marshall 1987x hiss reduction possible?

[MarkusBass]

Everything depends how the amp is used. If you play dark sounding guitar (e.g. Les Paul) and the Volume pot is turned fully clockwise, you won't even notice the problem. But if you play with Stratocaser with new set of strings and the pot is in the middle position, you won't be able to play the amp. Similar amps use about 100pF as bright cap. 4.7nF used as the bright cap forms a high pass filter and the result is hiss as mentioned by the OP.

Mark

[J M Fahey]

5nF/5000pF is the correct cap value in 1987 .

It has been so forever.

Ok, ok, not "forever"

Will 1970 (or earlier) do?



Net effect is that amp set to "2" (on a Log/Audio pot, by the way ) is already distorting a lot, VERY loud, very piercing, cutting through the stage ball of mud like a sharp knife, even when playing "clean" .

Do not think about it like a modern bedroom rocker, think like a 1970 successful Rock band, playing horrible acoustics cavernous halls, NO PA .

Closest thing available was horrible, muddy, always distorting 100W "voice amps" with 4 channels, driving 4x12" columns loaded with guitar speakers.

By the way, I see much worry about the "bright" cap, yet nobody even mentions the tight bass cutting coupling cap.

Yup, .0022uF/2n2 ..... and it's not a typo either .

Net effect is that when channel volume is set to 10, negating effect of bright cap , now .0022 coupling cap sees a load of 500k (1M volume pot in parallel with 470k+470k) cutting everything below 145 Hz ... plus first triode bass cutting cathode cap: .68uF//2k7=87Hz ... plus tone stack driver cathode RC .68uF//820r cutting below 285Hz plus mixing net 500pF/470K rising 6db everything above 680Hz (or cutting by 6dB everything below that frequency, same thing) plus presence control rising everything above 5k//.1uF 318Hz .

Are those errors or typos?

I think it would be a gross disrespect to find "mistakes" in the most successful distorting amp of all times, where clearly every step in that road pointed to the same objective.

Rather than chance, I believe in a hard effort of redesign and tweaking, tested live every weekend so as to quickly confirm or discard new mods.

As of the amp on 2 being unbearable with a Strat with new strings, it would definitely be if used so, no disagreement on that ... but if a Strat was used it was probably on 10, because it had weak single coil pickups.

There must have been a reason for everybody using Humbuckers (tons of LP and a few SG) with a few distinguished exceptions.

I find very funny (and misguided) Forum discussions (not here, thanks God) agonizing in 15 page long threads about capacitor brand or colours, tube brands, even whether front panel being plastic or metal is "the Secret", while what actually influences sound is design and parts value.

Back to OP: hiss? ..... what hiss?

Just get onstage, dime everything, play 1 (one) song with your similarly equipped buddies, a loud drummer, then answer

By the way, those hard hit cymbals 3 ft away , strategically placed at ear level, will do wonders to mask it .

[g1]

Back to OP: hiss? ..... what hiss?

Just get onstage, dime everything, play 1 (one) song with your similarly equipped buddies, a loud drummer, then answer

Amen to that, brother! If you're a Marshall player, and your ears can still hear hiss, you are not playing loud enough .