Tuning my $140 Monoprice Stage Right 15w tube amp into a FIRE BREATHING MONSTER! Amp mods

[@MuseumsBloke]

I have zero idea what you just said and did, but I thoroughly enjoyed it!

[@KleyDeJong]

LOL Thanks!

[@albertarguelles3262]

I only wish I understood half of what you were saying, It sounds so much better. Genius you are man

[@KleyDeJong]

@@albertarguelles3262 oh gosh, thanks! I started by watching videos from Uncle Doug and reading Rob robinette 's web page. You can do it!

[@genedean69]

I had an amp tech do some mods to mine. First was the cold clipper mod, then swapped the reverb tank for a 3 spring Mod unit, then he changed the output transformer to a Hammond 18w Marshall style one, he also put in a toggle switch for 8-16ohms when i play it with an extension cab and finally swapped out the 70/80 speaker for a 16ohm Celestion Neo Creamback. Oh and the cheap white plastic knobs are now metal smoked grey. Looks and sounds awesome. 👍😁

[@michaelmoore7975]

Got hot tweezers? Man, they work great on just that size SMD perfectly. I found some cheap ones that plug into my HAKKO FX888D. Life-changing. Soul filling.

[@codelicious6590]

Excellent wizardry! Im proud of you for tackling those damn pesky little SMD things man, I hate those things too.

[@KleyDeJong]

Lol they're crazy. Removing wasn't hard. I just hit it with the iron and they came up pretty without a fuss. Adding new components back on would have been much harder. Using through hole components like I did worked better.

[@John_Galimore]

Again, thanks for your good work. I felt it really shined in the higher registers and lead runs. But because of my personal musical tastes, maybe not as much in bass/power chord definition. Very valuable experiment which Skip Simmons would encourage. It seems serviceable though not fun to work on. I'll keep playing mine stock with the master nearly dimed and the preamp gain on 1 or 2 and try to let you know what eventually leads to it's demise. I enjoyed your lead playing. Good job, keep chasing tone!

[@scottfairclough9764]

I kinda understand what you are doing.Man you obviously know alot about electronics, thanks for you very informative video 😂🎉😊

[@lousekoya1803]

Love it !! It sounds more creamy with richer harmonics ! Love the riff you do with the red ! Awesome !

[@KleyDeJong]

Thanks! I also think it turned out very well.

[@lousekoya1803]

@@KleyDeJong Yes it did ! The only way I can approach this sound with mine is go trhough an NKT275 Germanium Fuzz dialed at 2 oclock. Well done !

[@chrisstevens4680]

Thanks for posting. I will be experimenting with mine. Just a thought, instead of removing the surface mount components, you could cut the track. That way you could put the circuit back to normal by simply rejoining the track with a bit of wire. Also it would have been good to hear the comparison between the speakers. Great video, thanks.

[@PaulG-m4v]

Hi Kley, a comment about changing the cathode resistor on V2B (R48): as you noted, V2B and V2A form a direct coupled cathode follower circuit (DCCF). When you increase R48 from 820 ohms to 1.5k, the anode current drops slightly because V2B grid bias goes more negative. This subtly changes the overall transfer curve of the DCCF, but not in a major way. Details can be found in the very useful book by Merlin Blencowe, "Designing valve preamps for guitar and bass", chap. 5. The addition of the 10uF cathode bypass cap across R48 will increase the gain of V2B significantly, which increases the amount of compression in the DCCF and gives more distortion at lower gain settings. The circuit appears to be lifted directly out of the Fender Bassman 5e6 amp circuit, except for the anode voltage which is higher in the Bassman at 325V. Thank you for the reference to the Laney Cub amp, that is the only place that I could find the circuit diagram of this Stage Right amp.

[@francoreia8147]

Love it. Like to see somebody take ideas from the best amps with effects loop and tube reverb. Tube rectifier. And build somewhere like 15 or 20 watts. Like how you rejoice this one only with turiboard or point to point.

[@KleyDeJong]

Thanks, that would be a cool idea. Worth looking into.

[@slartbarg]

with that second gain pot cranked all the way it sounds kinda like a gated fuzz, which is kinda cool for something built right into the amp

[@KleyDeJong]

Yeah I think that's what happens with no grid stopper. Interesting indeed.

[@funhousebaby3104]

​@These_go_to_eleven_1959 This is what my 50s princeton sounds like cranked, that kind of NY Crazy horse tone. AMAZING, try it before solidifying your opinion brother. It's amazing fun! I'd love to have this amp build. Been obsessed with 5 watt amps recently, been running that princeton and a 5 watt supro wet/dry. Fucking killer

[@johnosborne3187]

Excellent video. I know it would be very time consuming, but it would be nice to hear the difference that each mod makes especially the speaker swap. A speaker swap can make a world of difference. I would like to hear a comparison with the 70/80 before and after.

[@grizzlymanverneteil4443]

sounds great! also, how many air biscuits got eating while filming that demo?

[@Blues.Fusion]

Cool mods. I won't be modding mine except for a G12H30 55cs speaker mostly because I can barely see those SMDs let alone work with them.

[@kennethquintini658]

Great work 👍😃

[@johnreedy]

Sounds killer!

[@KleyDeJong]

Thanks!

[@leonarddaneman810]

I had one a couple years ago. Damn thing kept getting damaged in shipping so finally accepted a broken one, rebuilt the inside of the cab and hot glued the Tolex, glue and sawdust to make better screw holes. The 70/80 had a nice chime compared to the Celestion A . . . so speakers do make a difference. I sold it off . . . kept the little 5 watt Stage Right which is great for the office and harmonica.

[@KleyDeJong]

Yeah I did another video where I opened it up and the construction techniques and materials used are very basic. The amp is not very rugged. I think the cab was made from some kind of weird particle board type material with the silver corner protectors also providing structural support. No finger joints or cleating to hold it together from the inside.

[@LothyBluesCave]

Very nice! The speaker might be the biggest improvement.

[@KleyDeJong]

Thanks, I agree. The speaker made a big improvement. The voicing changes mostly helped it achieve higher gain at lower master volume settings. I do think the flavor of the clipping is different, but it is a subtle change.

[@diecuttingsolutionsinc6745]

if you want to impress us all, figure out how to get rid of the hiss white noise, changed tubes to the quietest you can buy - 81db, conductive copper tape inside where the head sits, replaced the rca cable to reverb with insulated shielded cable, just has to be some kind of DYI fix on the pc board to help this lil amp.

[@francoreia8147]

Love it great stuff,

[@KleyDeJong]

Thanks 👍

[@6stringcodger450]

Darn surface mount stuff is aggravating to work on at home. I used to design surface mount stuff back in the 1980's and thought it was great for production work. Fixes and mods were always a problem post production though, etch cutting an rewiring over a dozen layer board is surgery!!! I like the idea of the changes you showed here, but I will keep my cheap monoprice as is. Only change I made in 2 years is new power tubes and cooled down the bias. It literally burned through the first EL84s. You could feel the heat. Sounds great with a cool bias setting too. Dont know why the factory setting on these is so high by default. Schematic says test point should be -12.5 which cooled it way down. Initial setting was 5.0. This put it around 50% dissipation. Hoping these tubes will outlive me with this setting. The PC board probably appreciates the cooler setting too.

[@albertarguelles3262]

it sounds better. I've got one and would like to do this mod 2 it.

[@dcthegreatest24]

I feel like the amp already gets rainy enough stock from the factory. It really has a big muff fuzzy effect at the higher end of the Gain, not a metal style of distortion

[@roncarter2188]

Hey Kley I'm really enjoying your builds mods and repairs, keep it up. I emailed you about a few questions on the Hoffman 6v6 plexi build you did, that was awesome! I'll try to email you again, I had a couple questions because I'm using the same amp chassis as you did.

[@anthonybeers]

solder paste heat guns flux pens tweezers and 3x mag reading glasses get you along the path of surface mount work.

[@primedirective00]

Do you have any wisdom to share for an orange rocker terror 15? I feel like your wizardry would really help it

[@monto39]

Where did you find a TV front version? I had the other one w/front controls (now listed on Monoprice for $259 + shipping). I've never seen the TV fron design though. For $140 I'd get it, throw out the guts and house my 5E3 kit in there

[@KleyDeJong]

I got it at a used store locally.

[@monto39]

@@KleyDeJong I used to use mine as kind of a preamp for my harmonica (harp --> Mic w/Shure CM Element --> Monoprice 15w effect loop send --> Twin Reverb input 1). It sounded great for harp by itself too, just wasn't loud enough over drums. I got mine for $130 delivered, brand new. The TV front ones looked way cooler though....

[@clutch2827]

Had this amp for a few days. Just noticed if you want to plug your pedals into the fx return to bypass the preamp, it does not bypass the tone and reverb knobs. The reverb you can turn to zero of course, but the tone is in the way of my effects chain. What the heck?

[@KleyDeJong]

Check out my other video analyzing the schematic! The cut control is in the nfb loop, so it's essentially in the output section. Similar to a Vox style cut control.

[@oldasrocks9121]

You might have Trainwrecked it-- sounds fantastic!

[@KleyDeJong]

Thanks! It's a ripper.

[@michaelfuller34]

Where do you buy your bypass resitors😂

[@CeresKLee]

Monoprice Stage Right 15w tube amp goes for $279.99 in Feb 2024. And still not seeing this puppy sold used much.

[@derekwright5564]

Bcuz if simply just change the speaker our it becomes an absolute beast.

[@CeresKLee]

@@derekwright5564 what do you use?

[@joerivera3222]

Hey I made a schematic out of an class a amp and was wondering if you could look over it and see if I missing anything for it to work

[@redkurn]

i'm not entirely sure i'd trust an opinion from someone that solders like that using the wrong size solder (plumbing solder and rosin), could have just soldered legs to the surface mount points and it does not look like he knows what he is doing, but following a guide haphazardly. that thing is now a fire hazard.

[@DMSProduktions]

I got 1 of the newer 1s but it came broken! Got my $ back & kept the amp! Also only came in US power only! Not gonna bother with upgrading it now. It's ok but not amazing! Will fix the structural damage & sell it! It's a 1 of here.

[@scottdunn2178]

Trying to get a schematic for my Stage Right SB20 50w head. Want to add a Presence control...

[@KleyDeJong]

Try to find the NFB loop. Start at the speaker jack and work backwards. There should be a connection from the OT Secondary to the speaker jack. If there is also another signal path back into the amp circuit, that's where you go. Then look up a Bassman or something and copy the presence circuit from there.

[@scottdunn2178]

@@KleyDeJong Yeah, it seems like a Bassman type circuit that would be relatively easy tap into the negative feedback from the OT. It's actually a really good sounding amp for something made in China. Thx.

[@montygibbon1905]

​@@scottdunn2178 I'd been set on getting the 15w as a mini-mod project ~ but bailed on the grounds the SMD elements of the amp would be unkind to my dodgy eyeballs and shaky hands. The SB20 50w head isn't that much more expensive; what's it like inside? More SMD? Your insight'd be appreciated. Cheers.

[@joergl562]

Don't you think it's pretty strange that the amplifier is not seen once in the whole video? Why? Why is that?😳

[@KleyDeJong]

What? 10 minutes of the video shows me working on the PCB? AT 8:40 you can see the face plate?

[@bobtheblindbedroomguitaris8742]

Thank you very much for your video I enjoyed it a lot have the same amp probably a new version I think I remember the video I'm sure it was you when you got I stopped working on the electrical devices when I went blind or yeah my blindness didn't come all at once it's it's wrapped up and the overtime it's got progressively worse so yeah no modding for me except for a speaker which even that I might have someone else too LOL but I'm sure you did a nice neat job damn sounded fine sounds of great thinking of putting a queen back in mine I understand that if you change the V12 and the speaker that goes a long way on getting rid of a lot of that harshness on the top and that he appears thing brittleness and gives you more headroom for no use for pedals and stuff like that the headroom really y😅😅ó I guess I could say that about myself also you know too much partying when I was a kid LMAO I'm living on the Eastern tip close to the Eastern tip of Long Island and the capital of Suffolk county called Riverhead there is no guitar store well there is a music store music and arts I don't know if you have it where you are it's a owned by a guitar center but mainly they do business with band music renting a band instruments to a school kids and stuff they have like four or five low in the epiphone's and whatnot and a bunch of like cheap keyboards and stuff they do have a little did you have guitar tax service but it's not on premises they picked that they have a a Catholic who takes their guitars from 5 to 6 different stores and then they bring it to the tech and so you don't get to speak to the tech and that's really not really it's not the best situation the closest Taco Bell and another place which is about 35 minutes by car and since I don't drive it's not very and I haven't been able to find the excuse me an amtech at all probably could tell us something has one but I don't know about that LOL I bought mine 200 for $250 knew about 4 years ago I guess now yeah it's got to be 4 years maybe longer not 4 years maybe longer yeah and lllpI haven't had any problems at all with it it was stored in a very very dusty place and it has never been cleaned internally it had like an inter dust on everything so yeah I can't complain I have already got my money's worth out of it and yeah I am going to invest in a speaker for it though cuz even if I could see him next week the speaker you know I can just pop it out and you said for some other project anyway thanks for your video found it really cool and enjoyed listening to your place to it you and the amp respectively LOL sincerely Bob the blind PS please excuse any typos misspelled words lack of punctuation etc I am not illiterate I am not even a bad typer I'm just using speech to text which I just own unique take on the language and how it's written and it controls everything as far as any kind of text that appears in anything that I do so I should really put that at the beginning of any textures and I oh well live and learn

[@KleyDeJong]

Thanks for watching and I appreciate your thoughts!

[@ediek8048]

Mine started blowing fuses. I suspect loose or damaged tube sockets. Could that be it?

[@KleyDeJong]

I would take voltages first. Start with the tube sockets and the b+ rail. Can also try removing all tubes and then adding the back in from back to front.

[@skald9]

Another "cool" mod would be to get the tube sockets separated from the board.

[@CS_Murphy_R9]

I Modded mine by throwing it in the trash and buying a Katana! 🤣

[@BrianClem]

Is that a paduk warmoth neck?

[@KleyDeJong]

Yes

[@BrianClem]

@@KleyDeJong I recognize it because I have a similar except mine has traditional headstock direction.

[@Shadowcruise99]

The JST jacks and plugs look burnt. Not a good sign for longevity.

[@bigbasil1908]

From Stage Right to Fuzz Right

[@kentjackson3830]

At around 5 min 30sec in your video you play some background music. That guitar tone is the sound I’ve been trying to remember for over a year. I remember now that the tone in my head was a Robert Plant song Ship of fools which has a guitar tone almost exactly like what was playing in your video. I need to know was that you playing? If so, were you using this amp stock before mods? Really want to find an amp that does that sound, thanks.

[@KleyDeJong]

Thanks. Yes that was me playing on a looper. I believe it was my sunburst strat into a few pedals into my cake pan 5e3 amp. It's pretty heavily modded. I use the normal channel which adds a tone stack and nfb. I have a video on it called 'my favorite 5e3 mods'.

[@afronprime51]

Can't take my eyes off your mouth when you play. It moves more then your fingers.

[@derekwright5564]

Omg, now I cant unsee it.

[@benitorossi9380]

I will never buy an amp with SMD components, they are difficult to repair, at the first failure you throw it away

[@KleyDeJong]

It does seem to me that the amp was made without repairabiliry in mind.

[@J.C...]

Sucks to be you

[@J.C...]

​​@@KleyDeJongyou can blame that on Laney. It's their circuit. I'm pretty sure their amps even use the same pcb board. I mean it was essentially the same exact amp, inside and out. The only difference between the Laney Cub, 12R and the 1st Gen 15w Stage Right is that the Laney is black, has a slanted front instead of rectangular, and it has a digital reverb instead of spring. They even use the same cabinet with the only difference being the Laney has a slant in the speaker grille while the Monoprice doesn't.

[@romannumeral5547]

My hats to anyone willing to work those tiny components. Those were some great mods. Do have any suggestions for a Blues Jr? I rebuilt mine using a Hoffman kit in order to get rid of all the PCB stuff. The amp is killer but the pre-amp section gets loud at 3 and with humbuckers there doesn't seem to be enough highs. Thanks for posting this video.