Hack Chat Transcript, Part 1

A event log for Vintage Electronics Hack Chat

Where there's a tube, there's a way

Dan MaloneyDan Maloney 5 days ago0 Comments

Dan Maloney12:00 PM
OK folks, it's tube time! I'm Dan, I'll be modding today along with Dusan as we welcome Keri Szafir to the Vintage Electronics Hack Chat!

Hi Keri, are you online yet?

Bil Herd12:01 PM
Hi @Dan Maloney !

Dan Maloney12:02 PM
Technical difficulties, please stand by...

Dan Maloney12:02 PM
Hi Bil!

Dan Maloney12:03 PM
Just trying to get the chat rooms sorted out

Boian Mitov12:03 PM
Hi @Bil Herd

Bil Herd12:03 PM
Hi Boian!

Keri Szafir12:04 PM
hello everyone :)

jihernandez9513 joined  the room.12:04 PM

Keri Szafir12:04 PM
first time on HC, I got the rooms wrong :)

Bil Herd12:05 PM

Dan Maloney12:05 PM
Hey Keri, welcome aboard!

Keri Szafir12:05 PM
haha, nice seeing you :)

Dan Maloney12:06 PM
Can you tell us a little about how you fell into the Dark Arts of old gear?

Keri Szafir12:07 PM
I was learning electronics in my teens in the '90s, and never having too much cash, I couldn't just go to a parts shop and buy new - I mostly salvaged them from old devices, so old stuff was no new to me even back then

james.coleman12:09 PM
Is there an audio visual aspect to this chat? Feel like I'm missing something...

Dan Maloney12:09 PM
Nope, we just roll old school and do text chat.

RichardCollins12:09 PM


Keri Szafir's Profile

For getting out of my tiny lab to the broader world! Your regular mad scientist's plot to conquer the world. I've been building electronics for most of my life... Vacuum tube amps (guitar & hi-fi), vintage gear restorations, audio stuff, test gear, automation, fun projects etc. both for myself and for an occassional customer.

Read this on Hackaday

Dan Maloney12:09 PM
Although we can post pix and links, ofc

Keri Szafir12:10 PM
vintage, as in vacuum tubes? it was more like early 2000s (2003 or so) when I was at high school; I was fascinated by Fallout 1 & 2, with the '50s retro-futuristic aesthetics, all tube stuff (semiconductors were not invented in the alternate timeline the game's world took after WWII) and this got me into an interest in old Civil War era electronics, restoring and repairing devices, building my own inspired by the past

CJ joined  the room.12:10 PM

Nicolas Tremblay joined  the room.12:10 PM

Dan Maloney12:11 PM
Old TVs were always a great source of parts for me. Just don't forget to discharge the caps!

phase268212:11 PM
when I was learning electronics tubes were easy to get, ICs and transistors less so. Everyone was throwing out their B/W TV for Color TVs

RichardCollins12:11 PM
I am older than transistors. In the 60's there were lots of vacuum tube devices and resources. By the 90's a lot of that was gone and inaccessible.

Keri Szafir12:11 PM
I got acquainted with a bunch of guitarists and did amp service and building for them too, that's how I got into almost living and breathing old tech

Keri Szafir12:12 PM
I never did TVs, though I liked restoring radios

DrG12:12 PM
Keri, have you "evolved" toward early digital? I have questions on both :)

phase268212:12 PM
Most of my builds were for Ham Radio, there were still WWII surplus parts available as well. 1625s made for great finals

Dr. Cockroach12:12 PM
I can never resist a good Hamfest :-)

Dan Maloney12:12 PM
I've been hitting thrift stores looking for restoration-worthy tube radios, but alas...

CJ12:12 PM
Cool, yeah I repair tube amps for many musicians. I've got some old Silvertone amps on my bench now.... there are parts in this thing I've never seen, like a big Condensor. What the hell is that?

Nicolas Tremblay12:13 PM
What's the best way to discharge those old caps?

Keri Szafir12:13 PM
@DrG kinda, I sometimes worked with DTL

phase268212:13 PM
Hamfests and swap meets tend to have vintage radios at better prices than other sources. Just be ready to negotiate and walk away

Lt.Slothrop12:14 PM
@Keri Szafir do you have any favorite boxes or websites for learning old school electronics like vacuum tubes, tube radios or maybe even nixie tubes?

phase268212:14 PM
@Dan Maloney Hamfests and swap meets tend to have vintage radios at better prices than other sources. Just be ready to negotiate and walk away

Keri Szafir12:14 PM
speaking of hamfests, I had an electronics fleamarket in my old city - that's where I got quite a lot of stuff, anything I could afford (and cash was always a problem), tubes, sockets, potentiometers, whatnot... and I wish I could grab more cheap Soviet tubes imported by Belarussian or Ukrainian guys who sold them here in Poland

DrG12:14 PM
ok - question - I am the proud (and accidental) owner of a Blaupunkt Barcelona (1957 I suppose) it works well and I have done only minimal repair and cleaning - do I have to change all those caps?

Keri Szafir12:15 PM
@Lt.Slothrop Jogis Roehrenbude would be my favorite tube-related website, and there's Frank's catalog I use for reference

Keri Szafir12:15 PM
other than that, Youtube of course, my #1 being Mr Carlson's Lab

phase268212:16 PM


Vintage Radio Documents and Articles

A selection of scanned technical and historic documents and magazine articles that should be of interest to vintage radio collectors etc. 31 files available. Click a row in the table below to download the file. You may download up to 10 different files in a 15 minute period.

Read this on Vintage-radio

Benjamin Isaiah12:16 PM


Read this on Tubebooks

Dan Maloney12:17 PM
+100 for Mr. Carlson! I really like his new lab, too!

RichardCollins12:17 PM
DTL - Drift Tube Lineacs?

Do you make your own tubes?

phase268212:17 PM



Thanks for checking out my channel. I enjoy restoring old radios from the 30's through the 40's as a hobby when time permits. For those just getting started in vintage and/or antique radio repair/restorations, I hope you find the videos to be entertaining with a few tips inserted from time to time.

Read this on YouTube

Keri Szafir12:17 PM
as for caps - discharge them through a resistor (e.g. 10k 2W), change if there's visibly something wrong with them (bulges, deteriorated sealing etc.) or if tested and working wrong

CJ12:19 PM
@Keri Szafir where do you buy your caps for tube amplifiers?

phase268212:20 PM
and watch out for hot chassis on transformerless tube radios

Keri Szafir12:21 PM
I mostly use vintage caps for my own builds, or buy new in some electronics parts stores

Keri Szafir12:21 PM
oh yeah, hot chassis... I always use extra precautions for these

phase268212:21 PM has a lot parts and good infor on their website

Dan Maloney12:21 PM
Do you have a hard limit for replacing caps in terms of date? IOW, they may look fine, but teething was built in 1960 so just replace them?

Cooper12:22 PM
There must be a way to test caps, no?

Michael Jennings joined  the room.12:22 PM

Dan Maloney12:23 PM
ESR meter, right?

DrG12:23 PM
I think Dan is getting at why I asked...I get told that they all need to be replaced because they will blow and make a nasty mess.

Keri Szafir12:23 PM
I don't blanket replace caps, do it on a case-by-case basis, test for capacitance and ESR

Keri Szafir12:24 PM
I'll also build a leakage tester - a useful tool

Cooper12:24 PM
I would think the less R&R you could do to an older piece of tech the better

phase268212:25 PM
@Dan Maloney I replace electrolytics from 1970s and before. Any paper wax capacitor goes away as well. I have an old Heathkit cap tester but I found it tends to reform old electrolytic capacitors when testing. So I just replace the electrolytic capacitors so I don't have to go back later.

Keri Szafir12:25 PM
oh yeah, especially very old stuff (pre-WWII, though I never had one on my bench); in that case I'll restuff the old can with modern components to preserve the visual originality AND not add anything modern on the bottom part of the chassis

Keri Szafir12:26 PM
paper wax goes, no questions asked - these parts were utterly crappy and prone to failure

Cooper12:26 PM
Keri - that's an interesting idea

phase268212:26 PM
I had an old Hallicrafters that I recapped in the early '80s and had to replace the electrolytics again a few years ago

Bil Herd12:27 PM
who would have thought that we would outlive capacitors

Keri Szafir12:27 PM
back then things were often built to last, though you're never sure - always check it!

phase268212:28 PM
The technology for capacitors has come a long way over the last few decades. That is why you can stuff old cans with new capacitors and have space left over

Bil Herd12:28 PM
I like Keri's intro where she talks about smells, fixing things in the old days was deffinately a multi-sensory experience.

Keri Szafir12:29 PM
oh yeah

phase268212:30 PM
I am impressed with anyone that takes the time and effort to restuff old components. @Keri Szafir My restores are usually not that valuable or historically significant.

Dan Maloney12:31 PM
I love when someone restuffs those big old can caps for a restoration. Such attention to detail!

Keri Szafir12:32 PM
that's how I'd do it on something remarkable - other than that, I'd probably use a vintage cap from my stash

DrG12:32 PM
I am personally VERY impressed with the careful point-to-point component soldering that I see in that radio....and of course, the schematic was included. It was built with quality.

The problem for me conceptually is when does a restoration mean no longer original - I guess always...but better to have it working.

phase268212:33 PM
When restoring do folks usually test the tubes or only if the equipment doesn't work?

DrG12:33 PM

DrG12:34 PM
blows me away going through it

Cooper12:34 PM
I agree that it's better to have it working at all. Maintaining the original aesthetics on the interior is a major bonus

Keri Szafir12:34 PM
I test tubes on amps, and when something's wrong, on radios too

Dan Maloney12:35 PM
Just think about how labor-intensive it was to mass produce electronics before PCB construction. Blows the mind...

Keri Szafir12:35 PM
oh yes - and it was mainly ladies who did it!

phase268212:35 PM
That is why TVs and Radios were expensive back in the day, a family only had one

Dan Maloney12:36 PM
And they did it fast, too. I think it was mostly piecework, so they got paid by the chassis

Boian Mitov12:36 PM
Not to melon manually programming Rope memory... ;-)

Keri Szafir12:36 PM
oh yes, ferrite core memory...

RichardCollins12:36 PM
Is this a chat about capacitors or vacuum tubes?

Can you reproduce the Franck-Hertz experiment for class room use in high schools, colleges and universities world-wide?

Dan Maloney12:37 PM
It's a chat about vintage electronics, so - yes!

RichardCollins12:37 PM
Can you make your own vacuum tubes?

phase268212:38 PM

wells gardner story.pdf
4 MB

Download File

Keri Szafir12:38 PM
I can't - don't have the lab for that

RichardCollins12:38 PM
What would you need?

phase268212:38 PM
Wells Gardner story with radio assembly photos

Nicolas Tremblay12:39 PM
Glass lathe, glass blowing equipment, vaccum pump

Nicolas Tremblay12:40 PM
And the metal pieces doped with sometime dangerous materials

RichardCollins12:40 PM
Is there a university near you or research facility? I could write and recommend they help you. Or you can start a crowdfund.

Keri Szafir12:40 PM
I'd need materials (barium oxide cathodes for indirectly heated, or tungsten for directly heated), metals for electrodes, glass, high vacuum pump setup, getters, burners for glassworking...

Keri Szafir12:40 PM
lots of expensive materials

phase268212:41 PM
Others are building their own tubes, been posted in Hackaday

Dan Maloney12:41 PM
This guy:

Dan Maloney12:41 PM


A Homemade Tube Amplifier Featuring Homemade Tubes

With the wealth of cheap and highly integrated audio amplifier modules on the market today, it takes a special dedication to roll your own from parts. Especially when those parts include vacuum tubes, and doubly so when you make the vacuum tubes from scratch too.

Read this on Hackaday

Keri Szafir12:41 PM
ah, jdflyback :)

RichardCollins12:41 PM
How much would it cost? Could you improve on vacuum tube technolgy using new methods of design? What from the past would help. Thanks Dan

phase268212:42 PM


Nixie Tube & Clock Manufacturer

Today, we're running a small-scale production The distinct look and functionality of our Nixie tubes trail years of design, testing, and refinement. Each is produced in a laboratory setting, with hopes to one day employ large-scale production means to ensure access for everyone.

Read this on Nixie Tube & Clock Manufacturer

Nicolas Tremblay12:42 PM
In tube technology, I think the only thing that improved is the level of accuracy

Dan Maloney12:42 PM