sjs

Phono Stage Rebuild

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Some 15 odd years ago I built a pair of preamps for friends. Both had an MM phono stage and 6SN7 based line stage. Fast forward many years and one of them died a bubbling mains transformer death last year. :RIP:

At that stage it underwent significant open heart surgery, and as it was only being used for the phono stage the line stage and preamp components were ripped out, however it remained aesthetically challenged, actually more so than previously due to proliferation of redundant holes in the casework.

Long story short it is now back in for a trash tv style extreme make over which I have been asked to document with a few photos, so here goes.

First off, get a new case

MD-case1.jpg

that was easy !

trouble is my machining skills are legend, in that they are utterly terrible :doh: so, I needed an alternative approach......

so, after some head scratching, a crash course in "simple cad", what an f'in oxymoron that is, and a couple of weeks :nerves:this arrived

MD-case2.jpg

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and inside the nice shiny box were these two

MD-frontpanel.jpg

MD-basepanel.jpg

- - - Updated - - -

Is that one of the Hammond cases? If it's not it looks very similar to the one I'm looking at.

Did you go for silver or black aluminium?

Looks very smart

Yes it is one of the Hammond cases. I went for the natural version as its cheaper, but didnt want the panel anyway, as you will probably have now realised :D

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I sized the top and base panels a little larger and a little thicker than the Hammond panel to give a nice snug fit

MD-casetop.jpg

MD-casebase.jpg

which appears to have been achieved quite nicely

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EC8020 :shock: I've been looking at the E55L as possibly a more affordable alternative. A bit easier to find too.

Looks very nice. Will watch with interest.

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Looks like EC8010 unless my glasses are buggered again!

Schaeffer for the panels Simon?

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EC8020 :shock: I've been looking at the E55L as possibly a more affordable alternative. A bit easier to find too.

Looks very nice. Will watch with interest.

EC8010, I think, more reasonable!

Simon, what's the thinking between the mix of 417A and EX8010 as they seem rather similar in terms of characteristics?

They're both very nice toobs, tho'.

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My shitty monitor. :doh:

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Super Wammer

Wow, looks really neat! Where did you get the cutting/printing done? :)

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Schaeffer for the panels Simon?

Indeed, Schaeffer in Germany and their Front Panel Designer software :?

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Indeed, Schaeffer in Germany and their Front Panel Designer software :?

Used them a couple of times. Superb service and quality, but you do need to be careful, as what you design is what you get. When I did most of the Thorsten modifications (and some extras) to my old EAR834P I had a new front panel from them and carefully spelled TdP's name incorrectly :oops:

I also got the size of the mains switch cut-out wrong, and in enlarging it managed to put a drill bit right through the mains trafo windings. Mind you, I'm not the only one who's done similar. Hi Pete :)

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Used them a couple of times. Superb service and quality, but you do need to be careful, as what you design is what you get. When I did most of the Thorsten modifications (and some extras) to my old EAR834P I had a new front panel from them and carefully spelled TdP's name incorrectly :oops:

'Tmi'? 'Mit'? 'Imt'? How hard can it be? :rofl:

I also got the size of the mains switch cut-out wrong, and in enlarging it managed to put a drill bit right through the mains trafo windings. Mind you, I'm not the only one who's done similar. Hi Pete :)

Up yours you jolly old cnut. :P

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EC8020 :shock: I've been looking at the E55L as possibly a more affordable alternative. A bit easier to find too.

Looks very nice. Will watch with interest.

EC8020 I wish! If I had any it would be worthy of a fully tricked up implementation....

EC8010 in this case, it is still very nice, and was a toss up between this and a triode strapped D3a as the input stage. For phono stages I like high mu high gm tubes, so there are various options, including E55L, D3a, EC8010, 5842/417A, 6C45PI etc along with the unobtainable EC8020, 437A and 3A/167M. They all require some tlc to avoid vhf oscillation, but can reward with a very entertaining presentation.

If possible I like to avoid having the same gain stage replicated within the system, hence the mix of valves, but more of that later.........

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Up yours you jolly old cnut. :P

And in return dear boy.

Managed a day with the slodering rion and now have all the Coleman boards done. There is progress. Albeit minimal progress. Tested briefly, and all seem in spec.

Anyway, we diverge from the topic. Looks good Simon. Looking forward to seeing this in a more finished state.

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