New Amp Day: Marshall 4203

[tbonesullivan]

So, even though I'm a dyed in the wool carvin amp fan, I've been wondering a lot about other amp makers, particularly Marshall. I knew that it's has to be more than just a name to be that popular with so many users. So, I fired up craigslist, and found this amp: a Marshall Artist 30 4203. 30 Watts. 2xEL34 and 1 12AX7 phase inverter. Preamp is solid state. Pretty basic set up. It's essentially a 1 channel amp with a "boost" setting, so I guess it's really a 2 channel amp. Has a Master volume and reverb, tone stack on the clean channel + volume, and Gain Volume, and Tone on the lead channel.

 

I checked the chassis, and it's got a 1986 build date with signatures from everyone who worked on the amp, drake transformers, etc. Has a Celestion Ipswitch made G12 Vintage 8 ohm speaker

 

The tubes it came with were Siemens EL34s, and a National 12AX7, made in china. Part of me thinks these may be the original tubes it came with (uh oh).

 

So, the sound is actually pretty good. I get some nice crunch from the clean channel. Some complained that the clean channel broke up too much in reviews. Well, this is a MARSHALL clean channel, which is to say, not very clean at all. If you want glassy cleans go find a Fender. The boost channel has more volume/hair on it, and really kinda goes insane when you dime the gain, but in a good way.

 

So, anyone had one of these recently? Any suggestions for new tubes? Also I've heard that the amp is actually a class A amplifier? I'm not really in the know regarding stuff like that.

 

Pictures:

 

 

 

 

[TheRecordFable]

Nice!

[FredZepp]

Yeah, Marshall does a good job of making sure that you get that Marshall tone... even when maybe it's a hybrid design.

You make that one sound like it is an interesting amp.

There are some amp gurus here, not me, that can maybe help you if you want to re-tube with your eye towards a certain change in tone...

But hey, you sound pretty happy so far with it...... I love lil' rockin' amps like this .. so much fun.

[212Mavguy]

Siemens el34's as a rule are very nice power tubes in longevity as well as tones. It will be hard to improve on those with any new production tube today. Yours appear to have lots of life left in them. A bias measurement tool and multimeter will help you learn whether they are drawing similar amounts of plate current.

 

I have read often that the brand of phase inverter tube has little if any effect on your tone, and my repeated experiments have caused me to disagree, it does make a difference to my ears!

 

Another desired trait of a phase inverter is for both triodes to be matched in output. I agree with that, but frankly,the kind of construction in Marshall mass produced printed circuit board type amps is not all that great with regard for the quality as well as consistency of parts used, the phase inverter circuit containing that tube (in theory) also has to be matched on both sides, and that is often NOT the case in most mass production guitar amps. Maybe if you get a hand made boutique amp from a great builder, that builder will measure the components used in the phase inverter circuit and through measurements make sure that the sides are balanced, putting in a pair of balanced in output power tubes as well, but as a rule in mass production amps, not necessarily the case.

 

I like vintage old stock (not necessarily unused) euro 12ax7's with short plate designs like RFT, Siemens, Mullard, Philips, Amperex, and Brimar tubes in Marshall combo style amps, both for the quality of their tones and their resistance to microphonics, they are usually pretty good in that regard unless they have gone through a large number of hours of use or on/off cycles. They are spendy because they are no longer made. They will tend to a warmer, fatter, smoother, less shrill tone than the Chinese tubes.

 

It's a good thing to play a Heritage guitar through a pimped out amp!

[tbonesullivan]

I've been told by a few others now that I should just keep the siemens tubes in, as they look to have a lot of life left in them. I did change the phase inverter to a new production EHX tube, which may have some effect on the sound when pushing the amp really hard, as the PI usually starts breaking up before the power tubes do. So far it seems to be a great amp, and built like a TANK. Also... weighs as much as a tank. Time will tell whether it's a keeper or just a passing thing.

[bolero]

I've got one of those, it's a GREAT little amp...nice it has reverb too

 

 

has some really good distortion tones & will cop a good JCM800 vibe; for a little combo it is a bit of a sleeper & is LOUD enough to keep up with a drummer

 

I find the V30 makes it sound a bit bright on it's own, but with a band it fits in the mix really well, and is nice & defined

 

 

there is an easy cap mod ( C13 I think) you can remove to warm it up a bit, Randall Aiken came up with it after I sent him the schem, it's on harmony Central somewhere

 

congrats, it's a nice grab & go jammer...

[tbonesullivan]

Yeah... the reverb is nice. it's a must for a combo IMHO. I think all of my current amps have reverb, which is nice. One has digital reverb, but I don't really care about that, as it actually sounds better than some spring reverb I've heard, and it won't rattle around!

 

Now I've gotta consider if I have too many amps. I've got 2 practice amps (I count the Artist 30 as a practice amp) and 3 "gig level" amps that are 100 watts tube with at least 2 12 inch speakers. Might be time to sell my half stack *sniff*

[smurph1]

Yeah... the reverb is nice. it's a must for a combo IMHO. I think all of my current amps have reverb, which is nice. One has digital reverb, but I don't really care about that, as it actually sounds better than some spring reverb I've heard, and it won't rattle around!

 

Now I've gotta consider if I have too many amps. I've got 2 practice amps (I count the Artist 30 as a practice amp) and 3 "gig level" amps that are 100 watts tube with at least 2 12 inch speakers. Might be time to sell my half stack *sniff*

Nah..Take a deep breath and repeat after me "More amps good...More amps good..."

[tbonesullivan]

Nah..Take a deep breath and repeat after me "More amps good...More amps good..."

nah... I mean I gotta make room for the used TSL122 that should arrive next week!

 

yes, I've got marshall fever.

[mark555]

I think, but I am willing to be corrected if I am wrong, that a class A amp is a Valve amp that is more natural in that it's not meant to be a high gain, more of you basic purist amp.

 

any one able to clarify that for me?

[bolero]

about halfway down he talks about class A/AB etc

 

http://www.aikenamps.com/TI_Aiken_Q&A.html

 

short answer: class A just refers to whether the output tubes are on full cycle all the time, vs class AB etc where they are not

 

 

so it's independant of the preamp...I'm sure you could have a veryt distorted class A circuit...and by definition, every single-output-tube design is class A

[bolero]

caveat: I'm no expert, I just read this on the internet

[tbonesullivan]

I think, but I am willing to be corrected if I am wrong, that a class A amp is a Valve amp that is more natural in that it's not meant to be a high gain, more of you basic purist amp.

 

any one able to clarify that for me?

Wouldn't that refer more to "super linear" mode? Class A simply means that the tube is running at 100% all of the time. Class B means that the tube is off when not in use, and on when in use. Class AB, like most amps are, is halfway between. There is the bias current keeping the tube idling at 40-60% dissipation to avoid crossover distortion as the tube has to power up.

 

A lot of Class A amps are single ended, as opposed to Push Pull, so one tube does both sides of the waveform. I believe you can have class A Push Pull amps as well. Also note that a lot of people think the Vox AC30 is Class A, which it really isn't. It is just a class AB amp biased very hot. But there are other things involved such as the level of negative feedback on the power tubes, yada yada.

[bolero]

how is the amp doing? you still like it after the honeymoon?

[212Mavguy]

I think, but I am willing to be corrected if I am wrong, that a class A amp is a Valve amp that is more natural in that it's not meant to be a high gain, more of you basic purist amp.

 

any one able to clarify that for me?

 

From my experiences with a boutique amp that has a switch for operating in Class AB and class A, my ears have learned what helps answer this question.

 

If your desired tones are more to do with the hardcore rock tones like Aerosmith, GNR, stuff like that you will want your amp biased into class AB. That is where your typical Marshall-y tones are found. The reason for that is that a class AB bias combined with a push pull power section cause a canceling out of the even order harmonics. As a result, since the even order harmonics are somewhat canceled out, the odd order harmonics prevail.

 

You can hear the first even order harmonic appearing as a note an octave above the played note. The first odd order harmonic appears as an octave and a fifth above the played note.

 

A class AB biased amp tends to a brighter, more snarly distorted tone and a brighter clean as well. Pick harmonics are more easily coaxed out.

 

A class A biased amp puts out more of the even order harmonics due to the fact that the power tubes operate through both sides of the waveform, so there is less canceling out of even order harmonics. There is a fatter, warmer, sweeter, sometimes more punchy at pick atack sound that results, possibly more sustain. and although one can use class A for highly distorted tones, it really sounds good in lower gain settings, great for blues, jazz, and cleans.

 

You will hear even ordered harmonics clean and dirty gain settings out of a single ended amp, which must be biased into class A for it to work properly since there is only one power tube.

 

Tbone, I hope you really like that new amp. If it were mine, I'd stick an RFT 12ax7 in V1...they are great, and Marshall used them in their very old days as original equipment. Spendy now and worth every penny!

[tbonesullivan]

how is the amp doing? you still like it after the honeymoon?

yeah, it's a good amp. But I can see what people are saying about the brightness being a problem, and also the boost channel is kinda anemic until you get the gain around 7 or 8, when it starts to really open up and sound good.

 

But... compared to the TSL122, it's got nothing.