help with PT-2 install on Paramour I

[jeff g]

I'm installing a PT-2 on my Paramour I amps (after a bit of a delay).

Ideally, I'm looking for installation instructions - step by step.  I've searched but wasn't able to find much and previous guidance from PJ, Grainger and others was helpful, but not enough direction and I haven't done any building for quite awhile.

I have a couple specific questions.

1.  is it ok to shrink wrap the unused PT 2 leads?
2.  I'm going to put in new caps.  Should I do the install / test first or just switch everything at once?
3.  are these parts ok? they were the closest i could find but are different than the P1 parts

220uf cap: 
http://www.digikey.ca/product-search/en?lang=en&site=ca&KeyWords=493-2028-nd&x=0&y=0

47uf cap:

http://www.digikey.ca/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&keywords=p13563-nd&x=14&y=19&cur=USD

1.2k10w res:
http://www.digikey.ca/product-detail/en/20J1K2E/20J1K2E-ND/822935

10K res:
http://www.digikey.ca/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&keywords=alsr5f-10.0k-nd&x=0&y=0&cur=USD
270 5w res:
http://www.digikey.ca/product-detail/en/AC05000002700JAC00/PPC5W270CT-ND/596709

Thanks in advance

Jeff

[Paul Birkeland]

Start with the transformer swap, don't do everything at once, as troubleshooting will be tough.

Does your original Paramour transformer still have the ID sticker on it? 

We can go off this pic (thanks to Wardsweb):

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwardsweb.org%2Faudio%2Fparamours%2Ffinal%2Ff05.jpg&hash=c880db692112fe105064a7ddaaed958f15e08323)

The green pair of wires is 6.3V (Terminals 8/10 on PT-2, ground 9)
The yellow pair of wires is 2.5V (Terminals 6/7 on PT-2)
The red and white pair of wires is 120V (Terminals 4/5 on PT-2)
The triple braid is the high voltage secondary.  (Sort of Terminals 1/2, see below)

The original Paramour had a full wave rectifier, the new one has a full wave bridge.  To swap the transformers, you will need to complete the bridge by adding two diodes to each amp.  (Reply if you need assistance with this)  These should be UF4007's, and they can go right on the original 5-lug transformer.

After the transformer swap is up and running, then proceed with the parts upgrades.  I think your parts choices are OK (assuming 47uF is power supply, 220uF is cathode bypass).  There is a 68uF/450V Panasonic ED that would be an excellent replacement for the 47uF/450V cap.

-PB

[jeff g]

Start with the transformer swap, don't do everything at once, as troubleshooting will be tough.

Does your original Paramour transformer still have the ID sticker on it? 

We can go off this pic (thanks to Wardsweb):

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwardsweb.org%2Faudio%2Fparamours%2Ffinal%2Ff05.jpg&hash=c880db692112fe105064a7ddaaed958f15e08323)

The green pair of wires is 6.3V (Terminals 8/10 on PT-2, ground 9)
The yellow pair of wires is 2.5V (Terminals 6/7 on PT-2)
The red and white pair of wires is 120V (Terminals 4/5 on PT-2)
The triple braid is the high voltage secondary.  (Sort of Terminals 1/2, see below)

The original Paramour had a full wave rectifier, the new one has a full wave bridge.  To swap the transformers, you will need to complete the bridge by adding two diodes to each amp.  (Reply if you need assistance with this)  These should be UF4007's, and they can go right on the original 5-lug transformer.

After the transformer swap is up and running, then proceed with the parts upgrades.  I think your parts choices are OK (assuming 47uF is power supply, 220uF is cathode bypass).  There is a 68uF/450V Panasonic ED that would be an excellent replacement for the 47uF/450V cap.ick

-PB

Thanks for the quick reply Paul.   The photo helps. The diode replacement was one thing I was;t sure about, so clarification there would help.
I'll hold off on the parts swap til the PT2 is in.
Please note this may be a bit of a slow process as I'm not sure when I'll have time - but I appreciate all responses.
Jeff

[jeff g]

forgot - there is no sticker on the original transformer, but it is the hammond.

[Paul Birkeland]

Ok, with the stock setup, you have two diodes in the power supply.  Both of them have the banded ends facing the positive DC rail.  You'll also notice that one of the wires on the original power transformer feeds the ground bus.

To implement the new transformer, you will put two more diodes in.  Each of the new diodes will have the banded end facing the terminals where the two high voltage ac wires come in, and the unbanded ends to ground (where the previous 3rd transformer wire went).

-PB

[jeff g]

think I've got it, but want to make sure.

T1/T2 on PT2 go to T1/T2 on the amp. the 3rd wire used on the original is left off (previously went to T5 on the amp)

all other PT wiring is unchanged.

T4 (0V) and T9 (GND) on PT2 are not used.


2 diodes go from T1 to T5, bands facing T1 - reversed from original
2 diodes go from T2 to T5, bands facing T2 - reversed from original

do you run each diode to the terminals or twist ends to a single lead?

Assuming all this is correct, is there a list of test values (res./volt) somewhere - assume it's not the same as the original?
Thanks

[Paul Birkeland]

T1/T2 on PT2 go to T1/T2 on the amp.

T4 (0V) and T9 (GND) on PT2 are not used.

2 diodes go from T1 to T5, bands facing T1 - reversed from original
2 diodes go from T2 to T5, bands facing T2 - reversed from original

T4 is the 120V primary winding, this is half of the black/white pair that you had originally.

T9 goes to the ground buss, which in the Paramour I was the twisted pair of enameled magnet wire that runs through the amp.

In the amp pictured originally, it looks like we have the high voltage AC wires coming from the transformer and landing on terminals 1 and 2.  From terminal 1, there is a diode connected with the banded end connecting to 5, from terminal 2 there is a diode connected with the banded end to terminal 5.

If this is correct in terms of how your amp is wired, then you need to add a diode connected between terminals 1 and 4, with the banded end towards 1, and between 2 and 4, with the banded end towards 2.

If the twisted pair of copper wires do not pass through terminal 4, then post a pic of one of your amps so we can have a look.

-PB

[jeff g]

T1/T2 on PT2 go to T1/T2 on the amp.

T4 (0V) and T9 (GND) on PT2 are not used.

2 diodes go from T1 to T5, bands facing T1 - reversed from original
2 diodes go from T2 to T5, bands facing T2 - reversed from original

T4 is the 120V primary winding, this is half of the black/white pair that you had originally.

T9 goes to the ground buss, which in the Paramour I was the twisted pair of enameled magnet wire that runs through the amp.

In the amp pictured originally, it looks like we have the high voltage AC wires coming from the transformer and landing on terminals 1 and 2.  From terminal 1, there is a diode connected with the banded end connecting to 5, from terminal 2 there is a diode connected with the banded end to terminal 5.

If this is correct in terms of how your amp is wired, then you need to add a diode connected between terminals 1 and 4, with the banded end towards 1, and between 2 and 4, with the banded end towards 2.

If the twisted pair of copper wires do not pass through terminal 4, then post a pic of one of your amps so we can have a look.

-PB

I'm not sure I understand now...

I will upload photos as soon as I get registered with a hosting site - waiting for reply now.

My original amp is as you've described:
Hi-v to T1/T2
ground buss (twisted enamel) from jack to T14 to T4
diodes from T1 - T5 and T2-T5 (silver band facing T5)

I don't know why I said T4 wasn't used.  I started wiring it up and used T4 - here's what i've got.

PT2 Terminal          Amp Connection

1 (0V)                    T1 or T2 - not sure which
2 (300V)                 T1 or T2
4 (0V)                     T9 power cord
5 (120V)                  power switch
6 (0V)                     A4 or A2
7 (2.5V)                  A4 or A2
8 (0V)                     B4/5 or B9
9 (GND)                  wire connected to some point on ground buss?  where?
10 (6.3V)                 B4/5 or B9


for the diodes, I'm supposed to leave the 2 as is and add 2 more in opposite orientation, like this:

T1-T5 band facing T5
T2-T5 band facing T5
T1-T4 band facing T1
T2-T4 band facing T4

[Paul Birkeland]

PT2 Terminal          Amp Connection
1 (0V)                    T1 or T2 - not sure which
2 (300V)                 T1 or T2
9 (GND)                  wire connected to some point on ground buss?  where?
for the diodes, I'm supposed to leave the 2 as is and add 2 more in opposite orientation, like this:
T1-T5 band facing T5
T2-T5 band facing T5
T1-T4 band facing T1
T2-T4 band facing T4

Yes, the 0/300 pair goes to T1/T2, it doesn't matter whether the 0 goes to T1 or T2, same for the 300 connection.
The GND can go to the solder tab on the transformer mounting screw, that should be easiest.

The stock diodes are T1/T2 to T5 with the band facing T5.  The new diodes are T1/T2 to T4 with the bands facing T1/T2, so both the unbanded ends face T4 (the ground buss). 

Here is a picture of what the wiring looked like in the Paramour II.  You can see the red/black twisted pair that comes from the 300V winding, the diode bridge, then the output (a black wire in this case is analogous to your copper twisted pair ground buss).
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fimg6.imageshack.us%2Fimg6%2F9616%2Fparamouriib.jpg&hash=55c330b29f80a89387123b9549b8afd2697a1d99)
(Note that these diode leads would need to be trimmed after soldering)

[Paul Joppa]

Power transformer terminal 9 (it's the center tap of the 6.3v winding) should go to the safety ground - the same point that the various transformer cores are connected to. This is not the same as the signal ground.

Signal ground will work, it's just not quite as quiet.

[jeff g]

thank you both - getting there now; still have  a couple questions.

for the 6.3 V wires, does it matter which goes to B4/5 and B9?

I assume the safety ground is the ring tab on one of the PT mounting screws?  there is currently only one connection there - from the power wiring.   bare wire, stranded or solid ?

and what are the test values I should be checking against?

thanks again

[Paul Birkeland]

for the 6.3 V wires, does it matter which goes to B4/5 and B9?

I assume the safety ground is the ring tab on one of the PT mounting screws?  there is currently only one connection there - from the power wiring.   bare wire, stranded or solid ?

and what are the test values I should be checking against?

Yes, the ordering of the 6.3V wires is not important.

The safety ground is the buss that goes from each piece of iron in the amp (plate choke, output transformer, power transformer) to the chassis ground and the ground feed from the power cord.  Stranded or solid core wire isn't that important, solid core will be easier to work with.

Check your DC voltages against the original circuit, they should be reasonably close.

-PB

[jeff g]

for the 6.3 V wires, does it matter which goes to B4/5 and B9?

I assume the safety ground is the ring tab on one of the PT mounting screws?  there is currently only one connection there - from the power wiring.   bare wire, stranded or solid ?

and what are the test values I should be checking against?

Yes, the ordering of the 6.3V wires is not important.  OK

The safety ground is the buss that goes from each piece of iron in the amp (plate choke, output transformer, power transformer) to the chassis ground and the ground feed from the power cord.  Stranded or solid core wire isn't that important, solid core will be easier to work with.  Where is this ?- I don't see any ground that's common to all iron

Check your DC voltages against the original circuit, they should be reasonably close. OK
-PB

[Paul Birkeland]

All the solder tabs connecting to all the mounting screws for each transformer/choke all tie to a ground screw on the chassis (or the center lug of a terminal strip), this is the safety ground.

[jeff g]

ok, that's T9 - where the power cord comes in.  the OT mounting screw is on the terminal, the PT2 and choke both connect by ring tabs on the mounting screw and enamalled wire.

but, isn't the PT2 already grounded by the ring tab attachment?  I need to run another wire to the same connection (T9)?