D-LA2A Support Thread

[stereokillah]

Thanx again Silent arts for yours fast reply i will recheck it,

 

[stereokillah]

ok ,
it's good now, don't why perhaps a bad stuff, i had 100 ohm on the 4 heater to ground i have stuffed all the wire H1 and H2 and all seems work .


i will do audio test tomorow if i can.
i 've forgoten to put the resistor before the + of vu meter and i need to take 5v for all my led.

i will sleep bester now thanx Silent arts

 

[stereokillah]

I'm happy to test it , even i have problems it's only small probelem.

First the sound crack on bypass mode when i put the volume  above the 0db perhaps it's normal
and same on compressor mode .
second i have a hi cut around 15khz and low cut around 120hz  i think it's edcor transfomer problem as i read before about the Bernbrue unit.
and i need to calibratre the VU.

SO i think i wil  change the gain pot like a lot a guys and tehe audio transformer.

 

[rob_gould]

Hi All,

I'm confused by all the different transformer information that's floating round for this project.

I was thinking about getting Sowter to do a custom version of the 4383 but with 1:1 ratio, just to control the input gain a bit more. 

All the input trannys for this project seem to be 600/10k which makes sense, but over at Frank's place Volker recommends using a 1:1 input tranny with 10k/10k impedance.

I did not think that changing ratio would make a difference to the impedance that should be used, because the impedance depends on the circuit connected to the input on one side of the tranny, and the input stage of the LA2A circuit connected to the other side of the input tranny?

Aaargh  ???  Can anyone help me out on this?!

Thanks 

Rob

 

[stereokillah]

i think you can choise your transformer yourself to have the sound as you like but this projects be more sure and adapted with the swoter input and output like you can see on the board.

For me , it's a cheaper price choise but i think i will take input sowter .

Second thing the 4383 seems to be 600/10k check it http://www.sowter.co.uk/specs/4383.htm

 

[rob_gould]

Yeah it's Sowter that I intend to go for, but the impedances are the part that confuses me.

Top of the page you linked to says this by the way : 600/10K Line Input Transformer.

Have I got it wrong that this means 600 on the primary side and 10k on the secondary side?

 

[stereokillah]

yes soory 600 to 10k input

 

[Silvas]

Hello

It is safe to use a lower voltage rated poly cap for the 0.1 c102, c202, c103, c203 ? according to CJ's voltage chart, there's around 100 volts DC to block...and i'm short of 0.1/400v caps, but have lots of nice ERO mkp1840 which i would like to use if their 160v rating isn't a problem here. What do you think guys?

Also : i'm having some trouble locally sourcing the silver mica caps (i forgot to put them on my big parts order from USA), it is possible to substitute them with other types ? what about their influence in the sound of the unit? But maybe i'll just do a small order from Small Bear...

Thanks so much !

 

[MartyMart]

Hi Silvas, I have to do a similar thing with those caps so I think that you'll be OK
I have several 250v in those sizes though.
Smallbear are quick and fairly cheap for the mica's
A few years ago on evilbay, I got a HUGE bag of mica's in lots of values for $50
wish I had bought more as they seem expensive these days !!!

MM

 

[stereokillah]

hello guys,
like i'm a beginer , i would to know weach fuse i need to use in this unit please, or simple how to know.
thanx

 

[Silvas]

Hello

It is safe to use a lower voltage rated poly cap for the 0.1 c102, c202, c103, c203 ? according to CJ's voltage chart, there's around 100 volts DC to block...and i'm short of 0.1/400v caps, but have lots of nice ERO mkp1840 which i would like to use if their 160v rating isn't a problem here. What do you think guys?

Also : i'm having some trouble locally sourcing the silver mica caps (i forgot to put them on my big parts order from USA), it is possible to substitute them with other types ? what about their influence in the sound of the unit? But maybe i'll just do a small order from Small Bear...

Thanks so much !

I figured it out....i can use the 160v polypropylene on c102, c202 (around 90 volts dc) but not on c103, c203. Anyway, i was only 2 caps short (c102 and c202). Still not sure about using other types for the silver micas.

 

[Silvas]

Hello

It is safe to use a lower voltage rated poly cap for the 0.1 c102, c202, c103, c203 ? according to CJ's voltage chart, there's around 100 volts DC to block...and i'm short of 0.1/400v caps, but have lots of nice ERO mkp1840 which i would like to use if their 160v rating isn't a problem here. What do you think guys?

Also : i'm having some trouble locally sourcing the silver mica caps (i forgot to put them on my big parts order from USA), it is possible to substitute them with other types ? what about their influence in the sound of the unit? But maybe i'll just do a small order from Small Bear...

Thanks so much !

I figured it out....i can use the 160v polypropylene on c102, c202 (around 90 volts dc) but not on c103, c203. Anyway, i was only 2 caps short (c102 and c202). Still not sure about using other types for the silver micas.

I ended up ordering the silver micas from small bear anyway....now, i´m waiting for the antek power trafos (one for the HT/heater and a small one for relays) to turn the D-LA2A on...

 

[stereokillah]

Great GReat GREat GREAt GREAT!!!

I 've put the swoter input and all work fine , i've tried  Tung sol 12AX7A and Sovtek 12AXLPS

Definitively i keep the sovtek the tungsol give me a bad noise about -65 db  but sovtek -80

Just have some difference between the two vu meter don't know why.

So thank you for all th help .

 

[[silent:arts]]

cool 8) 8) 8)

what is the difference between the two meters?

and don't forget some pics with the tubes inside - looks much better in your banner ;D

 

[stereokillah]

Hi SIlent arts

for my vu meter , with the same signal one give me -7 and second -8 same thing in GR for same zero depart
it's JLM meter like sifam al 19
the R 3k9 seemed not to be enought strong i 've put oe trimer on the + to

Thank you

 

[SIXTYNINER]

"photo cells" are custom T4b ?
8)

 

[[silent:arts]]

"photo cells" are custom T4b ?
8)

yes, you won't buy them at mouser, digikey, farnell etc

 

[RedNoise]

congrats StK ! Very nice DLA2A...Too fast for me bro! ;D

Did you finally screwed the Sowter?(or did you rubber them?)

 

[stereokillah]

thanx Rednoise!

it's screwed to the support plate

 

[stereokillah]

"photo cells" are custom T4b ?
8)

sorry
come from Drip electronic