring this out.

v1 pin1-247, Pin3-1.68, Pin6-0, pin-0

v2 pin1-218,pin3-74.3,pin6-52.94,pin8-0

v3 Pin3-402.4,pin4 -296.6, pin5-42.38

v4 Pin3-402.6,pin4-402.5,pin -42.38

V5 Pin2-376,Pin3-5.6,pin4-173.6,pin5-5.6,pin6-176.4


There is no reverb not tremolo...  Like I said it sqeals Hums makes terrible noise at 75% -100% Volume.....Some of the other pots hum and squeal at times also.

I will give pictures after  work. I used the Hammond 175 0H OT and the 290 BX PT

[tdvt]

V1/P6 voltage missing in action is where I would start.

[silat]

  I should probably say although I have been building tube amps for years I have never really understood what I was doing. I never had anyone really teach me. So I am the worst of newbies. I am just good at being a COPY-CAT and have had some luck at making my builds work. I wanted to let you all know where I am coming from on this. I feel like I am just just now after many years starting to learn a few things. But nothing like any of you here. I would appreciate guidance in learning. I mentioned before I was a plumber not dealing with any electronics whatsoever.

Thank you in advance for your patience with me.

[tdvt]

V1 P1 & P6 should have similar voltage, as should V1 P3 & P8, so something is amiss there.

V2 looks wonky too as V2 P3 & P8 are supposed to be tied together (same voltage)

[silat]

tdvt, Thank you for answering my post so promptly! I did not have time yet to post pics but will soon. I have the 6v6 version.

[Rontone]

I'm just preparing to do the same build,

Are V5 GZ34 Pins 2 and 8 the 5v heaters?

You have 376v [is that DC?] on Pin 2, yet Pin 3 and 5 for the HT connection have 5.6v on them, get some pics of that rectifier wiring too,

176v ish volts on Pins 4 and 6 is about half your HT voltage, are you using backup diodes? I don't know what would happen if they were the wrong way round,

Maybe remove those tubes in case of damage to them and check the rectifier socket pin AC voltages with no tube in...

[sluckey]

yet Pin 3 and 5 for the HT connection have 5.6v on them

I suspect those readings were operator error on the meter.

[pdf64]

… 176v ish volts on Pins 4 and 6 is about half your HT voltage, are you using backup diodes? …

The schematic and layout show backup diodes.
Yes, the weird readings at terminals 4&6 are almost certainly due to them already having rectified the waveform there.

[Rontone]

Phase Inverter V2 Pin 3 has 74v on the cathode?

Be careful when testing Silat, make sure that you are safe first,

Check your chassis and grounding connections in case something is wired wrong on the High Voltage side of the power transformer

[silat]

Here are some Pictures.

[silat]

More.

[silat]

The board.

[sluckey]

Your soldering job may be a factor. What kind of solder are you using? What soldering iron?

[Rontone]

In the first picture, your large blue power caps have some burn marks/scratches on the side, the metal can inside could touch and short on close by parts, watch out for that

[silat]

Your soldering job may be a factor. What kind of solder are you using? What soldering iron?

Kester 60/40

[silat]

I am using a 30 watt  soldering iron.

[silat]

I know my builds are nothing like you all submit. I am not going to give up though. I will keep trying until I get to where they are just as good as some of yours. May take awhile. I have a lot of learning to do. I enjoy doing it. I am afraid to submit my pictures since your builds always look so good in comparison, even first timers look better than Mine.  I do not want to kill myself doing it either so I try really hard to practice safety. I hope somebody can tell me what they see with fresh eyes.
 

[silat]

In the first picture, your large blue power caps have some burn marks/scratches on the side, the metal can inside could touch and short on close by parts, watch out for that

Yes I need to watch-out for that.  I did not realize I gave a thumbs down. I meant to give a thumbs up to your comment. Thank you!

[tdvt]

I am using a 30 watt  soldering iron.

Used one myself for many years of simple repairs but no build.


Bought an older model of this 10+ years ago (LINK) & it was truly a game changer.


You will not regret the expense to move up; fine control, consistent heat w/extra heat available for de-soldering, the holder/sponge/cleaner. A great package.
.

[silat]

I am using a 30 watt  soldering iron.

Used one myself for many years of simple repairs but no build.


Bought an older model of this 10+ years ago (LINK) & it was truly a game changer.


You will not regret the expense to move up; fine control, consistent heat w/extra heat available for de-soldering, the holder/sponge/cleaner. A great package.
.

Ok I will look for it. Thank you.

[silat]

That looks a little more stream line than the fat clunker I have from Sears.

[silat]

… 176v ish volts on Pins 4 and 6 is about half your HT voltage, are you using backup diodes? …

The schematic and layout show backup diodes.
Yes, the weird readings at terminals 4&6 are almost certainly due to them already having rectified the waveform there.

Yes, I am using back up diodes. Pins 3-4 and pins 5-6 on the GZ34.

[Rontone]

I was a bit worried when you said you had come from the world of plumbing you might be using some pipe solder! 

What sounds good doesn't always look good inside!

I notice you have put cap values facing upwards which is good practise for reference, carry on checking the power wiring, and that rectifier socket solder connections, that they are just like Robs layout plans and getting the right AC voltage to the socket, are the backup diodes the correct way round,

Don't put that GZ34 in yet, they are expensive, don't want to run it backwards.... best to blow some cheap diodes first,

[silat]

I was a bit worried when you said you had come from the world of plumbing you might be using some pipe solder! 

What sounds good doesn't always look good inside!

I notice you have put cap values facing upwards which is good practise for reference, carry on checking the power wiring, and that rectifier socket solder connections, that they are just like Robs layout plans and getting the right AC voltage to the socket, are the backup diodes the correct way round,

Don't put that GZ34 in yet, they are expensive, don't want to run it backwards.... best to blow some cheap diodes first,

I am pretty sure I have them right. Positive side with the grey line would go to pin 4 and  pin 6.

[silat]

Just like this drawing is how I have them.

[Rontone]

I can see some little bits of excess leg on some connections, check all over for little bits of overhang touching etc, cut any excess or redo those connections

If you have some needlenose pliers, put a little curve/loop on the end of the tinned wire to get a good connection to the tab on the socket, it hooks it onto the hole a little better

[silat]

I can see some little bits of excess leg on some connections, check all over for little bits of overhang touching etc, cut any excess or redo those connections

If you have some needlenose pliers, put a little curve/loop on the end of the tinned wire to get a good connection to the tab on the socket, it hooks it onto the hole a little better

yeah I am going to go through and recheck and reheat etc. making sure it is good.

[sluckey]

The fact that you have 400VDC on the 6V6 plates pretty much says the rectifier is wired correctly. However, the workmanship at the rectifier socket is less than desirable.

[Rontone]

I'm not sure about the finer details of layout, but is it easy for you to move that bias pot away from your first preamp tube? Get it somewhere down near the power supply end, closer to the power tubes,

What's the top side like for space in that area, just near the output transformer and power supply end of your board, I can just about visualise where your output transformer is from the wires,

I'm wondering if your preamp tubes are quite close together, and close to the power tubes, could the bias supply and mini balance pot move down near the power tubes, and then those 2x preamp tubes can shift up one or two spaces towards the input side[I see some holes cutout already]

It would involve moving their wires, some of them are underboard connections so may be annoying for you to do, but the wires seem long enough

[silat]

The fact that you have 400VDC on the 6V6 plates pretty much says the rectifier is wired correctly. However, the workmanship at the rectifier socket is less than desirable.

I will rework it then and see If I can get it better than it is.

[silat]

I'm not sure about the finer details of layout, but is it easy for you to move that bias pot away from your first preamp tube? Get it somewhere down near the power supply end, closer to the power tubes,

What's the top side like for space in that area, just near the output transformer and power supply end of your board, I can just about visualise where your output transformer is from the wires,

I'm wondering if your preamp tubes are quite close together, and close to the power tubes, could the bias supply and mini balance pot move down near the power tubes, and then those 2x preamp tubes can shift up one or two spaces towards the input side[I see some holes cutout already]

It would involve moving their wires, some of them are underboard connections so may be annoying for you to do, but the wires seem long enough

I will try anything to get it to work. I don't think moving the bias pot would be too much work to move. 

[silat]

Here is the top view of the chassis arrangement. I have a little wiggle room to move two tubes down and move the bias pot toward the power tubes.

[Rontone]

Don't forget your problem you have right now might be simple to fix without a lot more work, your amp is mostly working, it just has a fault, it may simply just be wiring or a few solder joints,

Its a bigger chassis than it seems on the inside pics, quite a bit of room on the end there, it would be good to space things out a bit more, for the heat from the tubes too, definitely an inch or more

But mostly to help those 6V6's cool a bit if spaced out, and make a rock solid build, maybe that last preamp tube socket next to the power tubes could be opened out to octal size [its hard to do when the hole is already punched out to get a good centrehole on the punch and get it to hold in position....] then moving those preamp tubes 'further on up the road'

The preamp tubes would then be much closer to your inputs for your sensitive signal wires, their high voltage plate connections and other wiring will be short and not crossing over etc etc, also close to their preamp parts on your board and they won't have signal wires going past the bias supply/power supply area, making it easier for you to get your soldering iron in around the tonestack and volume pots area

The heater wires will be going further if the valves are spaced out so will need to be well twisted going up to the preamp end, the input sockets will be close to the preamp tube sockets and in the way etc for soldering, but inputs could be removed and put in last while your soldering everything,

Its a lot of work, some drilling for bias pot etc [watch out for drilling bits getting on your circuit when drilling an already built amp etc]  pull all wires off those preamp sockets and one of the power tubes, redo heater wiring, and all socket connections cleanly back on, but its less than you have done already I suppose, as long as it doesn't introduce more problems! 

[Rontone]

Is this bit of tag strip on your power tube socket connected to anything?

If you have more pieces with a few more tags on, would make a good anchor point for your bias pot circuit to support the parts a bit more, the resistors coming off the pot etc can be on the tags, a bit studier, the bias power diode up on the board and the bias circuit electrolytic cap etc stay there and wire down to it

I'm just doing the same thing tonight, working on an old 60's chassis putting some tagstrips on and drilling out old rivets to work out a bias pot assembly, and move the power tubes apart a bit...

[silat]

I have my bias filter grounded to it.

[silat]

I am not going to start working on it until Monday.  I am off on Mondays.

[tubeswell]

So you've already been told to look at the no-voltage occurring at V1 Pin 6. What did you find? This is a plate pin - should be at around 2/3rds of the voltage that is present on the pre-amp filter cap node. Did you miss a wire?

[silat]

So you've already been told to look at the no-voltage occurring at V1 Pin 6. What did you find? This is a plate pin - should be at around 2/3rds of the voltage that is present on the pre-amp filter cap node. Did you miss a wire?

v1 pin 6 219.5 VDC

[silat]

 I do not know How it had 0 the first time I checked it. The wire is clearly soldered to pin 6

[silat]

The pic is pin 6 of V1

[silat]

 I am moving my bias pot and trim pot closer to the power tubes. My preamp tubes further downstream from the 6v6's.