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The "Members Only" Riaa Tube preamp. Gets a walnut cabinet)

So! the CineMag transformers arrived the other day and I mounted them up the same way as i mounted up the previous units and the tubes. I once again used NEC relays to change the turns ratio of both units using one simple toggle.

The relays are stuck into TE sockets which are intended for integrated circuses, but I use them so that i can replace failed relays and so that I don't damage the relay with excessive heat, which isn't likely to happen. Still i think the right way is to use sockets so thats what i do.


I used a piece of stainless all-thread to connect the board to the transformer chassis via a piece of tubing. It came out nice enough that I probably won't redo it.


The SUT sub-chassis will probably get placed over in the left hand side of the chassis where it is far from the power transformer and power supply. It will ride on the same type of floating mount as the tube sub-chassis.



The whole thing is beginning to look a bit spaghetti-esque. It will all work out just fine and in the end it will sound spectacular.



The power supply photo is just there because I'm proud of how it came out. Clean, orderly and easy to service.
 
300b4me said:
Also where did you source the transformer "cans " for potting the transformers?
Thanks
Click to expand...
I found the transformer cans on ebay, and once I confirmed fitment, I ordered 4 of one size and 2 of another. The epoxy potting sauce is available on eBay too. I usually avoid ebay like the plague, but these items were both units I'd ordered previously and we're of a known high quality. I can send you some schematic diagrams via PM.
 
I've gotten lot of work done on th Preamps lately . I finished this box for the prototype, which turned out ok... I learned wht I need to do differently next time.20200214_180915.jpg
The next one is nearly done. I really buckled down on it and got it to the point where it passes signal through the phonostage and line stage on the test bench and the input switching works!
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I used green leds instead of blue, because I didn't have enough blue. 20200222_200918.jpg
It's all basically done besides the moving coil transformers which I still need to order...
 
Well, one of my preamps found a loving home. I built this one for Roger, and it came out looking really great, and it sounds perfect. He has been playing records cds, and streaming through it from his dac, and he loves it. Since he flies a helicopter for our local hospital, Alan thought it would be fun to use a locking toggle switch for power. We searched and searched and finally found the exact switch which Roger starts the chopper with, and we used that part on all 4.
Ive got 2 more to deliver after i get my cinemag issues sorted.
Anywho here it is, set up in his main system cranking out the tunes, and playing nicely with gear that is far nicer than i can afford.
IMG1059551165272889324.jpg IMG6070689354789184764.jpg
Im pretty damn proud of myself for pulling this off.
 
As an automotive mechanic, who works outside of the normal licensed shops, ive been "recruited" by various forms of "organized crime". While its nice to know my skills are valuable, and in demand, those "organizations" weren't doing anything outside of making money, which interests me.
Car clubs, and motorcycle clubs exist in nearly every american city, and those who get noticed have custom macines, built by members of the club, which are inaccessible to those outside of the brotherhood...
That is to say, they drive/ride the baddest machines arround, because they recruited the best talent to their organization.
We have another amp builder in our group, and a man who builds beautiful speakers.

I have resisted some great offers over the years, who knows how life may have turned out had i joined up. While i wish those people no harm, i had to find my place, where i fit in, where my skills are valued, and im doing something i love.
Ive found my community with the Chico Audiophile Club, and i sleep much better at night.
 
I recently came into a stash of really beautiful aged black walnut. I made a few things for practice and then once I felt confident I could accomplish it, I built a walnut case for a "Members Only" amp. It came out good, and I plan to do 3 more for the other guys.
An old friend used to say "drywall hides a multitude of sins"
An inch of Black Walnut, doesn't hide anything, but rather adds the finishing touch to an already beautiful tube amplifier.
What do you think?
 

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Hey a guy could be proud of that...
To have built it, or to have it displayed in their listening room.
I personally could never afford gear like this, unless I piece it together as I have done.

"Let the stone that the builder refused become the head corner stone"

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The difference in lighting and angle cause all sorts of patterns to pop out of this wood.
You can see one of the more vivid examples above...
 
2 weeks ago I delivered the last of the preamps to Anton. I had just ordered (reordered rather) the cinemag transformers i needed to make pairs and get my personal preamp set up for moving coil carts.

I ended up using a blue and a red cinemag 3440, because that's what I have on hand right this very moment and I hear enough difference between my Mc cart and the one I was using, that I wasnt willing to continue using it. (Shure v15III)

I mounted the transformers on aluminum, isolated from chassis and used relays to switch the primary windings such that each coil within the unit, can be driven via the entire winding or 1/2 the winding, and another switch which puts those into parallel or series. This gives me 6 different loding options while still maintaining my grid circuit right in the neighborhood of 50k
Beautiful, and very heady.
On mine I put the switches on the front panel because I'm me.
Everyone else has to open theirs up in order to change the turns ratio.
I used the same relays for the Mc section as I did for the input selection. Nec ea2 12Nu. They work well for switching signal, contacts cant get dirty, I've used 100 of them at this point, no failures, and they come in 3, 5, 6, 12, and 24 volt control coils. Latching types are also available if you want to get really tricky. While I've got this one pulled out of my system I think I'm going to make a walnut box for it. I have just enough walnut left, and the plywood box i built, while very industrial, looks like crap.


I want to get this one all buttoned up,(the prototype) then the plan is to build one in a 4" par metals chassis just like the club got (much neater more finalized layout). I have an extra tube lineup, transformer, and chassis divider plate, as well as a switchboard. Most of the hardest stuff to fabricate is nearly finished. Obviously I have the tubes...
What's stopping me?

Well ordering Parts, I've always said is the most difficult part of this, that hasn't changed. I need to make an order from Par metals, and I'm tempted to try and meet the second price break.
Meaning I have a choice to make.
Do I build one for me and stop, or do I start buying parts in sufficient quantities to build lots of 10 and offer them to more interested people?
 
Unfortunately as a pensioner with a wife who lovingly handles the finances, I’ll not likely casually purchase a custom built preamp of this quality anytime soon. I have recently come off a complete methodical overhaul of each and every component in my current system, as well as a few upgrades along the way. So my wife while understanding and accommodating of my hobby, knows she isn’t married to a rich man. There are those who can afford Such luxuries, like your helicopter pilot friend. The build series shows the care and thought that went into your design and execution. Possibly you could continue the build series with some performance test and result posts. Those could further influence them that are interested in your work. You and a few lucky folks have a piece of art thanks to you. Peace!

Bill
 
I settled on 3, par metals 4" chassis. Between them and the 2 Jon is making for me, I'll have sufficient stuff for 5
Looks like I'm building 5.
I ordered 4 transformers today from Edcor and potting cans will be next.
I have potting epoxy
I need to start drawing up some cad files in order to have parts cut. I think I have homes for at least 3 of them. Obviously I'm getting one. Theres a local man who I decided needs one, he doesn't know it yet but he's getting one, (as extreme peer pressure to join the club) and an undisclosed celebrity has indicated to me that he'll buy one, which I'm excited about. By the time I finish them I'll probably have owners figured out for all of em.
Stay tuned this thread may be old but the project is continuing to mature.

Btw the moving coil install in the prototype preamp was a great success. I'm back to using my Denon DL-103R.

I'm stoaked!
 
You dont need a million dollars. The parts cost was under 1/10th of 1% of 1 million.
They just look like a million bucks.

I went ahead and ordered 4 chassis instead of 3. I got 2 black, and 2 in gold alodine finish. The Gold Alodine looks a lot like the HH Scott tube amplifier face plate finish, but less glossy.

20210606_170648.jpg

I find that batching them is the way to go, as it only takes a few more minutes to mark and drill 4. Vs 1.
So I'll have 4 in par metals chassis, his batch and when they arrive I'll do 2 more in the chassis Jonathan designed.

Good times.

I shook hands on one the other night, so there's one for me, one for Antons son, one for the celebrity, and another to go to a local audio nut, who only gets it if he starts hosting meetings.
 
How do you like the cinemag transformers? I just ordered a pair of 1254 for myself, and I am keen to try them, although they may take a while.
 
I absolutely love them, and I love that I can call right down there and the owner answers the phone. They do however take forever...
Yeah like way forever...
 
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