Ceriatone OTS Mini Build Help

[Probably_not_Famous]

So I measured the voltage and attached the measurements. Voltage Chart for the OTS mini is up top for reference, my measurements are highlighted below them. I'm getting an open loop on both power tubes at pin1. Pin 8 on both power tubes is about half of what it should be. Any suggestions on to what could be causing this??

[xtian]

"Open loop" is an odd phrase. Do you mean "open" as in, not connected or infinite resistance? That's fine because the 6V6's pin 1 is not connected to anything inside the tube. Your chart shows values for pin 1 in the sample build because in that amp, pins 1 and 8 are tied together, which is also OK, unless you're going to use EL34s.

[davebolden44]

pin 1 is nothing, no need to measure. are you taking your cathode reading from pin 8 to ground with your meter on D.C. volts? check your grounding

[pompeiisneaks]

The low millivolts reading just means the tubes aren't conducting much current, and you need to adjust the current via the bias adjust up to the right level for the amp if I reading that right

Sent from my SM-T900 using Tapatalk

[davebolden44]

on the layout it shows pin 1 being used as a solder lug for your grid hookup from the pi. I assume you would get no D.C. reading there as it is after coupling. If one were to expect the same voltages as pin 8 I would say they should be connected as you would wire up for el34 tubes. make sure you aren't grounding your signal out there.

[Probably_not_Famous]

Thanks for the clarification on that.

In regards to the input wiring, I have some questions...There's discrepancies between the diagram and the actual photos. The diagram has a ground going to the shield, but I can't seem to find that in the actual photos. it just looks like the wire is going straight to the ground, and nothing is going to the shield. See attached photos

Screen Shot 2017-05-27 at 12.02.37 PM.png

Screen Shot 2017-05-27 at 12.02.21 PM.png

Screen Shot 2017-05-27 at 12.02.03 PM.png

[davebolden44]

the shield itself will be grounded to the chassis when it is installed in the amp. measure the solder lug that goes to the shield to a chassis ground and you should get 0 ohms. the 1 meg should be grounded in parallel to signal input and the cable going to v1 grid should be shielded on one end only

[jackT]

resurrecting this old thread -- OP, were you able to get this sorted out? I've just built one of these and as it's all fresh in my mind I can help.

[Rockwell666]

Maybe it's the dark image, or my old eyes, but many of the solder joints look starved.
The solder doesn't appear to flow smoothly from the lead to the hole. If this is how they actually look, I'd apply more heat to the lead and flow a little more solder.

I have had dozens of amps come in that people have built or modified and they come in with no sound... its nearly always cold solders... multiple cold solders. I would scope signal

[TUBEDUDE]

The Orange drop under the right relay looks like it missed the solder on each leg.

[mehfuzhoss]

Hello,

I am building my first amp. I am starting to solder parts together. i will use 6v6 and 12ax7s and following the current layout from ceriatone site. Any tips and tricks on which order the parts should be soldered would be nice. I am planning on soldering all the parts on the board today and may be put the pots on the chasis as well. I will post picture as i move along this project.

Thank you.

[pompeiisneaks]

Not really any specific order. Just make sure of two things in my mind for order:

1. make sure everything is already set in the chassis so you can just drop the board in as the last step
2. make sure the board has all the wires soldered in and through the holes etc and give plenty of extra lead wire so you can connect it up wherever it goes in the chassis.

I've had to desolder a few wires and put in new ones because I didn't give them enough length

~Phil

[mehfuzhoss]

In the layout there are 1k5 and 1k5 2w resistors. Unfortunately, ceriatone didn't mark any of the resistors with value or wattage. is there an easy way find out which 1k5 is the 2watt !

Help is appreciated.

[mehfuzhoss]

I sorted out the parts and have few questions before i solder them.

Please refer to the circled resistors (red marked) on my board. Ceriatone board shows a much bigger size higher watt 100k resistor. I think the small ones that I installed on mines are 1/2 watt and the big ones are 1 watt. is it okay to proceed with the small watt resistors instead of the bigger ones! Thank you.

ceriatone board:
https://ibb.co/kKqmrV

my board:
https://ibb.co/gxoT5q

[drew]

If they are legit Dale RN resistors, they are fine. If they are Dale look-alikes that Ceriatone has made, then who knows what they really are, but they’re probably OK to use if they are being supplied with this kit.