FEELER: Authentic P2P Pultec MEQ-5 chassis

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ron_swanson

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letterbeacon said:
Oh, that’s a bit annoying! Thanks for letting me know!

Letterbeacon,

I have 4 x160012 in the post supposedly scheduled to be delivered tomorrow. Assuming I’m getting what I was promised,  you’re welcome to purchase one.  They were a bit on the pricey side and of course, I’m in the US so there’s shipping to consider too.

Let me know if you’re interested?  We’ll try to work something out.

Greg
 

ron_swanson

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Anyone have or know where I can find internal pictures of a real MEQ-5 or of their close constructed clone they care to share?  I'd love to see how the capacitors and inductors wehre mechanically laid out and / or fastened.  My Google searching skills must be off as I can't find much of anything.

Thanks in advance!

Greg
 

ron_swanson

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Finished my MEQ0-5 build last night.  All seems to be working as expected.  Yay!

Checked all voltages marked on the schematic I have.  No issues.  No distortion, buzzes, hums or other artifacts found or being presented so far...

I inadvertently wired the bypass switch backwards - off was on, on was bypass, so had to re-wire that, but after making that fix, the unit sounds amazing!

My first point-to-point build...

My capacitor planning / execution leaves a little to be desired.  Might re-look at that.  It wasn't clear to me where or how the caps and inductors were mounted in vintage units, so I ended up throwing caution to the wind. 

That aside, I used a vintage Triad HS-56 input transformer (had three of these in my parts cabinet), but so far haven't found a HS-50, so using a Sowter 1290 that I ended up mounting internally. 

The bypass switch is a NOS Switchcraft and the frequency rotary switches are ceramic NOS parts sourced from Eastern Europe. 

Vintage Windings inductors.

Of course, as soon as I nearly finished my build, I found a NOS Traid R-7A transformer in the original box and another used (?) R-7A which are both in the mail at the moment.  Debating whether or not to replace the current Hammond in favor of a vintage R-7A?

With the exception of the reverse pot, the rest are NOS Allen-Bradley pots . 

The 2k5 reverse log pot is a Mouser sourced modern part which unfortunately is a mini pot that I kludged into fitting with a home made shim around the bushing to make it fit properly in the chassis.  I recently learned of and ordered a small number of full sized 2k5 rev log pots from Blore Edwards Limited in the UK.  I'll probably swap that part out just to have a full sized pot in place even though the mini pot is working. 

Thanks to Martin for making this chassis available.  Great project!  A second build is likely ahead of me in the near future!  ;-)
 

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ron_swanson

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Of course, as soon as my MEQ-5 build was nearly completed, I found a pair of Triad R-7a power transformers and a pair of Triad HS-50’s to compliment the Triad HS-56 input transformer already wired in. 

The surgery was successful. 

Now my build has a full set of vintage Triad transformers. 

Sounds amazing!!!


Cheers, Greg
 

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ron_swanson

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Shout out to Blore-Edwards who made me some custom 2k5 Reverse Log pots for this build. 

https://www.blore-ed.com/

Excellent quality.  Beautiful feel.  Like them maybe a little more than the Ohmites!
 

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rainton

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Your unit looks amazing!

Great work! I used the same set of transformers in my build - and the only problem about having one MEQ-5 in my repertoire is that now I want a second one  ;D

I already have the HS56 and a HS50...
 

ron_swanson

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rainton said:
Your unit looks amazing!

Great work! I used the same set of transformers in my build - and the only problem about having one MEQ-5 in my repertoire is that now I want a second one  ;D

I already have the HS56 and a HS50...

Thanks rainton!

I too have another set of Traid transformers and I also have a second build on my mind...  ;D
 

soapfoot

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Hey, I think I'm about to spring for two of these.

The only thing holding me back is the report above that the Sowter transformers on the BOM (at least the 1290e) don't physically fit.

Does anyone have any more insight into this, or ideas of alternatives (besides the rare original Triad units) that would properly fit?
 

rainton

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soapfoot said:
Hey, I think I'm about to spring for two of these.

The only thing holding me back is the report above that the Sowter transformers on the BOM (at least the 1290e) don't physically fit.

Does anyone have any more insight into this, or ideas of alternatives (besides the rare original Triad units) that would properly fit?

All my chassis kits as well as adapter plates for mounting Sowter transformers are now available on my website www.analogvibes.com ;)
 

soapfoot

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rainton said:
All my chassis kits as well as adapter plates for mounting Sowter transformers are now available on my website www.analogvibes.com ;)

Thanks so much for the response, and understood!

Hopefully I've just misunderstood what I've seen above, but this quote from AusTex64 seems to say that (mounting notwithstanding) he found the Sowter's 44mm diameter to be too large. Is this not correct?

AusTex64 said:
what did you guys use for the output transformer? Not many options for a 5:1 that will fit. The Sowter is a bit too big. Triads are hard to find and outrageously expensive. A-24 isn’t far behind. The Cinemag is too big too. It’s a pretty tight fit on that chassis.

I also noticed that Ron Swanson ended up fabricating a means to mount his internally instead of using the adapter plate. I assumed this may have been for a similar reason?

Because I don't have the means to fabricate an internal mount, I just want to be double sure I have a good plan. A transformer that hangs over the edge of the chassis will unfortunately not work in my application (limited rack space).

Just digging for some data, the Sowter 1290e has a diameter of 44mm, and I think (but can't manage to verify) that the width of the HS-50 is 39mm. This isn't a massive difference, but in pictures the HS-50 seems to run right to the edge of the enclosure.

So I guess I'm asking explicitly if it has been verified that the 1290e, mounted with the adapter plate, physically does not hang over the edge of the enclosure. And if yes, is the fit reliant on also using the Sowter 3603 (with its small 34 mm diameter), or would I be able to combine the Sowter output with a Triad input (39mm)?

I know that's a lot of questions, but I want to get it right. If there happens to be an illustration of the enclosure's rear panel with measurements, that may answer my questions as well. Thanks again for any information!
 

rainton

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I just replied to your email, but just in case someone else wants to know:

as far as I know the Sowter output transformer would only hang over the top edge of the back panel by around 2.5mm (3/32") and the Faceplate of the unit is around 3mm higher than the top edge of the back chassis, so it shouldn't be too big of a problem.

Correct me if I'm wrong @ron swanson?

If you use the (smaller) Sowter input you could also extend the transformer mounting hole downwards on the adapter plate with a file to move the output transformer slightly downwards...
 

soapfoot

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I received your mail, and your reply here is perfectly clear as well.

Looks like it will work just fine, considering that the rear of the chassis is 3mm lower than the front panel, and should not cause any racking issues.

I will also most likely do a slight bit of filing on the adapter plate center hole to move it down just a touch, as well.

Thanks again for your responses!
 

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