Liverpool treble cap differences
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- Ledvedder5150
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Liverpool treble cap differences
I'm noticing different treble cap values used on some different schematics. Some show 47pF, which is what my build currently has. Others show a 500pF cap. Does this make a dramatic difference?
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- Reeltarded
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Re: Liverpool treble cap differences
YES
The treble cap moves the midband down the larger it is, leaving the 1kHz dip wider with a smaller treble cap and very steep and narrow by comparison with a 500p. I can't imagine any control on the amp doing much with a 500p treble cap.
I turn mids.. amp maxed.. treble.. amp maxed.. bass is an off switch at the bottom and there isn't a clean sound with volume above .3!
47p is somewhat balanced to my ears. The treble authority is in control.
The treble cap moves the midband down the larger it is, leaving the 1kHz dip wider with a smaller treble cap and very steep and narrow by comparison with a 500p. I can't imagine any control on the amp doing much with a 500p treble cap.
I turn mids.. amp maxed.. treble.. amp maxed.. bass is an off switch at the bottom and there isn't a clean sound with volume above .3!
47p is somewhat balanced to my ears. The treble authority is in control.
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Re: Liverpool treble cap differences
Be careful when comparing schematics, the 50pf cap works with the 1M treble control (classic Vox values). the 500pf cap is often used with a 250k pot. So you might not be comparing apples with apples.
For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or may not like. I would try a 100p or put another 50pf on a switch in parallel to see if you like it.
On the liverpool amp though I do think the 2.2nf coupling cap feeding the 68k grid leak gives a fixed treble and high mid boost so that you don't need to boost the high mids in the tone stack. happy for you to prove me wrong!
For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or may not like. I would try a 100p or put another 50pf on a switch in parallel to see if you like it.
On the liverpool amp though I do think the 2.2nf coupling cap feeding the 68k grid leak gives a fixed treble and high mid boost so that you don't need to boost the high mids in the tone stack. happy for you to prove me wrong!
- Ledvedder5150
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Re: Liverpool treble cap differences
Yep, I realized that after looking at the pot values! It's obviously the sum of all parts. But that makes me wonder why a 1M was used in the Liverpool, but a 250k was used in the Express. I wonder if it was just the Vox vs Marshall origins of both circuits?guitarmike2107 wrote: ↑Mon Jan 30, 2023 4:00 pm Be careful when comparing schematics, the 50pf cap works with the 1M treble control (classic Vox values). the 500pf cap is often used with a 250k pot. So you might not be comparing apples with apples.
For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or may not like. I would try a 100p or put another 50pf on a switch in parallel to see if you like it.
On the liverpool amp though I do think the 2.2nf coupling cap feeding the 68k grid leak gives a fixed treble and high mid boost so that you don't need to boost the high mids in the tone stack. happy for you to prove me wrong!
Check out my band: https://www.facebook.com/ungluedband
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Re: Liverpool treble cap differences
Could be, I was surprised about it when putting the kit together. I am sure Ken had his reasons
If you haven't already, you should download the tone stack calculator and plug in the values to get an idea how cap changes affect the tone stack.
If you haven't already, you should download the tone stack calculator and plug in the values to get an idea how cap changes affect the tone stack.
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Re: Liverpool treble cap differences
250k pot with 47p will put you at the end of rotation trying to get more. 1M and 500p you would be asking how to cut highs after hitting 1 on the dial.Ledvedder5150 wrote: ↑Mon Jan 30, 2023 4:34 pmYep, I realized that after looking at the pot values! It's obviously the sum of all parts. But that makes me wonder why a 1M was used in the Liverpool, but a 250k was used in the Express. I wonder if it was just the Vox vs Marshall origins of both circuits?guitarmike2107 wrote: ↑Mon Jan 30, 2023 4:00 pm Be careful when comparing schematics, the 50pf cap works with the 1M treble control (classic Vox values). the 500pf cap is often used with a 250k pot. So you might not be comparing apples with apples.
For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or may not like. I would try a 100p or put another 50pf on a switch in parallel to see if you like it.
On the liverpool amp though I do think the 2.2nf coupling cap feeding the 68k grid leak gives a fixed treble and high mid boost so that you don't need to boost the high mids in the tone stack. happy for you to prove me wrong!
Liverpool is lacking headroom for control changes to affect much with volume up anyhow. It's all 84 by the time it's driven. Wrrrrrrrrr
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
Re: Liverpool treble cap differences
It makes a huge difference. Ken Fischer has built a Liverpool with the 500pF. 50pF (47pF) is typical, the 50pF sounds smoother, the 500pF (470pF) sounds fatter.Ledvedder5150 wrote: ↑Sun Jan 29, 2023 7:17 am I'm noticing different treble cap values used on some different schematics. Some show 47pF, which is what my build currently has. Others show a 500pF cap. Does this make a dramatic difference?
Yours Sincerely
Mark Abbott
Mark Abbott
Re: Liverpool treble cap differences
The Liverpool and the Express both use 1M pots, the Komet amp uses 250K pots.Ledvedder5150 wrote: ↑Mon Jan 30, 2023 4:34 pmYep, I realized that after looking at the pot values! It's obviously the sum of all parts. But that makes me wonder why a 1M was used in the Liverpool, but a 250k was used in the Express. I wonder if it was just the Vox vs Marshall origins of both circuits?guitarmike2107 wrote: ↑Mon Jan 30, 2023 4:00 pm Be careful when comparing schematics, the 50pf cap works with the 1M treble control (classic Vox values). the 500pf cap is often used with a 250k pot. So you might not be comparing apples with apples.
For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or may not like. I would try a 100p or put another 50pf on a switch in parallel to see if you like it.
On the liverpool amp though I do think the 2.2nf coupling cap feeding the 68k grid leak gives a fixed treble and high mid boost so that you don't need to boost the high mids in the tone stack. happy for you to prove me wrong!
Use 0.0047uF instead of 0.0022uF it sounds better.
Yours Sincerely
Mark Abbott
Mark Abbott
- Ledvedder5150
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Re: Liverpool treble cap differences
For me, it's already bassy enough with the 2n2 cap.Mark wrote: ↑Fri Feb 03, 2023 7:58 amThe Liverpool and the Express both use 1M pots, the Komet amp uses 250K pots.Ledvedder5150 wrote: ↑Mon Jan 30, 2023 4:34 pmYep, I realized that after looking at the pot values! It's obviously the sum of all parts. But that makes me wonder why a 1M was used in the Liverpool, but a 250k was used in the Express. I wonder if it was just the Vox vs Marshall origins of both circuits?guitarmike2107 wrote: ↑Mon Jan 30, 2023 4:00 pm Be careful when comparing schematics, the 50pf cap works with the 1M treble control (classic Vox values). the 500pf cap is often used with a 250k pot. So you might not be comparing apples with apples.
For treble caps, doubling the cap value gives an obvious change in hi mid response that you may or may not like. I would try a 100p or put another 50pf on a switch in parallel to see if you like it.
On the liverpool amp though I do think the 2.2nf coupling cap feeding the 68k grid leak gives a fixed treble and high mid boost so that you don't need to boost the high mids in the tone stack. happy for you to prove me wrong!
Use 0.0047uF instead of 0.0022uF it sounds better.
Check out my band: https://www.facebook.com/ungluedband
Re: Liverpool treble cap differences
What cab and speakers are you using?Ledvedder5150 wrote: ↑Fri Feb 03, 2023 6:40 pmFor me, it's already bassy enough with the 2n2 cap.Mark wrote: ↑Fri Feb 03, 2023 7:58 amThe Liverpool and the Express both use 1M pots, the Komet amp uses 250K pots.Ledvedder5150 wrote: ↑Mon Jan 30, 2023 4:34 pm
Yep, I realized that after looking at the pot values! It's obviously the sum of all parts. But that makes me wonder why a 1M was used in the Liverpool, but a 250k was used in the Express. I wonder if it was just the Vox vs Marshall origins of both circuits?
Use 0.0047uF instead of 0.0022uF it sounds better.
I haven’t had issues with the amp having too much bass.
Yours Sincerely
Mark Abbott
Mark Abbott
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Re: Liverpool treble cap differences
A Suhr 2x12 with greenbacks.Mark wrote: ↑Sun Feb 05, 2023 3:05 amWhat cab and speakers are you using?
I haven’t had issues with the amp having too much bass.
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Re: Liverpool treble cap differences
Looking at Suhr’s range of 2 X 12” cabs, there are two that are open backed and two that are closed back. I assume you have the closed back cab.Ledvedder5150 wrote: ↑Mon Feb 06, 2023 1:00 amA Suhr 2x12 with greenbacks.
Yours Sincerely
Mark Abbott
Mark Abbott
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Re: Liverpool treble cap differences
Yes sir! PT15-212, https://www.suhr.com/electronics/amplifiers/pt15-2x12/Mark wrote: ↑Mon Feb 06, 2023 7:01 amLooking at Suhr’s range of 2 X 12” cabs, there are two that are open backed and two that are closed back. I assume you have the closed back cab.
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