All things LA2a related

[Scenaria]

just use turrets and for grounding use grounding lugs screwed to chassis...

no soldering is done directly to the chassis...

oh and the size really doesnt have to do with the amount of singal the tranny can handle..

the HA-XXX series simply has more shielding...

the A10 I believe is about as decent as the HA series and is in the smaller series cann

U all have to be patient when looking for old UTC's just take your time... you will find em.. in the past year ive probably nailed a dozen A-24's and two dozen HA100X's and A10's

they are out there :green:

but.. the sowters do sound pretty decent and are readily available.

if this is your first DIY.. I would suggest sitting down and itemizing your expenses... figure out your budget... I think many are surprised when they realize the la2's start climbing over $500-$600

 

[EmoRiot]

On ebay now there's an HA100X. It's got three days of bidding left and it's already sitting at 300.00!!!

Am I correct to assume that this thing has already surpassed its value and we should all be waiting for either an A-10 to come up on ebay, or for a HA100X auction involving more rational bidders - or at least more impoverished bidders? I mean, this thing might get near 500 dollars by the time bidding and sniping is done! :shock:

So much for my eSnipe that was set up.


Also, Scenaria, when you mention the HAXXXs having more shielding than the A-10, what effect does that have on sound? Thanks for any info.

 

[Bluzzi]

See, thats what I meant about prices being too high. The occasional one goes for reasonable amount.

The Sowter is always there and will do the job quite well I'm sure.

There is also an A-24 at $131.00 already ! Nope I'll pass, thanks.

Jim

 

[EmoRiot]

When Scenaria said "I think many are surprised when they realize the la2's start climbing over $500-$600", he might as well have said "I think many are surprised when they realize the TRANSFORMERS for the la2's start climbing over $500-$600!" :shock:

 

[CJ]

Remember, the A-10 is a better transformer than the 100X. The extra shielding of the X reduces noise, but takes off more high end due to capacitance to ground. There is a trade off for everything. Improve one thing, and you sacrifice another. Electrically, they are the same transformer.

Consider the A-26 as a sub for the A-24 if you spot one. I got two for 50 bucks one time. Same x-former as the 24 except higher pri. impedance, which might be a good thing.

 

[Bluzzi]

CJ - If you look on eBay for A-26 you will see a whole bunch of "wiring" machines for sale. It looks to me like they really are "winding" machines.

If anyone is into winding transformers (I know CJ is) maybe these are a good bargain. They even have a turns counter.

Jim

 

[Guest]

does any one know what are exceptable voltage diffrences,

im using alen bradly 1/2 watt carbons , most all my voltages seem
fine give or take 1-10 on a few.

and i know carbons can be +/- 10-20%


how critical is this?

i have a ua reissue , but the voltages differ from the schematic

give or take 20-30 volts on some.

and then also there are a few different voltages in jahnsens book too.

the UA is wired similar to cayocostas layout except the strange little

zener next to the ne-2 , and the 500 pf near the arco vari cap.

(bastards)

thanks

 

[Scenaria]

if the voltages are in the ball park.. I would say your fine for testing...

ive built about 8 of em and they are all different

the zener was added later as to stabalize the meter reference as the voltage wouldnt drift as much with heat


you will notice that the neon on its own will regulate a little different as heat build up.. this is why you have the zero adjust on the front panel..

you could put a zener in there if you want but its really not that important I just trim my meter with the front panel control.. no biggie

 

[Bluzzi]

Another question. Can any standard VU meter be used or adapted? I imagine the answer is yes but just checking before I start looking to buy.

Thanks.

Jim

 

[DIYDan]

A good question. One I'd like to know the answer to as well. My VU meter is a Sifam.

It has a note on the back for its lamp that says 12V 40ma. Is it tough to incorporate this into the schematic?

 

[Guest]

thanks so much , i appreciate the feed back :thumb:

driller45

 

[EmoRiot]

If a description of an A-10 reads like this:

"Tested OK for continuity. Half of one of the U shaped terminals are gone on pin 2. Pins 8 & 9 are connected together."

Does that sound like it's useable or destined for a repair?

 

[CJ]

Probably usable.

 

[Bluzzi]

I'll be keeping my sight out for UTC trannies but the Sowters seem to be readily available and guaranteed to work (you never know from eBay).
Also CJ pointed out some equivalents UTC, Thordarson etc. Right now everyone seems to be going for the A-10 and the A-24. Prices lately have been ridiculous on those.

What about meters though? Is it OK to get any VU meter? I got no response before. Anyone?

Again here I would like to eBay them but I am also looking at the Sifam and teh Modutec. The Modutec looks cheaply made as opposed to the Sifam but is less costly of course.

Any of you make the La2A with the Modutec? If not what meter did you use?


Jim

 

[EmoRiot]

Firstly, I don't want to get off the topic of what Bluzzi is asking, so I'll second the motion for a clarification of meter selection. :wink:

But...

I just picked up a pair of HA100Xs on ebay. They just posted and I used "buy it now" to save me the emotional roller-coaster of bidding, sniping, and ultimately losing the auction!

Yesterday a HA100X went for 370 in a regular auction. These two were 375, so all-in-all... they're way more than they should have been but if eBay's got them going 370 for a single, I figure I can always sell one of them (since I only need 1) and possibly make all the cash back... like getting a free HA100X in the long run. Or, if I build a second LA2A, I've already got the 100X and avoid the hunt. Either way, win/win.

Here's my question:

The pair I just got look like they're missing some screws on the top, but I'm not sure. I'm only basing my assessment on the picture of the HA100X that sold on ebay yesterday for 370. Take a look at that one (I've added arrows pointing to what looks like screws):

Now look at a shot of the pair I just picked up (top view):

Is it missing something? Are those screws hard to find or they a simple trip to the hardware store?

ps. Yeah, what about those meters?

 

[Bluzzi]

EmoRiot - congrats on your buy. II saw them but didn't want to buy at those prices. Prices seem to be on the rise as of late. If you look back a bit they were reasobly priced.

But...I can sympathise with just wanting to get it over with and getting them. I would sell the other one and try the Sowter as they are the same thing. I was being stickly in the beginning of my search but when I see guys like CJ and Scenaria mentioning other equivalent parts, hey, they know better.

I am building 2 so I need a pair of everything.

I can't be certain about the screws but I wouldn't worry about them. Probably for mounting.

You know JBL-Pro has the best price for the T4B (unless you want to DIY one).

The only I need to research now is the meter. I can go for the Sifam which I know will work but I am not sure about others.

Please keep this thread going if you are making one I would like to keep in touch with you as we both progress. If it is too much for a thread you can PM me.

After wanting to build first a Green Pre then I switched to a Tube Mike then to a tube preamp I am finally committed to an LA2A. I need compressors the most and wanted to start with a tube design.
Once I get near completion I will post my experiences (sourcing etc) if it helps anyone.

I am very excited about making an LA2A. Feel like a kid!

Jim

 

[EmoRiot]

Bluzzi: "I am very excited about making an LA2A. Feel like a kid!"

lol... yeah, this is legos on steroids! :green:

 

[EmoRiot]

Bluzzi,

I hope that someone with more expertise than you and I way in on this meter thing, but I'll tell you the info I've got from Jahnsen's book.

"The Selco AL39WF is close to the same size meter as the Beede used in the LA2a. (Beede is making electronic parts for Ford now and is no longer making meters. For a great vintage look, check out the Selco "Vintage" Meter types 20A SQ and 25A SQ."

Now, this information is old. Selco was, i believe, the US distributor for Sifam. So Sifam is the new name... but the product numbers are the same - at least for the vintage ones (that I can confirm).

You can check out the vintage meters HERE. The regular Sifam meters are also HERE

If you need a place to order from, I can recommend IMS. They're in Los Angeles, CA, which probably means mail order for you but you don't come across a store just for meters very often and the guy there knows his stuff. You could probably even ask him your meter questions and get a fast answer. They do mail order. The number is 818-243-0416.

Another source of meters is SURPLUS SALES. They've got some of the Anthony De Maria Labs' meters, among others.

Someone else asked something about the power needed for the meter. It makes me wonder also... do different meters draw different amounts of power and is it tough to make that work? For example, backlit meters vs. non-backlit. There's got to be a power discrepency here, right?

 

[cannikin]

Hey Guys;

I'm putting my Bloo together, I have Sprague Atoms for C7a/b/c/d
They are HUGE! I was wondering if I could attach wire to the Leads of the caps and mount them a little (not much) but farther away from the tag strips, so I have some room to work.

Anything I should consider before doing this? I have Belden Hi temp. 800V hook up wire.

I think I'm going to have to mount the Power trannie now too, so I can get to the screws.... Ugh!

 

[Scenaria]

you dont really need atoms for the power supply... my advice would be to get smaller caps... there isnt much space in there to begin with..