Anyone doing Larry heater CT at input grounding?
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azatplayer
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- Joined: Thu Feb 26, 2009 7:59 pm
- Location: Great Southland
Anyone doing Larry heater CT at input grounding?
Looks odd. Anyone using it chime in with some goss?
Re: Anyone doing Larry heater CT at input grounding?
Yes, I've wired two Marshall builds using the "Larry" grounding scheme and have no negative complaints. Here's the JTM45 which is quiet as a mouse. The only small change was instead of drilling another hole for a node near the treble pot,I just used the board standoff location near the grid bias resistors.
TM
TM
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Hellhammer
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Re: Anyone doing Larry heater CT at input grounding?
Is there a layout for this somewhere? It would be interesting to check it out.
/Stewart
Re: Anyone doing Larry heater CT at input grounding?
Here's the scheme.Hellhammer wrote:Is there a layout for this somewhere? It would be interesting to check it out.
http://www.larry-amplification.de/cms1/
TM
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azatplayer
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Re: Anyone doing Larry heater CT at input grounding?
This is what i stumbled across at Metro.
http://forum.metroamp.com/viewtopic.php ... 3ccc66d6f3
http://forum.metroamp.com/viewtopic.php ... 3ccc66d6f3
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azatplayer
- Posts: 556
- Joined: Thu Feb 26, 2009 7:59 pm
- Location: Great Southland
Re: Anyone doing Larry heater CT at input grounding?
Killer looking build TM, real nice.
I scored a mojo smallbox and a chassis recently thru a buddy. I had a jtm PT and a merc plexi OT on the shelf, everything else in the drawers too, so i figured a JTM50 was on the cards.
Kinda worked my own board layout, PS caps and droppers at each cathode, and using separate cans for each spot to keep the grounds in line.
ALl makes sense to me except the heater CT. Larrys builds are pretty amazing, and theres enough of a following to guess this is good. Just aint heard of it before.
But its goin in this 50 watter! So will report back!
I scored a mojo smallbox and a chassis recently thru a buddy. I had a jtm PT and a merc plexi OT on the shelf, everything else in the drawers too, so i figured a JTM50 was on the cards.
Kinda worked my own board layout, PS caps and droppers at each cathode, and using separate cans for each spot to keep the grounds in line.
ALl makes sense to me except the heater CT. Larrys builds are pretty amazing, and theres enough of a following to guess this is good. Just aint heard of it before.
But its goin in this 50 watter! So will report back!
Re: Anyone doing Larry heater CT at input grounding?
Azatplayer,
I used Larry grounding on a 100W modded Marshall build for a fellow. The amp was remarkably quiet even idling at high volume. No buzz or hum at all and very little shot noise/hiss. The amp had a switchable gain stage in front of an almost stock Plexi preamp.
The one exception I made to the Larry grounding scheme was not grounding the PT's filament center tap to V1a input. Instead, I made a separate voltage divider and cap and elevated the heaters to about +80VDC. I do this whenever possible and especially if the build calls for a cathode follower which may be operating at heater-to-cathode voltages close to or in excess of the usual 100V spec for a 12AX7.
I used Larry grounding on a 100W modded Marshall build for a fellow. The amp was remarkably quiet even idling at high volume. No buzz or hum at all and very little shot noise/hiss. The amp had a switchable gain stage in front of an almost stock Plexi preamp.
The one exception I made to the Larry grounding scheme was not grounding the PT's filament center tap to V1a input. Instead, I made a separate voltage divider and cap and elevated the heaters to about +80VDC. I do this whenever possible and especially if the build calls for a cathode follower which may be operating at heater-to-cathode voltages close to or in excess of the usual 100V spec for a 12AX7.