Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Login
Proper values for VR1 and VR2 in Legato
Options
View
Go to last post Go to first unread
Previous Topic Next Topic
lindamar  
#1 Posted : Thursday, August 12, 2010 7:59:58 AM(UTC)
lindamar

Rank: Advanced Member

Groups: Member
Joined: 2/7/2009(UTC)
Posts: 51
Location: Spain
I´ve just got my Legato I/V and did realize there are no instructions on how to setup the VR1 and VR2 multi-turn trimmers and their proper values.

Any advice would be much appreciated.

best regards
Pepe
Back to top

Wanna join the discussion?! Login to your Twisted Pear Audio Support forum accountor Register a new forum account.
Back to top  
avr300  
#2 Posted : Thursday, August 12, 2010 8:05:56 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
Yes, here..

http://www.diyaudio.com/forums/twisted-pear/166975-legato-ivy-iii-outputs-buffalo-ii-6.html#post2264243

Edited by user Thursday, August 12, 2010 8:34:50 AM(UTC)  | Reason: Not specified
Back to top
lindamar  
#3 Posted : Friday, August 13, 2010 7:34:18 AM(UTC)
lindamar

Rank: Advanced Member

Groups: Member
Joined: 2/7/2009(UTC)
Posts: 51
Location: Spain
Thank you !
Back to top
dhmpan  
#4 Posted : Thursday, October 28, 2010 9:36:31 AM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
sorry but I cannot follow...
1. the manual says 0 V dc at input...
???
2. You say about measuring AVCC at BII...How?
3. Then check the BII outputs...
check what if there's DC ?
4. All these apply also for SE users?
Back to top
avr300  
#5 Posted : Thursday, October 28, 2010 9:39:47 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
Hi..


1,2 and 3 - take at look here.

http://www.diyaudio.com/forums/twisted-pear/166975-legato-ivy-iii-outputs-buffalo-ii-17.html#post2284681

4. Yes

Edited by user Thursday, October 28, 2010 9:49:47 AM(UTC)  | Reason: Not specified
Back to top
dhmpan  
#6 Posted : Thursday, October 28, 2010 9:50:17 AM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
thanks...
let's see

1. We do this with both units on and stacked?
2. measure each to gnd...
3. devide ...(should they be equal?)
4. measure at what points while adjusting VR's

sorry you do help....but I feel I have some more way to go...Drool
Back to top
avr300  
#7 Posted : Thursday, October 28, 2010 10:04:01 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)

1. Yes.
2. Yes.
3. They are (within the margin). I guess, you will measure 3.4v at AVCC points, and you will adjust to 1.7v at input.
4. At inputs of the Legato.
Back to top
dhmpan  
#8 Posted : Thursday, October 28, 2010 10:14:50 AM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
yes but when they are stacked the output of the BII doesn't become the input of the legato?
So what's the point? Aren't they forced to be equal?

the legato's inputs are +/-/gnd
where should we check for 1.7? + and gnd ?
Back to top
dhmpan  
#9 Posted : Thursday, October 28, 2010 10:14:52 AM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
yes but when they are stacked the output of the BII doesn't become the input of the legato?
So what's the point? Aren't they forced to be equal?

the legato's inputs are +/-/gnd
where should we check for 1.7? + and gnd ?
Back to top
avr300  
#10 Posted : Thursday, October 28, 2010 10:22:16 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)

"+ to GND" and "- to GND" will always be equal, so you can just measure "+ to GND" and trim it to 1.7 V

I have tried timing both unconnected and connected and to makes no difference. The Legato forces the DC offset of the BII to whatever you adjust it to.
Back to top
dhmpan  
#11 Posted : Thursday, October 28, 2010 10:32:49 AM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
hmmm
it seems to be more clear now...
Do you think there would be any harm done to the unit if they are not set correctly ?
(I mean I don't know if the initial settings of the VR pots will have any crazy values)
Back to top
avr300  
#12 Posted : Thursday, October 28, 2010 11:13:51 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
No.
Back to top
back  
#13 Posted : Thursday, October 28, 2010 10:51:31 PM(UTC)
back

Rank: Member

Groups: Member
Joined: 8/24/2008(UTC)
Posts: 61
Location: greece
hi guys.
i just finished my legato and avcc measures 3.5 volt.
i tried to adjust vr1,vr2 but nothing changes.
is there a problem if i leave it like this?

george.
Back to top
avr300  
#14 Posted : Friday, October 29, 2010 3:24:46 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
The AVCC will not change when you adjust vr1/vr2.

The voltage at +/- input will.
Back to top
back  
#15 Posted : Friday, October 29, 2010 7:07:43 AM(UTC)
back

Rank: Member

Groups: Member
Joined: 8/24/2008(UTC)
Posts: 61
Location: greece
so i need to make the voltage input 1.7 volt?
Back to top
avr300  
#16 Posted : Friday, October 29, 2010 9:06:41 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
yeps
Back to top
dhmpan  
#17 Posted : Friday, October 29, 2010 2:27:14 PM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
I don't know if I did something wrong
but
when I first set the VR's so that the input reads 0
then it still reads 0 and I have to take it all the way to 1.75

So what is the point of setting it to 0 in the first place?

the legato BII combo plays just fine..but I don'tknow what I have adjusted

Edited by user Friday, October 29, 2010 2:28:02 PM(UTC)  | Reason: Not specified
Back to top
avr300  
#18 Posted : Friday, October 29, 2010 11:39:17 PM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
If you can obtain 1.7v at input of the Legate you're good to go.
Back to top
dhmpan  
#19 Posted : Saturday, October 30, 2010 12:19:39 AM(UTC)
dhmpan

Rank: Advanced Member

Groups: Member
Joined: 9/1/2009(UTC)
Posts: 31
Location: Greece
avr300 wrote:
If you can obtain 1.7v at input of the Legate you're good to go.


look
I have 3.54 on avcc.
So I set them to 1.77
but...
since I set them initially to 0, when I mounted the buff it still showed 0.
So I took them to 1.77.
What is the point of setting them to 0 if in the end they have to go to 1.77?
Back to top
avr300  
#20 Posted : Saturday, October 30, 2010 12:54:50 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
Just to ensure your initial setting. If you had made an error assembling Legato board and the inputs was at -15V - your BII now would have been upset.

You have done it just right.
Back to top
Rss Feed  Atom Feed
Users browsing this topic
GuestUser (2)
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.

Youtube
Copyright © Twisted Pear Audio