INX5 BUILD THREAD

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Re: INX5 BUILD THREAD

Postby Joe Malone » Sat Aug 11, 2012 9:29 pm

glbaudio wrote:I'm working on a couple of Mac + INX5 with a Lundahl LL1539 (wired as 1:1) and a 2520 DOA clone on output...

ok

I'm watching about the differences between the INX5 and the LA500...
- i see in the LA500 R4 in an half of R3 (as R6 is an half of R5), this means that the gain of the input stage is an half

Yes as it sets the input headroom to be correct. You will have unity in and out at the moment as you are using a 1:1 instead of the 1:2 fro output transformer. But it is best to drop the input 6dB when it changes from balanced to unbalanced so clipping doesn't occur in the input stage. But when you do this you will need to add 6dB gain to the output amp due to the 1:1 output transformer by changing the gain pot to 10k rev log.

- R13 is 470R instead 51R in the INX5
should i do those changes in my 2 INX5?

It should actually be changed to 1k like in the MAC kit to limit the makeup gain to 20dB (1k due to R16 = 20k on INX5. 470R due to 10k on LA500)

Do u think i still need the RV2 Gain?

No the makeup pot on the front panel is RV2

P.S. the pict is old, now i've substited the led (now wired to the VuMeter Led) with a switch...for the link!

Looks great :-)
Joe :-)
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glbaudio
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Re: INX5 BUILD THREAD

Postby glbaudio » Sat Aug 11, 2012 11:23 pm

Joe Malone wrote:
glbaudio wrote:I'm working on a couple of Mac + INX5 with a Lundahl LL1539 (wired as 1:1) and a 2520 DOA clone on output...

ok

I'm watching about the differences between the INX5 and the LA500...
- i see in the LA500 R4 in an half of R3 (as R6 is an half of R5), this means that the gain of the input stage is an half

Yes as it sets the input headroom to be correct. You will have unity in and out at the moment as you are using a 1:1 instead of the 1:2 fro output transformer. But it is best to drop the input 6dB when it changes from balanced to unbalanced so clipping doesn't occur in the input stage. But when you do this you will need to add 6dB gain to the output amp due to the 1:1 output transformer by changing the gain pot to 10k rev log.

- R13 is 470R instead 51R in the INX5
should i do those changes in my 2 INX5?

It should actually be changed to 1k like in the MAC kit to limit the makeup gain to 20dB (1k due to R16 = 20k on INX5. 470R due to 10k on LA500)

Do u think i still need the RV2 Gain?

No the makeup pot on the front panel is RV2

P.S. the pict is old, now i've substited the led (now wired to the VuMeter Led) with a switch...for the link!

Looks great :-)

tnx Joe, done all the changes, but the out was really strange (35dB less), so i have shorted the trafo and the difference is much less: 4,6dB (measuring with Pro Tools and an M-audio Firewire410, generator on one track, and reading value on another track, in bypass i read exactly the gerator value). Still strange.
This means my trafo is wired uncorrectly or broken...ok
this the datasheet: how should i wire it?
http://www.lundahl.se/pdf/1539.pdf
Anyway, actually with the makeup pot at 10K (this unit have the double track, wired only one) and R16 at 20K, i can trim the VuMeter only with "digital" signals, if i try to trim it with analog value (-20dB/-18dB digital) is not possible...
i'm using OPA2604 in input and a cloned 2520 DOA in output
The VU meter is a Nissei TR-35 0dB=1.288V DCR= 650Ω If=450uA

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Re: INX5 BUILD THREAD

Postby Joe Malone » Fri Aug 17, 2012 7:34 pm

Ok something is shorted or wired wrong then. You can make a test plug for the JLMIO port so you can test the INX5 PCB by itself without the MAC PCB.

make a Test plug for JLMIO port.

Link pin 1 to pin 5 (links the unblanced out to the unbalanced in to loop the audio.)

Link pin 3 to pin 8 with a 2k7 resistor (activates the relay to bring the UNX5 pcb out of bypass.)

The balanced in and out can now be used to listen to and test the INX5 PCB

1k tone level at input XLR pin 2 should = level on input XLR pin 3 except out of phase and should also = level at unbalance loop (pin 1 to pin 5). If correct this proves the input balanced to unbalanced amp.

With the makeup fully CCW. You should have the same output level at the balanced output and the balanced input. If not there is a problem with the unbalanced to balanced output amp.
Joe :-)

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Re: INX5 BUILD THREAD

Postby glbaudio » Thu Aug 23, 2012 10:43 pm

Joe Malone wrote:Ok something is shorted or wired wrong then. You can make a test plug for the JLMIO port so you can test the INX5 PCB by itself without the MAC PCB.

make a Test plug for JLMIO port.

Link pin 1 to pin 5 (links the unblanced out to the unbalanced in to loop the audio.)

Link pin 3 to pin 8 with a 2k7 resistor (activates the relay to bring the UNX5 pcb out of bypass.)

The balanced in and out can now be used to listen to and test the INX5 PCB

1k tone level at input XLR pin 2 should = level on input XLR pin 3 except out of phase and should also = level at unbalance loop (pin 1 to pin 5). If correct this proves the input balanced to unbalanced amp.

With the makeup fully CCW. You should have the same output level at the balanced output and the balanced input. If not there is a problem with the unbalanced to balanced output amp.

done, the Bal to Unbal stage works perfectly, the problem is on the Unbal to Bal, on both the units on the pin 2 (output +) is ok (the same value in the unbal point, too), but on the pin 4 (output -) is less than an half... a couple of picts in attachment:
OUT2.png

OUT4.png
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Re: INX5 BUILD THREAD

Postby Joe Malone » Fri Aug 24, 2012 3:40 pm

If you are using a output transformer it is floating so you cannot measure +out to 0v or -out to 0v as they will be be floating at any offset.

Unless you fit 2 x 470R resistor to reference the 2 outs to 0v (1 resistor from +out to 0v and the other from -out to 0v)

Best way to test is below

You need to put the ground probe from the scope on to -out and measure +out with the tip of the probe.

And to prove the output transformer is ok do the same with the connections reversed to see check you have the same volts to prove the transformer has no internal shorts.

(reversed = ground probe from the scope on to +out and measure -out with the tip of the probe)
Joe :-)

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Re: INX5 BUILD THREAD

Postby glbaudio » Fri Aug 24, 2012 8:17 pm

Joe Malone wrote:If you are using a output transformer it is floating so you cannot measure +out to 0v or -out to 0v as they will be be floating at any offset.

Unless you fit 2 x 470R resistor to reference the 2 outs to 0v (1 resistor from +out to 0v and the other from -out to 0v)

Best way to test is below

You need to put the ground probe from the scope on to -out and measure +out with the tip of the probe.

And to prove the output transformer is ok do the same with the connections reversed to see check you have the same volts to prove the transformer has no internal shorts.

(reversed = ground probe from the scope on to +out and measure -out with the tip of the probe)


to do those tests, i've DETACHED the transformers, and shorted on P+ to S+ and S- to 0-

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Re: INX5 BUILD THREAD

Postby Joe Malone » Fri Aug 24, 2012 8:38 pm

With no output transformer and a DOA opamp there is nothing to drive the -out so you should get no signal on -out (you are just getting in phase resistive blend on there at the moment).

-O should be linked to -P to 0v ground it to make the output run as quasi balanced (signal on +out and noise canceling pickup on -out)

-out is only driven when a transformer is fitted or a dual DIP8 opamp.
Joe :-)

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Re: INX5 BUILD THREAD

Postby glbaudio » Fri Aug 24, 2012 8:55 pm

Joe Malone wrote:With no output transformer and a DOA opamp there is nothing to drive the -out so you should get no signal on -out (you are just getting in phase resistive blend on there at the moment).

-O should be linked to -P to 0v ground it to make the output run as quasi balanced (signal on +out and noise canceling pickup on -out)

-out is only driven when a transformer is fitted or a dual DIP8 opamp.


good. this means my modules are working...right?

and this means i cannot use this trafo, that have balanced in and balanced out...or yes? if yes, how?
this the datasheet:
http://www.lundahl.se/pdf/1539.pdf

glbaudio
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Re: INX5 BUILD THREAD

Postby glbaudio » Fri Aug 24, 2012 9:28 pm

glbaudio wrote:
Joe Malone wrote:With no output transformer and a DOA opamp there is nothing to drive the -out so you should get no signal on -out (you are just getting in phase resistive blend on there at the moment).

-O should be linked to -P to 0v ground it to make the output run as quasi balanced (signal on +out and noise canceling pickup on -out)

-out is only driven when a transformer is fitted or a dual DIP8 opamp.


good. this means my modules are working...right?

and this means i cannot use this trafo, that have balanced in and balanced out...or yes? if yes, how?
this the datasheet:
http://www.lundahl.se/pdf/1539.pdf


a solution can be to use the DOA in input, and use a dual DIP8 on output...right?

glbaudio
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Re: INX5 BUILD THREAD

Postby glbaudio » Sat Aug 25, 2012 3:19 am

glbaudio wrote:
Joe Malone wrote:With no output transformer and a DOA opamp there is nothing to drive the -out so you should get no signal on -out (you are just getting in phase resistive blend on there at the moment).

-O should be linked to -P to 0v ground it to make the output run as quasi balanced (signal on +out and noise canceling pickup on -out)

-out is only driven when a transformer is fitted or a dual DIP8 opamp.


good. this means my modules are working...right?

and this means i cannot use this trafo, that have balanced in and balanced out...or yes? if yes, how?
this the datasheet:
http://www.lundahl.se/pdf/1539.pdf


I've answered by myself to this: after a series of tests with the trafo, i've found this Unbal to Bal connection:
LundahlConn.jpg

where the crocodile yellow is the + Input and the black is the - (on the left side)
and on the other side is there the balanced out.
this the result out mounted on the INX5 (with the single DOA on output):
INX5 out.png


what u think about it?

now i try to reconnect the MAC and to trim it!

:)
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Re: INX5 BUILD THREAD

Postby glbaudio » Sat Aug 25, 2012 10:45 pm

well, i've reconnected one unit with the last parameters, it work (the trimming is now performing as analog values too), the only think I don't like is i have a loss of signal when not in bypass (1,40 Vpp in bypass, 1,04Vpp on ON with no compression), i think this is because the configuration (unusual) i've used this trafo, that is made to work with balanced signal in input (and output)...it can be?
I think now i will try on the second unit to use the DOA in input, a dual DIP8 on output and this trafo (in full balanced mode)
any advice on this config?

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Re: INX5 BUILD THREAD

Postby Joe Malone » Sun Aug 26, 2012 6:14 pm

To wire the LL1539 transformer as 1:1

Wire pins 2,4,5 to +P
Wire pins 1,3,6 to -p

Wire pin 8 to +S
Wire pin 12 to -S

Join pin 7 to 11

Let me know what values you have fitted for

Makeup pot 10k or 20k rev log pot?
R25? (should be 100k)
R16?
R13?

And I will work out how to get unity with the 1:1 transformer by changing one of the resistor values.
Joe :-)

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glbaudio
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Re: INX5 BUILD THREAD

Postby glbaudio » Sun Aug 26, 2012 10:48 pm

Joe Malone wrote:To wire the LL1539 transformer as 1:1

Wire pins 2,4,5 to +P
Wire pins 1,3,6 to -p

Wire pin 8 to +S
Wire pin 12 to -S

Join pin 7 to 11

Let me know what values you have fitted for

Makeup pot 10k or 20k rev log pot?
R25? (should be 100k)
R16?
R13?

And I will work out how to get unity with the 1:1 transformer by changing one of the resistor values.


Ok, paralleled the primaries, in serial the secondaries this was the resultant:
before.png


this because the central referrement was not definite, i've then wired 7+11 to the ground (P- in the inx5) and this is the result:
PIN 7+11 to GND.png


not bad.
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Re: INX5 BUILD THREAD

Postby glbaudio » Sun Aug 26, 2012 10:55 pm

Joe Malone wrote:To wire the LL1539 transformer as 1:1

Wire pins 2,4,5 to +P
Wire pins 1,3,6 to -p

Wire pin 8 to +S
Wire pin 12 to -S

Join pin 7 to 11

Let me know what values you have fitted for

Makeup pot 10k or 20k rev log pot?
R25? (should be 100k)
R16?
R13?

And I will work out how to get unity with the 1:1 transformer by changing one of the resistor values.


Time for the Values (always without MAC). A little difference in bypass and ON.

Here in bypass:
Bypass.png


Here in ON:
ON.png


On both the units Makeup Pot are 10k rev log (due i want to do the stereo link connection)
R15 = 100k
R16 = 10k
R13 = 1k

i have the same voltage in input balanced and at the unbalanced point
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glbaudio
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Re: INX5 BUILD THREAD

Postby glbaudio » Mon Aug 27, 2012 12:39 am

wired as this the second unit too, the value are the same

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