LA-4 Help Thread!

[Luny Tune]

Well, I do kinda recommend making your own optos for one reason and that is to do just that; Build your own. THAT's diy!

But NSL or Vactec optos will work just fine so it's not really necessary... But it gives you a sense of satisfaction to build your own.

And the danish groupdiy.dk is up and running again, SIXTYNINER.

Here's our danish shopping list for the LA-4. I'll keep an eye out for your questions if you have any.
http://www.groupdiy.dk/index.php?topic=1299.0

The LDRs are missing on it. I'll check up on it as soon as possible...

The part codes corresponds to this webshop's: http://www.el-supply.dk/

Here's what they write on the website about shopping from abroad:
"It is possible to order from EL-SUPPLY even if you live outside Denmark. Choose "Bestilling fra udlandet" when the order is send. You will then be contacted by EL-SUPPLY with information about how much you need to transfer. The amount can be tranferred using a credit card or our bank.

Please notice that orders from outside Denmark will be added a fee on approximately 10% or the total because of extra costs when receiving the money. The minimum amount added is dkk 10,-"

("Bestilling fra udlandet" means "Ordering from abroad".)

 

[SIXTYNINER]

HI LUNY
watched all pages but no list here
http://www.groupdiy.dk/index.php?topic=1384.90

:-\

6t9r

 

[Luny Tune]

Oops maybe I fixed it so you have to be amember to see the shopping list... :-[

Well, here it is:

1   567.050218    RINGKERNETRANSFORMATOR 2x18V/50VA 149,00 149,00    
1   263B250C1500  BROKOBLING RUND 420V RMS/1.5A 3,00 3,00    
2   251N4003      ENSRETTERDIODE 200V/1A 0,36 0,72    
4   251N4148      SMÅSIGNALDIODE 100V-0.2A 0,20 0,80    
1   27110         ZENERDIODE 10V/0.5W 0,66 0,66    
3   40TL074CP     TL074CP OP-AMP QUAD BIFET LNOI 14P 3,54 10,62    
2   45A.2D        RØD LED STANDARD 10mm DIFUS 3,06 6,12    
2   453.2D        RØD LED STANDARD 3mm DIFFUS 0,84 1,68    
2   30BD139-16    BD139-16 NPN TRANSISTOR 80V/1A/12.5W 2,34 4,68    
1   30BD140-16    BD140-16 PNP TRANSISTOR 100V/1.5A/12.5 2,34 2,34    
1   2827818       DC REGULATOR 18V/1.0A POS.TO220 3,80 3,80    
1   2827918       DC REGULATOR 18V/ 1A NEG.TO220 4,74 4,74    
3   211I1691      RADIAL ELEKTROLYT 6.8µF-63V 1,40 4,20    
3   211E3101      RADIAL ELEKTROLYT 100µF-25V 0,54 1,62    
2   211H4101      RADIAL ELEKTROLYT 1000µF-50V 4,20 8,40    
3   11803         10 mm H TRIMMER LUKKET 500 OHM 1,44 4,32    
1   11807         10 mm H TRIMMER LUKKET 10 KOHM 1,44 1,44    
1   11811         10 mm H TRIMMER LUKKET 250 KOHM 1,44 1,44    
2   12122.6       DREJEPOTENTIOMETER MO. 10KOHMB 6mm AXEL 9,20 18,40    
3   064499        1% 4.99KOHM METALFILM MODSTAND 0,80 2,40    
4   065100        1% 10.0KOHM METALFILM MODSTAND 0,80 3,20    
6   051522        SFR 25 22kOHM METALFILM MODSTAND 0,80 4,80    
3   051533        SFR 25 33kOHM METALFILM MODSTAND 0,80 2,40    
1   051530        SFR 25 30kOHM METALFILM MODSTAND 0,80 0,80    
1   051582        SFR 25 82kOHM METALFILM MODSTAND 0,80 0,80    
2   051610        SFR 25 100kOHM METALFILM MODSTAND 0,80 1,60    
1   051482        SFR 25 8.2kOHM METALFILM MODSTAND 0,80 0,80    
2   051433        SFR 25 3.3kOHM METALFILM MODSTAND 0,80 1,60    
3   051447        SFR 25 4.7kOHM METALFILM MODSTAND 0,80 2,40    
1   051410        SFR 25 1.0kOHM METALFILM MODSTAND 0,80 0,80    
2   051247        SFR 25 47OHM METALFILM MODSTAND 0,80 1,60    
2   051215        SFR 25 15OHM METALFILM MODSTAND 0,80 1,60    
1   051333        SFR 25 330OHM METALFILM MODSTAND 0,80 0,80    
1   051347        SFR 25 470OHM METALFILM MODSTAND 0,80 0,80    
2   051710        SFR 25 1.0MOHM METALFILM MODSTAND 0,80 1,60    
1   065750        1% 75.0KOHM METALFILM MODSTAND 0,80 0,80    
3   064357        1% 3.57KOHM METALFILM MODSTAND 0,80 2,40    
1   051422        SFR 25 2.2kOHM METALFILM MODSTAND 0,80 0,80    
1   051456        SFR 25 5.6kOHM METALFILM MODSTAND 0,80 0,80    
4   172I100       WIMA MKT KONDENSATOR 100nF/63V 5mm 1,44 5,76    
1   173I220       WIMA KONDENSATOR 220nF/63V 7.5mm 2,40 2,40    
1   172Hµ2.2      WIMA MKT KONDENSATOR 2.2µF/50V 5mm 11,40 11,40    
1   15112         KER. KONDENSATOR 4.7 pF 1 MODUL 0,60 0,60    
1   15119         KER. KONDENSATOR 18 pF 1 MODUL 0,60 0,60    
1   15120         KER. KONDENSATOR 22 pF 1 MODUL 0,60 0,60    
1   15226         KER. KONDENSATOR 100 pF 2 MODUL 0,60 0,60    
2   15234         KER. KONDENSATOR 470 pF 2 MODUL 0,60 1,20    
2   6052          DREJEOMSKIFTER 2plx6st.m.L.Ø. 6.0mm AX 17,00 34,00    
1   6040D         DREJEOMSKIFTER 1 PL. 230V LORLIN 15,00 15,00    
2   6020          MICRO VIPPEOMSKIFTER 1 PL 7,20 14,40    
1   4821          APPARAT CHASS.BØSNING 3PL.HAN m.SIKRH. 17,70 17,70    
1   5022          XLR BØSNING HAN 3PL PLAST 15,36 15,36    
1   5023          XLR BØSNING HUN 3PL PLAST 16,08 16,08    
1   5003HVID      PHONOCHASSISBØSNING HVID 2,64 2,64    
6   5556.03       3 PL. PINRÆKKE M.FLIG LIGE MOD 2.54 1,20 7,20    
6   5556.02       2 PL. PINRÆKKE M.FLIG LIGE MOD 2.54 1,14 6,84    
5   5595.02       HUNSTIK m. PÅMONTERET KABEL 2PL 4,74 18,96    
5   5595.03       HUNSTIK m. PÅMONTERET KABEL 3PL 5,40 27,00    
3   5557.03       LØS CRIMPHUS M.LÅS 3 PL MOD 2.54 0,36 1,08    
3   5557.02       LØS CRIMPHUS M.LÅS 2 PL MOD 2.54 0,35 1,05    
 
 
Pris ialt DKK 460,65  
25% Moms DKK 115,16  
Pris incl. Moms DKK 575,81

It can be copy/pasted in a mail to the shop if you call/email them beforehand. They're very helpful over there.

Anyways, you can find the missing parts on your list here.

 

[Audioman]

Hi Luny,
I starting the order of the component for the LA-4 but i have a doubt about the resistor value :

-Are all 1/2 Watt ?
-250 Volts ?
-5% 0r 1% ?
-Normal metal film ??

Did you have a BOM with the farnell or other code ??
Please let me know
Fabio

 

[Luny Tune]

Check note number 1 in the schematic on page 31 in the manual.

No I have no BOM for Farnell. "Only" for the shop I mentioned just above your post.

 

[Audioman]

Hi Luny,
Okkey now all is clear thank you !!
Another question : if i use 1% resistor is better or not than 5% ? (from the sound point of view )
Thank you again
Fabio

 

[Luny Tune]

Well, if you use 1% resistors, in teory two stereo strapped units would sound closer to eachother sonically... but I really don't think it matters as I think all relevant tolerances are adjusted and compensated for during the adjustment procedure.

NOTE that there ARE some resistors that MUST be 1% and those are the three 4K99Ω and the 10KΩ around IC3-B in the schematic.

 

[Audioman]

Okkei
Thank you Man !!!
Fabio

 

[kazper]

Some Mouser part numbers for the PCB mounted 10 mm pot's.

500R = 531-PT10V-500
10K = 531-PT10V-10K
250K = 531-PT10V-250K

The layout fit is fine. On the Original offered board's I had to enlarge the PCB holes with a #56 drill bit.

#56 = 1.1811 mm =0.0465"

AS a note, Lunny said he was going to enlarge the holes on later revisions offerings.

Kaz

 

[MrZpliff]

Hi !

Been gathering all the parts during summer, so time to start building.

A question concerning the meter though. Since th Sifam AL-29 is
rather expensive I'm looking at Hairball's meter:

http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=40

I've been comparing it with the one in the LA-4 manual and they seem just about the same.
I don't care for level too much I use the meter as an indication of gain reduction most of the time.

Any reason it won't work ?

 

[Luny Tune]

That'll work fine!

 

[SaMpLeGoD]

Hi! I'm building a dual LA-4 unit, and I realize from the schematic that the unit don't have any connection to bypass them... right? should I go thru making some with relays right? just to know!

Cheers,

Eddie

 

[Luny Tune]

In my opinion it's unnecessary.

Having inserted it on a channel in a console you can just pull it out of the patchbay or push the "Insert in/out" button on the channel if you're on a large format console with such features on it.

In the computer you can just bypass the In/Out plugin you're using...

 

[kazper]

Hi! I'm building a dual LA-4 unit, and I realize from the schematic that the unit don't have any connection to bypass them... right? should I go thru making some with relays right? just to know!

Cheers,

Eddie

Agreed that it is typically unnecessary as Lunny suggested but [Silent:Arts] Volker may have something for you in his web shop once it's open. He had a fairly nice PCB and you can use common voltage relays  as you bypass means if you so desire. There may be a offering from Guvatone also in his Orange 86 stuff.

 

[geoff004]

He had a fairly nice PCB and you can use common voltage relays  as you bypass means if you so desire.

I setup one power section for the LA4s and the other for bypass relays in my dual LA4 build.  Just change out the 7818 for a 7812 and use a 12v relay.

 

[SaMpLeGoD]

He had a fairly nice PCB and you can use common voltage relays  as you bypass means if you so desire.

I setup one power section for the LA4s and the other for bypass relays in my dual LA4 build.  Just change out the 7818 for a 7812 and use a 12v relay.

Nice idea! but, I'm already have a 12VDC PSU made for suply the festoon lamps for both VUs... the lamps needs 140mA each, plus the Relays and some leds, I thought's better use a cheep small tranf 230 -> 12V to do the job alone... surely my 30VA toroid could do the same, but... just in case... why not!
Thanks a lot!

Eddie

 

[SaMpLeGoD]

hey... just a quick question... di you wired the OEp's primaries and secondaries both in serie or paralel? since they are 1+1:2+2 wich impedance it should have for this project?

Series  = Prim-> 600Ohm and sec-> 2.4KOhm
Paralel = Prim-> 150Ohm and sec-> 600Ohm

I guess Paralel, since it will go out mic level :S
Thanks a lot... sorry the rookie question!

Eddie

 

[Luny Tune]

I mounted it in parallel and backwards first (it's secondary is my primary and vice versa) but I changed something...let me see what I did. I'll check some time today...

 

[SaMpLeGoD]

Hey Lunny, thanks for replying!
Ok so we need a step up for the output... Can I use the OEP 262A3E (1+1:6.45+6.45) reversed? too much for output gain? Just asking because I have some hanging around 
If not, no problem! I'll use the OEP 262A2E!
Thanks a lot

Eddie

 

[SaMpLeGoD]

I mounted it in parallel and backwards first (it's secondary is my primary and vice versa) but I changed something...let me see what I did. I'll check some time today...

Hey LUny, what did you changed beside that? can you post it?
Thaks a lot! just finishing mine!

Eddie