Twisted Pear Audio Support
»
Product Support
»
Analog
»
Legato Discrete I/V Stage
»
Voltage drop on negative rail when connecting Legato to Placid BP
Rank: Member
Groups: Member
Joined: 10/20/2010(UTC)
Posts: 4
Location: Norway
|
When I connect my Legato to the Placid BP, the voltage on the negative supply rail drops to ~ 1 V. The drop on the positive rail drops only 0.6 V in comparison. The unloaded voltage is +- 12 V. My Legato uses a single Placid BP as supply, and I've installed the integrated Ballsie and output buffer. I recently discovered that I don't need the output buffer as the load to be connected is about 100 kohm, but I guess that the voltage drop should be small anyway. I've checked for any cold or dry solder joints and short circuits, without being able to solve the problem. Any suggestions to where I should start troubleshooting, and what I should look for?
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 2,868
Location: Massachusetts, USA
Thanks: 2 times
Was thanked: 141 time(s) in 134 post(s)
|
How have you set the current, and what are you using for a transformer?
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 10/20/2010(UTC)
Posts: 4
Location: Norway
|
Something went wrong with the first Placid BP kit I built, but luckily, I had another kit one in spare. Hopefully, my second attempt will be more successful.
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 10/10/2010(UTC)
Posts: 21
Location: sweden
|
My setup behaves a bit like this as well, even though the voltage drop is smaller. It drops maybe 0,4-0,5V on the negative side and less on the positive. I am using the LCBPS at +/-15 Volts. Do I have a problem or is this normal variation?
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 6/17/2008(UTC) Posts: 921  Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
|
How much current are you shunting in the Placid ?
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 10/10/2010(UTC)
Posts: 21
Location: sweden
|
Im not using a placid for the legato but an LCBPS. THe legato is stripped of the buffer and driven from +/-15 Volt.
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 6/17/2008(UTC) Posts: 921 Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
|
Ohh, sorry. Wasn't paying enough attention. Ok, is it playing ? If yes, the voltage drop is due to the fact that the LCBPS has a rather high resistive input filter. You can try shorting R1-R4 on the LCBPS and see the voltage drop is eliminated. Or you can measure across R1-R4 on the LCBPS. Here you find your voltage drop. But again, if it's playing, it's normal behavior with this power supply. Edited by user Thursday, October 28, 2010 7:55:49 AM(UTC)
| Reason: Not specified
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 10/10/2010(UTC)
Posts: 21
Location: sweden
|
Right, thanks for the help. It is playing so I guess its alright then.
I get the feeling that the general opinion is that the placid would be considered an upgrade to the LCBPS. Perhaps I'll go down that rout eventually, but when I placed my order there were no Placids available. Listening to the thing I cant say I worry to much about it though!
|
|
|
|
|
|
Twisted Pear Audio Support
»
Product Support
»
Analog
»
Legato Discrete I/V Stage
»
Voltage drop on negative rail when connecting Legato to Placid BP
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
