Intro to Amp Mods?

['59]

Howdy fellas, I've got an Ampeg GVT5-110 at my college apartment that doesn't quite cut it in comparison to the Marshall 212 I have at home. I don't remember the model name on it however.

Anyway, how can I get into modding amps? I know a 110 is never going to sound like a 212, but it seems like a good place to experiment. Are there any books on amp modding I can look at? I figure the best place to start is the speaker since it's actually making the noise, and maybe the tubes too. Currently it has a Celestion Tube 10 speaker in it and I find it's lacking in bass and several other qualities I'm not verbose enough in musical speak to explain. I know guitar speakers aren't the absolute height in audio technology, but I think the speaker could do better.

Where should I start to become more knowledgeable about this stuff?

 

[PFDarkside]

Speakers are always the first place to start. I really like the Eminence Ragin Cajun.

I’d start with Uncle Doug’s YouTube channel.

 

[NegativeEase]

I started with reading all of Ken Fischer's writings and my dad's amp knowledge.

But nowadays there are Youtube channels that can teach you much more in a shorter time.

 

[Ewizard]

There are a couple of books such as the TUT ( The Ultimate Tone ) book series, and the Valve Wizard white pages, but beyond that, it is mostly electronics 101. It sounds like you are not looking to go super deep. Speaker and tube changes are not what I consider to be " modifying " an amp. The whole tube craze is a bunch of malarky. There is absolutely ZERO guarantees that a NOS tube will sound good, or even better than a modern production one, the idea is perpetuated by confirmation bias. The results are subjective, so better is subjective. All the rest of the tubes in the world are made by one of three factories, all of which produce great tubes that do exactly what they are supposed to do. Changing tubes for tonal, or amp character changes is a way, but not THE way to achieve a goal.

Speakers are the easiest and perhaps most economical way to change the sound of your amp. The speaker is probably 7-9/10's of the resultant tonal sound of the amp actually. Change the speaker, and you will absolutely have a different-sounding amp. Changing a tube may not be so apparent or even noticeable. Changing components in the amp may change the character of the amp, but may not actually change its tonal shape.

To me, an amp is the sum of its parts. If you buy a Soldano SLO-100 and you want it to sound like a Fender Deluxe, well you bought the wrong amp, it will NEVER sound like a Fender Deluxe. If you are not happy with the tonal character of an amp, changing the speaker or using an EQ pedal is the easiest and most impactful way to shape its sound. If you want to make a Fender Deluxe break up like a Soldano SLO-100, well it never will unless you change the entirety of the amp.

 

[Mincer]

There are probably a few dedicated DIY amp forums out there with people that have lots of experience and don't mind sharing it.

 

[El Dunco]

There are a couple of books such as the TUT ( The Ultimate Tone ) book series, and the Valve Wizard white pages, but beyond that, it is mostly electronics 101. It sounds like you are not looking to go super deep. Speaker and tube changes are not what I consider to be " modifying " an amp. The whole tube craze is a bunch of malarky. There is absolutely ZERO guarantees that a NOS tube will sound good, or even better than a modern production one, the idea is perpetuated by confirmation bias. The results are subjective, so better is subjective. All the rest of the tubes in the world are made by one of three factories, all of which produce great tubes that do exactly what they are supposed to do. Changing tubes for tonal, or amp character changes is a way, but not THE way to achieve a goal.

Speakers are the easiest and perhaps most economical way to change the sound of your amp. The speaker is probably 7-9/10's of the resultant tonal sound of the amp actually. Change the speaker, and you will absolutely have a different-sounding amp. Changing a tube may not be so apparent or even noticeable. Changing components in the amp may change the character of the amp, but may not actually change its tonal shape.

To me, an amp is the sum of its parts. If you buy a Soldano SLO-100 and you want it to sound like a Fender Deluxe, well you bought the wrong amp, it will NEVER sound like a Fender Deluxe. If you are not happy with the tonal character of an amp, changing the speaker or using an EQ pedal is the easiest and most impactful way to shape its sound. If you want to make a Fender Deluxe break up like a Soldano SLO-100, well it never will unless you change the entirety of the amp.

Don’t get me started on NOS tube prices because of it this. They seriously go for 10x what they’re even worth because of this “magic mojo” bs and science just doesn’t agree. I swear you can sell magic tone healing crystals to these people (that’s not a joke, it’s a real product.)

That’s why I made the thread about power tubes and come off so annoyed. Power tubes make amp work loud… without being the price of a used car… get outta heeere!

 

['59]

So what are the most popular speakers out there and what terms are generally used to describe them? Right now I think the biggest problem with Tube 10 is the amp just sounds small.

My car has two 8" midrange drivers that just sound huge, so I'd be willing to bet there's a guitar speaker that can do the same thing, even without modern speaker technologies.

 

['59]

Speakers are always the first place to start. I really like the Eminence Ragin Cajun.

I’d start with Uncle Doug’s YouTube channel.

All of the sources I'm seeing online about this speaker seem like its a step in the right direction. How much of a part does the speaker play in the role of accommodating bass guitars? It doesn't need to work for bass, I'd just prefer if it does. I know the weakness in converting a guitar pedal to a bass pedal is adjusting certain input filters, do amplifiers also filter out low end on the input?

 

[Ewizard]

It is sad to say, but there are only truly a few noted options that define the core sound that guitarists are most interested in. The G12M ( greenback ), the Vintage 30, the G12 Heritage, and dare I say the Alnico Blue. Between these four speakers, all from the same maker, you have pretty much the entirety of the desired speaker sounds.

Eminence too, has a bounty of options, but the majority of their options are not sought after like a G12M Greenback. The Swamp Thang, The Wizard and The Legend are a few of their more popular options. They are not often listed as the speaker in the amp du-jour though.

Warehouse guitar speakers, Weber Guitar speakers, and Scumback guitar speakers are also popular and often more affordable options. They also have many of their options tailored to approximate the more popular names and tones listed above.

The long and short is that changing guitar speakers for a tonal change is almost as much a shot in the dark as sending your amp in to a tech to have it electronically modified. You may like one aspect of it, but not another. The only way to know what speaker you really want is to try it.

I have thought of doing a business that has every major speaker option and configuration available to have available for rent, so you can actually try it out, but shipping costs are the hang up. I have also thought of a way where I could have all the speakers in stock to then play back your pre-recorded signal through, so I could show you the re-guitar cabbed result. Again, it requires the end client to have a way to record their guitar amp, less a speaker cab, and be able to do it in a way that is consistent with my needs to be able to capture it properly through the cab when re-played. Basically, it is just easier to buy a few speakers and return the ones you don't like. Amazon FTW.

 

[El Dunco]

It is sad to say, but there are only truly a few noted options that define the core sound that guitarists are most interested in. The G12M ( greenback ), the Vintage 30, the G12 Heritage, and dare I say the Alnico Blue. Between these four speakers, all from the same maker, you have pretty much the entirety of the desired speaker sounds.

Eminence too, has a bounty of options, but the majority of their options are not sought after like a G12M Greenback. The Swamp Thang, The Wizard and The Legend are a few of their more popular options. They are not often listed as the speaker in the amp du-jour though.

Warehouse guitar speakers, Weber Guitar speakers, and Scumback guitar speakers are also popular and often more affordable options. They also have many of their options tailored to approximate the more popular names and tones listed above.

The long and short is that changing guitar speakers for a tonal change is almost as much a shot in the dark as sending your amp in to a tech to have it electronically modified. You may like one aspect of it, but not another. The only way to know what speaker you really want is to try it.

I have thought of doing a business that has every major speaker option and configuration available to have available for rent, so you can actually try it out, but shipping costs are the hang up. I have also thought of a way where I could have all the speakers in stock to then play back your pre-recorded signal through, so I could show you the re-guitar cabbed result. Again, it requires the end client to have a way to record their guitar amp, less a speaker cab, and be able to do it in a way that is consistent with my needs to be able to capture it properly through the cab when re-played. Basically, it is just easier to buy a few speakers and return the ones you don't like. Amazon FTW.

That’s a very neat idea. It’s similar to the reamping service I offer without necessarily having to be a client but you have essentially the “ultimate,” speaker collection plenty of guitarists without the resources to get their own would love that.

That being said, I’m with you, I want to hear new sounds, more variety! Be it by blending in a speaker you’d never think to use or at least blend it in. The sound stability of a high-power modern speaker blended with say, a Celestion tube 10 (10”) can be very interesting without sacrificing the goodies.

 

[El Dunco]

With enough wiring knowledge, not a whole lot more than knowing how to install pickups (and knowing how to safe about it,) there’s a case to be made for changing some values here and there if your sind is 90% there and the mod can easily make it exactly what you want, more personal and more “you.”

There was a huge modding community for the Marshall JVM. There’s records of the mod instructions even if the forum doesn’t exist anymore. A lot of them revolved around making it more like a classic Marshall. I didn’t go nearly that far, as it being a great, tight plug-in-and-play metal amp is exactly what I liked about it. It was even closer with the right cabinet. I just made it smoother and 100% the sound I want from it combining aspects of the Plexi and Fortin mods.

I agree that hoping to fundamentally change the character of your amp through mods means it’s the wrong amp. If I want the Mesa sound, I have that (which again I’ve made minor mods to just to get it exactly what I want from it when it was mostly perfect) if I want something brighter and tighter, with no boosting needed, I have that. Plus the ability to blend. Just the right tools for the right job.

It’s why trying amps out and really getting to know them is so important. It’s responsible for so much misdirected hate towards certain amps because people don’t know how to use what they have, or it’s wrong for what they want. People expecting a major tone difference from changing tubes or expect way more difference from a pickup change that any pickup could ever do is just nuts.

 

['59]

I agree that hoping to fundamentally change the character of your amp through mods means it’s the wrong amp. If I want the Mesa sound, I have that (which again I’ve made minor mods to just to get it exactly what I want from it when it was mostly perfect) if I want something brighter and tighter, with no boosting needed, I have that. Plus the ability to blend. Just the right tools for the right job.

I'm really less concerned with turning a trash amp into a great amp, or even really turning my okay amp into a good one. What I'm looking for here is the ability to gain some practical experience messing with electronic circuits now that I've freshly acquired a degree in the field.

For now I'm thinking I'll just mess with the speaker as the common consensus is the speaker is the weak point of the amp. From there I figured I'll try and tweak component values and maybe add a stomp box level effects loop and master volume.

 

[Demanic]

I ported and added a crossover and tweeter to my Kustom 16 watt bass combo, just for s&g. But it does make a great practice amp.

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[El Dunco]

I'm really less concerned with turning a trash amp into a great amp, or even really turning my okay amp into a good one. What I'm looking for here is the ability to gain some practical experience messing with electronic circuits now that I've freshly acquired a degree in the field.

For now I'm thinking I'll just mess with the speaker as the common consensus is the speaker is the weak point of the amp. From there I figured I'll try and tweak component values and maybe add a stomp box level effects loop and master volume.

If you have a degree it will be a breeze. You could even start with building an amp from a kit.

 

[devastone]

A new speaker and depending on what kind of sounds you want, maybe a Friedman BE-OD or Catalinbread amp-in-a-box in the flavor of your choice. A new speaker may sound much better (or may not), and the appropriate pedal into the amp set clean will give you your flavor of choice. As mentioned, you probably aren't going to get a hot rodded Marshall tone directly out of that amp.

If it was me, I would probably go for the pedal first, the current Celestion speaker is probably a decent speaker.

 

[GuitarDoc]

I was amazed at how great the Swamp Thang sounded. Very full, rich tone, and a high spl which translates to it being very efficient and loud. I originally put it into a 22 watt tube amp and it ended up sounding huge.

 

[Demanic]

I was amazed at how great the Swamp Thang sounded. Very full, rich tone, and a high spl which translates to it being very efficient and loud. I originally put it into a 22 watt tube amp and it ended up sounding huge.

I have one paired with a Texas Heat in a 2x12.

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