liver pool hiss prob

[harris51]

with a guitar plugged in or not.just barely cracked I would say 1/2 it sounds like my amp is going to explode (hiss) and take out a small village , it sounds scary

[geetarpicker]

It is a little hard to describe what normal hiss levels are. Still I've owned many vintage 4 input Marshalls. In my experience if I compared a liverpool/express side by side with the old marshalls the trainwrecks actually had less noise. That comparison being with the amps set for similar gain levels, the marshall being with all or most of the knobs dimed and the wreck with everything on about half. Yes the wreck would be noisier if set for even higher gain but only then.

Still pot values in a wreck clone may greatly effect where the knobs actually fall. Is there a possibility you have linear taper 1megs in your wreck?

Still to say this again I find a wreck to actually be quiter than a vintage marshall when set to similar gain/distortion levels. I also find that if I try to simulate the gain of a wreck with most pedals (into a clean amp for comparison) the Trainwrecks will also still have lower noise when set for similar gain.

[harris51]

I have the 53c3 1meg rv4naysd 105a clarostat are you saying I don't want the linear 1 meg right? I couldnt get the gain above 1 before the amp goes crazy hiss loud couldnt use it on stage that's for sure

[martin manning]

That part number corresponds to linear taper- you definitely don't want that. Volume pots are always log or "audio" taper. A 10% audio pot will be on "5" when it matches your linear taper pot on "1."

[Cliff Schecht]

Being a student means I'm perpetually broke and always salvaging stuff to save money. I've got a big stash of AB pots in most values but it seems most of them are linear taper. I usually don't care so much in my personal amps but the Rocket I sold my buddy has the wrong tapered pots for the volume, treble control and PPIMV and it's very touchy on those knobs. Once you get used to this it's not such a big deal but it can be annoying at times.

I was used to this before building amps from building dozens of effects with the wrong tapered pots. Tubescreamer builds are infamous for this because the pot should be a reverse taper 20k or something weird and most people try a linear or log 25k. Makes it really touchy and hard to find that sweet spot.

What I've started doing when I use the wrong taper is leaving the knobs off. It seems like when I do this they are less likely to get kicked out of their sweet spot (or in the case of an amp bumped out of position while moving). Also I usually mark (and take a picture) where I want everything set to make things easier to setup for shows. I like to be the one guy in the band whose stuff works every time I plug it in so I can help others get going quicker as well.

[harris51]

Thanks Glen I just ordered an Audio taper that should do it

[geetarpicker]

Better get analog taper pots in ALL three 1meg positions. A linear in the treble position will both make the amp bright and more gainy with the knob barely turned.

[harris51]

Hey Glen my layout only shows (2) 1meg pots, gain and treble does that sound right?

[geetarpicker]

x3 1 meg pots!

Volume, Treble, and bass all 1 meg audio taper and a slow rising audio taper at that. Like I mentioned, they only read 100k at 1/2 way up.

[martin manning]

The Liverpool doc's posted here show a 250k linear bass pot, where it's 1MA in the Express. Is there some question about that?

[Mark]

I had a photo somewhere of the insides of a Liverpool and I'm 99% sure it is 1M ohm instead of 250K.

All that said and done. I don't think most people would really notice the difference between 1M and 250K, it isn't a linear change in tone.

As far as the hiss goes, check your input jack, I've encountered new jacks with very poor switch/shorting connectors/lugs in them. The give away is the amp is quieter if you plug your guitar in and turn the volume all the way down.

The other issue is the shielded cable. Have you tried shielded cable on the wiper of the volume pot to second triode?

Ken did run this wire along the chassis, but the wiper is extremely sensitive to noise. In the Funk Liverpool amp, there is shielded cable from the wiper of the volume pot to the second triode. However the shield is connected to the plate.

[harris51]

just curios why wouldn't you use all audio taper pots?

[Mark]

I used all audio taper pots, and my findings are the same as Glenn's remark regarding a 10% taper on the volume pot being more desireable.

I accidental put a linear pot in as a bass pot and I didn't like the way it reacted, it didn't sound right when I was adjusting the pot.

[funkmeblue]

that's funny mark, I had a 1 meg audio for the bass and then noticed your schematic that had 250k audio and changed it. Seemed more right to me with everything on noon and has been there since

[harris51]

so what Im hearing is (3) 1 meg audio pots gain, treble, Bass and the rest audio or does it matter if there linear?