Marshall MA 100C 100 Watt All Valve Amplifier

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Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 18 Apr 2013, 12:52

Hi everyone, I recently decided to buy some new music gear so I went to Sounds Of Music, a music shop in Casuarina, and put a Marshall MA 100 C 100 Watt all valve combo amp on layby, I've been gradually paying it off over the last three fortnights and have only one more payment to make and then I'll officially own it, after it's paid off I'm going to get the Sounds Of Music staff to order a new yellow PRS Santana SE Electric guitar for me, here's pics of the amplifier and guitar:
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 30 Apr 2013, 11:09

Well, I've finally got the amplifier home and, although it works, the reverb doesn't appear to be working, even if I crank the reverb knob all the way up, so I'm going to go and see the staff members at Sounds Of Music and see what they can do about getting the Reverb fixed under warranty, by the way this amp is heavy and I guess that's to be expected, it's also pretty loud even when the master volume for the Overdrive channel is turned right down to zero, the Clean channel sounds nice, Overdrive sounds a bit thin with the volume on zero but fattens-up when the volume's turned up, the amp does seem a bit dry sounding without the reverb.... :hmmm:

Boy, does it get warm, I guess that's to be expected with 4 X EL34 power valves glowing happily away...... :thumbsup


Apart from the problem with the Reverb I'm happy with the amp, the Reverb issue shouldn't be too hard to get fixed.... :thumbsup


Might post a pic of my amp a bit later on......stay tuned..... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 30 Apr 2013, 12:50

Here's a pic of the amp:
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby JiM » 03 May 2013, 01:56

Hi Simon !
I often use a similar set-up, as this is one of the amps available (and the only all-tube) in the rehearsal studio where my band spends most of its friday evenings. I also have a PRS SE Custom 25th anniversary. I can get quite a good rock tone with those !

However, i find the overdrive channel on the MA100 to have too much treble, i usually set the treble knob to about 1 out of 10.
At first, i wondered how is the "Crunch Balance" knob works, but after reading the doc it makes more sense : the "Boost" mode is the normal operation mode of the overdrive channel, and the "Crunch Balance" is just a footswitchable gain reduction option.
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 03 May 2013, 11:22

JiM wrote:Hi Simon !
I often use a similar set-up, as this is one of the amps available (and the only all-tube) in the rehearsal studio where my band spends most of its friday evenings. I also have a PRS SE Custom 25th anniversary. I can get quite a good rock tone with those !

However, i find the overdrive channel on the MA100 to have too much treble, i usually set the treble knob to about 1 out of 10.
At first, i wondered how is the "Crunch Balance" knob works, but after reading the doc it makes more sense : the "Boost" mode is the normal operation mode of the overdrive channel, and the "Crunch Balance" is just a footswitchable gain reduction option.



I'm finding that the Overdrive channel has a bit too much treble in it too, I found adjusting both the treble tone control and the Presence seems to help it, also I bring up the mids too, note that my Ibanez guitar has Infinity pickups on it which are high-output types and sound a bit too muddy for me, I'm surprised at how smooth the sustain is on the Overdrive channel in boosted mode, I think it has all the gain I could ever need and if I want more I can simply just use some kind of a booster pedal, you're right about the Crunch Balance control, it does take a little bit of getting used to but it does make sense to me, the Resonance control also seems to help the treblyness too, I tend to have it adjusted to just below about 12 o clock...... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 30 May 2013, 17:07

Well, I've just come back from doing a live gig Jam Night at the Happy Yess club in Brownsmart, and guess what?, the amp died, the funny thing is I didn't even have the amp turned up any where near it's maximum volume, I think the main HT fuse might have blown so it looks like the Amp's going to have to go back to the shop for a complete warranty service...... :shock:
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 30 May 2013, 17:40

What makes me suspect that the main HT fuse has blown is that the amp does power-up, and all the heaters light, I switch the amp off standby and there's no sound even if I turen the master volumes up, one other thing is I noticed that when I switch the amp off standby there's none of that characteristic blue flourescence in the power valves, that I see when the amp was running normally..... :hmmm:


Just wondering if it's something I could sort out myself or would I be better off getting it sorted under warranty, the amp is practically brand new..... :hmmm:

By the way, I did try a known good instrument lead, so it's definitely the amp...... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby JiM » 30 May 2013, 18:38

DrNomis wrote:What makes me suspect that the main HT fuse has blown is that the amp does power-up, and all the heaters light, I switch the amp off standby and there's no sound even if I turen the master volumes up, one other thing is I noticed that when I switch the amp off standby there's none of that characteristic blue flourescence in the power valves, that I see when the amp was running normally..... :hmmm:

This is indeed consistent with a blown HT fuse : exactly like on standby.
The question is : why did the HT fuse blow ? A bad tube could be a good candidate.
Anyway, if the amp is still under warranty, run to your dealer !

If not, here is a schematic : http://elektrotanya.com/marshall_ma100_ ... nload.html
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 31 May 2013, 00:39

JiM wrote:
DrNomis wrote:What makes me suspect that the main HT fuse has blown is that the amp does power-up, and all the heaters light, I switch the amp off standby and there's no sound even if I turen the master volumes up, one other thing is I noticed that when I switch the amp off standby there's none of that characteristic blue flourescence in the power valves, that I see when the amp was running normally..... :hmmm:

This is indeed consistent with a blown HT fuse : exactly like on standby.
The question is : why did the HT fuse blow ? A bad tube could be a good candidate.
Anyway, if the amp is still under warranty, run to your dealer !

If not, here is a schematic : http://elektrotanya.com/marshall_ma100_ ... nload.html




Cheers for that JiM, one thing I did notice just before the amp died is that I heard an intermittent high-pitched "Blatt" coming from the amp when I was playing through it with the amp switched to the clean channel.... :thumbsup

As I was going to get the reverb effect fixed, I might as well just get the amp serviced under warranty anyway, I'll probably be without the amp for a good few weeks but I do have another amp I can use in the meantime..... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby bato001 » 31 May 2013, 00:43

DrNomis wrote:What makes me suspect that the main HT fuse has blown is that the amp does power-up, and all the heaters light, I switch the amp off standby and there's no sound even if I turen the master volumes up, one other thing is I noticed that when I switch the amp off standby there's none of that characteristic blue flourescence in the power valves, that I see when the amp was running normally..... :hmmm:


Just wondering if it's something I could sort out myself or would I be better off getting it sorted under warranty, the amp is practically brand new..... :hmmm:

By the way, I did try a known good instrument lead, so it's definitely the amp...... :thumbsup


You have not had that amp for more than a month, definitely take it back for a warranty repair. Last time I kept blowing fuses it was a bad preamp tube.
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby lead2203 » 31 May 2013, 01:13

bato001 wrote:
DrNomis wrote:What makes me suspect that the main HT fuse has blown is that the amp does power-up, and all the heaters light, I switch the amp off standby and there's no sound even if I turen the master volumes up, one other thing is I noticed that when I switch the amp off standby there's none of that characteristic blue flourescence in the power valves, that I see when the amp was running normally..... :hmmm:


Just wondering if it's something I could sort out myself or would I be better off getting it sorted under warranty, the amp is practically brand new..... :hmmm:

By the way, I did try a known good instrument lead, so it's definitely the amp...... :thumbsup


You have not had that amp for more than a month, definitely take it back for a warranty repair. Last time I kept blowing fuses it was a bad preamp tube.


Its most likely.. just a bad power tube here.
The preamp tube blowing the fuse is weird..unless it took out the DC supply to the filament and that does happen more then it should!!
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 31 May 2013, 01:45

No worries and cheers for that guys, I'll see if I can organize some way of getting the amp back to Sounds Of Music where I bought it and talk to the staff about getting it fixed under warranty, last time I talked to them about getting the reverb fixed they were happy to do it under warranty, anyway I'll let you know how it all goes..... :thumbsup

It could very well be a bad Power Valve that caused the HT fuse to blow, I've been reading about this problem in a Marshall forum and it seems to be a fairly common issue with the MA series, possibly due to the amps being manufactured in Vietnam...... :thumbsup


I read that the MA series are basically entry level Marshall amps.... :thumbsup


Just found this:

https://groups.google.com/forum/?fromgr ... 9_tqngV_NE
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby lead2203 » 31 May 2013, 03:51

DrNomis wrote:No worries and cheers for that guys, I'll see if I can organize some way of getting the amp back to Sounds Of Music where I bought it and talk to the staff about getting it fixed under warranty, last time I talked to them about getting the reverb fixed they were happy to do it under warranty, anyway I'll let you know how it all goes..... :thumbsup

It could very well be a bad Power Valve that caused the HT fuse to blow, I've been reading about this problem in a Marshall forum and it seems to be a fairly common issue with the MA series, possibly due to the amps being manufactured in Vietnam...... :thumbsup


I read that the MA series are basically entry level Marshall amps.... :thumbsup


Just found this:

https://groups.google.com/forum/?fromgr ... 9_tqngV_NE


Its not the amp...well maybe :lol: but I would get a bias checker and order new good tested tubes myself. The problem is the tubes are not so good these days AND Marshall and most other big amp companies do not check them..They just bias them cold and send them out ...hope for the best. The repair guy might just do it the same way..most do.....but ask him about that..there are some that do care..and see if he can get you a set of matched and tested tubes
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby bato001 » 31 May 2013, 04:54

DrNomis wrote:No worries and cheers for that guys, I'll see if I can organize some way of getting the amp back to Sounds Of Music where I bought it and talk to the staff about getting it fixed under warranty, last time I talked to them about getting the reverb fixed they were happy to do it under warranty, anyway I'll let you know how it all goes..... :thumbsup

It could very well be a bad Power Valve that caused the HT fuse to blow, I've been reading about this problem in a Marshall forum and it seems to be a fairly common issue with the MA series, possibly due to the amps being manufactured in Vietnam...... :thumbsup


I read that the MA series are basically entry level Marshall amps.... :thumbsup


Just found this:

https://groups.google.com/forum/?fromgr ... 9_tqngV_NE


100 watts, all tube and 2 channels. That's alot of amplifier for an 'entry' level piece of equipment.
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 31 May 2013, 06:24

The amp's at the shop I bought it from now waiting to be repaired under warranty, in the meantime I've got a 300 Watt Behringer Keyboard/P.A. amplifier that I can use along with a Zoom G2 pedal so I'm still able to do some gigging, thanks for all your contributions..much appreciated.... :thumbsup

Update about the PRS guitar: It turns out that Sounds Of Music were having problems with the distributor they were ordering my new PRS SE Santana guitar from, so, as Sounds Of Music already had two PRS guitars in stock I asked them if I could buy one of them instead, they agreed and asked me which guitar I was interested in, I showed them a Flame-Maple Cherry Red PRS SE Custom they had hanging on the wall and they said it retailed for $1,400.00, but they said they could sell it to me for $1,200.00 if I was happy with it, I said I was happy so they refunded the $200.00 deposit on the PRS SE Santana and I put the PRS SE Custom on Layby with it, will post a pic of the guitar once I get it home so stay tuned..... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 10 Jul 2013, 19:02

Update:

Still waiting on the amp, apparently they had to send it to a service tech located elsewhere in Australia, I'm not too worried about it, as they say "Patience is a virtue", I made another payment on the guitar on Tuesday 09/07/2013 and now I only have $299.00 left to pay off the guitar before I officially own it...... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby bajaman » 10 Jul 2013, 22:21

2 months to find and replace the bad tube :roll: :roll: :roll:
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 11 Jul 2013, 00:59

bajaman wrote:2 months to find and replace the bad tube :roll: :roll: :roll:



Yeah I know...lol.... :lol:


I did some internet research and apparently from what I've read, the MA series amps manufactured in Vietnam seem to be shipping with some output tubes of dubious quality, I'm strongly suspecting that the main HT fuse in my amp blew because my amp had suspect output tubes in it, one thing I did notice was that the amp sounded a bit thin on the overdrive channel before it stopped working properly, it powered up and all the heaters lit, but I got no sound out of it when I switched it off standby.... :thumbsup
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby uncleboko » 11 Jul 2013, 07:59

I love that guitar shape, very similar to my Les Paul Junior!
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Re: Marshall MA 100C 100 Watt All Valve Amplifier

Postby DrNomis » 23 Jul 2013, 06:11

Ok, new update....I've just got the amp home from being fixed under warranty, everything's working now including the reverb,...and I've also got my new PRS SE Custom 24 Electric guitar home too, tried it out and it doesn't sound as trebly as I thought it would played through the Marshall amp, it's kind of like a cross between a Stratocaster and a Les Paul, but I love the smooth sustain I'm getting now, very happy with it so from now on it's going to be my main gigging guitar, pic of the guitar coming soon, stay tuned.... :thumbsup


BTW, I tried my Baja Real Tube Overdrive pedal with the guitar through the clean channel, sounds great so Bajaman thanks once again for designing it..... :thumbsup


OK, the Pics..... 8)
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