D-lator heater wire question

[jlatrace]

Should I twist the heater wires running to the 12AX7 tube? The pictures I've seen do not.

I ask because the noise floor on the #102 I just finished is the lowest of any amp I have ever had and it makes me wonder can I get the same low noise floor when the D-lator is plugged in. I am only getting a barely auditable hum that in any other amp I would accept as normal. However, when I bypass the D-lator, the noise floor drops back to wisper quiet.

Things I have already done are:
1 - Install Cliff sytle jacks (++ improvement in noise level)
2 - Move the ground heater to the power section star ground, it was routed to the signal ground (minor improvement in noise floor)
3 - Tried ground lift cables (added noise, removed them)
4 - Changed the 12AX7, no change.

Rewiring the heaters will be a small pain so I wanted to check with to see if anyone had good experience with twisting the heaters beforeheand.

Thanks for the help.
Les

[rogb]

As far as I have seen in good builds, all AC wires should be evenly twisted to cancel hum.
There are Dlator photos around that show heaters twisted for sure, I certainly did on mine.

Strangely, I have just this minute sat down after installing the (carefully twisted) heater wires in my latest Deluxe AB763 build. It is now complete and ready to fire up tomorrow

[talbany]

For max hum cancellation..Twist them and lay them on the chassis and separate them from DC
Also try lifting the ground on the effect..

Tony

[jlatrace]

Thanks I just twisted the heaters and it made a small difference.

I think I'm OCD over this because the noise level w/ the Dlator is better than a blackface.

Now on to getting my multi-effects unit working without a ground loop .

[jlatrace]

For max hum cancellation..Twist them and lay them on the chassis and separate them from DC
Also try lifting the ground on the effect..

Tony

Twisted the heaters an dinterestingly the hum is still there and it's between the d-lator and the ODS, without any effects. I wonder if I have the AC primary too close to the B+ lines and the B+ line is carrying 60 cycle hum to the 12AX7 (can this happen?).

I'm going to re-route the wires tomrrow to see if it helps.

[rogb]

https://tubeamparchive.com/download/file.php?id=12773

Here is mine, you can see all AC wire are twisted and there are 2 grounds, one by the PS board and one near the tube board.

The only signal; wires crossing AC are shielded.

I get a slight hiss but no hum. This is very dependent on gain levels and the tube used

[tubedogsmith]

Put a pic of the whole thing if you can. I'd be looking at the grounding.

[jlatrace]

I rewired and separated the AC lines from the signal wires. I checked all solder joints. But, still a 60 cycle hum.

Here are some pics, please take a look and see if you can ID any issues.

In the meantime I am going to strip the paint away from the signal and the power star ground points. I read a post with similar issues and that seemed to solve the problem.

[jlatrace]

Another thing is that I have isolated the hum as follows.

When I run my guitar into the "in" and to the power amp from "send" there is no hum. When I run my guitar from "return" and the power amp from "out" there is hum. When I engage the bypass switch, there is no hum.

also the Drive control has no impact on the hum. The In and the Out pots attenuate the hum.

I scrapped paint & changed 12AX7's.

And I'm still left with hum in what seems to be the recover stage.

Ho hum

[catears]

Another thing is that I have isolated the hum as follows.

When I run my guitar into the "in" and to the power amp from "send" there is no hum. When I run my guitar from "return" and the power amp from "out" there is hum. When I engage the bypass switch, there is no hum.

also the Drive control has no impact on the hum. The In and the Out pots attenuate the hum.

I scrapped paint & changed 12AX7's.

And I'm still left with hum in what seems to be the recover stage.

Ho hum

I would clean up the solder joints on the pots and make sure one of the shields from your coax arn't connected at one end, or maybe even both. First make a mechanical connection and then apply your solder. Use only as much as the joint needs for the mechanical connection to be supported. even if your center conductor is teflon coated- you can overheat the center or the shield once a bunch of solder is flowing in there and they can become connected and introduce a world of noise. The wire routing looks very nice, and from a quick one over everything seems too be in the right place. Check the solder joints

[jlatrace]

I would clean up the solder joints on the pots and make sure one of the shields from your coax arn't connected at one end, or maybe even both. First make a mechanical connection and then apply your solder. Use only as much as the joint needs for the mechanical connection to be supported. even if your center conductor is teflon coated- you can overheat the center or the shield once a bunch of solder is flowing in there and they can become connected and introduce a world of noise. The wire routing looks very nice, and from a quick one over everything seems too be in the right place. Check the solder joints [/quote]

Thanks, I will clean up the coax and be careful whenresoldering them.

[martin manning]

I'm not sure it will help, but parallel routing of filament wires and shielded runs is something I'd avoid. See if moving the filament pair as shown does any good.

[tubedogsmith]

If after getting your grounding points cleaned up good it still hums try lifting the ground on the short lead from the middle pot to the board.

[Structo]

Yeah, I had to lift that ground as well.

[SoundPerf]

I just realized you have a bypass & switch on it. Have you tried removing the bypass (coax from jacks & and any ground) and see what happens. The only thing I see different from my d-lator is the bypass.

Aside from cold or poor connections your work looks ok. While I followed good lead dress techniques, I didn't have to do anything crazy as far as routing to have a dead quite unit. I even have two trafos in mine (seperate heater) and it's stuffed into a smaller enclosure.

One other little thing. Have you established that the hum is constant and not dependent on proxity of your guitar. With single coils when I have the dlator top off and get too close there's lots of hum.