1940s Knight 30S PA Tube Amp Guitar Conversion (6L6)
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- Опубліковано 25 тра 2016
- In this video we'll follow the conversion process of a 1940s Knight Allied Electronics PA Head Model 30S into a guitar amplifier. The 30S began production in 1941, according to the schematic, and featured 2x 6SJ7, 2x 6SC7, 2x 6L6G, and one 5U4.
- Наука та технологія
![ОРБАН приехал к ПУТИНУ и "отчитался" о поездке в Киев 😁 [Пародия]](http://i.ytimg.com/vi/_0ukDovOWq8/mqdefault.jpg)
My late father has a Hohoner Madcat in his ciollection. When he bought it i think he only payed £230 in the early 80's and i think that was considered quite pricey for a T style especially by Hohoner who were known for making less expensive models of popular Guitars.They put their own spin on the 'Madcat' and is now well sort after with Genuine H S Anderson originals reaching 4 k for good examples. I was very lucky to have had a father who collected his Guitars through the 60's.70' and 80's even the odd one or two in the 90's just before we lost him.Their all heirlooms for my children and i would love to play them and i do often go to the secure storage and look through the collection wishing i wasn't left handed. That he found quite amusing openly telling me that ' your going to have to try twice as hard to accomplish what you are setting out to accomplish.' Of course i knew he was right, right handed players are far better catered for even now and premium prices put on left hand Guitars is descrimination to be brutaly honest. I have gathered a nice collection of lefties myself some very expensive, i sometimes wonder is it realy woth collecting vintage Guitars. Fortunately i was given my Dads and it's amazing but i to look for left hand equivalents of a pre CBS Fender Strats and it's getting very difficult to track them down. Still i continued and became quite adept at trackin
Love those old school amps. Great video Sir thanks for sharing
Very cool amp conversion! Man that is really cool! And nice Prince story as well. Brings back a lot of nostalgia from my youth!
Thanks for watching. And yeah, man, Prince's death really hit me. All those feelings I had from my youth came flooding back - walking the playground ghetto blasting those opening notes of "Let's Go Crazy", wishing I could dart off into the woods and not go back to class.
Great video, thanks. I learned a lot watching your method of evaluating the amp condition. Good to see how slowly you bring the voltage up. I've got a similar 1959 "breadbox" case Knight coming from Ebay in 2 days. Has a turntable on top! Time to get my variac out.
I love your vids, hard to believe you didn't have a proper cab. That sounds great!
I know, right! Just a speaker on a table.
Well, I had to go buy another shop speaker cab last night. I'm going to make a proper end result demo of this in the next few days. I plugged it in briefly today and got yelled at by the spousal unit. "TOO LOUD!" she said.
\w/
that is 2 funny i have one of those 2!
The Guitologist , haha. That's exactly how I ended up with my Line 6 Spider III amp 1 x 12 75w for £25. About $32 with today's conversion. His unit was about to put it out on the street.
Where can I hear it? :))
Wives; can't live with them, can't hack them up and use the for dog food.
Wow, what a great sounding and very cool looking amp. I want one.
Very cool. I had a Knight stereo tube amp that my parents got my for Christmas in 1968. I think maybe that was the house brand for Radio Shack. It was purchased at a Radio Shack store at River Oaks shopping center in Calumet City, IL. After watching this, I think I'll look for another on the Bay. Thanks for these videos.....love them.
Realistic was the Radio Shack house brand. I think these Knights may have been sold both pre-built and as kits.
Love the Prince story!... great work, great vids.
Thanks for commenting. I appreciate that.
love the sound of that amp
Brad, I found a Bell & Howell PA amplifier in perfect condition at the swaap meet. I paid $28 bucks for it. 2 pre-amp tubes, 1 6L6 and and a rectifier tube. It even had a bias knob. I love the swap meet.
08/14 my birthday. This amp is awesome. Would love to play period music with this amp.
sound freak here , got a great ear ..tubes just way better for my ears ,ty for your work. world is is better
Brad....Ran across this while checking out some of your older videos. For awhile now, I've been looking for a tube power amp, for a Leslie mod. project, and had never considered Knight...until this reminded me! I haven't seen a Knight kit in ages! Checking oBoy auctions, I scored an 80-watt (more or less) PA 93-SZ-695 in working condition!! Probably needs a re-cap, but I paid less than the transformer's worth as scrap!! Thanks for the memory jog! :-)
Bargain!
...and I just found a SAMS manual for it! Should be better than the little 20-watt 6V6 amp that came in the Leslie....and complement the '53 Hammond C2 nicely! (Yeah, I get excited easy! LOL)
That thing is sick!
Sounds great.
Thanks, Jerome. I was pretty fond of the tone on this one. Sold it before I could properly demo it.
Sounds good already. Curious to hear more when properly finished.
Purple Rain is still an epic album.
Rest in peace, brother.
He was the best singer songwriter out there he will be sorely missed RIP Prince, I think that sounds like a 500w guitar amp you will need a proper speaker cabinet and 4x 4R 500w speakers to be sure.
Oddly enough, I found this to watch & the Date is August 13 2021( 80 years ago exactly). I was going to skip it because i was in the mood for something else to watch. 🎸
the cabinet made me think of the old Bogen PA head I've got in storage, haven't seen for about 30 years.green and tan I think.
does anyone else blown a load when the tops are taken off and you see the inside with all the tubes! it's like a vintage piece of art even when it is all cleaned up like at 24:06 that is beautiful.
Damn. You ought to build a bunch and sell them. Sounds killer
Allied Electronics is probably the nation's oldest electronics supply business, founded in 1928 as Allied Radio. They are now part of Electrocomponents plc, the British parent company of RS Components.
The owners and employees of Allied should be proud to work for a company with such a long and proud history. That's rare in today's world.
very nice. I hope I find one of these.
+Jason Kirkham score*
definetley. do you still have it ?
Great sounding amp! Thanks for posting this : ) On these old amps do you usually add screen resistors or leave them stock?
Too cool. An ole 1940's lunchbox p.a. head. Wow
Awesome conversion. I'll be on the look out for old tube equipment in general now. Quick question. I notice you use a scope quite often in your newer videos. When did you start implementing it in your troubleshooting routine?
Sounds absolutely killer and this is, I'm coming to find, business as usual.
So will we still get a proper demo with everything buttoned up and a proper speaker cab? (I do hope so!)
Thanx for another great vid and...
cheers
I've just got one of this kind with 2 channels. But unfortunately with no gain. What's the simpliest way to get a built in gain stage (not with a pedal)?
i want to install a fx loop in my ao-35, can you do a video on how to do such a thing?
So, Brad do you get drowned with inquiries as to the availability for purchase for all of these great projects or just add them to an already fascinating collection to jam and share with friends or...(?)
Inquiring minds want to know... (;-p)
That one rips what about that jumper plug in the back don’t it change ohms?
I am a newbie in audio and english is not my dominant language.
Can you explain why many Sound engineers and Amp techs
sa the famous " HEADROOM " word ??
You mentioned, changing amp tubes to get or have Max Headroom !
Phono inputs can get some good gain as guitars have a hotter signal than a record player
hey brad thanks for the reply! watch mr karlsons video on his new low voltage cap tester youll want to throw one together for your bench!
I have a knight model 30 would you be interested in converting mine? 2nd question how much would it run me
крутая гитара, мужик!
That’s actually pretty good foresight by someone at Knight. Can’t hurt the output transformer if you can’t turn the amp on! Is that a resistor or a handle attached in the WRONG place? These PA’s CAN sound really good but they generally take a good deal of reworking in my limited experience. I’m sure SOME are good for guitar right out of the gate. But they were usually meant to be used for school announcements and what not. They’re also not configured for sustained use. Heat build up wasn’t a consideration with some of their designs. They’re fun canvases to work with ,tho.
I know it pretty and nitpicky but the OL on the meter stands for overload not open lead:).
if i won the lotto i would hire the guitologist full time to make these crazy cool amps for me all day!
This is very good guitar playing. And the reason it is so good is the amp. :))))))) (JMO)
Hey Guitologist, Good mod. From the sound demo, it will Rock. Maybe a 1KHz tone and check the power output, be interesting to know what it's pumping. Take care, keep one hand in your pocket, C.
I'll bias it for the 6L6GC and squeeze the most out of them. The 6SL7 pentode into that pair of 6SC7 triodes paralleled takes care of any gain you'd need. The output needs to be set for max headroom. I will tweak it and move it along.
Where's the best place to purchase replacement capacitors and tubes for old guitar apps I have a 1963 Ampeg amp that I want to read to been recap
I get my caps from Antique Electronic Supply's wholesale subsidiary, I order at least 10x of each cap value at a time so I get a better discount. Shipping from them is high though. You can try Mouser also.
How crucial is it to bring the amp up on a Variac after a Re-Cap?
Twisted Robot they say it's easier on the electrolytic caps to slowly form them when brand new but it's mostly because if something's wired wrong or you made some other sort of mistake you will not damage anything serious before you find out aka things will just get a little hot or smoke a little bit instead of taking out a transformer or destroying tubes
That is my point tiny cad is so simple to use it’s a
pleasure and you can’t say about most software.
Also In my den I have a 1k Wien oscillator with output pot,
and I use that for all audio stuff and it’s great with the scope too, I’d send
you the design if I knew how.
I enjoy your videos they remind me of my earlier work
Thanks! And thanks for watching. I might check out that software if I feel the need to make some neat schematics again.
When you did this sort of thing it would be great if you drew out a schematic of whatever mods you'd made ;-)
I've got a 1960's knight PA I'm trying to do something similar with now. Not nearly as good as you are at this though.
I wonder if the speaker jacks having to many pins were originally designed for speakers with field coils.
No, it's actually so that the amp cannot be turned on without a load attached, Saves your output transformer. Safety feature.
What a cool amp! Makes me wonder if Andy Marshall of THD amps copied the design for his Uni-Valve and Bi-Valsve series.
The way the top can be removed by thumb screws make life so much easier.
Just looked a schematic of a Univalve. It's a SE amp with 12ax7, so altogether different. But 99% of all amps are either direct copies or spinoffs of something built 50 or 60 years ago, but mostly with inferior components. The Univalve looks very similar to a lot of the same stuff that was in the original RCA manuals and AT&T, Western Electric design books.
Not knowing much what is under the chassis of THD amps I like the fact that I can get to the tubes easily to swap them out without having to bias them.
As an owner of a THD Bi-Valve I have shoved almost every tube known to man in it looking for the "holy grail" tone.
After a year a of swapping tubes I finally found it.
The tube values I now use are a trade secret so please don't ask....LOL
This style of chassis and cover was universal and they made dozens of off the shelf ones you could buy in addition to many brands making their own.
Never did find it did you? No one else neither.
Hi I use a freeware schematic drawing prog called Tiny cad so I can keep track of mod I make in circuits.
I have a program I've used before too, but it's too much work to both shoot the videos and mess with all that. Guess I'm just lazy. But on the flip side, by the time I drew out all these schematics in that program, I could have completed a whole other video. :)
That thing looks old as the hills
Prince was for sure one HELL of a guitarist! At around 3:30 in the video here on youtube of the tribute to George Harrison at the rock and roll hall of fame "While my Guitar Gently Weeps" His solo is astounding! Very cool conversion with not much changed very impressive! Thanks for sharing! Video is ua-cam.com/video/6SFNW5F8K9Y/v-deo.html
i thought you were saying 'pinto'...pentode..hehe. been nice to see a diagram
I gave one away 😢
It's easy to build an amp like this just grab a random handfull of components screw them up and Chuck them in a box! Violla!!
Ugh!.. You guys that do this type of work are going to hate me for telling this story,, but I'll tell it anyway.
Years ago my Dad was an electrician for a large wire and cable manufacturing company, and when the plant closed down he was able to get quite a few left over electrical components and whatnot for his at home tinkering.
Before he worked at this company, he had his own radio and TV repair business, so one of the things he brought home when this plant closed was a large container of brand new tubes. Imagine a 55 gallon drum cut in half, and packed to the brim with new tubes of various sizes.
Well, one day when Dad was at work,, my brother and I (we were probably around 10 and 12 years old) went poking around and found this drum of funny looking glass things. We soon found out that they made a really cool POP when we threw them on the ground. Over the next few days we probably destroyed over 100 tubes. We thought we had covered our tracks by getting rid of the packages,, but then Dad walked out to get the mail one day and walked back in holding a piece of a broken tube.
I'm 48 now, and every time I see tubes like this I picture my Dad standing there holding that broken tube fragment... lol
I think I just died a little on the inside. ua-cam.com/video/JeXUrUnvCiY/v-deo.html
yup, just dumb kids that didn't know any better. We sure got an ear full that day!. I don't remember getting a butt whoopin for that, but looking back, I wouldn't have blamed him.
Great videos by the way. I don't mess around with electronics myself, but I enjoy watching folks do this kind of work.
lock stuff up when boys around ,and keep a eye on the puppies
Turns out it's "bad pot"....I hate that ...when you get bad pot....lol
Yup, death is part of it. Imagine if Adam and Eve didn’t mess up. We’d all be reproducing and no one would EVER die! We’d literally be living on TOP of people!! 😂