Vintage Strobe Tuner (Tone o Graph)

[gibs08]

Hey! hope everyone is doing well. So I'll get right into it I've purchased this old stobe tuner recently and I've hit a couple road blocks, first it doesn't have all the right tubes and it's missing the bulb. Also, as far as the internet is concerned it doesn't exist.... so I have zero reference. If anyone has seen one of these before or can tell me the exact tube set its supposed to have and can help me track down the exact bulb it would be much appreciated. I've attached several pictures, let me know if I need to post anymore. Thanks for your help everyone!

[dorrisant]

Welcome to the forum, Caleb!!

If you can, list the tubes that are installed in it. It runs the filaments in series from the line AC. They should add up to line voltage if correct.

Something like a 35xxx rectifier, 50C5 power tube and two 12xxx octals for preamp tubes. That would at least add up to 110v for series filaments.

[gibs08]

Thank you! I'll post them asap!

[gibs08]

Here's a picture of the tubes that were installed. One of them is not readable I'll get more info on that when I get home and give you guys an update as I forget off hand what that one was.

[gibs08]

Here's the full tube set:

50L6 GT

35Z5 GT

12SQ7

6SQ7

Let me know if I can post anything else to help you guys out!

[LOUDthud]

12SQ7 and 6SQ7 in the same piece of equipment ? Seem strange because the series arrangement of the heaters requires they all use the same current. Are all the heaters in series ? The 6SQ7 has a 300mA heater while the others are 150mA.

[gibs08]

Unfortunately I cant answer that. I dont have enough knowledge on circuits or amplifiers in general so I wont be much help. I do know the voltage should add up to 115v so something is definitely not right with it. I'll attach a few more pictures hopefully something stands out to you guys and you can figure something out.

[dorrisant]

I looked at this thing and could tell that the 12SQ7 would work for either of the preamp tubes. 12.6 x 2 + 35 +50 = 110.2V

[gibs08]

The motor is rated at 115v, would 110v be enough? Also, any idea on what bulb it should have? Thanks for your help!

[LOUDthud]

The first amp I ever built had series heaters. They didn't quite add up to 110V so there was a 5 or 10 watt resistor in series with the heaters.

[gibs08]

So two 12SQ7's are what I need, thank you. Now the bulb

[gibs08]

So.. it's been a little while and still haven't had any luck with finding a new bulb. Anyone got any ideas? Thanks again!

[maxkracht]

Looks like a ba15d socket, no idea what voltage. Guessing 12v is most common. I am far from an expert and it's hard to tell the scale, so it could be another socket type. Your filter caps are blown and should be replaced as well.

[gibs08]

Just now saw you're reply.. thank you for the info.