What is Tube Amp Sag? Part One in the Search for a Saggy Nirvana

[@hardball107]

I like to repair old radios' and build Class A practice amps most times repurposing old tube equipment. I'm just a hobbyist and I love video's like yours explaining these concepts, helping me to understand. I built a small amp with a 12AX7 and a 6AQ5 with diode rectification, it's my experimentation amp. After listening to you I wanted to install one of the Webber Copper Cap rectifiers and make it switchable to compare the sound. Hopefully now that we are getting into the cold weather I might add a tremolo circuit, for me it's a great pastime to keep my old brain working and your efforts really help.

[@theguitaramptech]

Brilliant. I like the sound of your projects. Where are you from? We are in Spring in Sydney. I think its good for both of our aging brains to keep working with electronics, my friend.

[@Subcritical96]

Came here looking for info on Sag and learned a bit about compression! Dang! I am impressed! Thank you!

[@Subcritical96]

I subscribed

[@omarogunhe1385]

"What is Sag?" ☝🏾 That's the topic. #HeDoesnt

[@theguitaramptech]

I'm not sure if you have watched all the videos in this series, but I will try to answer your question in a couple of sentences. When you make a sudden demand of volume on your amp, it may drop in volume for a fraction of a second before it recovers. Very similar to a compressor. This effect is called "sag".

[@ofthetree]

I typed "sag tube amplifier" in the search field this morning...

[@theguitaramptech]

COOL!

[@mohitrahaman]

Well presented. A gem. All the best to you sir.

[@theguitaramptech]

Thank you, Mohit !

[@theleftymonster]

Thank you Sir. That explains why guitar players testing the sound of a good tube amp modeler or pedals that emulated tube saturation by the way it interact with the volume knob and whether or not the sound cleans up when you roll back the volume knob! That means that in the tube amp the amount of distortion is based on the dynamic of the note and that gives the musicians an amazing expressive tool to introduce emotion into the song.

[@theguitaramptech]

That is very well expressed, Lefty

[@joshuamichael4312]

I just built an18w Marshall plexi clone. I cascades the normal channel into the plexi TMB side for some extra grit and this is how I learned about the beauty of sag. At first I didn't like it because all my other amps had solid state rectifiers or were solid state completely, so it was foreign to me. Now I can't get enough of that sag! I completely 'get it' now, all the fuss about 100% all tube amps is warranted.

[@theguitaramptech]

Thanks for sharing that Joshua. A great story.

[@TippitoWOW]

Glad I found you mate, God bless you!

[@theguitaramptech]

Thank you Anderson 🙏

[@denlianergoist3125]

Looking forward to next chapters. Thanks!

[@theguitaramptech]

Thank you. I hope you enjoy, and get some thing out of the videos

[@lestelie4410]

Excellent. I am hooked.

[@theguitaramptech]

Thank you!

[@campy3888]

I'm very reliant on visual learning and your presentation helped me a lot. It is difficult to navigate through the jargons sometimes as an aurally challenged person.

[@theguitaramptech]

Thank you for your kind words. I am very happy that I was of some small help.

[@petertimp5416]

Nice to see an Aussie doing this type of content on KZbin

[@theguitaramptech]

Thanks mate!

[@andyreevesarchive528]

Always informative and enjoyable. Thanks!

[@theguitaramptech]

Thank you for your kind words, Andy.

[@krauz111]

Great personality hope to see new videos soon, I've seen them all

[@theguitaramptech]

Thanks you Carlos. I want to get back to making videos too. I enjoy them. I have been swamped with repairs and as a working Tech I have to give priority to my customers before my interests. Yep, the story of my life...sigh.

[@KevinKing-j9t]

Very nice

[@theguitaramptech]

Thanks, mate!

[@cisswalk]

Looking forward to this journey - thanks for putting the time in to do it. Haven't got any valve amps however my Boss Nextone has these values that are a complete mystery to me so hopefully I'll know what to do by listening to you

[@theguitaramptech]

Thank you Stephen. Half the challenge, and joy, is converting what you hear in your head into technical terms. Imagine the look on your Tech's face when you go to him one day and say "I want you to convert this to a solid-state rectifier with the biggest filter caps you can fit...oh and reset the bias to suit. HAHAHA!

[@GertjanRoossien]

Thanx man big fun stuff

[@theguitaramptech]

Thank you Gert-Jan

[@ivanduke]

Thank You for sharing your knowledge with us!!

[@theguitaramptech]

And a huge thank you for comments, Ivan

[@michaelwhite1247]

Great vids Chris!! Really enjoy them all. You can demonstrate sag with my JTM if you like ha haa lol.

[@theguitaramptech]

Thanks Mick. That’s an excellent idea. I love the way your JTM clips asymmetrically just at the point where we see the beginning of tube sag. The next chapter will be relevant to your little gem. I don’t know why I’m having such a shit time with the audio of my videos. I usually master it on Studio One but this time it lost sync with the video. A whole day spent trying to make it work and in the end I just uploaded the sound and video from the camera. Crap sound.

[@daviedirt]

This is good stuff dude. Keep it up!

[@theguitaramptech]

Thanks, will do, Davie. Lockdown is being lifted in 2 days, and I have hungry musicians clamouring for their amps to be repaired. I will sadly miss this uploading this weeks instalment of Chapter 4, but I will have it up the next week. Thanks for your understanding. :)

[@drownthepoor]

Did he ever explain what sag is?

[@theguitaramptech]

I thought I had, but I sure don't remember. I find it hard to watch myself after countless hours of editing. If I find a good definition I will link you to it.

[@DeadKoby]

This is a tough topic to take on. Best wishes from a fellow amp jockey. I am pleased that I finally made a compressor that I like.... only 2 knobs, and great sound.

[@theguitaramptech]

Thank you. Yes, it is a huge topic. I have written 5 chapters so far...just as an overview! Unfortunately, some people think the answer can be given in a few minutes. Hopefully, I can help viewers get an overview of the complex interaction of parts. Yes, I enjoy your work and have followed your channel for quite a while.

[@AlexAnder-or3kq]

That savage amp looks like an E-Tone

[@theguitaramptech]

AHA! Two names from Aussie musical history. E-Tones were fabulous speakers, but sadly Savage amps were not. That Savage amp on my bookshelf is my reminder of why I did Electrical Engineering at Uni. They were never designed well and were notoriously unreliable. My Savage 4x12 cabinet had very nice Plessey speakers, which I believe were based on the Rola Greenbacks.

[@3MonkeysGarage]

I may be totally perceiving "sag" incorrectly, but (always), in my understanding of it in my own tube amp is that, your tubes, in association with all the caps and resistors are theoretically set (biased) to an optimum amount of electricity flow. When I play harder, (attack) this pushes the draw on those tubes, requiring more power to keep up. And, depending on the Transformer and Rectifier used, it loses that demand request. Now, for me, it provides me with that soft clip you speak of, but also a somewhat organic delay and restraint of over aggression in my playing. Result, smoother delivery with some unique sound and feel. If I use a solid state rectifier, the amp will be supplied with more current and voltage, if I go with a 5y3gt tube, It is less efficient and cuts down on the voltage and current going to the other tubes. This will change the attack response and the smoosh. But if you want to get all sciency, we can go with your explanation. :p Let's keep it going. I been waiting for more videos from you. It costs too much for me to be buying tube amps to experiment on.

[@theguitaramptech]

Thank you Alta! You’ve pretty much nailed it. We will go into each of the areas you spoke of, and explain a bit more as to WHY it happens and HOW it happens. There are some areas you have control and others where it’s damaging. I hope I have pitched my series at a level where someone like you can add to their knowledge without going too deep that I lose the vast majority. Excellent insight. Thank you.

[@3MonkeysGarage]

@@theguitaramptech I am on for the full ride. I enjoy your amp videos. Keep em coming.

[@theguitaramptech]

@@3MonkeysGarageIt could be a long ride, so I am glad you're coming along.

[@wglennhowells]

My God I hope you know how entertaining (and informing) you are. You sir are a fount, not a cup!

[@theguitaramptech]

HAHAHA! Thank you William. It has been my life's mission to become a Font!

[@Lavabug]

Very interesting. Can you please make a video about poweramp damping factors and voltage vs current feedback in poweramps? Some old solid state guitar amps play tricks with those to create a more convincing tube-like bottom end and presence.

[@theguitaramptech]

You’re right, Ostx, that would be interesting, but it is way too technical and outside the scope of my presentation. We would have 2 viewers, you and me! LOL! KZbin prefers to have us engage with as many people as possible. In its simplest form, the damping factor is a way of expressing the output impedance and how it reacts with a mechanically resonant speaker load. The “ideal amplifier” would have a zero output impedance. An amplifier with a higher output impedance will provide less damping of the loudspeaker as its impedance adds to the total impedance of the ideal output circuit. A tube amp may have a low damping factor of 20-30, compared to a solid state amp with a damping factor in excess of 100. We’re getting into the lonely wilderness when referring to Current Feedback Amplifiers (CFA) compared to Voltage Feedback Amplifiers (VFA), so I won’t go into an explanation of the differences. CFAs are more difficult to design than VFAs for a given level of performance. Thank you for your question, Ostx!

[@dontuckerjr]

I have an old Lab Series L7 and wondered why out of all effects they would have only compression plus an odd tone circuit. I suppose these were early attempts at emulating tube sound. A lot of press about the tone quality at that time with big name endorsements. Thanks for the info and I did subscribe.👍

[@theguitaramptech]

Thanks Don. Yes, I suspect you’re right about the tube emulation. Didn’t BB use a Lab Series?

[@stevehead365]

At my age, sag is par for the course, a new GZ34 will not fix this.

[@theguitaramptech]

That is hilarious, Steve!! I think we both need to go silicon rectified.

[@samizdat113]

Billy Gibbons of the band Zed Zed Top (see how dumb that sounds?) likes amp sag.

[@theguitaramptech]

HAHAHAHA! Yep. Zed Zed just doesn't work. I'm unclear as to your Rev Billy comment. Did I foolishly say that he doesn't like sag? D'oh.

[@samizdat113]

@@theguitaramptech No, that he does.

[@roccos.4819]

G'Day mate! Well done, looking forward to the rest of the series...

[@theguitaramptech]

Thanks Rocco! Chapter 2 is ready for upload next week. I hope you like the series.

[@omarcusihuaman4261]

What is sag😢???

[@theguitaramptech]

Omar! Of course you are 100% in asking that question. I am an idiot. I have committed the age-old sin of “The Error Of Assumption”. I assumed that you would know what Sag was, not just how it happens. In my explanations of “how” you may pick up some of “what is sag”, but you are right. I should have explained it first up. I have already completed and edited Chapter 2. I will try to explain the "what" better in Chapter 3. Thank you for bringing it to my attention.

[@shirleymental4189]

The only thing with sag in my house is my testicles ;(

[@theguitaramptech]

HAHAHAHAHAHA! Brilliant