Skip to main content

6J1 Preamplifier

6J1 Preamplifier

I purchased this 6J1 amplifier from eBay. The seller was located in China. Below is a my experinces building the preamp. I have not had a chance to give it a full test. I will update this post once I have had that chance. 

It took a little over an hour and a half to finish building the kit. The board seemed a little tight for installing everything. The board itself runs on 12AC and from what I can gather it takes the 12AC and runs it through a voltage doubler which then gives the "B+" voltage.The tubes are 6J1's and obviously have 6volt filaments that run in series. I can not find a lot of info on the 6J1. Link to Data Sheet .

There is not a lot of instructions. Most everything is in chines and so I cannot read it. I was able to follow down the parts list and figure out what everything was and where everything went. I used a multimeter to check the resistors before installing them because the colors were not easy to interrupt. Overall this is a neat little preamp and an easy build.  

The box with a flash light for scale. 
The box.
These are the instruction. 


Here is the initial unpopulated board and the bag of parts.


Below is the finished kit.



Labels:

Comments

  1. UnknownJanuary 12, 2018 at 2:00 PM

    I just finished the same project. I ran into the same issues that you did.

    ReplyDelete
    Replies
    1. UnknownMay 2, 2018 at 5:00 PM

      Just bought the same kit through Wish. Is there anyway one of you could throw together some instructions on how to build this thing? Or maybe provide more detailed pictures so we can see where everything goes? You can email me directly at blumenthala@gmail.com.

      Thank you in advance if you can!

      Delete

Post a Comment

Popular posts from this blog

Seeburg Digital Control Center

The Seeburg Digital Control Center came into use around the 1970's. This was model DDC1. Seeburg continued the use to the digital control center line until around 1977. The last model used was a DCC42-56. The DCC is used to supply 27 volts DC, -27 volts  DC and -13 volts DC to the jukebox. The DCC has test points on the side to measure these voltages.  Below you can see a DCC3. Once you flip over the DCC you will see two circuit boards. The top board is the data buffer board. Generally you will not have any issue with it. The second board (on bottom) is the power supply board. This where you may have issues. The power supply board is where the DC voltages are created and regulated. Below is the power supply board removed. The first thing I always do when working on a DCC is start by replacing all electrolytic capacitors. Below is the schematic.  In my case as you can see below I had other issues. As you can see transistor Q3120 has ...
Post a Comment
Read more

Seeburg SHP3 Repair July 2017

I have just finished repairing this Seeburg SHP3 for a friend. My friend collects and refurbished jukeboxes and he occasionally brings me the amplifiers. Initial Photos : The above photos show the amplifier as I received it. It was obvious someone had done some work before. The driver transistors as well as the output transistors were not originals. Also, Q5114 had been changed. It is the big silver transistor you see on the driver board. The initial power up  using a dim bulb tester showed that the right channel was not working and too much current was being drawn. Why I use a dim bulb Tester:  Notice the red enamel wire running along the top edge of the driver board. A trace should be there, but someone ran the amplifier with shorted transistors and burnt the 32+ volt trace off the board. Repairs: Replaced Q115 and Q116 (Driver Transistors Right Channel) -Shorted Replaced Q5117 and Q5118 (Output Transistors Right Channel)- Shorted Replaced Q5114...
Post a Comment
Read more

Bell & Howell Oscilloscope Model 34 DeVry Tech

The Bell & Howell Oscilloscope Model 34 was purchased at an auction and then give to me. It was made by Heathkit for DeVry Tech (DeVry University). Below is a photo of the front after I finished electronically going through it. There was nothing interesting that came up while working on it. Below you can see some before and after of the underside. Below is the top side. The 2 filter cans were 4 sections of 20mfd for a total of eight 20mfd capacitors.  Below is the solution I came up with to replace them. It consists of eight 22 mfd on a PCB that is zipped tied to the bottom of the chassis.   Overall this is a simple oscilloscope and was a simple electronic restore.  Here is the schematic.
3 comments
Read more