D-Lator start-up issues

[jlatrace]

Well I finished my #102 without any issues. However, I cannot get my D-lator to function properly and no matter how many times I go over it, I cannot find my mistakes. I am posting to see if I can get some help or tips on trouble shooting the issue.

I started with a kit by Nik (C-lator). I wired it up using help, schematics and layouts from this site (I did not follow Nik's layout). The issue existed before and after I added the bypass switch.

My issue is I have little volume and the sound is thin and tinny.
Here are my voltages and I will post pics in the next posting:

Transformer CT = 137 vac
HT B+ @ 47uf filter = 371 vdc
B+ after 15k dropping resistor= 338 vdc
Pin 1 & after 100k dropping resistor = 238 vdc
Pin 2 = 15 vdc
pin 3 = 28 vdc
pin 6 = 216 vdc
pin 7 = 1 vdc
pin 8 = 2 vdc
heaters measure 3.15 - 3.2 vac

[jlatrace]

Here are some pictures

[67plexi]

I can’t tell from the photo, Is your heater pin 4 & 5 tied together on the tube socket.

[jlatrace]

Sorry about the pics, yes the heaters are properly wired. I just performed the following tests successfully.

https://tubeamparchive.com/viewtopic.ph ... +operating

"It should be trivial to isolate the problem to either the cathode follower or the return stage. Plug the PREAMP send from your amp into the input of the D-lator and then take the FX out of the D-lator and plug it back into the POWER AMP IN in your amp. Dime the SEND control and you should have close to unity gain. If not, the problem is in the gain stage. [Done - worked properly]

If the problem is in the return stage, you can plug your guitar into the FX return in the D-lator and take the OUT from the D-lator into the POWER AMP IN of the amp. You should get a really loud sound (like the amp itself) like that when the stage is operating properly." [Done - worked properly]

My guess is my FX send/return bypass is improperly wired or my jack is deffective. I iwll post a high quality close-up in a moment.

[jlatrace]

Jack pictures

[jlatrace]

Well it's definitely my FX send & return jack bypass wiring. I plugged one end of a cable into fx send and the other in the return, worked perfectly!
Now, what is the issue with my jack wiring?

I followed this layout:

[Teleguy61]

More often than not on the DLators, with the problem you have, it is the jacks themselves.
Those look like Switchcraft or clones, and they have been problematic
for good contact between switch and tip.

[jelle]

Just needs cleaning.

[jlatrace]

More often than not on the DLators, with the problem you have, it is the jacks themselves.
Those look like Switchcraft or clones, and they have been problematic
for good contact between switch and tip.

Thanks, I'll try cleaning the contacts and, if that doesn't. work, put a new jack (maybe cliff jacks)

[jlatrace]

Just needs cleaning.

Roger that, I'll give this a try later today. Thanks.

[martin manning]

Transformer CT = 137 vac
HT B+ @ 47uf filter = 371 vdc
B+ after 15k dropping resistor= 338 vdc
Pin 1 & after 100k dropping resistor = 238 vdc
Pin 2 = 15 vdc
pin 3 = 28 vdc
pin 6 = 216 vdc
pin 7 = 1 vdc
pin 8 = 2 vdc
heaters measure 3.15 - 3.2 vac

Looks like you have one problem identified, but I'm not liking some of these voltages... pin 2 should be only a couple of volts below pin 3, and pin 7 should be ~zero.

[jlatrace]

Thanks, that is very helpful voltage information. I'll run this down later today.

[jlatrace]

[quote="martin manningLooks like you have one problem identified, but I'm not liking some of these voltages... pin 2 should be only a couple of volts below pin 3, and pin 7 should be ~zero.[/quote]

I'm unclear whether pin 2 voltage is too low or pin 3 is too high. Would you mind clarifying this for me? Thank you for your help!

[martin manning]

I'm unclear whether pin 2 voltage is too low or pin 3 is too high. Would you mind clarifying this for me?

~30V is good for the cathode (pin 3), but the grid (pin 2) is 13 volts below that. If those are accurate then the bias is way off. Are you sure the value of the bias resistor is correct?

[jlatrace]

Thanks, i will check the bias resistor value. It was pre-installed by Nik. I went over the board checking values before I assembled the unit but I easily may have missed it.