DSL40CR Issue With Ultra Gain Channel

Discussion in 'Marshall Amps' started by Bob O'Donnell, Nov 12, 2020.

  1. Kochens

    Kochens Member Silver Supporting Member

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    They where dull sounding I would say , without dynamic. I prefure the stock Marshall.
     
  2. Bob O'Donnell

    Bob O'Donnell New Member

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    Thanks for the info. Yes, I did a bit more research and discovered JJ Tubes are a brand and having recently pulled out all four of the different preamp tubes on the DSL4CR (in my effort to fix my lack of distortion on the Ultra Gain channel), I would say that the stock Marshall components certainly appear to be JJ Tubes.

    Interestingly, the tube on the far left side of the amp (when looking at it from the back) had red printing on it, while the one to the right of it had gold printing, then the remaining two on the right had red printing. Based on a quick glance at the TheTubeStore, these seem to be different variations of ECC83-S tubes that JJ Electronics makes. Do the two types have any kind of audible difference? Reviews on TheTubeStore site seemed a bit inconclusive.

    Also, this leads to another question that I asked earlier that I'm curious about it. Do each of the four tubes control the four different preamp settings (Clean/Crunch/OD1/OD2) individually or do each of those settings use combinations of those tubes? Also, I've seen references to tube locations like V1, V2, etc., but again, as a tube beginner I have no idea what that's referring to. So, is V1 the first on the left (again, looking at the back of the amp) and does it control the Clean channel, V2 the next one over and it covers Crunch and so on, or does it work differently?

    Would love to get a better understanding.

    Thanks.
     
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  3. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

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    The one closest to the instrument input is V1 left on the front, right looking in from the back, you have it correct.
    Sorry for the mixup I just edited my post
    Cheers
     
    Last edited: Nov 22, 2020
  4. Bob O'Donnell

    Bob O'Donnell New Member

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    Well, when then the amp is turned around, the instrument input is actually on the right, so I'm confused. Also, because that one on the far right (again when looking from behind the amp) is covered by the spring-loaded metal shield, was thinking it could actually be V1, but honestly don't know.
     
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  5. Jethro Rocker

    Jethro Rocker Well-Known Member Silver Supporting Member

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    Metal shield is V1. It controls some of the initial gain stages of the amp. I do not know the exact tube layoit of the 40CR. Likely V2 affects the higher gain stages and V3 can be effects loop, rectifier, eq..V4 or the last one in line always is the phase inverter tube which flips the signal over to correct the phase. It is technically part of the power amp.
    V1 will have the largest effect tonally by far. The PI tube can too of you run the volume really hot.
    Someone else will kmow the exact pirpose of each tu e.
     
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  6. Gene Ballzz

    Gene Ballzz Well-Known Member

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    @Bob O'Donnell

    First off, each of those 12AX7/ECC83 preamp tubes is actually two tubes in one glass bottle, sharing a heater filament as well as the bottle. The one closest to the large power tubes is the "phase inverter" which provides the necessary alternating phase signals to the power tubes for their push/pull operation and this tube is not specifically part of the preamp. That means that the other three preamp tubes are in fact six different tubes in the preamp, of which I believe at least one or two of them have functions that are shared by both channels. And yes, the preamp tube at the end of the amp closest to the input jack is usually referred to as V1. Some schematics for some amps may show the "V" numbers differently, however I don't think this amp would, but can't be absolutely certain, as no schematics are currently available yet for these amps! :pissed: :realmad:

    If you have not yet sent the amp back to SweetWater and are in the Used To Be United States, a call to U.S. Music Corp might be better. They are the stateside service center for Marshall and are pretty much on top of their game and quite courteous. Their turn around time is pretty good also. One benefit of having it repaired/serviced (following a detailed written/typed description of all perceived anomalies, provided with the shipped amp) they will not only repair it, but also test/check all of the amp better than was likely done prior to leaving the factory in Chinesiawanoreanam! Though I don't have the direct phone number, you should try to be in contact with Kevin Drury at US Music Corp and he will help you out. If you get Sweetwater to simply exchange the amp for another, you run the risk of getting one with the same or other anomalies as the one you currently have.

    Another possible benefit of sending the amp for warranty service, is that if you're good at playing their sympathy, you may convince them to comp you one of the hard to find, sought after vinyl "Marshall" slip covers for the amp, or at the very least a Marshall T-shirt! Especially if they take longer than they should. I got both the cover AND the T-shirt! :cool: :naughty:

    And as far as you having thrown away the shipping carton (I never do for this very reason), you may try contacting your local Guitar Center or Sam Ash, to see if they have a similarly sized or maybe even from the same model amp that you could acquire or maybe evn save for you over the ensuing few days. It may even be worth to ofer $10-$20 for them to help you out. On the other hand, SweetWater may be willing to ship you an empty DSL40CR box (with all its associated packing materials) to avoid the "full weight" extra shipping of you returning the amp for an exchange! The other pitfall, is that you don't even have the original box to get the amp back to SweetWater.

    Just My :2c: & Likely Worth A Whole Bunch Less!
    Gene
     
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  7. Jethro Rocker

    Jethro Rocker Well-Known Member Silver Supporting Member

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    Yes, one half of a tube circuit could have a different function from the other half. Like V2 can be a gain stage for half amd EQ section for half, etc. But the initial input gain is V1.
     
  8. SkyMonkey

    SkyMonkey Well-Known Member

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    Last edited: Nov 22, 2020
  9. Gene Ballzz

    Gene Ballzz Well-Known Member

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    @SkyMonkey
    Is there another page of that schematic?

    Also, given that you have access to that, might you also have access to the DSL20CR/HR? And might I suggest that with Marshall being so close lipped about their documents, you may want to share through private message/conversation, instead of publicly? We certainly don't want to see anyone (including you) getting into any kind of trouble. It would be a shame to lose you from this forum!

    Just My $.02,
    Gene
     
    Last edited: Nov 22, 2020
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  10. SkyMonkey

    SkyMonkey Well-Known Member

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  11. SkyMonkey

    SkyMonkey Well-Known Member

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    Cheers @Gene Ballzz.
    I've removed them from my post now.
    Those were originally posted nearly 2 years ago by @_ripper_
     
    Last edited: Nov 22, 2020
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  12. Gene Ballzz

    Gene Ballzz Well-Known Member

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    Yeah, it turns out I already had those (likely same source as you) and I have a couple pages of DSL20, but actually two missing for that amp. I'm wanting to discern if the PT is multi-tap for the different power settings or.......? It does appear that V1 has a DC power supply? Its a shame that Marshall are such "Secret Squirrels!" Now wait a minute, isn't that another loose term for monkeys that fly in the sky? :p :nutkick: :facepalm:

    Thanks,
    Gene
     
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  13. purpleplexi

    purpleplexi Well-Known Member

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    Could this not be a tube issue? Reason I ask is that when my 40CR stopped working on the full power setting a lot of explanations were offered. Turned out to be a dead tube. After I schlepped the thing all the way from southern Spain to Bletchley. But I'm not bitter. I would swap the preamp tubes one by one to see if it makes any difference. I might even do the same with the power tubes. If spares are not available just keep swapping them around and see what happens. Worth a try.
     
  14. Bob O'Donnell

    Bob O'Donnell New Member

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    Thanks all, really appreciate all the tube information...clearly a bit more complicated a story than I first presumed. The good news is that Sweetwater has agreed to send me a new DSL40CR with 2-day shipping and I can then use that box to send back my old one (and they pay for the shipping both ways). That way I'm never without an amp, which is great service in my mind, so thanks to the Sweetwater folks for that!

    As for calling MusicUSA/Marshall US, I actually did do that earlier in the week and based on the descriptions of the issues they thought it could be a preamp tube issue, which is what led me to request the tubes from Sweetwater. Interestingly, they sent me two Groove Tube 12AX7-C's which, based on TheTubeStore site are not JJ Electronics made (as the stock Marshall tubes from my first amp seemed to be), but come from Shuguang. In the end it didn't matter, unfortunately, because I tried replacing all four of the original tubes with the two Groove Tubes in various combinations (including at least one attempt to use both new Groove Tubes in place of the original Marshalls), but none of them fixed the issue and the Ultra Gain Channels remained distortion-less.

    So, figured I'd cut my losses and just get the new one. Given how many DSL40CRs are being sold (noticed it's currently the 6th most popular amp on the Sweetwater and 7th on Musician's Friend) I have to presume odds will work in my favor and I won't get a problematic unit this time around.

    Thanks again for all the info. Will report back on the results of the new one when it arrives.

    Bob
     
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  15. Kochens

    Kochens Member Silver Supporting Member

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    I figure they are Shuguang made
     

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