LA-2a 'rescue' documentation

[SSLtech]

I was approached recently by another lab member to see if I was interested in finishing off their LA-2a clone. They'd apparently built it about two years ago, and had bought some VERY nice parts for it: all orange-drop capacitors, all metal-film resistors, all new sockets, Par-metal case, Jensen transformers etc... -all very nice stuff.

Apparently it had never worked correctly, and they'd tried to troubleshoot it, and started taking bits apart to see about making it work correctly, but to no avail. Eventually they were more interested in getting out more or less what they'd put into it, and had lost interest in completing the project.

Since there was a recent thread about another lab member looking to buy an LA-2a but not necessarily looking to pay the $2,000 or so which the BLOO versions tend to sell for, I thought that this might make an interesting project.

So, I contacted the two lab members, the 'seller' agreed to sell me the unit, and the 'buyer' agreed to buy the unit after I've finished it. I bought the unit, and here's what arrived in the mail:

Front view:

A bit big and bold, and I'm not sure about those knobs... but nothing unworkable.

Rear view:

...pretty tidy, all things considered...

Inside view:

...not bad, but could maybe use tidying up a little.... -once it's fixed, of course!

So here's a shot of the knobs which I'm going to put on it... it's the exact same knob as is used on the Universal Audio reissue LA-2a's.

The meter has got a little bit banged up, hence my recent Ward-Beck Simpson meter post...

...And here's a picture of the patented SSLtech labeling transfer sheet...

FOr a start, the two handles are going to be done away with, and the pencil guide lines are obviously going to have to be removed. In addition, as part of the plan to make the front panel look a little more like the original units, I added a third hole for the meter switch... a 3-position dual pole rotary. This meant relocating the power switch down an inch or two, so I filled in the hole with a power indicator light, of the appropriate vintage. In addition, I added a hole for the compress/limit switch.



Here's a shot of the labeled front panel after varnishing, sitting on the unit while it dries...

Same again, without flash:

I could put a SIFAM meter on there, but it doesn't look 'period-correct' if you know what I mean...

Close-up of the power switch, light and metering switch:

And then it was on to repair the unit...

I did discover a couple of wrong wiring issues, and the 'bridge' circuit for the GR metering wasn't working at all well, but some of that may have been due to what was removed as a try to fix it...

Once it was all fixed and working, I tidied up the insides a bit, and neatened it up a little:

The back received some labeling, and some nice polished tube socket sheilds (apart from the 12BH7A, which I can't find a polished shield tall enough for, so it has a slip-on military-type tube shield):

And here's the beauty shot next to my original Bloo:

Oh, I've also added a couple of 'faux' thumbscrews in place of the top two handle-mounting holes... I think they look pretty good there!

It measures beautifully flat, and the compression characteristic looks right on the money. The only thing about it is that it's using Jensen transformers, and that means that the input sensitivity is way down (some would say that's a good thing) and also the peak reduction threshold sensitivity is also down quite a bit... I think I'll be switching the Jensens out for Edcors pretty soon... I've been VERY impressed with how the Edcors compare, indeed!

Well, there you have it... a quick photo-summary of a DIY unit which was languishing and got 'rescued'. It'll be on its way to its new owner's place after I've had a couple of weeks to live with it and make sure that it's not got any particular 'quirks'.

Keith

 

[abby normal]

I like! Nice touches. That's water decal? Did you clear coat it?

 

[maxwall]

next

 

[SSLtech]

It's not water decal, it's the SSLtech-patented 3M Super-77 transfer method.

It's a rub-down color laser print, since a one-off silk screen print would probably cost at least a couple of hundred bucks...

The Jensen mod was carried out as per the Jensen web site, although when the Edcors go in, the mod will be undone, and returned to the original Teletronix circuit.

I can measure and test a meter, though I have a supply of Sifams locally for about $25 each, so I'm not in need of any at the moment myself...

Keith

 

[maxheadroom]

whats behind of the patented SSLtech labeling transfer sheet secret?

 

[SSLtech]

A colour laser printer, some 3M super 77, a sharpie, some transfer backing, and a few hours worth of work...

Ignoring labour (I give myself such a good discoult on labour!) it really doesn't cost much in materials. I think a search should turn up the method somewhere in the forum, I posted it a LONG time ago.

The big cost is in time to preapare the design, make sheets and re-do if things go wrong... then there's drying time and the whole thing has to be lacquered afterwards so that it doesn't wear off, but the materials are cheap, you just have to put in the TIME to do it.

Keith

 

[seavote]

i can get the 3m super 77 .but what type(brand) transfer sheet are you using? something nice and thin?

 

[SSLtech]

Avery laser labels backing paper... throw away the labels, print (reversed) onto the 'slippy' side of backing sheet, then spray on the super 77 and LET IT DRY FOR 5 MINUTES!!!
Once it's nice and tacky (do this in a DUST-FREE environment!) align and rub-down the labels with a sharpie lid.

If the labels get out of whack, you have to start over with the panel. -To remove EVERYTHING from the panel, just wipe it with a clioh soaked in naptha (Zippo lighter fluid..same stuff but MUCH cheaper if you buy it from a paint supply place by the quart) then THOROUGHLY dry it off, re-spray with Super-77, let it dry for another 5 minutes, and start again.

Once it's correct, let it dry IN A DUST-FREE ENVIRONMENT(!!!!!) and after 24 hours, apply a coat or two of Krylon clear. There's a skill to this where the temperature of the can makes a differnece to the 'smoothness' of the final coat, but it's not too difficult.

Search Super-77 and I think you'll find another write-up somewhere...

Keith

 

[jamesfei]

Hi Keith: I don't know much about Ward Beck equipment, but the meter might be a Dixson, with that clear top section. I'll look through my parts, I may have some Dixson VU's (oddly with external rectifiers, if I remember).

James

 

[abby normal]

Thanks for the tip Keith I'll have to try that one.

I've used water decals in the past on projects that need a screen print look to them. I used to clear coat with paint but I've found a way to do it that's tough as nails. I do the water decals but I clear powder coat and cure in a crappy oven that's not used for food. You can do this over an already powder coated surface. Just be sure not to let it sit too long and set the temp a little lower to prevent the decal from getting burnt.

Here's a cheap powder coat system you can get used on ebay around a $100

http://www.sears.com/shc/s/p_10153_12605_00917288000P

And the clear coat you can get here, great stuff btw

http://store.columbiacoatings.com/c...mplate=PDGCommTemplates/HTN/SearchResult.html

 

[SSLtech]

cool tips...! :thumb:

I'll give them a try!

Keith

 

[abby normal]

Oh I forgot, it has to be an electric oven. Gas ovens make powder coat go boom-boom. Lol

Stuff that used to take a couple of days to dry in order to screw down nuts, pots now takes like 20 minutes and it's ready to work on. No kidding. The other perk and I don't know how it does it but it makes the water decal edges go away so it does not look like you used a water decal. That might depend on the surface or background color you use them on but I've tried it on a bunch of stuff and it works great.

 

[seavote]

thanks for the info :grin:

 

[Kid Squid]

Nice....
Very Nice.......

I can feel another one coming off shortly.........
:thumb:

 

[SSLtech]

[quote author="Kid Squid"]I can feel another one coming off shortly...[/quote]
How many times have I warned you about eating beans...? :twisted:

Iechyd da!

Keef

 

[Kid Squid]

Just like Blazin' Saddles , Keef-san :grin:

 

[noulou]

Will this do?

If yes, PM me your address. :guinness: :thumb: :guinness:

 

[SSLtech]

Perfect!!!