Just wanted to say that your videos are probably the best on the net for techs explaining things. You are in my opinion a bloody genius . Wish I had your knowledge of amps. Keep up these great videos mate. Thanks from Niagara Falls, Ontario, Canada
20:20 I believe that schematic was drawn by Mark Huss back in the late 2000's. Builders of the popular 6V6 Plexi can trace their amps back to his schematics. He also runs a great website on Hiwatt amps. The mods you did sound incredible. I just built a 2204 clone and may try to incorporate some of your mods. Thanks for sharing.
Probably so, I did infact build the 20 watt Plexi brought to us by "Sluckey" (Steve Luckey) who made reference to Mark Huss's original schematic. Nice fun project, and my main gigging amp.
Excuse me for writing about your comment, I am from Colombia, and I read that you made a clone of a 2204, at this moment I am thinking of making a clone of this same one, but I do not have technical information on the transformers to have them made, you Could you help me with the technical information on the transformers for this equipment? thank you
yes this drawing is great to find. everyone I have found has been terrible quality until this one from Mark Huss. you can actually read the voltages which is so important.
Thank you again for these videos Jason. I'm sure your life would be much easier not doing them but for me they are incredibly educational. Not just specifically for this particular amp but for following schematics. Thinking about mods and learning about mods I've never considered (elevated DC heaters).
Really great work Jas. You’re a good man to be passing all this on, spelling it out into terms that us mere mortals can better understand. Well done, thanks.
Wow.!! Those are amazing tones. Really dig those schematics tutorials. OH Please just plug the DI out on the kemper and make some profiles...that would be epic?!!
First of all: thank you for your amazing content. I have a JCM800 Reissue which sounds great and has all the kerrang I could ever wish for. I also own a JEL20 from Friedman which definitely has the most kerrang in the Friedman line but just not to that satisfying amount like the Marshall… well it’s way less watts/smaller transformer, could it be that?!? Anyways, I‘m not able to mod the JCM by myself and in Germany there is not many guys who mod tubeamps as far as I am aware of. So I was thinking about that Mr Scary Mod from Legendary Tones. Did you ever have the chance to try one and what are your thoughts about it? Thanks in advance, Christopher
No-the .47uf cap in series with the 10K resistor off of the V2b cathode for the Jose clipping mod as shown in the schematic at 38:30 in the video, and shown and discussed at 50:50.
Good afternoon, I am writing to you from Colombia, I am in the project of assembling a clone of the Marshall JCM 800 2204, but I do not have information on the transformers to have them manufactured, it is possible that you could help me with the technical information on the input and output voltages of the transformer. power, as well as the output and shock
I would like to thank the algorithm that made it possible to watch good videos, and I hope that you will succeed as you have worked hard for your dreams. This morning, I opened a RU-vid window to find pretty videos. Where did your striking image come from? An unknown and mysterious algorithm led me here. As I watch your wonderful videos, I keep falling in love with them. Whether it's a coincidence or a relationship according to the algorithm, your video appears on my RU-vid window and I'm watching your video like a dream. The moment I saw it for the first time, it made my heart flutter. Thank you so much for watching your valuable videos on such a fine day with clouds floating in the blue sky. As you try to achieve success on RU-vid, there are only a lot of difficulties, but you can only achieve it if you always make a firm resolve that you will do it again someday. Your video makes my heart flutter because I have a feeling that I will soon receive a lot of love. I liked your video, especially because it was impressive and natural. Another happiness came from having RU-vid while I was living. However, working with RU-vid videos is like standing alone in a windy expanse. You have the ability to make your videos instantly stunning and attractive.
@@HeadfirstAmps Ahh . So it’s the same function as the 1meg in the Headfirst Sat switch. Once things come off the board and go to a switch, I get lost.
Can you mention what voltage value the .47uf coupling cap in series with the 10K resistor off of the cathode before the tone stack? I'm assuming something like 600v, but want to be sure. Thanks for the great video and sharing the info.
Try changing the 470K to ground to a 1M between the first preamp tube and the second preamp tube. Put a 470pf on outside terminals of master volume. Replace the first stage cathode bypass cap to a 330mf. This, for starters, will warm up the amp nicely.
I've always wanted a 2204 with the ability to channel switch from low to high inputs. No need for any distortion pedal anymore. Thank you for the video!
Thank you for this video. I have the same amp and have done various mods to it including changing it to tube rectifier, changing it from 6550 to el34, adding boost by changing cold clipper cathode resistor, changing gain by changing coupling caps and plate resistors. The only thing I kept was the el34s. After hearing the JEL mod and the general simplicity of it alone, I am planning on performing that mod. I did build some relay boards 30 years ago to give my 2203 channel switching but removed all of it years ago and brought it back to stock. The 4010 is a cool amp by itself but I think the JEL mod will wake it up. I use the amp regularly and run it through a 1960B cabinet but wow thanks for posting this video.
That is one of the best sounding JCM 800 I have ever heard. The bright cap mod does all the difference and the boost, my god it boost but retain all the greatness of the tone. By the wat greak skills playing. Would it be possible to mod a JCM 800 SC20 too sound like this ? Thanks you
You should develop boards for all the crappy boards in the millions of Fender hot rod and reissues amps. Their is a huge untapped market!! They do sound very good ,except the hotrods, but by design they burn themselves up!!!
🤘😠🤘, that's my amp, bought in '86 or '87 🤔.. It came with a 1x12 cabinet. I now run mine thru a 4x12 loaded with greenbacks. I've also heard it called the Elliott Randall stack...
Hi man i love your channel. I have this same amp that has already been modded by Scott Splawn. I do some mods myself sometimes. Is there anyway to add an effects loop to this amp?
I'd love to see you do a video on how you got your start in electronics and amplifier repair and modifications. We're you a guitar player in a band and started working on your own amps? That would be a cool video I'm sure many subscribers would love to see how all that transpired.
God I really wish I hadn't seen this video. I'm right in the middle of collecting parts and components for what was to be a nice straightforward no-strings-attached 2204 build with maybe a few manually switchable basic mods. But no..... This video had to come along with a selection of awesome mods and features to interrupt my little plan. A friend is giving me his old broken Carvin combo for me to gut for this build and seems as a perfect medium to carry a JCM800 2204 type amp for gigging. The idea of having a volume adjustable clean/dirty channel is an obvious boon to a flexible amp, and the diode clipping I always though was just some cheap excuse for cheap distortion pedals but in the context of this amp really adds some useable and quality distortion texture/responses. An amp like this would make my local classic rock (70's and 80's) gigs so much more interesting and engaging. I built and gig with a Robinette Fender amp and a Sluckey 20 watt plexi amp which are serving me well but, it would be awesome to move away from the Runoffgroove Tube-to-Fet conversion pedals into the real McCoy. (don't get me wrong, I have been successfully fooling audiences into hearing Marshall JCM800 type sounds for years now, they aren't the worst things one could use). This amp sounds beautiful and is just so flexible I don't think I can properly live with myself if I don't take the extra steps and just-do-it.. Question. Are these relay channel switching boards something you can purchase at a website? Thanks for the excellent video's - so well explained and inspiring. And I love the tone and response that your are getting.
Hi Philip, thanks for the comment. There is nothing tube amp gain, a pedal can get close but still not the same! Yes, all these boards and more are at headfirstamplification.com You might find one of my main boards will give you everything you need in a single PCB.
mate, when i replicated the gain stages on V1 by swapping the 10k for a 2.7k/.68uf the distortion was so high the sound disappeared it sounded like V1 was overloaded or something. Any ideas?
Hey mate, a cascaded 2k7 setup should be ok...are you on FB? If yes, please join my DIY Builders group there and post. I, and others, will all chip in and help.
I really enjoyed following along the stock 800 vs moded. You presented it perfectly. As for using FET circuite, what is the difference between just using a good drive pedal in front of the amp? Which of the presented modes that were presented in the firs half of the video can still benefit an 800 if I just stick to pedals fir drive? (No FET, no Diodes, no chanel switching)
HI Jason if you are there. I keep going to order the Cali board plus a couple others (FET boost and FX loop) but I keep coming back to this video and realizing that I really find the base tones "no diode clipping) to be the tone/responses that are very reminiscent of the genres I cover with my bands. (Perhaps more vintage and not as modern/gainy) Will there be a way to get the Cali to also capture the kind of response/tone that you were getting in this video near the beginning when you had the diode clipping off? Don't get me wrong, I dig everything about the Cali, just wondering it there will be maybe and added panel switches I could put on to bring it a little close to what we are hearing here. Thanks for your patience with me Jason!
Just learning here, but I noticed that first schematic that comes up in this video for K1 & K2, the 1M resistor is going from ground to in front of the 68K. between the 68K and the fet boost before going into V1B. whereas the the 1M on the stock schematic you show first has the 1M resistor going behind the 68K between the jack and the back side of the 68K. Does it not matter if it's solder behind or in front of the 68K resistor? is that part of how the mod works for the channel switching? Thanks...
This isn't a criticism I think your 2205 mod would be great for my amp, when you have modded amps for people have they ever asked for it to be changed back after using it for awhile, my amp tech won't do any mods anymore because of this.
This is the one I decided to build which has begun. I do have a question - are we good to go with also providing switchable bypass cathode cap (like the one that on the bottom of the chassis) and also a a switchable means of restoring the cold clipper to a 10k resistor, only? I was just entertaining bringing the amp further back even closer to vintage spec while keeping all the great mods that are already in this video. I want them all? Do we see any issues with also including the 2 extra mods I just mentioned? Thank you for this. Very much excited to add this one to my build collection. Thank you again.!
This is the best Marshall circuit channel on RU-vid. I have been a builder and hobbyist for years and cant wait to try these mods. I cut my teeth with Metro and I recommend Valvestorm who has many of the Metro parts and also links to the SDM layouts.
I love mods, and those look cool. But, except for the 0 loss fx loop, why add all this diode clipping mods at the front end when you can just use pedals?
you're asking why someone would have a small, simple and effective switch on a piece of gear they already own, than to go out and buy another piece of gear or more to simulate that same function? i think the asymmetrical clipping sounds phenomenal and can be implemented for very little cost and space.
great work Jason. Just wondering, Johan Segeborn here on youtube mentioned in one of his videos that the only difference between 2204 combo and head version is 4n7 Cap on the mid pot in the combo. That cap is not included in this schematic
@@HeadfirstAmps More on topic, would you ever attempt a Bogner Snorkeler circuit? I realize that information on Bogner's old stuff can be either unreliable or difficult to find, but I thought I'd ask because that tone on Alice in Chain's Facelift is such a grail tone for me
A couple comments on this video: 1. You chose the 47uF 3rd stage cathode cap, but if you want Ed's value and tone there, you/one needs a 470uF cap, not 47u. 2. The 470p on the 100k Cathode Follower does exactly what you communicate, but just want to note that this can be found abroad and in Friedman amps as Dave's "DARK" MOD! 3. Interesting you chose a 8 ohm tap with a 100k NFB resistor! It's all in what the end-user wants, but typically and if one wants Marshall values....the higher the resistor, the lower the tap! Soo, if you look at say Ceriatone 1967/68/69 schemos for 2203's, you can see a 100k is typically on a 4 ohm tap, 56k or so on a 8 ohm, and 47k or so on a 16 ohm tap! Enjoy and Cheers!
I tend to go with what sounds/feels best and on my own build ended up with my 100k on the 16 ohm tap! Way off spec but soo good! Way too loose and dirty on anything less. Cheers.
it's my understanding that just about anything 47uF or greater for a cathode bypass cap is going to have exactly the same effect, as all audible frequencies are already passed at the point 47uF sets. your notes are awesome, just wanted to point out the 47uF to 470uF likely will make a negligible difference, if any, so one might as well save the extra dollar!
