Some Mods for Marshall Class 5

[keysandguitars]

I put both switches to the right of the input jack. I think it looks great, wouldn't have known it wasn't stock had I not done it myself. I'll try and post a picture for you tomorrow. As for recordings, I'll see what I can do. I don't have much of a recording rig, only a SM58 for a mic. I'll see if I can get a decent sound.

Now I'm trying to decide if I should replace the 10" or either see if a 12" would fit (would it even sound right in a small cab?) or if I should make/buy a cab and throw a 12" in that. I'm planning on building some amps from kits down the road and would need a cab anyway. I've been looking at the Scumbacks and listening to all the sound clips I can find. I'm impressed by what I've heard and what people say about Jim and his product.

[NXC1978]

Alright, you guys got me fired up too so I ordered all the parts to do the upgrades to the board that Lyle suggested. My class 5 is bone stock so I also got some quality tubes while I'm in there and the Merc Magnetics Multi-choke.

Thanks for sharing this info with us, Lyle!

[keysandguitars]

You're in for a treat!

I took my amp over to the guitar shop where I bought it to do a side by side with the stock Class 5. The guys were very impressed with how much improvement there was. The best way I can describe the difference in words is it's as if the mods removed a thick blanket from the front of the speaker allowing for more depth and dimension in the tone. It has more clarity and....balls. That's the only way I can describe it.

I called Jim Scumback per Lyle's recommendation and he suggested his SA10H-75, 30W 16ohm speaker. He said it should really add more tightness to the bass not causing it to fart out like the stock speaker. So, in 10-14 days or so I should be back with more info.

I just bought a LP Studio Faded Cherry today. I've played 7 studios over the last two months and this one just felt really good, better than the others. It's amazing how much guitars vary coming off the same line.

[NXC1978]

Originally Posted by keysandguitars

You're in for a treat!

I took my amp over to the guitar shop where I bought it to do a side by side with the stock Class 5. The guys were very impressed with how much improvement there was. The best way I can describe the difference in words is it's as if the mods removed a thick blanket from the front of the speaker allowing for more depth and dimension in the tone. It has more clarity and....balls. That's the only way I can describe it.

I called Jim Scumback per Lyle's recommendation and he suggested his SA10H-75, 30W 16ohm speaker. He said it should really add more tightness to the bass not causing it to fart out like the stock speaker. So, in 10-14 days or so I should be back with more info.

I just bought a LP Studio Faded Cherry today. I've played 7 studios over the last two months and this one just felt really good, better than the others. It's amazing how much guitars vary coming off the same line.

That sounds very promising, I can't wait to get my parts! I thought I'd hold off for a while on the speaker, but I'll probably end up replacing that too if you think it's worth it. I'm sure you'll let us know!

[Don]

I did these mods, including the choke.


Wow! I never liked this amp's clean sound (but enjoyed it cranked with my Les Paul). Now it's wonderful! Dirty is better as well. The mods turned a fling into a possible keeper!

[Lyle Caldwell]

I'm really glad you guys are enjoying the mods.

It's really puzzling to me why Marshall didn't get this better right out of the box. Aside from the choke, the mods are just slightly different values and the cost of the amp would have been the same if they had an improved circuit to begin with.

[Don]

My amps sounds great now except...

I notice a slight sizzle in the background when I'm playing, even playing clean. It comes when I play a note and then stops when the guitar is silent. It's not really noticeable until the note is decaying. The amp is pretty much totally silent when I'm not playing.

I did not notice this before installing the choke (this is the choke from AES that has been mentioned in this thread). I'll try it again w/o the choke.

Any long distance diagnosis ideas?

[Lyle Caldwell]

Could be the choke, could be a tube, could be a bad solder joint.

[Don]

All easy enough to check. Thanks.

[NXC1978]

My tubes came so I decided to go ahead and swap out the stock tubes. I replaced them with a JJ power and 2 Tung Sol reissues in the preamp. The $9 JJ sounds much better than the stock tube. It's "clearer" sounding and the amp is noticeably louder for whatever reason. The Tung Sol preamp tubes didn't make too much of a difference to my ears clean or dirty, but I left them in anyway. After the cap/resistor changes, I'll probably A/B the tubes again just out of curiosity. Also, I was surprised to see a TAD sicker on a "Marshall" tube on one that I removed...

[keysandguitars]

Don,

To add to Lyle's suggestion, just make sure you got everything snug and tidy in terms of wiring and possible sources of vibration, especially the power tube (I think that bracket was vibrating against the chassis and making some noise). I fixed the vibration issues prior to the mod and have been experiencing some again. It's probably because I was in a hurry to put everything back on and play. I hope it's as simple as that.

I'm really enjoying the 12AT7 I put in V1, especially the cleans with an OD pedal I built from BYOC.

Lyle (or others qualified) what are your thoughts about maybe trying to mount the tubes to the bottom of the chassis so that they are easier accessed? Is this a bad idea all together? It'd be nice not to have to completely tear the thing apart to swap tubes.

[Don]

Thanks. Unfortunately, it's not that simple. Those things all check out fine.

I'll try the tubes and choke first. My preamp tubes are a couple of old Mullards that have been sounding very good.

My amp is older (September 2009) and came with a Marshall branded JJ power tube that was noisy as hell and did not have a good sound. I replaced it with a TAD that sounded good and was quiet but I broke the tip off of it when I was pulling the chassis out of the amp one day! I went to a tube amp tech friend's house and we found this quiet Sovtek. I tried a bunch. This one was the quietest of the tubes that sounded good.
I have a couple more quiet TAD power tubes but they don't sound as good. I have a few other Sovteks that sound incredible but are too noisy to use!

[Shades of Blue]

Originally Posted by andjar

i thought it was only me finding the class 5 sounding like crap after listening to so many youtube videos.It has a plexilike crunch with an early ac/dc flavour but much more raspy and fizzy than that.I do hope some 12" speaker's will make the head version sound better but it also obviouslly needs some mods.
I really want to like the coming little class 5 head.I think many people including me have waited and dreamed about a fulltube ,low wattge,low end marshall plexi head.But,right out of the box,a blackheart(both the 5 and the 15 watters) is killing the class 5 both in terms of classic marshall tone and circuit design.

My wife bought me my Class 5 for Christmas. I'll be honest, when I watched the YouTube vids, I was almost dreading plugging it in.

But, the Class 5 sounded WAY different in person than in the vids. I absolutely love it. I find just the opposite of what the OT suggests. I find that it sounds much better with single coils than humbuckers. It is already a muddy amp, so it really adds some life to my strats.

Couldn't be happier with the tone.

[rocknhorse1]

Originally Posted by keysandguitars

I put both switches to the right of the input jack. I think it looks great, wouldn't have known it wasn't stock had I not done it myself. I'll try and post a picture for you tomorrow. As for recordings, I'll see what I can do. I don't have much of a recording rig, only a SM58 for a mic. I'll see if I can get a decent sound.

Now I'm trying to decide if I should replace the 10" or either see if a 12" would fit (would it even sound right in a small cab?) or if I should make/buy a cab and throw a 12" in that. I'm planning on building some amps from kits down the road and would need a cab anyway. I've been looking at the Scumbacks and listening to all the sound clips I can find. I'm impressed by what I've heard and what people say about Jim and his product.

If you put any type of Scumback in there it's gonna sound killer. I have 3 different kinds of Scumbacks and they are all great, with each serving up a different version of a smooth classic sound. I would guess either the 10" Scumnico in the original cab, or the 12" in a seperate cab would sound very good. I have the 12" Scumnico, and the H75, and H55. they all sound fantastic. I am running the Scumnico with an H75 in a 2 X 12 closed back Bluesbreaker cab right now, with an 18 watt version of a JTM45, and the result is one of the best sounding cabs I have ever had...if not THE best.

[keysandguitars]

A Mule fan! Thanks for the encouraging words. Jim said I should go with the H75, 10" of course. I decided to buy the LP Studio over building a cab and a 12". I guessing with the "Lyle Mod", the Scumback and the LP, I'll be pretty happy.

Did you build your 18watt? I'd love to get details if you did. I'm sure that's a fantastic sounding rig.

[NXC1978]

I got all my parts in as of today! The multi choke was on back order, but it's here now...

[deepblue]

Youd figure after almost 50 years Marshall would know what works and what doesnt.
The only new Marshall amp id even consider is the 1974X...and even that is a reissue.
They really need to step up and make amps like they used to.

[nutsauce]

Originally Posted by singlecut

exactly why i don't buy the latest flavor of the month,mass produced cheap amps that are reviewed here with such gusto by members when they get them.
so here we have an amp repair guy saying how bad they really sound .
let me see, who do i believe.
someone with a world of experience in the field? or someone who plays at home,maybe has never owned a decent amp in the first place to compare it to and is convinced their amp is the best ever right out of the box.but it's a marshall.
i'll go with the amp guy every time.

i had played one of these as well, and was not impressed. but, everyone so far here it seems thinks they are so good.i don't think i've read a negitive word on them here. until now.
so where are all the class 5 owners ?
glad to see the truth come out for a change. it's usualy just buyers gushing during the honeymoon period.it seems some are more concerned with the amps actual color.to each his own i guess

Right here is one of the Class 5 owners. Everyone is entitled to an opinion but I have been in the music business for a long time and I do think it's a very good sounding amp considering it's a $399 Marshall tube amp. I mean what do you expect for that money. I own some very expensive amps and I'm no longer in the honeymoon stage with the Class 5. It's a great amp for the money, end of story. I'm sure it can be improved upon with the right mods but no need for all the hate.

[keysandguitars]

Well said, Nutsauce. Good bang for the buck, especially post Lyle mods. Sub $375 (what I paid) there isn't much else I'd even consider.

I bought it as a project amp knowing that it had great potential with a few tweaks. I was fortunate enough to stumble across Lyle's post. Thanks to his time and generosity, the amp sounds a lot better. It isn't perfect, but what is, especially for $375?

I figured it'd be a great little amp for jamming at home and tossing in my car for quick jam sessions. I hope to learn more, maybe even enough to make a PTP board with some more tweaks.

Doing the mods gave me enough confidence to decide to make my first PTP kit. Money is almost set aside and I'm narrowing down what I want to build first. I think I'll start with a Bassman. Any kit builders out there that can recommend which company to use? Mojotone, Weber, Marsh?

[NXC1978]

Originally Posted by keysandguitars

Any kit builders out there that can recommend which company to use? Mojotone, Weber, Marsh?

I plugged into a few of the Mojotone completed amps at their booth when I was at the Arlington, Texas guitar show. They all sounded really good. They had a decent Strat, Les Paul, and a Tele to use and I played around with all 3guitars plugging into various amps like a kid in a candy store. I'd really like to build one of their tweed kits at some point. I just need to move into a bigger place to accommodate my ever growing gear collection...

[NXC1978]

I have a question for anyone who may know. It's my understanding that the OT is this guy inside the chassis...


But, what is this thing that looks like a smaller transformer on the outside?...

[Lyle Caldwell]

The one inside is the power transformer. The one outside is the output transformer.

[NXC1978]

Originally Posted by Lyle Caldwell

The one inside is the power transformer. The one outside is the output transformer.

Cool, thanks Lyle.

[Don]

The erroneous sound on my amp was a noisy power tube. The amp has always been hard on power tubes but it has more punch now, making it worse! It sounds great though and is even usable at lower volume levels.

[NXC1978]

Got my amp finished on Saturday and man it's a lot less muddy! The cleans are very good, before I didn't like the cleans so much. The tone when cranked is still great too. VERY worth the time and effort!!!

Might have to take the extra step and swap the speaker now, since I've come this far!

[keysandguitars]

Glad to hear man! I completely agree on the cleans. Did you ad a 120pf cap for the bright switch? I only had a 240pf so it's a little bright for my taste.

I've been reading about running 2 10" 16 ohm speakers in parallel. The marshall forum has a lot of users who are running that setup at 8 ohms and say they haven't had issues. I hooked up the stock (outside the cabinet) to the Scumback I put in and it really makes me want to find a cheap cab to put the stock 10" in and wire up an extension jack. It really sounds good with 2 10"s.

[NXC1978]

Originally Posted by keysandguitars

Glad to hear man! I completely agree on the cleans. Did you ad a 120pf cap for the bright switch? I only had a 240pf so it's a little bright for my taste.

I've been reading about running 2 10" 16 ohm speakers in parallel. The marshall forum has a lot of users who are running that setup at 8 ohms and say they haven't had issues. I hooked up the stock (outside the cabinet) to the Scumback I put in and it really makes me want to find a cheap cab to put the stock 10" in and wire up an extension jack. It really sounds good with 2 10"s.

I did the 120 cap accross LK18 and LK19, but no switches and I'm happy with it. How's the scumback in comparison to the stock? Did you opt for the FBI on the Scumback? My stock speaker isn't even broken in yet so that's why I've been on the fence about swapping it right now. I'm hoping that Marshall will make an extension cab for the head coming out that will match our combo amp cabs so I can make a mini stack.

[John R]

Originally Posted by Lyle Caldwell

Mike,

That's tough, as I don't know everything on the market.

The AC4TV is a horrible little thing with no headroom and then a harsh whining overdrive. It can be fixed (I converted one to an EF86 channel and it sounds sweet) but out of the box it's dreadful.

The Class 5 needs fewer mods to sound good, but some like it just the way it is.

The Egnater Tweaker is perhaps the best of the inexpensive amps, though it is the most expensive of the inexpensive.

And then there's the option of a used amp vs a new inexpensive amp. You could get a used Deluxe Reverb amp or Blues Jr (good amp, iffy reverb) or Peavey Classic 20 and you might be thrilled.

All those are louder than the AC4 and Class 5 though.

If low volume/practice are important, the old Vox AD30VT is a good option. It can be very low in volume.

I'm going to have to go ahead and disagree with you there... The Tweaker is awesome on paper. And it is easily the most versatile amp in this segment. Which is why I bought one. But after you spend a couple weeks with it, you stop wanting to flip the switches and start just wanting whatever tone it is that you like. In my case, I couldn't quite seem to get it. Every sound I got out of it was good (which is more than I can say for most amps), but nothing quite blew me away.

But then the things that aren't obvious when you demo it at Guitar Center cropped up... First off, it sends way too hot of a signal to the effects loop. As a result, most pedals in the loop will either sound like garbage or clip. This is a known issue, but they're not changing the design. They will offer a free fix if you bug them (and there's a wiring diagram for it floating around on the net), but getting in touch with them is difficult. I had two emails go unreturned and many phone calls that didn't get answered before I tried a different number and finally got me to someone. Even then, he denied it and tried to blame my pedals before admitting this is a known thing with the amp (but insisted it's not a defect because there's no internationally agreed-upon standard for the line level of an effects loop). I don't really need a loop in my practice amp, but it would have been nice to have.

I was still going to keep the amp. But then I took it to play with some buddies for a bit. I was going to hook it up to a Mesa 4x12, so I tested it first at home with my Marshall 4x12 to get a sense for how that would work out. Now, I must admit I made a mistake here... The Marshall cab is 16 ohm and so is the built-in speaker. I accidentally had both hooked up (effectively an 8 ohm setup), but still had the impedance switch at 16 ohm. I only played like this for a minute and then headed off to the studio where I hooked it up to the 8 ohm Mesa cab and correctly set the impedance before turning it on. It played fine that night and (as always) sounded good, but not great. This was the first time I really cranked it up though (albeit only a little more than halfway). The next morning it was buzzing noticeably, even without a guitar plugged in. Whether that had something to do with the brief impedance mismatch or if it just couldn't handle being used at a moderately high volume, I dunno. But it went back to GC the next day. The only reason I didn't want a Class 5 originally is that you have to crank it up so loud to get it crunchy. But for the price of the Tweaker, I decided I could get a Class 5 and a Fulltone OCD to dedicate as part of my practice amp and still have money left over. So I did that. And I have to say I am really liking it.

As I'm reading these posts, I'm wondering to what extent the views I'm getting here are a result of this being a Les Paul forum. That's not me trying to say there's anything wrong with Les Pauls! I'm just asking because they are very thick sounding guitars. On the other hand, a lot of this discussion is in the context of using the Class 5 with a strat, so maybe that's not the issue.

The other thing I'm wondering about is how much your knowledge of electronics may or may not be coloring what you hear. If you're convinced the circuit is ill conceived, you're likely not to love the way the amp sounds (no matter what it sounds like).

The guitar I use most is an Ibanez with DiMarzio pickups -- an overall bright sounding guitar with hot pickups. I find the Class 5 sounds pretty damn good with all the knobs fairly close to the 12:00 position. I'm not saying there's no room for improvement. But I'd be really curious to try the modified version described here side by side with a stock Class 5 and see if it really makes a difference to my ears.

Alright, I've written too much already.

[NXC1978]

Originally Posted by John R

As I'm reading these posts, I'm wondering to what extent the views I'm getting here are a result of this being a Les Paul forum.

I'm more of a "Strat" guy myself and I noticed the most improvement with my Fenders after the mods. I wish I had access to a stock Class 5 to make demo with. I can say that there is a VERY noticable difference from stock to the "Lyle" mods even without having a stock one to A/B it with.

[Lyle Caldwell]

John,

What I'm about to say will at first sound like I'm just being a dick. So please bear with me and read the whole thing and try to look past me arguing with you. I have no dog in this fight and no urge to contradict you hoping in some way to "win" an argument here.

First, to me, it sounds like both the "blah" sound you got and the buzzing were caused by tubes. The Tweaker, like most import amps, comes with not-particularly-fantastic tubes which are then shipped here from Asia, bouncing around in trucks etc. But instead of trying different tubes you returned the amp.

Second, yeah, Egnater's right, effects loops are NOT SUPPOSED TO BE USED WITH INSTRUMENT LEVEL PEDALS. The whole point of an amplifier is to bring the gain WAY UP and then send it to the power stage. The level after a preamp is called LINE level. It is much much hotter than most pedals are designed to work with. There are impedance issues as well which I won't get into here. In my own amps I have the loop circuit designed with switchable -20dB max attenuation for the Send and +20dB max makeup gain for the Return, so a player may use pedals in the loop of my amp. But the loop portion of my amp costs about what the entire Tweaker does. This kind of ultra-pro feature is frankly not to be expected in a very reasonably priced amp.

Third, I don't judge amps by reading a schematic. When the client's Class 5 arrived, I hadn't even looked at a schematic. I did much what anyone else here would do - I said "Hey, it looks sharp! Hope this rocks!" Then I plugged in a Strat. Then I plugged in a Les Paul. The stock amp just. Did. Not. Sound. Good.

$20 of mods later, it sounded pretty darn good.

Originally Posted by John R

I'm going to have to go ahead and disagree with you there... The Tweaker is awesome on paper. And it is easily the most versatile amp in this segment. Which is why I bought one. But after you spend a couple weeks with it, you stop wanting to flip the switches and start just wanting whatever tone it is that you like. In my case, I couldn't quite seem to get it. Every sound I got out of it was good (which is more than I can say for most amps), but nothing quite blew me away.

But then the things that aren't obvious when you demo it at Guitar Center cropped up... First off, it sends way too hot of a signal to the effects loop. As a result, most pedals in the loop will either sound like garbage or clip. This is a known issue, but they're not changing the design. They will offer a free fix if you bug them (and there's a wiring diagram for it floating around on the net), but getting in touch with them is difficult. I had two emails go unreturned and many phone calls that didn't get answered before I tried a different number and finally got me to someone. Even then, he denied it and tried to blame my pedals before admitting this is a known thing with the amp (but insisted it's not a defect because there's no internationally agreed-upon standard for the line level of an effects loop). I don't really need a loop in my practice amp, but it would have been nice to have.

I was still going to keep the amp. But then I took it to play with some buddies for a bit. I was going to hook it up to a Mesa 4x12, so I tested it first at home with my Marshall 4x12 to get a sense for how that would work out. Now, I must admit I made a mistake here... The Marshall cab is 16 ohm and so is the built-in speaker. I accidentally had both hooked up (effectively an 8 ohm setup), but still had the impedance switch at 16 ohm. I only played like this for a minute and then headed off to the studio where I hooked it up to the 8 ohm Mesa cab and correctly set the impedance before turning it on. It played fine that night and (as always) sounded good, but not great. This was the first time I really cranked it up though (albeit only a little more than halfway). The next morning it was buzzing noticeably, even without a guitar plugged in. Whether that had something to do with the brief impedance mismatch or if it just couldn't handle being used at a moderately high volume, I dunno. But it went back to GC the next day. The only reason I didn't want a Class 5 originally is that you have to crank it up so loud to get it crunchy. But for the price of the Tweaker, I decided I could get a Class 5 and a Fulltone OCD to dedicate as part of my practice amp and still have money left over. So I did that. And I have to say I am really liking it.

As I'm reading these posts, I'm wondering to what extent the views I'm getting here are a result of this being a Les Paul forum. That's not me trying to say there's anything wrong with Les Pauls! I'm just asking because they are very thick sounding guitars. On the other hand, a lot of this discussion is in the context of using the Class 5 with a strat, so maybe that's not the issue.

The other thing I'm wondering about is how much your knowledge of electronics may or may not be coloring what you hear. If you're convinced the circuit is ill conceived, you're likely not to love the way the amp sounds (no matter what it sounds like).

The guitar I use most is an Ibanez with DiMarzio pickups -- an overall bright sounding guitar with hot pickups. I find the Class 5 sounds pretty damn good with all the knobs fairly close to the 12:00 position. I'm not saying there's no room for improvement. But I'd be really curious to try the modified version described here side by side with a stock Class 5 and see if it really makes a difference to my ears.

Alright, I've written too much already.