Will it float?

[Eulipian]

Aloha boys and girls. I just picked up this beat up Knight K-15. I'm a complete noob but it looks to me as there may be an 18 watt hiding inside of it. Looking at the schematic, is there anything that screams "you can't add a 12ax7/ECC83 do not try this at home!"?

Thanks,

Carl

Knight_KM-15 Schematic.jpg

[JMPGuitars]

Hi,

You don't need to add a 12AX7, you need to add a tone stack, lose the "tuner" input/switches, and change the phono input to a 1/4" jack.

Besides that, you'll probably need to make some component value adjustments, but that depends on what you want the amp to sound like. To make it more like an 18 watt, you'd need to make a few changes, but it doesn't seem too terrible doing a quick review of the schematic. I think the amp is point-to-point though, so you need to be extra careful if you're going to modify it.

Do a google search on the model, I think others have messed with that amp too, so you can get an idea of what it looks/sounds like.

Thanks,
Josh

[Eulipian]

Thanks Josh. It looks like the third 12ax7 would only be necessary if I were to add the tremolo or TMB channels. In terms of degrees of difficulty, I don't want to make myself too sad on my first build, but I'm interested in the tremolo and NF. I was thinking that if I take out the phone switch and circuit, I've got an perfect location for an additional wiper, though not 2, But, then where do the inputs go???So, I'll poke around on the google and see if anyone's come up with other ideas. Maybe just gut it and start with new chassis, or maybe the Lite is the way to go on build numero uno, and stick with this chassis? Decisions.....

Thanks,

Carl

Knight 15.jpg

[JMPGuitars]

You said you're new to this stuff, so...

I would say that this will be a bit of a learning curve working with a true PTP (point-to-point) amp, even if you stick with the 18 Watt Lite. Remember, working with PTP is harder, requires a lot of planning, and can leave you fighting oscillations and other issues. If you stick with this chassis, personally I would stick with Lite 2b.

If you want tremolo, strip the amp and work with a turret board. You'd probably need a new chassis as you mentioned, but that's the easiest way to follow a known good layout/schematic rather than digging deep into a rat's nest of potential trouble. Of course, if you're SUPER patient that could be fun, but whatever.

How comfortable do you feel working with PTP? Have you looked inside yet?

[Eulipian]

Well I'm over-informed but very rudimentary in skill, Josh. I have patience, good lighting and magnifying specs. There's quite a bit of room underneath--not like working on a Filmosound or something like that. It's a hobbyist kit to begin with. But, the chassis will limit design and probably prohibit me from some combo designs. I'll look online to see what a chassis costs and decide from there. Not going to Uncle Doug it and build my own. I don't have enough talent or time for that. I do like the idea of the tremolo, though and it'll be a factor in the decision. BTW, one of the odd features of the KT-15 is the NF from the 16 ohm output tap. I noticed people commenting on it elsewhere.

Thanks,
Carl

[JMPGuitars]

Don't waste time with him. Some of his videos are dangerous and should simply be avoided, in some cases spreading dangerous/ignorant misinformation. There's much better resources on the internet, including this site.

If you need/want to watch videos about this stuff, D-Lab Electronics and Mr Carlson's Lab are a couple youtube channels with people that actually know what they're doing.

If you modify the amp to 18 watt specs, there should be no need for a negative feedback loop.

Tremolo exists in pedal form...which you can also make if you want.

[Eulipian]

I've seen them all. I understand and have seen threads of criticism of Doug, but I enjoy his work making old stuff new and basic theory. I can't vouch for his math or higher level (higher to me) analysis. Terry goes too fast and should explain how he's using his measurement devices, but overall great quality and nice guy. Carslon is for people who already understand electronic theory and no, it is not pronounced soul-dering by anyone. Don't forget the Guitologist to get your tube information with a dash or two of misogyny and right-wing conspiracy theories--but he sure can play. I'm sure they're more. And, I've been lurking here, at Doug Hoffman's (some smart minds there), Audio Karma, DIY Audio, TDPRI and Wattkins for awhile.

I had a couple questions for you Josh. If I go with the Lite IIb, can I redo later to add the extra tube and tremolo or TMB? What do you think about Hoffman's 18watt Stout TMB board and chassis if I decide to go the TMB route out of the gate? Before attempting TMB do I need to assess the OT to make sure it's right for the job? Are there resources on this site or Wattkins for building I should look at- I'm not keen on PCBs right now as I want to learn P2P and turret construction first.

Thanks you so much for your time,

Carl

[JMPGuitars]

LMAO! Carlson definitely pronounces things funny, but he's Canadian. It's funny, I spend some time on eevblog, and the guys that recommend him are also usually Canadian. I think he sounds normal to them, eh.

One of the older members here, Gabi, had some awesome videos for amp building on youtube, but I think he took them down for some reason when he closed his shop. Put the videos back Gabi! Those were great.

To answer your question: maybe? Think of it this way: the Lite 2b is essentially the 18 watt classic with the second channel chopped off with a small axe. You could hypothetically add the second channel in, but you'd be limited by things like space and time.

I haven't personally used Hoffman's stuff, so I couldn't tell you, and I don't want to spend the time to analyze the board layout. Personally I make my own boards based on the layouts in the Downloads section here. The best resource you have for the least amount of headaches is the Downloads section. If you don't have the tools to make your own board, I made a list of resources in the Downloads section also.

I'd say for this amp, try to make what you have work for what you want it to do. If you have to replace the chassis and the transformers, you're already making a new amp, so there's no point to the current amp anymore. Sticking to a Lite 2b PTP build, or something similar to that (or even just use the tone stack - whatever you actually need), you could have a working amp with a cool sound.

Then for the next amp, start from scratch with new iron and chassis, and build whatever you want. Take a look at gdsamps.com too. He's a founding member of this site, and he has some great kits/transformers.

Thanks,
Josh

[Eulipian]

Thanks for you reply Josh. I'm also a lurker on EEV or ("AyAyVay") as he says it. I think his voice is like a rat tail file for the ears, but he has good knowledge. And, his tool touts are usually legit. He did one on the stripped down $9 MK-28 for example that was good.

I think you're right: play the hand I've been dealt, learn some stuff and when I want to get fancy I can do that. By sticking with Lite 2b, I should be able to manage PTP and get some cool noises out of the thing. This'll be my $50 training wheel amp and if I just get it to work and sound 1/2 good, I'll declare victory. A lot of this will be stripping stuff out. I intend to try and test to make sure everything is within tolerances before leaving anything in. I have looked at the Downloads section and will try my hand at making a board after this one, unless the PTP becomes too daunting.

The Guitologist actually has a video on this amp. He used the phono section for the first input stage,which seems right. I think he replaced the phono switch with the 1/4" input jack, For whatever reason, he chose the Baxandall tone stack, which, as I understand it, was intended for Hi-Fi and bass because it's more linear, but that could be wrong. Again, I've listened to too many words and need to start breaking some stuff.

Thanks for helping me be realistic and curb my enthusiasm. Good to dream big, but work with what you got.

Carl

[JMPGuitars]

LMAO, are you talking about Dave's Australian accent? My wife thinks he sounds hilarious. He is pretty funny tho. I've mostly watched his teardown videos on different oscilloscopes and a few other pieces of gear.

Dream big long-term, you'll be happier that way. Keep us posted and share pics of your progress here too.

[Eulipian]

Yeah, by crikey. I think of him as the Steve Irwin of electrons. Hopefully, he'll have a better fate. I admire his dumpster dives and "how tos" but I get lost in the second reel of his more theoretical stuff. Very funny and entertaining though and great spirit to go with the intel.

I was looking at the swaging tools and wonder what the wing nut attaches to? Are there threads on the swage? Or am I just seeing things? Damn you 60s!

[JMPGuitars]

I was looking at the swaging tools and wonder what the wing nut attaches to? Are there threads on the swage? Or am I just seeing things? Damn you 60s!

Wing nut? The standard swaging tools are just a turret holder (anvil), and the thingamabob to press the turret (the actual swage tool).

This is how I rigged them up:


You could also simply use the tiny anvil in a vise or something, and use the swage tool with a hammer.

Where did you see a wing nut?

[Eulipian]

Nice set up. Half ton arbor press? What I was looking at was this kit on Allied's site. As I read this, the wing nut holds the turret or eyelet in place. Not used as a lever. But, it also mentions anvil so maybe it holds both for the impact version of the swaging tool.

Staking kit.jpg

[JMPGuitars]

Oh, that crap. lol

Some companies make weird bolts with a hole in them as the anvil, and the wing nut is to mount it. Those are really weak, I wouldn't go that route. In some cases, maybe this one, it might be an anvil holder. It's a little hard to tell from the doc without going to the site. That's not what I linked in the Downloads section though. Did you see the sets I posted?

Oh yeah, yes, 1/2 ton arbor press. Got it cheap at harbor freight. I drilled the base plate and a friend let me use his milling machine to drill out the ram, which was surprisingly tough.

[Eulipian]

Yes, I saw the sets you posted and followed links from Keyes (which does not sell directly) to Allied and found that impact set. 1/2 ton arbor sounds just dandy. It's just drilling the ram that'll be the trick if I go that route.

Thanks.

[JMPGuitars]

Yes, I saw the sets you posted and followed links from Keyes (which does not sell directly) to Allied and found that impact set. 1/2 ton arbor sounds just dandy. It's just drilling the ram that'll be the trick if I go that route.

Thanks.

Have you checked Mouser? I bought mine there. They have the 1715 for $12 or the TL-5 or TL-8 sets for $23.

Drilling the ram needed the mill. If you have some really good bits, cutting oil, and a lot of patience, you might be able to do it on a decent drill press...but I dunno. Don't drill too deep, measure 2/3 of the staking tool at most.