Bringing the 1974x closer to the 1974

junior marbles

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What would it take to improve the sound of the reissue? And it definitely needs improvement. Just listen to the comparison:

I have some ideas but invite others to speculate.

1. "Pre-aged" Greenback I call BS. I have originals from the 1960s and will replace the reissue speaker

2. Eastern European/Russian/Chinese tubes. Junk, all of them. No subtleties, no 3-D, no musicality. I will replace all of them with NOS GEC EL84 and NOS Mullard ECC83.

But that's all I can think of at the moment. I realize I will be stuck with recreations of the output transformer and current-production wiring and passive components.
Anything else?
 

anitoli

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Comparing an amp made in the 60's/70's ( not knowing what may have been done to it either) to a new production unit is pissing in the wind. Just the fact that even if the component values are identical manufacturing tech has improved ten fold. They won't sound identical.
 

neikeel

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I built one using NOS parts to original spec. Only new manufacture parts were the chassis and cab. Speakers are pulsonic T1220s.
The sound is nailed exactly.
I have EL84 Hex-plates in mine with mixed BVA ECC83s and Mullard EZ81.
I’ve built x4 different 18w and the magic ingredient for smooth and complex tones are the RS EL84 OT. Coupling caps are to taste but mustards are smoother and ceramic discs add a bit of bite. Just my opinion, loathe to shout too loud as people are selling these OTs for silly money now, out of my price bracket!!
 

stickyfinger

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RadioSpare's output transformer have been going for about 300-500$ at auction I've seen in the last year and would be a great addition.

Do beware of SteveUKs RS reproduction output transformer's being sold as original NOS units from scam sellers on Ebay/Reverb. To the untrained eye they look identical but really are not that close if you know what to look for. Watch out for a seller from Connecticut and San Rafael, California, also a MF member.
Here's Steve UKs repo being sold as a real one.
Radiospares EL84 Output Transformer Fits Marshall 18W Model 2061 & 1974 | Kwik-E-Mart | Reverb
 

jcm800gridlock

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The EC grill cloth is a big part of the tone. Will run you about 250$ USD.
I watched that video some time ago, to may ears, the vintage amp sounded warmer, smoother, and much better than the Reissue. Vintage speakers and maybe the rubbery-vintage grill cloth material contributed to the sound difference.

I put EC grill cloth on my 1962HW and the cloth added even more bass to my already bass-heavy Bluesbreaker (I like amps with plenty of low-end).

I was very tempted to buy more EC grill cloth for my last 1974x (owned two 1974x’s and a 1973x) to help add bass.

After too amp purchases and many dollars spent, it is my opinion that these 18 watt, EL84 powered amps lack low-end bass.

I did find that if I used a 7-band EQ in front of my 1974x, the EQ would add bass and fullness to my amp’s tone, especially at lower volumes.

I sold my last 1974x and swore that I would write-off buying another EL84 amp. Still, I love the look, size, and wattage of a 1974x. Maybe another 1974x someday and this time with Eric Collin’s grill cloth.
 
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Pete Farrington

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Valves have a flat response from DC to MHz.

The freq response of an amp is due to the circuitry around the valves, not the valves themselves.

Little OTs, with a low mag flux capability mag circuit, and low primary inductance, can’t put out high power at low freq.

The lack of deep bass aint the fault of the EL84, or at least that’s the case within the linear range. Of course heavily overdriven is a different matter, beam pentodes seem to hold a solid bass better than suppressor grid pentodes.
 
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Matthews Guitars

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Pete, thanks for saying that. You are correct. A 6L6 tube, for example, was designed to operate as a transmitter tube up to about 30 MHz. If swapping from one brand or type of 6L6 to another has any noticeable effect on the frequency response, it's not the tube at fault, it's just how its parameter variations interact with the rest of the amplifier's circuit, which is NOT designed for a broadband flat frequency response.

The same holds true for every tube type commonly found in guitar amplifiers.
 
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Pete Farrington

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If swapping from one brand or type of 6L6 to another has any noticeable effect on the frequency response
Has a quantifiable difference in the audio range ever been measured?
I’ve not checked a functional output valve that made a measurable difference to an amp’s freq response.
Of course different manufacture can sound a bit different, but I think that may be due to differences in their ‘beyond linear range’ characteristics. eg the particular curve of the forward biased g1-k diode’s ‘knee‘.
 

Matthews Guitars

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Every tube has certain measurable inductance, capacitance, and resistance characteristics, and thus must have SOME filtering effect, particularly when part of an audio circuit that is itself a filter. Since different tube construction variables will alter the RLC values, it does make sense that different tubes can alter the system frequency response to some degree.
 

Pete Farrington

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Since different tube construction variables will alter the RLC values, it does make sense that different tubes can alter the system frequency response to some degree.
Indeed, but my experience is that whilst they’ll affect usage in RF applications, in the context of a guitar amp, they’re negligible. If a difference can be measured within the audio range, it’s a fraction of a dB.
Differences in other stuff, eg speaker choice, guitar cable, perhaps grille material, will dwarf them.
 

mickeydg5

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I liked the 1974X best.

That was not a good comparison at all. This topic has been brought up before. You can have two amplifiers from the same run set the same and sound different. Two amplifiers with decades between will have a definite difference. They should have tried to dial each in to sound the same or as close as possible and then play.
 

neikeel

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Here's one quite like mine, if you plug it into a G12H 4x12 you make the most of the lows too, Tommy's recording struggles a bit but you get the idea?:

 

junior marbles

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I will find out soon whether installing an original Sixties Celestion Greenback and Mullard, GEC or Amperex NOS tubes will bring my reissue 1974x closer to "THAT" sound,

But if an original OT is so crucial for tone, and if fakery has progressed to the point that I need a deep Marshall authority to sniff out a fake, how would I go about this?

As to a tube's impact on the sound of a guitar amp: To me, it's never been about frequency response or other easily statically measurable parameters, it's how complex waveforms are processed, the analysis of which defies our relatively primitive level of quantification of sound phenomena.

My ears have yet to find a single currently-made good-sounding fake Mullard, fake Tung-Sol, fake you name it tube brand acquired by New Sensor and appropriated by using the original logos and names, then cheaply copied in Russian factories without changing the construction back to that of the originals.

Tubes constructed in such cost-cutting fashion, with cheap, insufficient cathode doping, missing or primitive Mica spacers, etc, etc. cannot possibly perform or sound the same as tubes before the mid 1970s whose economy of scale (millions) allowed for superior construction and performance without breaking the bank.

But no one forces anyone to buy tubes that predate the current cost-cutting era, if the difference is not appreciated and paid for.
 
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Slammintone

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I wouldn’t get to hung up on the “that” sound the 1974x is being compared to. My own 1974x sounds excellent. It is stock except for the tubes. I’m running an Amperex EZ81, black plate Sylvania EL84s, and a mix of Marshall, JJ and RFT ECC83s. It’s a bit bass shy up to about three, and the bass slowly but surely kicks in quite nicely between 4-8.

My Mojotone 1974TMB combo amp has bass to burn with its Celestion G12M 25 watt speaker. Even the normal channel has more heft in the low end at lower volume than the 1974x but cranking both amps gives a full and satisfying low end fullness in either. The mid crunch is killer with these amps. I especially love how the lead tone on the bridge pickups fatten and darken somewhat. It’s heaven!
 

Spanngitter

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I built a few 18W, normal (Tremolo) ones as well as TMB Version And even 18W 1959SLP. What worked and sounded for me the best is a TMB build with an IGPW Transformer Set, NOS ERO MKTs, CF Resistors and a complete Set of NOS Brimar Valves. It’s followed by my daily practice amp, a build with Classic Tone Iron, Vishay MKTs and TungSol RI valves. Both of them feed either a 2x12 or a 4x12 loaded with Tayden True Brits (too bad they make them anymore)….
Both love to be turned up but not to Spinal Tap Settings, depending on Venue and Set they are somewhere between 4 and 8 (I prefer the higher settings, FOH doesn’t)
 


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