Easiest Circuit with The Fewest Parts

[imgumby001]

Hey everyone!! What would be some circuits that are super simple and have the least amount of parts? I’m bored and looking for a build while my fam is out of town. I’ve already built a couple 5f1’s and a 5e3, so it would be great to build a different simple circuit from those.

Thanks all!!

NR

[Dave]

That's an interesting question. Personally, I have never done it. I start with the most complex and work my way down. I'd kind of like to build a dead simple amp someday. Hopefully, I'll live that long.


Dave

[sluckey]

This is the simplest amp I have. Chassis may be hard to come by. But just imagine the look on their faces when your family comes home and tries to heat up a bagel?   

     http://sluckeyamps.com/smoky/smoky.htm

[AlNewman]

This is the simplest amp I have. Chassis may be hard to come by. But just imagine the look on their faces when your family comes home and tries to heat up a bagel?   

     http://sluckeyamps.com/smoky/smoky.htm

That gain control looks pretty cool.  Does it work well?

[sluckey]

That gain control looks pretty cool.  Does it work well?

Yes. Useful tone/gain change.

[AlNewman]

That gain control looks pretty cool.  Does it work well?

Yes. Useful tone/gain change.

Yeah, looks neat.  Probably lots of ways to experiment with different values to dial in a certain sweep.

[Loomer]

Not quite the simplest with a whopping 3 tubes, but the vibro champ would give you a lot of amp for not a lot of components, even more so if ditching the tremolo, which would make it a two-tuber.

[imgumby001]

This is the simplest amp I have. Chassis may be hard to come by. But just imagine the look on their faces when your family comes home and tries to heat up a bagel?   

     http://sluckeyamps.com/smoky/smoky.htm

Steve, that is so cool I almost can’t breathe. I should have figured one of your designs would be added to my “next” list!! Now I gotta find a toaster!!!!

[imgumby001]

Not quite the simplest with a whopping 3 tubes, but the vibro champ would give you a lot of amp for not a lot of components, even more so if ditching the tremolo, which would make it a two-tuber.

It’s not a bad suggestion, I just have a 5f1 I like a lot, and I built a Weber revibe, so I kind of have all that already. Not that a straight fender circuit is EVER a bad thing, I’ve just built several at this point and I’m itchin to get into someone else’s designs. I definitely have all the parts for a Princeton, but I’ve got a LOT of parts for whatever as well!!!! That being said what I don’t have are board blanks. So I’m gonna have to build on strips, hence the “few components” thing.

[passaloutre]

Well you’ve already built the two I would have suggested. If you wanted to go bigger, but still sparse, I might suggest something like a Thunderbolt. No parts wasted there, well except that extra triode…

[TIMBO]

Did a clone of this one
Rex Mascot (el34world.com)

[imgumby001]

Well you’ve already built the two I would have suggested. If you wanted to go bigger, but still sparse, I might suggest something like a Thunderbolt. No parts wasted there, well except that extra triode…

I’ll look into this. Thanks bubba!!!

[imgumby001]

Did a clone of this one
Rex Mascot (el34world.com)

Now this is very intriguing!!! Thanks boss!!!

[roseblood11]

Read the build documents for the kits from Tube-Town . de. They have some interesting circuits.
https://www.tube-town.net/ttstore/bausaetze/amps/

Or the Madamp G3 (Rock or Blues versions), which was a forum project at the german musikding . rocks forum. It's a cheap build, as it's based on old russian tubes.

[dude]

How about Sluckey's PeeWee, no board needed, just drill a socket for a 12Ax7 and have a "Mini Twin", just need an AO44 Hammond chassis off ebay for $50, get one with tubes and you're almost done.
https://sluckeyamps.com/PeeWee/peewee.htm

[imgumby001]

Read the build documents for the kits from Tube-Town . de. They have some interesting circuits.
https://www.tube-town.net/ttstore/bausaetze/amps/

Or the Madamp G3 (Rock or Blues versions), which was a forum project at the german musikding . rocks forum. It's a cheap build, as it's based on old russian tubes.

I really like both those sites. I’ll have to look, but I think I actually have a couple 6n2p’s floating around…

[imgumby001]

How about Sluckey's PeeWee, no board needed, just drill a socket for a 12Ax7 and have a "Mini Twin", just need an AO44 Hammond chassis off ebay for $50, get one with tubes and you're almost done.
https://sluckeyamps.com/PeeWee/peewee.htm

This is actually a great option, and I may just have an ao44 left intact. I know I have the iron and an empty chassis, I just saw them yesterday!

[dude]

The PeeWee sounds like a baby Fender twin, an amp tone you don’t have.

[sluckey]

If you like the idea of the peewee but rather have a vox sound just steal the EF86 preamp from my Vox AC-15 lite.

     http://sluckeyamps.com/hammond/hammond.htm

[kagliostro]

As to go with less components, if your choice is an amp with a Tube Rectifier, just swap it for a Solid State rectifier and you'll have a less tube amp without effort


Franco

[mmack]

D-Lab Electronics on youtube has a 2 watt amp based on 6CL6. Schematic looks fairly simple although not sure how much simpler it is over a champ.. he claims it only costs ~$5 in parts. Not sure how good it sounds, I doubt it would be better than a champ although probably less volume.

The bassman micro from Rob Robinette seems really cool. Probably a little more complicated than you're looking for though.

[kagliostro]

I'm a big fan of the Smoky amp by our friend Steve

Very simple and different from "standard"

Obviously you are not obliged to find an Oven to put it on it 

May be this kind of Box will be easier to be find to be used as an unusual Cabinet



Franco

[bmccowan]

A few ideas - although I think the Smokey is a fine idea and I recall the discussion around Steve deciding on the circuit. That thread would be worth digging up.
 - Single ended octal - There is the earlier 5C1 Champ. But also Gibson and Valco versions. I built a Valco/Supro 6SL7 > 6V6 that is sweet and have a Valco that was private labelled for a music store/school that has a 6SJ7 preamp - similar to the 5C1.
 - 6BM8 amps. I love that tube. Lots of options. For SE you could look at the version of the Gibson GA-5T that uses that tube and delete the trem. Or simply go with the a one tube design using the triode and pentode of that tube. For P-P it'd be hard to beat a version of the mini-bassman/little wing or HoSo that use a pair of those. And you have Tubenit's experience to lean on.
 - Gibson simple P-P - BR6F I love the tone of this amp - just a volume pot.
 - Gibsonette - pretty much a Champ circuit with parallel 6V6 output. There are a few versions of this amp.

[Platefire]

First time I've read the story of Smokey. What a great history and fine re-purposing project. What was your wife's comments on that and was that really your last amp?

I've always had thoughts of building the smallest amp possible

[JPK]

This is a cool thread. I need ideas for this winter. That Pee Wee with ac15 pre is looking good. Toaster is awesome. I actually have an old metal toaster. May need to look at that closer when I get home.

[sluckey]

What was your wife's comments on that and was that really your last amp?

She said "where you gonna put that?" as she rolled her eyes.     She doesn't share my enthusiasm for "just one more amp".   

That should have been my last amp but then shooter messed me up by returning my old Plexi 6V6 chassis. So the Phoenix became my last amp.

[sluckey]

Vox AC-4 could be another candidate...

     https://sluckeyamps.com/misc/VAC-4.pdf

[shooter]

blame away 


here's my 2C worth amp, do SS rec and 1 EL84 for a 2 tube screamer.  ( not the final version, so some tweaks maybe required)

[Platefire]

That's what I was thinking looking at sluckey's AC-4. Remove the Trem circuit and use a SS Rec and you could pretty drastically reduce parts and space required
This is my Little Bear amp:

[kagliostro]

I'm still blocked on the Smokey with my preference

but if you want less part ........ One Tube Amp .....



https://zeppelindesignlabs.com/product/percolator-2w-amp-kit/

you can find documentation as to build it without the kit

https://www.zeppelindesignlabs.com/wp-content/uploads/docs/Zeppelin_Perc_ASSEMBLY%20INSTRUCTIONS.pdf

https://music-electronics-forum.com/forum/schematic-requests/52075-?t=50811


OT is around 6K primary - B+ is around 175V




Franco

[shooter]

Your part count is as high as the previous 2 amps combined


EDIT:  Your cab looks better though 

[kagliostro]

OK, you want the war 

PRR Third watt amp








Franco

[PRR]

The pot and cap on the screen grid of the output tube in the Nov '07 plan can be omitted for "fewest parts" use.

[Platefire]

I always had a hankering for one of these but the price is always pretty steep! They pack it together pretty tight. They are usually 12aX7/6V6/Rec? This one is $375

https://www.ebay.com/itm/195878254840?hash=item2d9b40f8f8:g:dNYAAOSwNOFksMRA&amdata=enc%3AAQAIAAAAwLZw2eiXlxQ6NnEWQ7wDgn8zGY6lofhIuS0DysLY%2BqxyK0Avi5l17nnfwmdPGZOxTbjRXY5lEyE4DB8OHDcXPPBm9aTgHHTBnlqo0SbzLInb7Xpafyr0kNO%2FBsmmtuxol%2BLEKrO9FmmxhGI4QW8QPV%2FA8DzaUHq2Fhb51KxB6PS0Acf1eVd2n4tSvJr7huqVzfT4avq%2FZ1fH9Uyr8bNN%2BcqsvjU%2Bvjf6pPdDeMUn2do9rvLpgEOier1YhkDxj176og%3D%3D%7Ctkp%3ABk9SR9jU1oS7Yg

[sluckey]

That's what I was thinking looking at sluckey's AC-4. Remove the Trem circuit and use a SS Rec and you could pretty drastically reduce parts and space required

When you remove the trem on the AC-4 it starts to look a lot like Smoky. Remove the gain and tone for a simple one knobber.

[Platefire]

Yelp, that's narrowing it down to the bare necessities. I guess we got carried away we lost imgumby001 somewhere along the way

[kagliostro]

Less of this I think is difficult

Gibson Mastertone Special


Gibson Les Paul


Gibson Les Paul JR


consider no Field Coil (use a resistor) and no Tube Rectifier (use Solid State Rectifier)

Franco

[imgumby001]

Yelp, that's narrowing it down to the bare necessities. I guess we got carried away we lost imgumby001 somewhere along the way

No, no bubba, I’m still here!!! And may I say a HUGE thanks to everyone who has contributed to this thread! You all have come through in the way I have come to expect from the members of this forum, all hands on deck style. The problem iiiissssss…

…now I want to build ALL of these circuits!!!!

[Platefire]

Hay imgumby001  Glad your pleased and welcome back.

I want to throw in another circuit that I built from a Revere Reel to Reel amp that I'm amazed at how loud and clean it can get in boost mode for a SE EL 84 amp. It uses a SPDT Center off switch to give you three amp modes, adjustable Negative feeback, Normal(center off) and Boost with cathode bypass cap on the second preamp gain stage. I used the reel to reel's transformers, so I have no recommendations on that. Champ types would be my best guess

[imgumby001]

Hay imgumby001  Glad your pleased and welcome back.

I want to throw in another circuit that I built from a Revere Reel to Reel amp that I'm amazed at how loud and clean it can get in boost mode for a SE EL 84 amp. It uses a SPDT Center off switch to give you three amp modes, adjustable Negative feeback, Normal(center off) and Boost with cathode bypass cap on the second preamp gain stage. I used the reel to reel's transformers, so I have no recommendations on that. Champ types would be my best guess

It’s funny that you mention transformers at the end of your post. Yesterday after I read through all the entries in this thread, I pulled out all my available iron. I then realized that should have been the first thing I did!!! All my PT’s waaayyyy overkill. I’ve got plenty of pp and se OT options, but man, I don’t have a single PT pushing less than 340-0-340. I’m starting to think I’d be better off trying to build a super twin instead!!!

[imgumby001]

After much consideration I’m thinkin I gotta build Slucky’s Smokey. It’s just too perfectly laid out for me!!! I’ve got about half the cheap parts already, just have to find affordable transformers!!!

Thanks to everyone who contributed to this thread!!!

[Platefire]

That looks like a good minimal amp. I'm just not familiar with those tubes. I figure they are a cheaper substitute for the original AC4 type?

[imgumby001]

That looks like a good minimal amp. I'm just not familiar with those tubes. I figure they are a cheaper substitute for the original AC4 type?

I’m not really either, but that’s part of the fun!!! I really like the little bear, it looks like a really cool circuit. I’ve even got a bunch of the parts. The Smokey just looks so clean, not that I can get it that way, but ya. I still my try the little bear in the near future. I put a couple “extra” small chassis in my cart just in case I NEED them!!

[sluckey]

Both of those tubes are 7-pin. The 5654/6AK5 was used extensively in old military/FAA radar receivers, mainly as a 30MHz IF amplifier. They're very reliable, low noise, and can be used in audio circuits as well as RF/IF circuits up to about 400MHz. Works very well in an EF86 circuit. The 6005/6AQ5 is kinda a 6V6 in a small bottle. It cannot take a high voltage like the 6V6 though.

Both tubes are pretty cheap and readily available. May not stay that way if word gets out about these tubes. 

[Platefire]

Thanks sluckey for the explanation on those tubes. All my old builds and store bought amps are tuned up and working great. I'm starting to ponder, what's next? I kinda miss the trouble shooting and amp repair but I found that is pretty stressful, so I don't want to go there again.I have a Fender Excelsior OT, so I reckon that's a good place to start

[imgumby001]

Both of those tubes are 7-pin. The 5654/6AK5 was used extensively in old military/FAA radar receivers, mainly as a 30MHz IF amplifier. They're very reliable, low noise, and can be used in audio circuits as well as RF/IF circuits up to about 400MHz. Works very well in an EF86 circuit. The 6005/6AQ5 is kinda a 6V6 in a small bottle. It cannot take a high voltage like the 6V6 though.

Both tubes are pretty cheap and readily available. May not stay that way if word gets out about these tubes. 

I’ve actually got a couple 6aq5’s that I had no idea what to do with. They’re actually nos still in the box. The 6ak I’ll have to source. Already have the 7 pin sockets in my cart!!! If you had to buy transformers new do you know which ones you’d choose? 

[sluckey]

I'd use Hammond 269EX for PT and Hammond 125BSE for output.

[imgumby001]

I'd use Hammond 269EX for PT and Hammond 125BSE for output.

Thanks boss!! I’m really looking forward to this. I’m thinkn I’m gonna whet my appetite with the Smokey and once it’s right, and fully functional, I’m gonna tackle the dual lite!!!

[Greenwichpaul]

When you remove the trem on the AC-4 it starts to look a lot like Smoky. Remove the gain and tone for a simple one knobber.

Hmmm. I just located a 5k/8ohm Carnforth OT, plus a 250V secondary toroid (over 100mA I'm certain) in my surplus box. I really fancy trying a Vox again. I am thinking the Carnforth should suit the EL84 - and the 250V would work with a diode bridge plus circa 1k dropping resistor for the AC-4. Does that logic seem sound?

[sluckey]

Hmmm. I just located a 5k/8ohm Carnforth OT, plus a 250V secondary toroid (over 100mA I'm certain) in my surplus box. I really fancy trying a Vox again. I am thinking the Carnforth should suit the EL84 - and the 250V would work with a diode bridge plus circa 1k dropping resistor for the AC-4. Does that logic seem sound?

Sounds good to me. There's an AC-4 layout on my website that may give you some ideas.