TW Express -Pacific transformers and voltages

[reverbus]

I'd like to see your comments, advice maybe...thanks in advance
I replaced my old transformers with Pacifics. (Ceriatone Express)
Before were voltages low (comparing to schematics), but now are even lower.

Standby switch ON, no Input signal:
Tubes are JJ, 3x ECC83S, 2x EL34
PT version EU: 240V
OT 6k6
Measured:
Voltage from the wall: 219V
PT output (280V-0-280V) = 530V AC measured
Heaters 5,9V
B+1 350V
B+2 339V
B+3 272V
B+4 257V
B+5 243V
Bias -29VDC (Bias set to 45mA/plate voltage is 350V)

Power tubes:
Pin1 348V
Pin4 332V

V1:
Pin1 180V
Pin6 160V

V2:
Pin1 225V

V3:
Pin1 171V
Pin6 170V

After 10 min playing with VOL on 11 (att.bedroom), PT was warm.
It's too late today, tomorrow I'll test it deeply.

Strange values, don't you think? Too low?
Express sounds good, better than before, and is still pretty loud.
Because of Bias value?

Regards

[paulster]

They are all about spot on when you factor in you're on 220V, and at the low end rather than the higher end of a nominal 220V wall voltage, and it's a nominal 240V PT.

Scaled up to 240V they're within 5% of my voltages.

[Allynmey]

PT secondaries are 300V for the Express (not 280V).

[M Fowler]

Allyn then why was the information given show 280v for Pacific Express iron?

[Allynmey]

Are you using the K&M PDF's from Pacific? Those aren't the KF Express trannys. Mine are made from Ken's line card and are 300V and 260V.

[reverbus]

@Paulster
I'll try today to increase 220V to 240V with my UPS.
Do you have any report with values for yours? To compare.
Aren't those voltages too low? What's your bias set to?

@Allynmey
Yes, Pacific told me they're identical to K&M and originals:
" The parts are identical to originals and all K&M knock-offs"
PT 32310 (280-250-0-250-280), OT 25525 (6K6)
Is OT also wrong one?
It's pity, all that communication, and finaly - PT is not right one...
...came all the way from L.A. to EU

Voltage difference between original and mine is almost 50V (B+1).
This must do some kind of difference.
What do you think about bias level (-29VDC/45mA)

[paulster]

B+1 404V
B+2 388V
B+3 317V
B+4 300V
B+5 286V

Bias 49mA (cathode), 44mA (plate), -33V

I've included two bias figures because the screen current is quite high on Siemens EL34s.

Wall voltage would have been in the 240-245V range.

[reverbus]

Thanks Paulster,

I think I'll try to find a company which will adapt "new Pacific" PT primary to 220V. In the afternoon I'll check B voltages with 240V from wall outlet (UPS).

[geetarpicker]

I seem to recall the B+ in my original Pacific Express and the two clones I built using Pacifics all run about in the 410-420v range. We run pretty hot here out of the wall with 124-125v or so.

[M Fowler]

This is very disturbing to myself and Reverbus as I had Allyn's Pacific tranny set on my Express build. I referred Reverbus to Allyn, Toneslut and rjguitar.

Correct me if I am wrong Reverbus I thought you had contact with Allyn or toneslut regarding the Pacific tranny set and referred directly to Pacific for 220/240 voltage tranny. So when you talked with Pacific they said yes these are the same sets being used, but apparently you and I were misled.

Way too much misleading information going around. Reverbus I must apoligize for wrong information on the Pacific tranny set. I did refer you to more knowledgable references but still ended up short?

I see no reason why the 6k6 OT would need to be changed.

Mark

[redshark]

Allyn could you pls post the correct wiring schematics for the pacific power and output transformers?

[reverbus]

@Paulster
Thanks for your data, my target is to get the one from schematics.
We'll find a way:-)

@geetarpicker
Sound from your CD is my bibel
Pretty hard homework to come close to your sound -:)
Therefore I'll do everything to assure the same basis (B+ and the rest)

@M Fowler
It's nothing you should feel disturbing at all.
I appreciate your help on this topic and all others, so stop thinking this way.
There isn't absolutely any reason I would expect your apologies!
We all learn this way or another , and I'm relative noob in this area.
It's all about codes which I followed and didn't take care about secondary and tolerance impact on primary.

It's true, too much misleading info is floating out there.
Sometimes is too mistique/confidental, or even just half or no info.
Mark, it has nothing to do with you!

So, if anyone will use this PT from Pacific with code 32310:
primary 240V
secondary 280-250-0-250-280
...with 220V supply from wall outlet you won't get B+1 395V!
I'll check with 240V supply instead of 220V.
It's 10% difference, hopefully it'll match 585V AC sec. and 395V B+1.
You'll get report end of week.

OT 6k6 seems to be OK.
Anyway, Express sounds good although B+ levels are not high enough...
I'm too busy these days, but we'll test it complete until end of the week.
We'll compare mine with some others with the same components built in, except trannies.


regards

[funkmeblue]

hey man....there just voltages man.....we should all just step back a second man............what was the question?

[Zippy]

I seem to recall the B+ in my original Pacific Express and the two clones I built using Pacifics all run about in the 410-420v range. We run pretty hot here out of the wall with 124-125v or so.

Hey Glenn,

We've had posts from Allyn in a similar thread regarding PT voltages - that the various trannies implemented did not have the same B+1.

Could you please comment on the pin voltages in your Express. If the B+1 is running hot(ter) with the Pacific PT, what were the voltages on V1, V2 and PI? Did Ken scale the dropping string to maintain a similar gain structure throughout the preamp or are these things just all over the map?

Thanks for staying engaged in the Express threads. There seems to remain a lot to sort out. Given that most of us will never play an Express in person, your contributions are a real resource.

[rhinson]

https://tubeamparchive.com/files/k_m_25 ... ic_201.pdf

that's the datasheet for the power trannie. here's pics of what you get on a hv sec leg of this pacific express power trannie when you apply the proper wall voltage (in my case 120v---calibrated to 120v exactly by my variac) to the primary. if you apply the proper ac to the primary you'll get what you expect to get. if you apply more (in glenn's case) you'll get a bit more, and in the case of the op a lot less. if your export speced trannie is a single pri. 240v, just tell them to add a 220v tap in the wind. or if it's dual 120v pri, just tell them to add a 100v tap in one of the primary winds and you can wire it for 220v that way.

yeah i know the datasheet says 280, but the readings don't lie---this is how they make them. you have to realize that the 280 number depends on who and how they do the rating. this probably means "280 @ 300ma" ----or in other words it will drop to 280v at full draw. you see specs like this in the ce dist trannie line for fender stuff. they'll say, for instance, 325-0-325@120ma----but when you get it home and measure n.l. voltage it'll be 342-0-342 or some such thing. other trannie winders will give you the straight n.l. voltage. if you get stuff wound for yourself, you can crunch the numbers and get it done how you want, say n.l. vs idle voltage based on experience and the circuit you're gonna use, etc. rh