Phosephene Marshall Four Hole Style Head

Make it loud here.
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HNB
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Phosephene Marshall Four Hole Style Head

Post by HNB » Wed Oct 21, 2020 11:41 am

I got this cool 50 watt head in trade from fever606 :)
fever606 wrote:
Tue Aug 25, 2020 5:36 pm
"like a Marshall 1959/1987 4 hole circuit, but with only one input jack, feeding both the bright and normal channels, in parallel". Partridge transformers from a Sound City head.”
It is really cool. I got to get a look at its guts when trying to figure out why the master volume pot wasn't doing anything. Turns out it is a push pull so if it isn't pulled out, it doesn't do anything. :) I think it needs new power tubes. When I cranked both channels with master volume low I was getting good distortion and then I noticed popping noises and the tubes were flickering with the popping sounds. The bright channel is cool, but much noiser than the other channel. I like being able to blend the two channels or have one up or the other. :) Here are some pictures for the people more techy than me.

ImageIMG_20201016_160534 by Christopher Louck, on Flickr

ImageIMG_20201016_153451 by Christopher Louck, on Flickr

Image2020-10-21_12-40-01 by Christopher Louck, on Flickr

ImageIMG_20201016_152940 by Christopher Louck, on Flickr

ImageIMG_20201016_152951 by Christopher Louck, on Flickr

ImageIMG_20201016_152958 by Christopher Louck, on Flickr
Last edited by HNB on Thu Oct 29, 2020 5:27 pm, edited 1 time in total.
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Re: Phosephene Marshall Style Head

Post by fever606 » Fri Oct 23, 2020 11:36 am

It’s a cool one for sure, glad it found a good home! Like most 4-input amps, blending the channels is where the magic really happens... this just saves you a cable! :D

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Re: Phosephene Marshall Style Head

Post by marqueemoon » Fri Oct 23, 2020 12:05 pm

Those caps are not messing around.

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Re: Phosephene Marshall Style Head

Post by HNB » Fri Oct 23, 2020 1:10 pm

They are like D batteries. LOL
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Re: Phosephene Marshall Style Head

Post by HNB » Thu Oct 29, 2020 5:27 pm

I am going to replace the tubes when they come in. I got two matched Mullard EL34's to replace the JJ 6CA7 power tubes. I also ordered a set of three Mesa Boogie 12ax7's for the preamp. Hopefully they work. :) I am hoping it was just those JJ's time to go and not something wrong I did. (Cranking channel one and two together and using the master volume to have it living room volume.)
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Re: Phosephene Marshall Four Hole Style Head

Post by fever606 » Fri Oct 30, 2020 4:17 am

I’ll say those JJs had some life on them - not a particularly hard life as it was used almost exclusively for recording but they’ve put in time.

Which is another way of saying turning both channel volumes up and taming with the MV is precisely how this amp was meant to be run. The fact that I never bothered with the MV (how did I not know it was a push/pull? :fp: ) is no shade against the amp...

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Re: Phosephene Marshall Four Hole Style Head

Post by HNB » Fri Oct 30, 2020 8:24 am

When I cranked both channels the tubes popped and flashed so I figured it was time for some new power tubes. :D
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Re: Phosephene Marshall Four Hole Style Head

Post by HNB » Mon Nov 02, 2020 3:27 pm

Got the Mullard power tubes today. I did my first ever bias. According to the internets, EL34's should bias around 37. When I powered it up, my multimeter showed it to be about 39. I turned the bias pot until it hit 36.9/37. Seems to be all good now. I turned the volume up on both channels and no popping or crackle. :) The preamp tubes should arrive tomorrow I think. Then I can seal it back up. :)
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Re: Phosephene Marshall Four Hole Style Head

Post by HNB » Tue Nov 03, 2020 3:00 pm

The Mesa preamp tubes came in. :) Sounds good to me! I wonder why the bright channel is so noisey.

https://youtu.be/1vHPIsC8zPM
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