DIY talk

I dropped cable TV 5-ish years ago. I had Amazon Prime and HBO Now. What I didn’t have was network TV. After a little research, I found I was in a decent location for over-the-air reception. Bought a cheap tuner from BestBuy, but was pretty leery of the antennae they had.

Another Google search led me to plans for Gray-Hoverman designs. I did a really cheap & cheerful single bay, no reflectors and 12 ga copper wire. I’m fortunate that all of the network channels are in line with my garage, so just particle board and vinyl siding to pass through and I can keep it indoors and right next to the entry of the now-disconnected cable TV.

And it worked. Mostly. Sometimes had some pixelation, and very occasionally FOX was really iffy, but good enough. The fact that Super Bowl LVII was on FOX got me to thinking about an upgrade. Figured just going to 10 ga and adding reflectors was a big enough jump looking at various antenna tests. In the end I chose this one.

I made some design decisions that were probably of no value, but just because – no metal except 2 screws that connect the balun to the RJ6, and minimal wood structure to support the antenna. Standoffs for the antenna glued to a Masonite board; reflectors & antenna caulked in place in case I wanted to modify later. Craftsmanship is nonexistent, as I only realized at the last minute that the reflector to antenna spacing in the new design is 100mm instead of 3.5”. I could flip the larger standoffs since they are 4” lengths of 2 x 4’s, but had to shim the smaller ones with pieces of molding I scrounged from my pile of scraps.

But it works really well! No pixelation on any channel, and to my eyes the picture looked better. But be aware that standard OTA is either 720p or 1080i. We have just one channel in this area that is ATSC 3.0 (supports up to 4K), and it isn’t FOX. I will probably get an ATSC 3.0 tuner when a couple more are available.

Total BOM was $35. There is a version that is 2 x the antenna I made, one above the other, if you need the extra signal strength. Thicker copper also gets you more signal strength, but I think 10 ga is the limit for straightening and bending by hand. Pretty sure for 8 ga I would need a mallet, anvil, vice, etc. I did use a small vice that had a horizontal groove to straighten the copper where it was wound around the hexagonal reel at Home Depot.

Pics or it didn’t happen:




Stonehenge

 

Saw these things and thought I'd share...
https://www.amazon.com/Innovative-Products-America-Diamond-Coated-Flexible/dp/B00GJ5U8FM

It's used for electrical contacts, but maybe could be useful for tube pins or other things too.

 

Hello all! I make headphones for fun and then move onto a new project after its finished because I'm just like that!
This is my first project using resin printing:
The idea was simple, make an over ear HP1! Yup, the yamaha hp1. It was...not bad, but i constantly got condensation issues on the speaker. Wasnt a fan of that, even with porting! I'll do something about that another time though


Next up, my own take on an hd800 in a custom body! I have no measurements atm due to lack of proper microphones, but I plan to get one soon to do them.
They sounded pretty gnarly I wont lie! The bass was fairly punchy, not distored with amazing dynamics and overwhelming treble. Im currently working on fixing that, for the treble as I enjoyed the bass a ton. Vocals came off smooth and clear, probably the best ive heard in a while. However that treble stops me from actively using them.



Lastly I am going to 3d print my very own headband, thats simple and functional! The concept works like the Koss gmr headphones, using an elastic band on the internals and covered with a piece of fabric. Suspension strap basically.
The headphone itself is not to sound or be good, just a random chassis to showcase the headband.

 

What changes do upgrading/changing the capacitors do in an amp?

 

Depends on where/how it's used. And there are many rabbit holes to fall in and many religious wars to be fought.

 

The basic argument is that real capacitors are not ‘just’ capacitors. They have non-zero resistance and inductance that lead to unwanted modifications to the signal. Better capacitors reduce these issues and push it closer to ideal behavior

There’s a different school of thought where design matters far more than component selection and that good design will minimize the non-linear issues from non-ideal components. These tend to be complex high order crossovers with more parts but cheap components

edit:

Oh but you are taking about in an amp. Which doesn’t really have capacitors in the signal path except for an OTL design like the Bottlehead Crack. So I assume you mean the power supply.

Often those are electrolytic capacitors because they are primarily to keep the voltage stable. The issue is that electrolytics do deteriorate over time and it becomes necessary to replace them.

 

^^^ many amps do have them in the signal path. On the input for DC blocking.

 

I am looking for a skilled modder in the SE Michigan area. I have a Lance Cocchrane 6l6 amp that I would like to add a volume pot to and an IEC or a new permanent power cord. Happy to pay for your skills just need someone who is good at this stuff. Im in Ann Arbor and could drive the amp to you.
best,
Josh

 

The ones I'm looking at replacing are the 0.1 uF interstage caps and the 10 uF parafeed caps. and posibly the 100uF cathode resistor bypass.

 

Hey all,
I'm having someone help me swap out a stepped attenuator for a potentiometer in the Dragon Inspire IHA-1a and the nice TKD or Alps Black Beauty won't fit.

Is there anything the size of the Alps Blue Velvet but better quality?

thanks!

(I know, stepped attenuators are "better" but it doesn't matter if they sound better if you can't listen to them because the volume is either too loud or too soft)

 

There are different sizes of TKD. I have a TKD pot and a DACT switched attenuator, and the TKD pot is the smaller of the two.

 

Alpha makes a high-end version of their pots. I can't really find them anywhere though except on this Indian DIY site

https://theaudiocrafts.com/electron...a-songhuei-2122g-series-a100kx2-potentiometer

 

I am just starting to get the camper ready for this season and it's making me smile. I put out a bunch of bluster about redefining my art practice during the pandemic.,..oh the books I'll read...oh, I'll do daily pieces....blah blah... in the end, I just worked on my camper. Here's a couple of stills from last year.

 

Would it be worth while to upgrade the potentiometers in the Kaiju if I'm just going to have them set wide open and use a pre-amp to adjust the volume?

I ended up buy some caps from Parts Connexion, since they are on sale for 20% off. To upgrade the stock caps. I noticed that there is no directional marker on them. Does it matter what way I install them?

 

Directions only matter for electrolytic capacitors because they are polarized. Film capacitors are the same either way

 

Thank you!

 

If you're going to leave it wide open, you might as well just bypass the pot. Find out what the input impedance is without a pot and use a couple of quality resistors if needed.

 

Interesting. As of right now I'm just leaving it wide open. In the future I do want to try using the amp on headphones which will, probably, require me being able to turn down the volume. So I don't want to bypass it completely.

 

I prefer the carbon pots made by Precision Electronics Corp to the Alps blue velvet, never heard the black beauty. They're not audiophile components, but they are high quality. Edited because I've been getting linear pots made by PEC for bias adjustment lately and thought they also stocked the logarithmic stereo pots but they don't. The only place I can find PEC stereo audio pots in stock is a site in Europe and they're charging too much. So this whole post is not much help I guess.

 

The Black Beauty used to be a highly sought after "audiophile" pot when it was in production - the trouble is that there are a lot of counterfeits out in the market so unless you stumble on someone with NOS stock ( as RD did ) then I would be weary as they run $150 average ( not crazy but not cheap )