EQP-1S5 - 500 series recreation of solid state EQP1A

[Tungstengruvsten]

in for a pair!  front looks great!

 

[Grooveteer]

I'd be in for one!

 

[mitsos]

I'm keeping track of people's names in a google doc, although as it stands the numbers aren't that high, but we should be ok to go through with a small run of about 50 so far. I'd like to hit 100 of course, so I hope people keep em coming.

I did a little drawing of a high-current 5534..  based on Gyraf's headphone amp, though I upped the 4K7's to 12K cuz ltspice was giving me -2dB a 20KHz.. Who knows how accurate that is of course... best bet is to perf this, I suppose, but I don't know that I'll have time. We'll see. Adding a trimmer to adjust for DC offset as per the 5534 datasheet, in case anyone wants to go capless. I thought to add a resistor to bias Class-A but I'm not 100% sure that would make much difference.

 

[mylesgm]

I should be down for two of the full kit if you haven't already got my order...

 

[jensenmann]

It´d become more clear for anyone interested if you had a rough guess of what the kits will cost.

 

[mitsos]

Hi Myles, got you down, thanks.

The past couple of days have been pretty good. Ironing out the small details in the PCB layout for ease of build. There is only one problematic part in the soldering due to the pots and switches being on opposite sides of the PCB. but a fine solder tip and steady hand should be all that's needed.

Jensenmann, as far as pricing, I had originally written between 300-400 USD per kit (should still be in that attachment in the first post I think).  We're still in that ballpark for a complete kit (as long as the quotes I got have not expired by the time we do this!). The Wima caps are expensive if bought as an individual set (about $50+ a channel, yeah I got quite a shock prototyping) so I will add them to the kit because in quantity they will only add $12-15 and they are really nice.

What is really holding me back from stating a firm price is metalwork. The cut/bent metal is already priced, but the finishing was sort of up in the air for the past few days. It was really hard to find a good powdercoater and even harder to find a silk screener. But I think I may have found both, so now the deciding is between this more traditional finishing and a very cool velvety adhesive label which came up in the (previously failing) search for a silkscreener. That was what I had referred to in the other post as the non paint/silk option.

There are several advantages with going with the label vs powder/silk. Some of them are:
1. the ability to make the panel a full 1.5" and not 1.49" (to allow for paint)
2. it is fully colored and the colors are more likely to match the pantone codes I give the supplier than with paint (painters will do a similar color, but to custom match is 3x the price!). 
3. Adhesion is much better and no chipped paints. This is a very sturdy material with a nice feel, much like labels on some older consoles.  And as you can tell from older consoles, some of those with silk legends tend to be unreadable after many years of use and finger rubbing, whereas the labels don't wear off. The adhesive used is very strong and should be ok up to 400 degrees or so. So, as long as the surface is cleaned prior to adhesion, there is no reason to believe it will ever come off (without deliberately forcing with screwdrivers/knives, using chemicals, etc).

so that's where we're at. I'm pretty sure we're still withing that 100 dollar range I gave earlier, though I don't know if it make sense to do partial kits on this, the additional costs of the left out components is minimal, what eats up the budget here is PCB, metal, switches, pots, and of course, custom vintagey goodness iron.

thanks for stopping by folks! I appreciate the help! We're almost there!

 

[mylesgm]

If the faceplate is the problem is it possible to get a blank faceplate with just the relevant holes drilled?  I often get my faceplates hand engraved or use a metal stamp for the letters and am happy with the bare metal as the faceplate 'colour' in fact one of my eq's faceplates is actually buffed and shined aluminium and it looks great.

M

 

[Brolik]

I will be down for one, maybe two. Probably full kits, but depending on cash flow at trigger pulling time.

 

[zayance]

Same here, in for one for now..., maybe two depending on cash....

 

[nielsk]

Good point, mylesgm, that would be another advantage of the label route. If you want to do your own finish, just don't use the label!

 

[mitsos]

OK so far...:
labels 1
paint 0

Myles, I'm curious about the metal stamp, sounds really useful.  Can you PM me any info please?

Niels, I could use some help with this project, if you have time, maybe we could set something up like last years' group buy?
I'll email you.

 

[nielsk]

I'm down with that
You know I want some!

 

[mylesgm]

here you go:

http://www.ebay.com.au/itm/LETTERS-NUMBERS-METAL-STAMPS-4mm-36pc-WOOD-BOX-/360310022097?pt=LH_DefaultDomain_15&hash=item53e4269fd1#ht_1257wt_720

They come in all different sizes and are relatively easy to use, pick your spot, grab your hammer and...

Best if you mark your faceplate with a water soluble felt tip first of course.

M

 

[Songguy]

im in for a pair!!!

 

[mitsos]

Hey guys, sorry for the delays, long holiday weekend here.

Good news is... well, it all works!  Yippee!  The prototype is all tested and mounted to a sled, everything is OK, except for a couple of mechanical issues, so I’ll do another proto PCB to sort that stuff out.  Some changes: 2u2 caps are very tall (you can sort of see it peeking up above the sled in the frontal pic) so will be replaced by 2x 1uf caps in parallel, switches will be 1/8”shaft, things like that, and some of the smaller caps were fatter than expected, so I had to spread them out more (you can see some other caps were used for testing and some of them had to go on the bottom of the PCB in order to fit).

More good news: I’ve already tweaked the layout, and I’ve talked to Niels; I’m going send him the next prototype to test (he did offer to help, so I may as well take advantage!).  This will be much faster than the first prototype with him being in the US and all. I’ll be ordering the prototype today. Hopefully another 2 weeks or so.

There are some frequency response plots I’m hoping to put up here soon, for those interested.

So far, the velvety label looks very promising, it looks sharp, and it gives everyone the choice of using my graphics or painting the panel pink or something.

Here are some pics of the proto build process. The sled is what was around, it's thicker than the 18AWG planned, and it’s hand drilled and all, if anyone wonders. 

 

[Biasrocks]

Nice project.

I'm in for 1 or possibly a pair depending on cash reserves.

Mark

 

[Scrappersa]

This project looks great. How much do you think the full kit would cost?

 

[mitsos]

hey guys, sorry to disappear! The project is moving along, the rev2 pcbs just arrived, and are going through a rigorous testing process! 

We expect everything should work fine, the second proto was to take care of mechanical issues (some of the huge polypro caps didn't fit very well) but I think everything should work fine this time.

I know I promised some freq charts, I've got most of them done here, but life has been keeping me so busy lately that I haven't been able to format them properly and post.

As far as costs, it's still not 100% set in stone, but we're trying to set the ceiling at $400 a channel, for everything minus the opamp. That's PCBs, metalwork (with faceplate painted/silked or velvety label, not decided yet), 3x grayhills, 5x conductive plastic pots with metal shafts, all Wima polypropylene caps, custom made toroidal inductor and 2x HS56 remakes (all iron made as close a possible to old ones), and misc parts (DOA sockets, resistors, trimpot, diodes, screws, nuts...). 

So you'll have everything minus the opamp, though I made a PCB to mount a 5534 in a DOA footprint, it's also being tested ATM. If this works properly, the PCB will be included so you'll get everything to make a working channel, although I'd recommend a vintage 2520 for authenticity's sake.  There are a few remakes on here, Dan Deurloo was looking into a group buy for the Scott Liebers red dots, but I don't know if the slight savings with that are worth the hassle of a GB, so it may work out best for everyone to purchase their own.

We may also be doing a few built/tested units for some local studios, if anyone is interested, it is a possibility.

thanks again everyone!
-d

 

[John Peacock]

I'm in for one (definitely full kit).

 

[jsteiger]

Dimitri

I saw that you mentioned 1.5" exact for a no paint faceplate. I would still under size that just to be sure considering the tolerance for the metal shop. All of my current clear plates are drawn at 1.493". I spec'ed 1.484" before powder for my last black blank run and those measure between 1.49" and 1.493" after the p/c. A few thou under is always ok but over is not good. I just calipered a 550B faceplate that I have loose and it's 1.491".

Just food for thought.
Cheers, Jeff