All things LA2a related

[ToroRojo]

Finished building my Bloo LA2A last night. Plugged it in, closed my eyes, turned it on AND...





NOTHING. The lamp didn't light up either. After reading through this thread, I learned that the meter zero adjust has the ability to control the lamp voltage. I tested all voltages after adjusting the meter zero, and everything checked out. Put in the tubes, measured everything again. Most of my voltage measurements were about 10V over, but I thought that was acceptable. Put in the t4b and hooked it up to bass di. It seems to be working great! No hum! The gain and peak reduction controls seem to be a bit hot, but it works and sounds great!

Thanks Scenaria!

 

[Scenaria]

no fire... no explosions?

bummer

:razz:

 

[ToroRojo]

Yeah, no explosions. It reminds me of that time I was stupidly welding next to an oilpan filled with some sort of liquid. I saw a spark fly off the metal I was working on. In slow, agonizing motion, it flew towards the pan of liquid. I saw my life flash before my eyes. Facing certain death or at least dismemberment, I came to terms with everything in my life in that instant. This is it. The end. Maybe I can meet Elvis a-and Marilyn Monroe too! The spark hit the liquid, AND...






















NOTHING.

So I kept welding. However, I cleaned my garage up after that and moved all explosives away from the welding station.


But regarding the LA2A, should the controls be this hot? I'm running the gain knob between 10 and 20. I thought this thing had low headroom! What kind of settings do you guys typically run? The LA3As I own are typically set in the 4-6 range for a good healthy output.

 

[CJ]

Remember that if you were using the LA2 for vocals that you will not have the same signal strenght as listeninfg to an over compressed 2005 CD relaease which is 20 db too hot. I guess it's better to have the gain and not need it...

Try it with a mic and preamp. I am sure you will be happy.

Steve, they wanted 75 bucks to send you that case of beer priority, so I opted for the 7 to 10 day thing. I hope your not pissed. But you will have to take a big piss in 7 to 10. :grin: :guinness:

 

[ToroRojo]

The signal chain I was testing with was as follows:

Fender J-Bass -> Phoenix Audio DRS-2 -> Bloo LA2A.

 

[Scenaria]

the la2's have TONS of gain... very rare to run he gain knob over the 10 oclock position...

more gain is better than less



yay for beer!

:guinness:

we'll see how many break between san fran and orlando..

 

[CJ]

Well, I wrapped each individual bottle with some faom and put them back into the cartons with plento o bubbles in between everything.

Lady at the PO:

"Are there any explosives, drugs, liquids or alchohol inside this? It feels a bit heavy?"

cj: "Hell no, just ship it, ******!" :razz:

 

[Scenaria]

you should seen when I shipped out an eel once

the box had on the side of it "live animal"

took it to a fedex station... the lady was like "umm, what kind of animal is in that box"

my response... was "3 southern pine rattle snakes"

she about **** her pants :green:

I had to open the box to prove it was an eel and not rattle snakes

 

[Butterylicious]

I'm seriously contemplating cloning a LA2A from scratch. I was shocked to discover I have the real McCoy UTC transformers in my "vintage gear collection". My question: The T4A seems to be a critical device. I did see the link on making your own T4A, but if it is as critical as I think it is, I don't wanna use a hack job device. Is it as critical as I think it is? What's the best route for me to take? Could someone please give me (a tech school drop out) a brief overview?

Thank you in advance.




Foot note:
"Vintage gear" may be defined by my wife as a "junk collection."

 

[CJ]

What do you want to know?

 

[SSLtech]

[quote author="Butterylicious"]The T4A seems to be a critical device.[/quote]
It IS the compressor! the rest is just a pair of high-gain amplifiers, a meter, a power supply and a box.

See CJ's page on the T4. Lotsa pics. Also some linked from Kev's page.

Keith

 

[Bluzzi]

What I chose to do for my first LA2A is to get all the original or closest to them. Then if I want to try a DIT T4B or a Jensen transformer etc. I have a working clone and a referrence.

If you already have the transformers you are most lucky! Get the T4B from JBL Pro for around $90.00.

Later on you can decide to try alternatives.


Jim

ps: just got my A-10s, Next T4B! Slowly but getting there.

 

[wilebee]

I would forgo the jbl t4b and go with sceneria's. as its been saind in this thread before the opto's are matched much better !!! I have both Wil

Wilebee

 

[Bluzzi]

I wasn't aware that Scenaria sold them separately.

What is your experience with both T4Bs?

Jim

 

[cannikin]

Replaced the 40uf/30uf caps, no buzz. Man.. its got a lot of gain - sounds great. Anyway its in my rack. thanks everyone.

 

[AnalogPackrat]

Way to go, Dave! :guinness: :guinness: :guinness: I spent three hours on mine last night. I think I'm about half done--can't wait to hear it.

Analog Packrat

 

[Butterylicious]

[quote author="wilebee"]I would forgo the jbl t4b and go with sceneria's. as its been saind in this thread before the opto's are matched much better !!! I have both Wil

Wilebee[/quote]

Well there you have it then. Hopefully sceneria will either email me or PM me some info on the goods. No big rush. This project is still floating around in my head and hasn't reached my fingers yet. Plus I need to finish at least 1 more restoration B4 I start something new.

Thanks Again!
-Richard

 

[SSLtech]

>I wasn't aware that Scenaria sold them separately.
He doesn't.

>What is your experience with both T4Bs?
They are sonically identical to the JBL/Urei/UA's. The only advantage to matching is meter tracking, when set with the correct R25.

It's somehow very ...uplifting... to build your own, -makes it "feel" more valuable than the real thing, available readily -if expensively- to any person willing to spring open his wallet.

If you buy the Bloo kit, you can plug in a real T4B, -I acquired an original CJ T4 for my LA2a, a pair of UA T4s for research and comparison, and I borrowed a NOS box of UREI-era T4B's from a colleague who has several original (VERY original!!!) LA-2a's; also for investigation/comparison. I've built, measured, compared and studied several of Scenaria's Bloo T4s. -Here's the summary:

I sold the UA's to ddt; -not that they were bad in any way, but they were no better, and I'd get a better price for them than the CJ or a home-made one in a plastic relay case. I'm keeping the CJ for my LA-2A and I'm getting a Bloo kit to use as a second LA-2a.

The Bloo is a real LA-2a in every sense that a UA is a real LA-2a.

Keith

 

[Bluzzi]

Thanks Kev - I was hoping Scenaria sold them individually so I will still go with JBL Pro. I have the intention of building some but only after I get my LA2As finished.

Jim

 

[wilebee]

oops I suppose I should have read back a few more posts sorry for any confusions or headaches I thought he was buying a kit My bad Wil