Recomended voltage ratings for PAS 3 resistors and caps

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I took some readings based on the voltages in the manuals maybe to help with getting a clearer picture of the state of my unit.
My homes VAC line voltage can be 125+ VAC.
So that might be boosting my readings some.

Start with the Quad CAP.

Square=  422 VDC      /spec=405V
Triange=  376 VDC      /spec=355v
Line=      340 VDC      /spec =330v
Half Moon= 230 VDC   /spec=210

12X4 Tube

1   350 VAC      /spec= 335vac
2   0               /spec=0
3  .511 VAC     /spec=10.5vac (LOW)
4  .303 VAC     /spec=10.5vac (LOW)
5  0               /spec=0
6  350 VAC     /spec=335vac
7  420 VDC     /spec=405vdc

PC 5 board Tubes (tubes installed)

1  177 / 175 VDC     /spec=175vdc
2  0/0                    /spec=0
3  1.5  /  1.6 VDC    /spec=1.45
4  .25 / .24 VDC      /spec= less than 1 volt
5  11.4 / 10.8 VDC   /spec=11vdc
6  210 / 205 VDC     /spec=200vdc
7  0/0                    /spec=0
8  1.1 / 1.1 VDC      /spec=1.25vdc
9  5.0 / 5.5 VDC      /spec=5.5vdc


PC 6 board Tubes   (tubes installed)

1  118 / 120 VDC      /spec=115vdc
2  0/0                    /spec=0
3  .7 / .7 VDC         /spec=.7vdc
4  0 /0                  /spec=0
5  11 / 10 VDC       /spec=11vdc
6 144 / 143 VDC     /spec=135vdc
7  0 / 0                /spec=0
8  .8 / .8 VDC        /spec=.8vdc
9  5.5 / 5.4 VDC    /spec=5.5vdc

Midwestside wrote:I took some readings based on the voltages in the manuals maybe to help with getting a clearer picture of the state of my unit.
My homes VAC line voltage can be 125+ VAC.
So that might be boosting my readings some.

Start with the Quad CAP.

Square=  422 VDC      /spec=405V
Triange=  376 VDC      /spec=355v
Line=      340 VDC      /spec =330v
Half Moon= 230 VDC   /spec=210

12X4 Tube

1   350 VAC      /spec= 335vac
2   0               /spec=0
3  .511 VAC     /spec=10.5vac (LOW)
4  .303 VAC     /spec=10.5vac (LOW)
5  0               /spec=0
6  350 VAC     /spec=335vac
7  420 VDC     /spec=405vdc

PC 5 board Tubes (tubes installed)

1  177 / 175 VDC     /spec=175vdc
2  0/0                    /spec=0
3  1.5  /  1.6 VDC    /spec=1.45
4  .25 / .24 VDC      /spec= less than 1 volt
5  11.4 / 10.8 VDC   /spec=11vdc
6  210 / 205 VDC     /spec=200vdc
7  0/0                    /spec=0
8  1.1 / 1.1 VDC      /spec=1.25vdc
9  5.0 / 5.5 VDC      /spec=5.5vdc


PC 6 board Tubes   (tubes installed)

1  118 / 120 VDC      /spec=115vdc
2  0/0                    /spec=0
3  .7 / .7 VDC         /spec=.7vdc
4  0 /0                  /spec=0
5  11 / 10 VDC       /spec=11vdc
6 144 / 143 VDC     /spec=135vdc
7  0 / 0                /spec=0
8  .8 / .8 VDC        /spec=.8vdc
9  5.5 / 5.4 VDC    /spec=5.5vdc

It's all ok.
It's higher then the manual reason is higher mains. No reason for alert.
Note that the 12x4 readings is measures between pin 3 and pin 4 !

It's all ok. It's higher then the manual reason is higher mains. No reason for alert. Note that the 12x4 readings is measures between pin 3 and pin 4 ! wrote:

I see, i had wondered why the ] was. Yep 11.8 VAC between 3 and 4

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PeterCapo wrote:With a 125+ VAC mains, I'd think the B+ should be a bit higher than what he's reading.  The filaments should definitely be higher than his readings, but no surprise with the original selenium rectifier.

125+ VAC is starting to redline a Dynaco Stereo 70, worse for a Latino Stereo 70, no?  I believe the Latino has a higher secondary voltage than the original.

Just for educational purposes which reading is the B+, would that be pin 7 of the rectifier or square on the quad cap?  By the way i had it on 125 V mains on the bench.  But when connected to the st 70 for listening, both are on a variac.

I do the the Dynaco PAS Z-PSU Power Supply coming so that should take care of some things

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This is what i do, take the reading from the variac's out, the meter is often wrong.

On an additional note,  I pulled one of the black cat caps as sample and one of the blue .22uf caps, both tested about dead on to whats printed on the caps with my cheapo component tester and  my fluke capacitance setting for comparison.

Based on this it would seem that dropping in a filament supply board , replacing resistors , getting a new volume pot and tube sockets, perhaps that's all this really needs??

I just am not sure what the unit is 'supposed' to sound like sonically.  To me it sounds kind of lacking in detail, hence me thinking that 'things need to be done' to improve on it.

I actually just re flowed all the solder joints on PC 5 . I can tell a good bit of improvement in the sound quality.
I may need to go over the whole unit.

I also took the sovtek tubes from the phono section and swapped them for the chinese no names in PC 5 . WAY better. I just took the sellers word for it that the tubes were good. Maybe they are,
but the sovteks really made an improvement.

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Midwestside wrote:This is what i do, take the reading from the variac's out, the meter is often wrong.

I also took the sovtek tubes from the phono section and swapped them for the chinese no names in PC 5 .  WAY better.  I just took the sellers word for it that the tubes were good. Maybe they are,
but the sovteks really made an improvement.

If you can hear a difference so notable just by this swap you definitely should get a good set of tubes before even thinking about component replacement. At the bare minimum replace the junk Chineese ones you already know are no good. You can spend a fortune on tubes chasing NOS or other exotics, but imho JJ makes an excellent tube. I would just get a new set of 4 like these to baseline things at known good.

https://www.amazon.com/12AX7-ECC83-Electronics-Regular-package/dp/B07P83B3NZ/ref=sr_1_6?dchild=1&keywords=12ax7+tube+jj&qid=1590418954&sr=8-6

EDIT: It is still essential to replace the can cap asap, or as an option, add one of the powers supply boards mentioned above. This would make replacement of the can cap unnecessary since it will be completely out of the circuit.

rjpjnk wrote:

Midwestside wrote:This is what i do, take the reading from the variac's out, the meter is often wrong.

I also took the sovtek tubes from the phono section and swapped them for the chinese no names in PC 5 .  WAY better.  I just took the sellers word for it that the tubes were good. Maybe they are,
but the sovteks really made an improvement.

If you can hear a difference so notable just by this swap you definitely should get a good set of tubes before even thinking about component replacement. At the bare minimum replace the junk Chineese ones you already know are no good. You can spend a fortune on tubes chasing NOS or other exotics, but imho JJ makes an excellent tube. I would just get a new set of 4 like these to baseline things at known good.

https://www.amazon.com/12AX7-ECC83-Electronics-Regular-package/dp/B07P83B3NZ/ref=sr_1_6?dchild=1&keywords=12ax7+tube+jj&qid=1590418954&sr=8-6

EDIT: It is still essential to replace the can cap asap, or as an option, add one of the powers supply boards mentioned above. This would make replacement of the can cap unnecessary since it will be completely out of the circuit.

Yeah, i decided to go with these:

TAD 7025

I have had JJ in another unit and they are good and reliable. And yes, I did not want to go chasing NOS until i figured out if I really liked this unit.

I have a volume control coming that Peter Capo recommended and TubeNirvana Filament supply board coming. I am sure that between those and reflowing more solder joints, I should be able to
refine the sound more and more. As i posted above, I tested some of the caps out of circuit and they were very close to spec, so maybe the next refresh would be changing to metal film resistors, but leaving the caps there.

rjpjnk wrote:

Midwestside wrote:This is what i do, take the reading from the variac's out, the meter is often wrong.

I also took the sovtek tubes from the phono section and swapped them for the chinese no names in PC 5 .  WAY better.  I just took the sellers word for it that the tubes were good. Maybe they are,
but the sovteks really made an improvement.

If you can hear a difference so notable just by this swap you definitely should get a good set of tubes before even thinking about component replacement. At the bare minimum replace the junk Chineese ones you already know are no good. You can spend a fortune on tubes chasing NOS or other exotics, but imho JJ makes an excellent tube. I would just get a new set of 4 like these to baseline things at known good.

https://www.amazon.com/12AX7-ECC83-Electronics-Regular-package/dp/B07P83B3NZ/ref=sr_1_6?dchild=1&keywords=12ax7+tube+jj&qid=1590418954&sr=8-6

EDIT: It is still essential to replace the can cap asap, or as an option, add one of the powers supply boards mentioned above. This would make replacement of the can cap unnecessary since it will be completely out of the circuit.

JJ E83CC is an exact reimplementation av TESLA E88CC which in turn is a copy of telefunken ECC803S
those are the famous "frame grid" tubes that costs an arm and a leg at ebay.
They are available at a decent price at eurotubes.com.

peterh wrote:

rjpjnk wrote:

Midwestside wrote:This is what i do, take the reading from the variac's out, the meter is often wrong.

I also took the sovtek tubes from the phono section and swapped them for the chinese no names in PC 5 .  WAY better.  I just took the sellers word for it that the tubes were good. Maybe they are,
but the sovteks really made an improvement.

If you can hear a difference so notable just by this swap you definitely should get a good set of tubes before even thinking about component replacement. At the bare minimum replace the junk Chineese ones you already know are no good. You can spend a fortune on tubes chasing NOS or other exotics, but imho JJ makes an excellent tube. I would just get a new set of 4 like these to baseline things at known good.

https://www.amazon.com/12AX7-ECC83-Electronics-Regular-package/dp/B07P83B3NZ/ref=sr_1_6?dchild=1&keywords=12ax7+tube+jj&qid=1590418954&sr=8-6

EDIT: It is still essential to replace the can cap asap, or as an option, add one of the powers supply boards mentioned above. This would make replacement of the can cap unnecessary since it will be completely out of the circuit.

JJ E83CC is an exact reimplementation av TESLA E88CC which in turn is a copy of telefunken ECC803S
those are the famous "frame grid" tubes that costs an arm and a leg at ebay.
They are available at a decent price at eurotubes.com.

Thanks, i will note that. This is why im on the forums.

Upon recommendations I got the tube Nirvana power supply kit.
Pretty easy to assemble and install.
Big improvement in sound. I think this is what was lacking and not the impedance thing i posted about in another thread.
Bass has more weight and slam now, top end shines but not overly so
Volume pot should be hear soon. Really loving to 'hear' the progress here.

Just added a 250K alps pot from parts express i didn't end up using for another project.
Definitely upped the game by alot.

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PeterCapo wrote:Does it have the loudness taps?  Six terminals or eight?  If so, did you use them or omit them?

I bypassed them.  6 terminals ,250k. I just wanted to 'see' what a new volume pot would do for now.
I have the one with the loudness tap arriving late june.

I wanted to see what it would sound like bypassed also.
I probably wont ever use the loudness switch, however when i do use the loudness switch
the the low end becomes 'tubby' and muddy.
maybe thats another problem i will need to address with the new volume pot if i decide to add loudness back.

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PeterCapo wrote:

Midwestside wrote:

PeterCapo wrote:Does it have the loudness taps?  Six terminals or eight?  If so, did you use them or omit them?

I bypassed them.  6 terminals ,250k. I just wanted to 'see' what a new volume pot would do for now.
I have the one with the loudness tap arriving late june.

I wanted to see what it would sound like bypassed also.
I probably wont ever use the loudness switch, however when i do use the loudness switch
the the low end becomes 'tubby' and muddy.
maybe thats another problem i will need to address with the new volume pot if i decide to add loudness back.

The loudness contour circuit is supposed to sound like that - it isn't a problem.  The loudness contour boosts the bass.

What I'd like to ask is this: without the loudness circuit, how fast does the volume get loud as you are turning it up?  Does it seem like it gets too loud with not too much of a turn of the volume control?

Without the loudness, it feels like volume scales evenly and naturally with the new pot and a little bit the same way with the old pot before i replaced it..  Nice low level listening at around 9 oclock on the dial, descently loud around 10 oclock on some tracks and then 'bother the neighbors ' in the apartment next door around 12.
Its louder than it previously was. Before the volume would plateau around 9 oclock and and then get louder around 1 oclock, but this could have been the old pot.