Tube Amp progress

My 6SN7 Tubes came in today. I started to put the chassis together and ran into a snag. The sockets are falling apart so I ordered three new ceramic sockets. But I still went on with installing the Power Transformer, mounted the Speaker and Output Transformer. Also in a last second change I am changing out the incandescent bulbs for the Radio Dial to LED. I have some Automotive bulbs and they work fine with a rectified 6.3 filament. I tried running straight AC but the LED didn’t like it so after tossing on a couple 1n4001 diodes and a 220uF filter cap it works like a charm. Since the LEDs are running under voltage they are not super bright and work wonders for the Dial lamp replacements. With the 220uF cap they have a slight flicker like an old incandescent bulb.

Once as I get the new Sockets I will post some pictures. Tomorrow I may or may not work on the cabinet some more.

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Selenium Rectifier VS Silicon Diode

Selenium Rectifiers were basically the first solid state rectifier to replace Vacuum Tube Rectifiers. In a nut shell it is a stack of plates with Selenium that can turn AC into DC. By today’s standards you should not use Selenium Rectifiers and use Silicon Diodes or if possible if it’s a Vacuum Tube device then use a Vacuum Tube Rectifier.

Now there is a dirty little trick when converting over to a Silicon Diode. Selenium Rectifiers¬†for some odd reason have the Kathode listed as Positive, in truth it is not. I guess they listed it for the flow of current. So remember Positive is the Kathode for Selenium Rectifiers. Also if you convert to a Silicon Diode chances are you’re doing this to a Vacuum Tube device be sure to check if the Tubes can handle the added voltage since a Silicon Diode has a voltage drop of .62 to .76 of a volt while Selenium can have a voltage drop of a few volts. So do the math and you might have to add a resistor to drop the voltage or put a few Diodes in line to get the proper voltage.

If you come across a Selenium Rectifier that doesn’t show the polarity you can’t use a Diode test on a Multimeter but testing each side in Mega Ohms works. The lest amount of resistance is the Anode (Positive). The higher side in resistance is the Kathode (Negative).

Here is a reason why you should convert to Silicone Diodes instead of leaving in a Selenium Rectifier. For one Selenium can just suddenly short out and put toxic fumes in the air, not to mention fry the power transformer of your device that you’re probably restoring. In other words can be a fire/safety issue.

Picking the proper Diode is easy. Since once again chances are it’s a Vacuum Tube device you’re converting so the old trusty 1n4007 Diode will work. It’s rated for 1KV Working Peak Reverse Voltage and 700volts RMS reverse voltage. It’s rated for 1amp but you can find different Diodes with higher Amp ratings. For an example in my RCA WV-77E I have a 1n5401. It’s rated for 3Amps and 280 volts but the Meter just uses 135volts.

For more info on the subject here is a PDF I found covering on converting Selenium to Silicon.

News 1/7/18

I haven’t done one of these for a while.
It’s a new year and a lot to do and cover.

I’m still putting the new shop in order. Going through boxes and drawers finding stuff and putting it away. Since the new house is a 45 minute drive from work of what free time I have during the week days I spend with the family and pretty much only got the week ends for my hobbies.

Last week I started putting together the blog post for running low voltage lines in the house but I had a computer crash. The pictures I copied over from my phone are gone and I attend to not keep pictures on my phone after I transfer them over. So I will have to try again when I run more low voltage lines. I was only able to run one line so far, really more turning an existing phone line into a Data line for the family computer. Since I don’t plan to ever get a LAN line I just relocated the end that goes outside to the Living room wall. I will however try again soon when I add more low voltage cabling to the house. I might even do it when I add the new shop lighting or the security cameras.

Last couple of Saturday nights the Kids and I have been having Nerf wars in the house. It is a load of fun but we keep loosing darts everywhere. The middle son and I have been looking into the Recoil Lasertag stuff and made plans to buy the starter kit next week. I think it would be fun to reverse engineer one of the guns and see about making custom weapons.

Since I found all of my parts for my new bench power supply I put a prototype together. It’s just mounted to a piece of wood. It’s really just a Linear back-end with one of those digital output controllers. It’s kinda odd that the Transformer has a 40 volt tap and after rectification it jumps to almost 70 volts. I tossed on a huge low value power resistor to see how it holds up and holy crap it only sags a couple of volts, way too much voltage for the controller so I had to use the 20 volt tap and with rectification and no load it’s around 35 volts. The controller I have is rated for 50 volts.

The vintage TrueTone d2626 radio I have been turning into a Class A amp is coming together slowly. I completely stripped down the chassis, wire wheeled it and painted the exterior with black enamel. The power and output transformers are fine and got cleaned up and a coat of paint. The tube sockets are trash so I need to buy some new ones. I got a couple of 6SN7GT tubes on their way. I also started on the cabinet and it is very rough. I ended up stripping the vernier on the sides and top off and plan to sand the top and add new vernier to the top. I’m not worried about the sides I plan to sand and finish it, has a real nice Oak grain. I also found a Klipsch speaker that will fit and work find for the radio.

I tried to get a Sencore t109 Tube tester and attempted to Bid for one on eBay. I almost won. When I was at Walmart with the Kids getting more Nerf darts I was minutes from the auction ending. I thought I had won because it said it ended and I won but when we got to the parking lot and decided to send payment I saw I was out bid by a dollar. Damn Walmart building hindered my phone’s data. So I am still in the market for one. All I can find for the price I want for the moment is for just the big Tubes. I would like to get one that can do the smaller tubes as well since I have a few devices that use them.

Adding Cabling to your home professionally yourself (Preface)

Before you can go gun-ho on something like this thinking “I can do it, who needs a cable guy!” You need to know a few things. Reason why I say this I do this as my job and always hear “I was going to do it but I just don’t know”. So with that said here are things you need to know.

1. – Safety
This requires to go into the Attic. You might want to plan for a cool day such as the Morning or Late Evening. Mid day you will sweat buckets within minutes if you live in a hot climate. If you never been in an Attic before you will learn quickly to watch your head for roofing nails and to be sure to walk on the supports, studs and trusses. Never walk let alone sit on the drywall ceiling, it will not support you. Also avoid stepping on electrical wire and watch the AC duct work.

2. – make land marks.
Before going into the Attic do a walk through to where you need to go and take note of light fixtures, AC vents and plumbing. This way when you go into the Attic you’ll know the room you want is the correct room. If you’re running Coax you can make a marker by stripping a large chunk and stick the bare copper (stinger) through the ceiling near the location. This will leave a small hole you can easily patch.

3. – Tools.
You’ll need a few tools such as a head lamp, drill with at least a 7/8 paddle bit (bigger if you plan to run four or more cables into the same location), Tape, wire cutters, Glow-rods or chain. These tools are needed for the Attic portion.

4. – Misc
Try not to use wire that already has connectors on them. If you have no choice then use plenty of tape on the connector end and if dropping more than one cable then stagger the cables if you they have connectors on them.
Also it is far much easier with a second person. They can guide you if you get lost by knocking on the wall and they can even tell you if the wire dropped all the way.
Avoid exterior walls. The insulation will hinder you. Also there is a chance you’ll run into fire blocking. Fire blocking is a 2×4 or 2×6 that is running Horizontal between two studs. They’re typically four to five feet up in the wall. A stud finder might be able to locate them, most stud finders are just metal detectors and locate a stud by finding nails and screws that secure the drywall on. Hopefully the Dry-wallers put a couple of screws or nails into the fire block. The only way around a fire block is to cut the dry wall to reveal it then notch it, break it out or just drill through it, just easier to drill through it.

5.- Cable
Avoid laying your cable on Can lights, they get very hot. Try not to follow the same path as electrical if you’re running Data, TV or Audio. If you’re running Data or audio have it four inches away minimum from any electrical. Keep in mind you need to measure the wall distance. For an example you want to splice into an existing TV and want to add a Coax cable to another wall in the same room and your walls are eight foot and the span twelve feet, add sixteen and twelve and add six to give you some wiggle room of slack, the total should be thirty-four feet of cable will be needed.

6. – Interior side of things
This is the easy part. You’re just “trimming” and if you had a helper it would be a breeze since the helper could have cut the drywall and pulled the cable ends through. However if you’re doing it alone then you would have cut the drywall for your plate and shoved a marker in the ceiling before going into the Attic.

If there is anything I missed it will be covered in the finished guide.

Planning for more shop lighting.

Currently the only light sources in my Garage shop are two lights. The Ceiling light and my desk lamp. It’s enough light for a few things but if I need to work with small things I need extra light. So to add more lighting at on a small budget and not require much attic crawling I am going to go with a Vintage look. Some pendant light fixtures with some “Edison bulbs”.

There will be a total of four light fixtures. One will replace the current light fixture and three more over the desk. I want to splice into the current fixture and run some romex to a junction box for the center light fixture for the work bench then use modern cloth-covered wire to branch over to the left and right fixtures that will also be over the bench. The wire will be exposed to give it that more of a vintage look.

If I need more lighting at the bench I can add some LED lighting under the pedestal I am using to mount a couple of LCD computer monitors.

Down the road I can find myself a vintage desk and chair to give my shop a Vintage look and feel. I’m still holding out for HarborFreight to put that wooden tool box on sale.

Anyway, The Pendant light fixtures I have been looking at are twelve bucks a pop. Also I found a three pack of the fixtures for sixty bucks. It’s cheaper to buy the four by them selves let alone the three pack doesn’t include the light bulbs. When it is all said and done I’m looking at anywhere from eighty to one hundred and thirty bucks for the lighting.

The shop is good to go.

Spent all day yesterday and got the shop in working order. Soon I will start getting back to builds and repair projects.
The first project in the new place will be running Cat5E and electrical for the media closet. I will show step by step on this process so you wouldnt need to depend on the cable guy or a VDV tech again.

Here is a big surprise

I finally have a shop. Well more like the wife and I bought a house but the two car garage is my new shop/man cave.

Soon I will be able to pull off the back burner projects and finally get stuff rollin.

For now I just neds to get the shop all setup and install a few things around the house.

Vaccum Tube amp for MP3 player.

Today I bought from the flea market a TrueTone D2626 SW/AM vacuum Tube radio that was made in the late 1940’s. The cabinet is a bit on the rough side but repairable and the chassis looks to be in good shape.

Since there really isn’t any AM stations worth listening to and I have no idea about short wave stations let alone the radio isn’t worth much that I decided to strip it down to the bare chassis and rebuild it into a Class-A Amplifier. This way I can connect an MP3 player or smart phone via bluetooth.

The build is super simple and already have most of the parts I can reuse from the radio. Just need the typical new caps and add a 6SN7 Tube for the Pre-amp. The radio already has a 6V6 Tube for the power amp. I’m still deciding to use silicone diodes for the rectifier or use the 6X5GT Tube that came with the radio.

A nifty idea came to mind for the dial face of the radio to be replaced with a LCD that can display what is playing but that would take away the vintage effect unless I can find an LCD that uses Red text with no backlight and have a bezel over it with the TrueTone logo or something. Yet there isn’t anything off the shelf that will work with the specifications I want and I really don’t want to wrap my head around trying to build one. Ether way I would have to add another power transformer to power the Bluetooth because if I use say the 6.3v filiment secondary I’ll end up with a nasty hum in the audio. Not to mention I might end up having to use one of those Automotive Bluetooth modules if I wish to use the LCD idea.

This is an up coming project. As for now I have other things going and will have a surprise soon.

Raspberry Pi 3 Model B

A few days ago I was goofing around and found a Raspberry Pi 3 Model B on Google Express. It was around $38.00 with a $10.00 off and free shipping promo so I jumped on the chance and ordered it, the seller was Fry’s Electronics as well. Shockingly it came in yesterday evening from FedEx.

I realized I did not have any monitors that have HDMI. I checked my huge box of wires and cables and just my luck I couldn’t find my 3.5mm to RCA video adapter so I had to go buy a HDMI to VGA adapter from Walmart. While I was at it I bought a 16GB SD card for it. I tossed on Raspbian with GUI and loaded it right up. I realized my USB adapter it’s letting the Pi draw enough current so I switched it to an old 5v 2amp walwart and the trouble started. I kept getting a black screen and even tossed in a 2GB SD card that has Raspbian Lite and still nothing. I honestly thought I screwed something up when I switched the power sources. After a quick google search I discovered the HDMI to VGA adapter was causing the issue. Since the Audio wasn’t work from the audio output jack I had run the raspi-config program to enable it and this made changes to how the HDMI acts. So I modified the boot loader’s config.txt file by changing some options.
Here are the changes I made to the config.txt file. You’re mileage may very.

hdmi_safe=0
disable_overscan=0
config_hdmi_boost=2 

Everything worked out fine however this morning when I turned it on it did it again. By this time I had SSHd running on the Pi and just logged into it from another PC and changed a setting in the config.txt. I had config_hdmi_boost= set to 4 but I changed it to 2 and rebooted it then regained the video.

I plan on building an electronics portable computer with this. I can use it here on the bench and maybe even at work troubleshooting audio and security.
These are the specs I’m thinking about.
7 inch touch LCD screen.
A beefy 5 volt power supply (Maybe make it use a 18volt Ryobi Plus One battery with some voltage regulators). This way I can have options of 3.3v, 5v and 12 volts. Maybe a LM317 to have a variable output.
A small bread board.
A square wave pulse output to even use it as a wire tracer.

There are so many things I could do but it all depends on what route I take on the build.

RCA VoltOhmyst WV-77E

I bought an RCA VoltOhmyst WV-77E VTVM from eBay. It was a total steal, the meter has already been calibrated and mostly recapped.

There is a small crack on the upper left of the meter movement but I might slap on the WV-97A meter movement. I already swapped the Zero adjust and Ohms adjust knobs.

On the inside I was a little shocked to see an added fuse with a small plastic bag to insulate it so I need to replace that. The Filter cap needs swapping out and there is a Selenium Rectifier so I should change that over to a Silicone Diode. One problem is when you change something like that there will be more voltage going into the circuit since a Selenium Rectifier has a larger voltage drop around a volt or more than a typical Silicone Diode that averages around .7 of a volt.

As for the other RCA VTVM I was restoring I decided to give that up. Reason being by time I would be finished with it I would have replaced just about every part.