This is what MILD blocking distortion sounds like.

[@jodyssey9921]

There is certainly a lot to learn! I designed and built a simple 1w amp using 2 6j1 tubes, sounded great on the first try, figured I knew what I was doing. Nope. Working on another version with 3 tubes now and it sounds like ass, that's what brought me here.😂 Trying to figure out if it's blocking distortion or a saturated transformer causing the problem. I'm not using a proper output transformer, it's a line transformer from a PA. The first amp used one as well but a different one. From listening to your clip I suspect it's the transformer, going to try the first type I used in the other amp tomorrow. Have to scavenge one from the ceiling before anyone else shows up at work in the morning.😂

[@amateurism1]

Ha! I hear ya, it’s like 1 step forward, 2 steps back most of the time… I’ll one day figure this out, but there is allot of trial and error. I will admit, I thought I knew enough and felt confident in my abilities before I started, that went out the window quick, I hope you can work out your issue(s) better than I could, I’m afraid every change I make seems to help and hurt at the same time.

[@chrisstevens4680]

You need to present/match the correct impedance to the o/p valves. This is a combination of the speaker and the correct o/p transformer. ‘Any old’ transformer won’t do.

[@grind18]

emmmm... what is actually wrong with all of those sounds I've just heard in this video ?

[@greggorr314]

Nottahekkuvvalot. Strings warp & waver during sustain b'kuz the direction of vibration rotates naturally (back&forth as up&down), and the warp in the note varies with how this crosses the pick-up's field. One direction & the b-field is slowing the motion, sending it nano-flat. 90° off & it stops pulling the note. This affects intonation throughout the sustain of a chord. Different strings are affected to a different degree. Overdrive just puts it all out front to be heard.

[@metalmix7773]

Cool man I'll check out your videos! I have been digging around in my amps quite a bit

[@room2738]

big thanks for making this :)

[@amateurism1]

You're welcome, I'm not sure why lol, when I posted this, I was honestly wondering if this was just another video for the sake of posting videos.

[@RocknJazzer]

Not a very good example. That is a very mild case of blocking (if it's that) compared to most I have heard. It may not even be blocking, maybe more like how you set your gain stages. Usually blocking is FAR more noticeable, when it's bad you really know it, to the point the amp will make very loud "blatty" popping bursts of noise and/or collapse on transients, in addition to a far worse case of what you do have now.

[@amateurism1]

Until this moment, I have never hear it before, I have no idea what it sounds like… so thank you for clarifying. Do you have an example to hyperlink here?

[@javableak]

Excellent video, I have a question. Have you added a cathode follover to the P.I circuit? what have you done exactly? would a scheme be possible? I find it very interesting. Thank you.

[@amateurism1]

I'll put some more stuff on here that will help, the cathode follower is part of the effects loop so-to-say, the cathode follower is present in the circuit even with the effects loop off. I'm still struggling with the effects loop, no point sharing anything if it don't work well. I've got a very good Plexi tone (the tone of a Plexi without jumping channels) going on at the moment; this was my goal (a lower volume Plexi grind). Still rying to tighten up the low end more. The low end should be massive with the 6550 power tubes, but it's too loose at the moment, once I get this figured out, there will be info available.

[@jackmatthews2840]

The long leads on any component acts like an antenna in all e!rd circuit he

[@JeremiahDaniel1995]

I’m getting the transformer box replaced inside my head tube amp because it’s old it’s not completely blown out but the distortion is not as heavy as it use to be so I gotta be couple hundred dollars to get the part installed without destroying the Circuit board that is attached the amp’s frame

[@jaggedstudios3315]

Sunn 200S ? That's a bass amp - you'd want it to be distortion free and have max headroom. Is this the Sunn guitar model, 'cause that's a different model number. Also, never saw that toggle switch on a Sunn amp - must be a mod. I have a mint Sunn Sorado, which is the same as a 200S. Only difference is the power tubes but both put out about 60 watts. Super clean sound for bass.

[@amateurism1]

Yes it is a bass amp, but every Sunn I've played had the same clean headroom as this amp did, it is now a guitar amp lol.

[@heythere6983]

I really like that growly clipping grind your getting. What gets the amp in that place? Iv been somewhat dissatisfied with amps realizing I can’t really get the right distortion out of em . Iv cL been looking into buying amps and moding them as I feel this might be the only way to get closer to what I may want . A lot of modern amps just have so much preamp gain it’s very saturated I like a more open clipping sound if that makes sense. Even old plexis get modded with master volumes and it throws off the sound of the power amp grind .

[@amateurism1]

You’re gonna hate this response: what got the amp in that place is preamp overdrive, it does have a unique grind going on. This has been a total learning adventure for me, I’m not sure I can you give you too much good advice at the moment, I don’t use modeling software.... What I can tell you is that you are not hearing any power amp distortion in this video. I’ll do a video of it cranked soon before I make further adjustments, I know what that thing sounds like in my bedroom, but not at stage volume. But.... That clippy grind before the cathode follower was added is two gain stages out of a 12ax7 with rather high cathode resistors on both stages. When the cathode follower is added, there is some weird stuff happening and I'm able to control it, I got lucky, as I try to refine the weird stuff, the magic quickly disappears, I'm all about good enough, I might leave it alone. I have some signal bleeding though switches and it happens to work like that, this is tough.

[@heythere6983]

To be honest even it’s it’s preamp clipping it sounds better than what Iv heard across many amps. I think people who like poweretage clipping do for that certain somewhat tight grind . Preamp distortion is life Convenient to control though without having to blast an amp so it’s pretty cool you managed to get it like this with pre amp distortion . You said you have some signal bleed? I mean some old plexis apparently have that aswell from what I know with the non master volume amps , so if it doesn’t sound bad I suppose it’s no biggie . The texture of that clipping just sounds great to me though . I think it’s all a balancing act so if you keep it in that ballpark (if that’s your main goal) then that’s success IMO. I’m not a huge effect pedal guy so for me the right clipping in the distortion is really where it’s at , along with responsiveness , dynamics etc. but my favorite sound is good quality gain/distortion when it comes to electric guitar

[@amateurism1]

@@heythere6983 thanks! That was very motivational to hear actually, that sunn amp has been sitting waiting for some time and attention, you just helped me focus again on it.

[@goodun2974]

What is the blue stick like thing you're using to push on the resistor? Is that some kind of a fiberglass scratch brush, or a spring-loaded eraser pen? The tip is yellow and appears flexible which isn't normal for a fiberglass scratch brush.

[@amateurism1]

It’s used to close potato chip bags, I’ve found a better uses for it from time to time.

[@oficinadomarcheto]

Um bloqueio de grade muito leve torna o timbre acrilico percebi que minha modificação no tiny terror no acoplamento v1a v1b 1nf para 22nf tipico de vox ac esta turbulento expelindo tornados pelo duto do gabinete o falante esta distorcendo com os graves

[@micahcech6708]

Hey man ever figure out what was causing this? I’ve got a 6550 sonaro on my hands right now but comparing mine to the 200s it’s circuit is identical transformers bypass cap and resistor values etc, same issue as yours but without any mods, debating if I should order in a new 6an8 as it’s the only thing I can think of that I haven’t changed out or tested, I did add a 470k grid stopper to the pi which helped a lil, but it’s hard to imagine that this is how the amp was intended to sound from factory

[@amateurism1]

I have not I'm afraid, my attention has been occupied with other projects after I moved (2 years ago lol), the issues in this amp however are all of my own doing, I don't think the your Sonaro had the same preamp as the one I have and i know my issues are in that area. My amp was healthy before I got creative. I would encourage you to get a couple 6an8's while you can, that is one tube that isn't being produced any longer....

[@micahcech6708]

@@amateurism1 thanks for the reply after 2 years haha, that’s the plan found a couple on eBay, after some research I have a feeling it might also be dc leakage in the old coupling caps as well. a few hifi guys seem to have had the same issues on a dynako circuit that these sunns were based after and the coupling caps getting tested and replaced sorted it out. Cheers

[@amateurism1]

@@micahcech6708the first thing I do before firing up these old amps is replace all the electrolytic caps, the decoupling caps were electrolytic on this one.

[@waynegram8907]

AMATEURISM, what do you mean by blocking distortion?

[@amateurism1]

Cited from "Designing Tube Preamps for Guitar and Bass" by Merlin Blencowe: -When a cap coupled tube is driven to the point of grid current limiting. -I guess the most practical way I can describe is, if two halves a 12ax7 are coupled together and the latter half has its signal blocked due to the change and discharge time of the coupling cap being near equal. I'd buy the book if you want to learn more, that response is as good as I can do without plagiarizing the whole section.

[@waynegram8907]

@@amateurism1 So the coupling caps RC Charge Time and Discharge time are EQUAL this will cause Blocking Distortion? I thought blocking distortion is when you overload the phase inverter tube so its in cutoff region?

[@amateurism1]

Yes. This is where I prefer books over info found on the internet…

[@mikecamps7226]

Thats not blocking distortion......you added a 12ax7 in the pathway...but not saying if its in parallel or series. Generally a effects loop is in series after the first pre-amp but the pre-amp is not pushed. Its one reason why you shouldn't add or use an effects loop in a tube amp......you have to know the gain stages and phase/inversions etc....and then to come to a ratio between wet & dry relative to an effects loop.....as usually the effects loop also functions as another overdrive gain stage.......and with a switched jack....that micro contact point of the switch has to pass signal and that contact point is a bottle neck in signal flow....and watch out when it gets dirty and oxidizes and your signal pathway. You did not state plate voltages or bias resistors nor plate resistors & cap.......all determine EVERYTHING

[@amateurism1]

I can’t tell if you’re trying to help me with the comment or not, half the stuff you type I don’t even know, I’m just screwed around with an amp, and I’m hoping that I can encourage others to do the same thing, I only know what I read in a book or what I read off the Internet. Yes, I had to play with plate, voltages and all sorts of other stuff after I adding more load onto the circuit, I didn’t mention any of that. I don’t see how a switch is any different than switching jack in other affects loop, give me a little bit of time and a break. I’ll tweak it until it works, I’ll figure it out. Thanks for the help if that comment wasn’t meant to be an insult to my intelligence. It’s a series effects loop.

[@mikecamps7226]

@@amateurism1 A switched jack is best to be replaced by a regular jack with a toggle switch for the pathway in & out because of the contacts....more surface area. A series effects loop will overdrive because you are INSERTING into the signal pathway. Adding another tube is dependent on if the power transformer heater filament winding has capacity. BUT the design fault if that they give a margin as it depends on the tube compliment the amp has to support. SO don't be fool by the margin. A Fender Reverb combo amp...think Twin or Super reverb BF/SF classic era.....the reverb circuitry is in PARALLEL. So dealing with the electronic phase from stage to stage, Fender cut a corner and really needed an extra tube gain stage for the reverb circuitry, but to deal with minimal parts, they did the work around by ATTENUATING the dry signal with a 3.3 meg resistor with a 10pf bypass capacitor for carryi9ng over high end content that gets lost by going through such a large value resistor as the attenuation factor. Hence they had to RATIO the wet/dry signals. SO the pre-amp gain is cut way back on the dry signal to compensate for the low signal of the reverb circuitry output. That Fender reverb was licensed out from HAMMOND starting back in 1962 for the new spring reverb effect. The reverb is an overlay and the reverb control on the amp's front panel is really a Volume control that turns up the effect as its basically always ON. They dealt with adding the effect of reverb by....dropping the dry signal strength....and using a resistor to cut signal strength. WHEN you do things in Series....you CASCADE gain stages and signal. A 12ax7 is 100 gain factor....a 12AU7 is like a gain factor of maybe 20.......so switching out the 12ax7 for a lesser gain tube would probably help you

[@amateurism1]

@@mikecamps7226 it sounds more like you’re helping now, sorry about my attitude if your felt it in the tone of my previous response. I have added a filament transformer for the extra tubes. Don’t worry about the switches please. My plate voltage are fine after changing the dropping resistor value and the dc signal is clean when looking at the ripple on a oscilloscope, loaded. Im honestly trying to implement an effects loop circuit that I got from a Lee Jackson KZbin video, and yes I’m having problems. Still trying to figure out why, it’s turned into a project that is moving down to the bottom of a list of things to get done. I get why the cathode follower is adding gain, I practically have this working, but as you put it, “I’m working on balancing things” by trial and error, I’ll try a 5751 tube, thank you for the suggestion. I just need to struggle a bit longer with this project and I’ll eventually figure it out, I’m either finding the limitations of my phase inverter circuit or I have a poor layout of components in the chassis at this moment that is causing some runaway oscillations when some pots are moved to a certain position. I started this adventure with the intention of getting some hands on learning and maybe making a few videos along the way, I’m at 75% done and lost steam, that’s all. Thanks for the help Mike.