Help wiring power transformer Transformer

[nosaj]

OT transformer is an Hammond 1750 N
http://www.hammondmfg.com/pdf/EDB1750N.pdf
on the primary side the red & blue wires go the plates (pin 3) of the el34's
& the white which i think is the CT is connected & the choke goes to the .5a fuse thats connected to the filter cap
on the secondary side there is no impedance selector only 3 cliff jacks which I've removed to hopefully help solve the problem .
I've taped off the 4 & 8 ohm wire & trying to 16 ohm (violet) wire with my load (16 ohm speaker) connected to the tip of my speaker cable & the common (black ) wire connected to the sleeve of the jack & to ground .
I don't have a photo hosting program but I will try to get some photos .
I re-flowed the most of the solder joints & I do have the V1 heater working . 6.7 volts across all the heaters
Now V1
1 346
2 0
3 3.68v
6 287
7 .003v
8 2.62

Have the rest of the voltages changed? Also are these all DC voltages?(can you notate with VDC and VAC when appropriate, just to avoid any confusion?)
Photos can be hosted here by clicking the pic next to the filmstrip icon when creating a message.
Just to ask the obvious this speaker your using is verified working? you can use a AA to do a click test).

You can verify if the white wire is a CT by using your meter measure resistance between red and blue wire, then red and white and then blue and white. The white wire and one of the others should be roughly half the number of Blue and Red hence Center Tap.

Good luck and keep plugging the guys here will help you get it squared away for sure.

nosaj

[GroundskeeperWillie]

I will take some more voltages but all voltages are in vdc except the heaters which are vac
i took some readings of the OT still in circuit &
between the white to blue 39 ohm
between the white & red 42 ohm
between the red & blue 82 ohm

[Tom Phillips]

...I don't have a photo hosting program but I will try to get some photos...

You can upload your photos directly to your post. Then they will stay with your thread and be easy for others to pull up your photos and offer you help. There are instructions on the page at Music Electronics Forum FAQ .

[GroundskeeperWillie]

I also checked the in diode mode . diodes & they are open one way & both are 5.6m the other way which is as it should be

[Enzo]

Please check diodes with the diode test function of your meter, rather than the ohm meter.

[GroundskeeperWillie]

1.17v a set or .6v each

[GroundskeeperWillie]

Voltages just taken through the dimbulb & I check voltages not through the dim bulb & the are all about 15 to 20 volts higher for most readings
V5
1 0
2 505
4 508
5 -113
6 508
V4
1 0
3 505
4 505
5 -113
6 507
v3
1 450
2 369
3 405
6 448
7 317
8 405
v2
1 234
2 .002
3 1.32
6 400
7 234
8 236
v1
1 346
2 .003
3 3.70
6 287
7 .011
8 2.66

[GroundskeeperWillie]

This maybe very helpful but I've noticed the I get sound from the touching the tip of the guitar cable for a couple seconds after i shut the amp OFF .

[GroundskeeperWillie]

The pot on the left is a depth control if you wondering
& i've eliminated the speaker jack & used alligator clips to the speaker cable to try & solve this thing

[GroundskeeperWillie]

& I've tried another new set of power tubes & preamp tubes .
Any one got a suggestion ? as i only hear sound of the guitar for a couple of seconds coming through After I shut the amp off

[nosaj]

& I've tried another new set of power tubes & preamp tubes .
Any one got a suggestion ? as i only hear sound of the guitar for a couple of seconds coming through After I shut the amp off

Try this , its called a circuit disturbance test, work backwards from speaker to input. Jack Darr Guitar amp book
page 53 more involved instructions
http://theguitar-blog.com/wp-content...r-Handbook.pdf

Thought bias voltage looks aweful high -113 i would think it would be -50 or lower would be more like it. Even though I am unsure and its just a shot in the dark I will say it anyways and hope someone corrects me or tells me it's right. Possibly when the bias is high the tube is in cutoff more(turned off) and when you remove the power the bias voltage lowers turning tube on then passing the noise you are making at the input.
Like I said i am pure speculating and I'm also still learning something new everyday.

nosaj
Thanks,
nosaj

[Justin Thomas]

If you turn the amp up, and play the guitar and then hit the switch while you are playing, then it's perfectly normal to hear sound for a few seconds after power is off. The tubes keep conducting, as long as there is voltage in the filter caps to put voltage on the plates. The cathodes don't stop emitting electrons the instant you turn off, because it takes time for them to cool down. So as long as there is voltage in the filter caps, the plates will keep drawing electrons and putting out signal. EVERY <TUBE> amp I've ever owned, new, old, homebrewed, has done it. It's really nothing to worry about, if you hear signal for a few seconds after power is shut off.

Now, if you were hearing full-blast RAWK more than ten seconds after shutoff, you probably should have your power switch looked at! >

Justin

Edit: Some of the coolest distortion tones I've ever gotten were from turning the amp full on 10 - all knobs, then hitting a bigass power chord and quickly hitting the power switch, usually with my foot through a surge strip. Granted, the awesome tone only lasts a second, but it's still pretty cool. Awesome tone is worth it, even if short-lived.

[nosaj]

If you turn the amp up, and play the guitar and then hit the switch while you are playing, then it's perfectly normal to hear sound for a few seconds after power is off. The tubes keep conducting, as long as there is voltage in the filter caps to put voltage on the plates. The cathodes don't stop emitting electrons the instant you turn off, because it takes time for them to cool down. So as long as there is voltage in the filter caps, the plates will keep drawing electrons and putting out signal. EVERY <TUBE> amp I've ever owned, new, old, homebrewed, has done it. It's really nothing to worry about, if you hear signal for a few seconds after power is shut off.

Now, if you were hearing full-blast RAWK more than ten seconds after shutoff, you probably should have your power switch looked at! >

Justin

Edit: Some of the coolest distortion tones I've ever gotten were from turning the amp full on 10 - all knobs, then hitting a bigass power chord and quickly hitting the power switch, usually with my foot through a surge strip. Granted, the awesome tone only lasts a second, but it's still pretty cool. Awesome tone is worth it, even if short-lived.

Hey Justin,
I think he's been saying he only gets any sound when it's being turned off.

nosaj

[GroundskeeperWillie]

Hey Justin,
I think he's been saying he only gets any sound when it's being turned off.

nosaj

That's right I have not got so much as a pop out of this thing untill i switch the amp off ..Then i get about 3 seconds before it goes quiet

[Justin Thomas]

Ah. I recant my comments then! But it certainly deepens the mystery.

Justin