Marshall Valvestate 100V Model 8100 Amp | Full Walkthru Demo + Mods

[@ApolloStrengthGarage]

About 10+ years ago a buddy and I modified my 8100 with a schematic we found online. Added a ton of gain and low end - then I messed with the op amps further and it was an absolute monster. I'm going to dig it out of storage now. 👍

[@soulsonicfx3826]

Lots of potential in these amps!

[@boomboomyumyum]

Any chance you can post a link to those mods?

[@DoomedVessel-666]

I took would like a link to said mods please and thank you!

[@psychwardfpv4353]

Any chance on getting a link to those mods?

[@mikepadgett8522]

Just stumbled across this and the amp sounds great. Super versatile. I noticed a 800 to modded 800 tones.👍🏻

[@theonegoose]

Thr white tolex really makes it pop. I think ox blood cloth/grill would great behing the logo.

[@ianedmonds9191]

10:49 is a beautiful Van Halen-esque tone. Luv and Peace.

[@soulsonicfx3826]

Thank you! I've always loved that sound.

[@epasternak4206]

I believe Tommy Victor used these, snap your fingers snap your neck...these heads are fantastic.

[@soulsonicfx3826]

Indeed, it is the same amp. Gets that tone instantly!

[@FraJa1980]

That white tolex looks awesome! And nice mods too man, I especially liked the socket mod for the op amps! Did you consider replacing the output transistors? There's a video on KZbin by a guy who did all sorts of tests with the pre amp out running into a better tube amp (I believe it was a Dumble) for the power amp with the exact same speakers and came to the conclusion that these amp's overly bright and hard sounding high's were caused by the type of output transistors Marshall used in these. So I wondered if those have any reputable replacements that are of better quality and sound? Seems to me that's where the amp has the most to gain.

[@soulsonicfx3826]

I haven't seen that video, but, hey, did they take into account that the line out jack of the 8100 has a filter that drastically cuts the highs? LOL I'll look for that video and see if that's what they did. I have upgraded output transistors in old solid state amps to higher quality modern types before, but this has only been with very old amps from the 70's where the new transistors make them more reliable and less prone to failing. I have experienced higher quality sound in the case of hi-fi amps - better high frequency detail and overall better "speed", etc... But, I'm not convinced swapping out the transistors would make a huge difference here. I think if the power amp is harsh sounding, it isn't the fault of the transistors they used, it would most likely be due to the design itself. Comparing it to a tube amp adds way too many other variables into the signal chain (transformers are a HUGE factor) for me to trust that the sound difference comes down to transistor type. And of course, yeah, that filtered line out would completely change the tone (it's supposed to be a crude speaker sim). People seem to really like the standalone 8008 power amp, which is the exact same design with same transistors, only difference being it has the switch to select between "Valvestate" or "Normal" mode; the 8100 is fixed in "Valvestate" (current feedback) mode only. Another interesting thing to note is that the 8200 stereo head has a completely different power amp using MOSFET transistors. It might be fun to run the preamp of an 8100 into an 8200 power amp and see what if any difference it makes.

[@FraJa1980]

@@soulsonicfx3826 Hi man, thanks for replying. To be honest I don't know if the guy took that into account, it sounded a lot better trough the dumble power amp tho. The video is titled "MARSHALLVALVESTATE! Still cool in 2021???" by Kohle Audio Kult if you want to see it, pretty cool video i.m.o. ... very metal based bias when it comes to tone tho but still nice. I've had two of these 8100 heads over time and found both too harsh but maybe it's like you said a design issue and just the nature of the beast. Too bad because they look awesome and are still (relatively) cheap .... seems like there should be SOMETHING one could do to one of these and make it sound better? I love the normal channel and even the drive channel I can work with just fine for a Bluesy Bluesrock tone but the 2nd od is too hissy and bright for me even with the contour at a low setting. I also had a Fender 2x80w stereo Powerchorus Red knob solid state series (Loudest amp I've ever heard) that was the exact opposite ... fat and muddy with barely any highs but it had a more usable contour control due to being able to switch the slope from mid cut/boost. Maybe there's a bit of improvement to be gained there modding the contour circuit? That does sound like a fun experiment running it into a 8200! I'd watch that.

[@soulsonicfx3826]

@@FraJa1980 Thanks for letting me know which video it is! I had seen that one listed in my search, but didn't realize it was the one you were talking about. I'll check it out today. I started playing guitar as a kid in the late 80's, so the red knob era Fenders have a special place in my heart. A little Fender RAD was my first "real" amp that didn't run on batteries. 😂

[@soulsonicfx3826]

@@FraJa1980 I checked out that video and he's playing with a Valvestate VS100, which has a different tone overall from the 8100. But, it also has the filter on the line out like the 8100, but instead of the basic passive filter the 8100 uses, it has a more sophisticated active filter, likely trying to sound more like a proper cab sim. When listening to the sound change in the video, it sounds like exactly the sort of tone change I would expect from the cab sim filter. It's way too drastic of a change to account for just being a different power amp. Power amps, regardless of what kind it is or the quality, won't have such a dramatic change of the frequency response unless there is some kind of filter or eq happening in there. You can experience subtle changes in feel and even tone because of the different ways that different amps control the speakers and if they distort - it can make the whole system sound more tight or loose or cleaner or more distorted, but it wouldn't be making such a dramatic shift in the overall tone going like that.

[@gregmccourt4730]

Good job! I want one of these.

[@akaboo69]

Sounds crunchy and like a jcm with a ss power section. I used to own one they are very tight in response while tube marshalls are flubby

[@zipchtkdn7804]

I bought both mine 75.00.and 100

[@tonya4157]

Very nice. Just sent you a message through Reverb.

[@lizetsanchez8976]

Hi, Do you do repairs/ servicing requests for the Valvestate 8100? I was wondering if taking this amp to a Marshall certified repair person should be enough to get it playing like yours. I’d like to ask for any advice for upgrading my amp to get the most out of it. I really appreciate the depth of your video.🤘

[@soulsonicfx3826]

Yes, I do repairs and mods! I received your email and shall reply soon. Thanks for your interest in my work!

[@zAvAvAz]

Great how much to build one of these with line out and fx loop stereo and without the chorus inside a slightly smaller format allowing all heat dissipation and cooling flow?

[@bvanfossen01]

it sounds badass!!

[@DC33879]

Did you use a boost at any point during this video?

[@soulsonicfx3826]

Nope, this is 100% the straight amp, with the only exception of when I plug the DD-5 into the effects loop. No other pedals, and no processing or eq in the mix, other than the speaker + mic sim in AmpliTube.

[@denialoflife666]

Superb video! I have a 93 myself but it’s black tolex. I have two of these… the 93 one is super hissy… should I change that 17:30 chip to get rid of the hiss?

[@soulsonicfx3826]

Yes, replacing that chip will likely fix the hiss problem. Also you could add protection diodes to keep the new chips from becoming hissy in the future. I will make another video about how to do that mod soon. It's an easy simple mod.

[@flapjack413]

What value is the contour pot? I was going to recommend you try a reverse log, then you mentioned them and W taper pots, which I didn't even think about. I have a TON of PC mount 100K W taper pots. Let me know if you want a few to try out. I think reverse log is going to be the answer there, though.

[@soulsonicfx3826]

The original value that was in there was 100K Audio taper. I had replaced it with 100K Linear because that is what the schematic called for. I agree reverse audio might sound better, because the audio taper one had a similar issue of most of the change being bunched up in one area. Or maybe a W taper would work best. I don't have this amp anymore, though I am considering hunting down another to experiment on.