1974x low end (none compared to C5 through 1974cx)

[jonnymags]

I usually rehearse with a Class 5 due to cupboard sized rehearsal space. Recently did a gig with my 1974x and on a song which required my guitar playing a bass part and having low end... well there wasn't any - we abandoned the song as it just sounded odd!

So I A/B'd my 1974x against my Class 5 through my 1974cx cabinet last night and the Class 5 + 1974cx has more low end punch and more of a 'marshally' midrange than the 1974x. I wasn't expecting that. (On it's own the Class 5 can't compare to the 1974x).

So the low end in the 1974x is not due to the speaker.

Tonally the 1974x was slightly (very slightly cork sniffing here) more complex and chimey in the treble - but only by jumping the channels. And actually less Marshally. In a gig situation I think the C5+1974x would cut through more (if it could be heard). If it helps I play on edge of clean and use fuzz.

a) How do I increase the low end in the 1974x (at the amp, not by adding eq pedal if preferable).
or b) How do I get that Class 5 tone but louder - is it based on a JTM/superlead at all? I used to have a JCM800 1987 that I sold for pennies as it weighed a ton and I was never allowed to have it above 0.5 on the vol! It reminded me a bit of that...

Thanks in advance! J

[Road King Police]

Hi Jonnymags,

I owned the 1974x. Wish I still had it, like so many others, yet, I had some issues with it that I might have been able to solve today. That said, I thought it's tone was wonderfully complex and very much had a 'Vox' vibe with Marshall thrown in for good measure. Love, love, loved the tremolo. I went and got the 1974cx to complete that rig. Yet, I let it go. I remember bottom end being an issue, but that's always been an issue for me. To answer to the Class 5 question, I see no cheap way of getting it's signal to your 1974x, unless you simply try the headphone out in to one of your x's inputs and see what you get. I don't know the schematic of the Class 5 and whether or not you could go the rout of an FX send or not.

When I owned the 1974x, 2061x as well, I was doing a praise and worship gig. For those gigs, both amps were too much to get the good out of them. Most other situations would be the opposite. But you've already been through that with your JCM800. So...on it goes. One thing I did not like with the 1974x, that I don't like on any amp, is it got hissy with pedals. It's why I dig my JMD and then got another.

I know it's expensive, but my advice is...don't get rid of that 1974x. It's beautifully simple and complex, and that EL84 set up with 112AX7 tremolo is divine. And that plexi combo look is to die for, IMO.

[jonnymags]

Thanks for the response RKP. Yeah, volume wise with a band the 18 watt is perfect for me. But I've noticed too that it doesn't take pedals well. There always seems to be something not quite... thick? enough.

What I need is a mod suggestion that increases bass (a proper mod, that shows on a freq chart! not cork sniffery) that i can ask my tech to do. As an aside my tech recently fixed a problem with my 1974x that caused the amp to drop all volume if the channels were jumped. It was dodgy resistors (I'm no techy but it was something electronic!) on the input of the tremolo channel. He said it was the worst soldering and wiring he'd seen in years (and this is coming from someone who owns many back in the day marshalls). No idea if it left the factory like that or the previous owner had been fixing with spanners... having said that I've seen a few others posting the same problem on various boards.

[Road King Police]

I would first try running through a different cabinet if there's one around, see what kind of tone another cabinet gives you, one that you know has some bottom chunk to it. Go from there. Obviously some clean eq in the front end, or even between jumping channels is an option, inherent pedal acceptance issue aside.

You'll have to go straight to a horses mouth on any internal mods, I believe. A tech has to have a handle on that going in. Where are you?

[jonnymags]

Cheers RKP. However I don't think it's the cab as the C5 delivers tons of bass - it's got to be the circuit. To be fair to the 1974x I think I should give some context to how I'm playing. When I've played the 1974x in a typical band with a bass player, using humbuckers with the amp cranked and riding the guitar's volumes (i.e. no pedal problems), there's no issue with lack of bass. It's tight, in the pocket, not fighting for frequencies. It does its thing exactly as it should, superbly... However, playing in a two piece black keys style (or in our case drums and two guitarists) then something needs bottom. Most amps, e.g. including the C5 offer that low end. Perhaps I'm trying to drive the 1974x on the wrong track!

[Road King Police]

Hey Jonny, I'd probably agree with that last statement. Gotta have the right tools for the job.

[mickeydg5]

Hey Johnny
Ask your technician to increase some coupling capacitor values like C2 and C16 to revoice for more lower frequency.
Also that TONE control VR1 on the NORMAL channel looks just a mess; I mean it does more harm than good. That design is removing most of the lower frequencies.
Have your technician rewire the TONE control. You can remove R27 100k connection from that one side of VR1 and connect it to the other side with the C14 10nF capacitor. That will help if it is wired as in the 1974X schematic.

If having a model 1974X and wished to modifiy it for more bass response I would connect that R27 to the C14 side of VR1, swap C15 with C16 and then increase C2 to 22nF.
That would probably do it.

[jonnymags]

Thanks Mickey. I'll pass on the info to my tech and see if it makes sense to him. If I can improve bass response without ruining the amp I may well go for some mods. If I go ahead I'll post back to let you know what happens!

[mickeydg5]

I do not know that those should even be called "mods".

[michael_dba]

I do not know that those should even be called "mods".

Hey mickeydg5 is part of that mod similar to changing the PI caps to .1 from .22?

[mickeydg5]

I do not know that those should even be called "mods".

Hey mickeydg5 is part of that mod similar to changing the PI caps to .1 from .22?

I am not familiar with other's modifications but there is only one .022uF coupling capacitor at the PI of the 1974X. I would not decrease it if desiring to retain lower frequencies. The other three coupler capacitors at the PI are .01uF. I did mention increasing one of those at the input from .01uf to .022uF, at C2.

Now following in the predecessor's footsteps, including the 20 watters, the Lead and Tremolo units used some smaller values while the PA and Bass used the larger values. This would be as in the case of the PI output coupler capacitors with the smaller being .01uF and the larger being .022uF.

Larger capacitors pass lower frequencies.

[michael_dba]

Now following in the predecessor's footsteps, including the 20 watters, the Lead and Tremolo units used some smaller values while the PA and Bass used the larger values. This would be as in the case of the PI output coupler capacitors with the smaller being .01uF and the larger being .022uF.

Larger capacitors pass lower frequencies.

You got it, I messed up, meant changing PI cap(s) from .1 to .022, not .2 Huge difference in bass response! I'm slowly learning this stuff.

"The more I learn, the more I realize how little I really know"