treble and bass pot values in express clones
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treble and bass pot values in express clones
hello there, i guess this is old material to most, but is everyone using 1MA pots for the treb. and bass controls? are some using 1ma for bass and 250kb for treb. (ala marshall) or maybe 250ka for both? just curious because i can't remember if the francesca amp's pot values were documented. thanks very much. rh
Re: treble and bass pot values in express clones
hello there, 50 views and no responses? i thought surely a couple of you frequent responders/builders would give just a short reply to a simple question of fact like this, since everyone's built amps lately. no love for the pvc612 provider, eh? rh
Re: treble and bass pot values in express clones
I used 1M for Bass and Treble, 25k for Mid, 5k for Presence, and 1M for vol. Now about those 612's. Got any left? 
Re: treble and bass pot values in express clones
RHrhinson wrote:hello there, 50 views and no responses? i thought surely a couple of you frequent responders/builders would give just a short reply to a simple question of fact like this, since everyone's built amps lately. no love for the pvc612 provider, eh? rh
It would seem that the schematics are all over the place on what was used. The two I built were like Jeph said, 1meg Treble and Bass and a 25k mid, 5k presence. The liverpool I'm building will have a 250k for bass per the schematic.
Dana
Re: treble and bass pot values in express clones
Hello
I'm new here, and I heaven't build a wreck yet but I tried the tone control when I was comparing a bunch of them to see the difference.
I you use 250k for bass and treble with 25k for the mid you get the mid point around 400Hz (roughly).
On the other hand if you use 1MEG bor bass and treble the mid point will be around 200Hz.
The first sounds better to me, (not on wreck though, but on Hiwatt clone, which I used for that test).
Actually only the value of treble pot affects that mid point shift, so keeping the treble at 250k seems right to me.
The value of the bass pot affects only the bass response, and if you use 1MEG you will get more bass on middle setting, than you would get with 220k.
My choice would be 250k for treble, 1MEG for bass, and 25k for mid.
I hope this helps
I'm new here, and I heaven't build a wreck yet but I tried the tone control when I was comparing a bunch of them to see the difference.
I you use 250k for bass and treble with 25k for the mid you get the mid point around 400Hz (roughly).
On the other hand if you use 1MEG bor bass and treble the mid point will be around 200Hz.
The first sounds better to me, (not on wreck though, but on Hiwatt clone, which I used for that test).
Actually only the value of treble pot affects that mid point shift, so keeping the treble at 250k seems right to me.
The value of the bass pot affects only the bass response, and if you use 1MEG you will get more bass on middle setting, than you would get with 220k.
My choice would be 250k for treble, 1MEG for bass, and 25k for mid.
I hope this helps
Re: treble and bass pot values in express clones
I like to use spice better, and then frequency analyzer to confirm it. Much easier when you get the hang of ot (i mean spice).
Here is a simple graph to show you what I meant. The three versions simulated using spice (checked).
The green line is what i liked the best out of three mentioned.
Here is a simple graph to show you what I meant. The three versions simulated using spice (checked).
The green line is what i liked the best out of three mentioned.
You do not have the required permissions to view the files attached to this post.
Re: treble and bass pot values in express clones
Which spice modeler do you use? I've started back up using Tina.
Re: treble and bass pot values in express clones
hello there, how many of you guys out there that have built clones using 1meg audio pots for the treb. control ever find it useful to turn it up much past halfway? a 1meg audio (standard 10%taper) and a 250k lin. pot will be about the same at their halfway rotation point. the reason i ask is because it's very difficult to solder/unsolder/remove/test if you build a cosmetically identical clone with respect to the buss wire on the backs of the pots. i guess i could snip the buss right at the treb. pot before i solder everything up and that way i could unsolder/bend it back to try either the 250kb or the 1ma. just a pain though. anyway i guess most are using 1ma for the treb. pot, correct? rh
Re: treble and bass pot values in express clones
I use LTSpice/SWCad which is free, and after some time getting used to it and tweaking I got it working just the way I need it. With tube models from duncan and koren it's very useful tool.
And I am strongly convinced that 250k (linear) for treble is the way to go (with the circuit pictured on standard schematic). The midpoint of 200Hz is way to low IMHO. That's just my expirinced guess. When you look at any other guitar amp tone stack, you will see that the midpoint is betwean 400Hz and 800Hz. I know wrecks are unique design, but not nececerly in every way.
It's not the value on the wippers mid setting of the pot that it is important, it is the total resistance of the pot . So you could use 250k log or lin, and that would only affect the response of the control but not the midpoint itself.
Correct me if I'm wrong
And I am strongly convinced that 250k (linear) for treble is the way to go (with the circuit pictured on standard schematic). The midpoint of 200Hz is way to low IMHO. That's just my expirinced guess. When you look at any other guitar amp tone stack, you will see that the midpoint is betwean 400Hz and 800Hz. I know wrecks are unique design, but not nececerly in every way.
It's not the value on the wippers mid setting of the pot that it is important, it is the total resistance of the pot . So you could use 250k log or lin, and that would only affect the response of the control but not the midpoint itself.
Correct me if I'm wrong
Re: treble and bass pot values in express clones
Anyone tried a 1meg treble and a 250k bass
Re: treble and bass pot values in express clones
Dear Dana
I have experimented with 250K for bass and treble. 1 meg treble and 250K bass, and of course 1 meg for bass and treble.
To my ears the 1 meg treble pot versus the 250K offered the most noticeable change in tone. I found the 1 meg pot to give the amp a chimier sound, and I found that desireable.
Regarding 250K versus 1M, I found it all much as muchness. I initial started off with a 250K linear pot which was a disaster. The log pot was a must.
Getting back to the point I found that the 1M bass pot seemed to give the same amount of bass as the 250K pot. By that I mean the 250K pot gave an increase in bass response over it's whole travel, while the 1M pot seemed to stop increasing bass response towards the end its travel.
I did experiment with this in 2003/2004 and used parts I had on hand, so I recommend trying this experiment out for yourself.
I could be wrong, or perhaps I wrote the wrong thing on my circuit diagram, but I seem to recall that the bass pot in the Liverpool was suppose to be 1M too. As I have previously mentioned, I don't think it is a big deal though.
Regarding 1M volume pots, I experimented with different brands of pots in an effort to find one which had the lowest resistance when the volume control was set to the mid position. My train of thought was that no sane person would be using the amp flat out, in fact I don't find the volume control all that useful after 3 o'clock. Thus a volume control with a more extreme log taper gives me more area over the volume pot to play with. If one is to use the bright caps I think this is relevant.
I hope this helps.
I have experimented with 250K for bass and treble. 1 meg treble and 250K bass, and of course 1 meg for bass and treble.
To my ears the 1 meg treble pot versus the 250K offered the most noticeable change in tone. I found the 1 meg pot to give the amp a chimier sound, and I found that desireable.
Regarding 250K versus 1M, I found it all much as muchness. I initial started off with a 250K linear pot which was a disaster. The log pot was a must.
Getting back to the point I found that the 1M bass pot seemed to give the same amount of bass as the 250K pot. By that I mean the 250K pot gave an increase in bass response over it's whole travel, while the 1M pot seemed to stop increasing bass response towards the end its travel.
I did experiment with this in 2003/2004 and used parts I had on hand, so I recommend trying this experiment out for yourself.
I could be wrong, or perhaps I wrote the wrong thing on my circuit diagram, but I seem to recall that the bass pot in the Liverpool was suppose to be 1M too. As I have previously mentioned, I don't think it is a big deal though.
Regarding 1M volume pots, I experimented with different brands of pots in an effort to find one which had the lowest resistance when the volume control was set to the mid position. My train of thought was that no sane person would be using the amp flat out, in fact I don't find the volume control all that useful after 3 o'clock. Thus a volume control with a more extreme log taper gives me more area over the volume pot to play with. If one is to use the bright caps I think this is relevant.
I hope this helps.
Yours Sincerely
Mark Abbott
Mark Abbott