How fast a 2520 can be destroyed ?

[nielsk]

you may want to note that this is a very early design, they went through many small changes, one of which wound up as a 47 ohm resistor, a 330 uf non polar cap, and a .1 uf cap all in parrallel on the output to the transformer.
BTW, I got some reverse log 25k pots (the correct gain pot) from Kaluka for just a few beans, he probably has more
don't forget the zobel on the input transformer

 

[vertiges]

[quote author="SSLtech"]You should be able to mock-up a 'test-check' unit to check the rest of the circuit... I stress this because you're not using a PCB butusing strip board or something similar, so there are a few unknowns here, and the possibility of overlooking a simple thing like a power rail connection is all-too-easy... (ask me how I know!!! )
[/quote]

I know very well what you're talking about !
After this project, I'm gonna learn to do some etching !

[quote author="SSLtech"]You can use a 5534 or similar as a simple substitution. -It won't drive high levels into the transformer, but if that too slews wildly to one rail or other at the output, your circuit is dead... if it looks good, the 2520 is likely cooked. [/quote]

Do you mean I replace the 2520 with a 5534 in the very same circuit ?
Do I keep all the values of the components around ?
May be I should reduce the voltage... I don't know how much voltage a 5534 can handle. Anyway, I'll check with the DATA sheet.

Thanks a lot,

eD

PS : I should try to burn some less expensive components !!! :evil:

 

[SSLtech]

5534 will do ±18V all day and all night... ±20V for a day or two... how many volts are you running?

For this simple circuit, just keep the output drive moderate if you try and push signal through it, and it should work well enough to tell you if your2520 is buggered or not...

Bonne chance... -A cett heure il me faut dormir!

Keith

 

[peter purpose]

There I go stampeding toward the clitoris, when all that is needed is a little foreplay.

 

[vertiges]

[quote author="nielsk"]one of which wound up as a 47 ohm resistor, a 330 uf non polar cap, and a .1 uf cap all in parrallel on the output to the transformer.
[/quote]

I'm not sure I understand that.
I will make a schematic.


[quote author="nielsk"] BTW, I got some reverse log 25k pots (the correct gain pot) from Kaluka for just a few beans, he probably has more
don't forget the zobel on the input transformer[/quote]

The input TX I choose just need a RL of 150k.

Thanks,

eD

 

[vertiges]

[quote author="SSLtech"]5534 will do ±18V all day and all night... ±20V for a day or two... how many volts are you running?

For this simple circuit, just keep the output drive moderate if you try and push signal through it, and it should work well enough to tell you if your2520 is buggered or not...

Bonne chance... -A cett heure il me faut dormir!

Keith[/quote]

No problem I'm running around 16 volts !

Bonne nuit Keith !

eD))

 

[SSLtech]

Tres bien...

Avec ca, on peut jouer! :green:

A tout a l'heure!

Keef

 

[vertiges]

I've no idea where I connect the ground on a 5534 :roll:

...

:green:

 

[peter purpose]

[quote author="vertiges"]I've no idea where I connect the ground on a 5534 :roll:

...

:green:[/quote]

No connection.

 

[vertiges]

[quote author="peter purpose"]

No connection.[/quote]

I like that kind of answer !!! :grin:


eD

 

[vertiges]

OK... here are the results with the 5534 in the same circuit...


PIN OUT : -15.08 VOLTS (5534 #6)
V+: 16.34 VOLTS (5534 #7)
V- : 16.34 VOLTS (5534 #4)
IN - : -3.43 VOLTS (5534 #2)
IN + : - 5.96 VOLTS (5534 #3)

(5534 #1, #8, #5, not connected)

eD)))

 

[peter purpose]

Similar to the other figures, so you may have dodged the bullet, but you may have assembled a washing machine and not a mic pre.

 

[vertiges]

:shock: But where do I have to put the clothes ?

OK, I will re-re-re-re-re-re-re check everything. Something is definitely wrong there, but I just don't see it...

Thanks,

eD)))

 

[vertiges]

Here are the new voltages I get when I disconnect the link between the output of the input tranformer and the IN +.
I unsoldered the red and the brown of the output TX.

PIN OUT : -15.08 VOLTS (5534 #6)
V+: 16.34 VOLTS (5534 #7)
V- : -16.34 VOLTS (5534 #4)
IN + : -3.43 VOLTS (5534 #2)
IN - : - 15.08 VOLTS (5534 #3)

(5534 #1, #8, #5, not connected)

So now, the circuit is basically a 5534, 1 resistor, 1 cap, 1 V+ and 1V-

eD

 

[drpat]

Is that a typo, or do you really have positive voltages on both rails??? :?

 

[peter purpose]

No ground connection anywhere?
While the op amp requires no ground, the circuit does.

peter

 

[SSLtech]

[quote author="peter purpose"]There I go stampeding toward the clitoris, when all that is needed is a little foreplay.[/quote]

http://youtube.com/watch?v=uDoQFcQEpOQ

(about 3:00 into the clip... :green: )

Keef

 

[vertiges]

[quote author="drpat"]Is that a typo, or do you really have positive voltages on both rails??? :?[/quote]

No, I forgot the "minus"... :?

eD

 

[vertiges]

Here is the circuit I'm testing :
(a schematic is better than 1000 words)

PIN OUT : -15.08 VOLTS (5534 #6)
V+: 16.34 VOLTS (5534 #7)
V- : -16.34 VOLTS (5534 #4)
IN + : -3.43 VOLTS (5534 #2)
IN - : - 15.08 VOLTS (5534 #3)

Am I missing something ? :roll:

eD)))

 

[SSLtech]

There's no DC reference connection to pin 3... connect a resistor to ground and repeat the test...