Legato or IVY III outputs for Buffalo II? - Page 2 - diyAudio
Go Back   Home > Forums > Commercial Sector > Manufacturers > Twisted Pear

Twisted Pear Superior quality electronic kits

Reply
 
Thread Tools Search this Thread
Old 21st May 2010, 06:29 AM   #11
sureshm is offline sureshm  Australia
diyAudio Member
 
Join Date: Sep 2007
Russ, whats the current output of the Legato? Is it similar to the IVY (150ma)? Will it be able to power headphones directly? Is there any point running the output of the Legato (without its buffer stage) through a class A buffer then in to headphones? I am asking because I have a few unused JISBOS sitting around? Thanks
  Reply With Quote
Old 24th May 2010, 12:38 PM   #12
needsp is offline needsp  United Kingdom
diyAudio Member
 
Join Date: Jun 2006
Hi Russ

I'm eagerly awaiting Legato, but....

It's not easy to adjust the regulators I'm using to +\- 12V to suite Legato. Possible, but involved, and certainly not suited to an easy comparison of Legato and IVY II.

Would Legato tolerate a 15V supply, and would there be any downside?

Thanks

Paul

I was impressed that you've tried to develop an op amp-free BAL to SE converter for Legato. Any progress? The op amp bothers me. Having heard IVY III I'd have to confess that this is irrational, but I just can't help it
  Reply With Quote
Old 25th May 2010, 05:31 AM   #13
nacder is offline nacder  Hong Kong
diyAudio Member
 
Join Date: Jun 2006
Hi Russ,

I wonder if the Legato concept can be extended to build a power amp. Though we have the chipamp based Sympatico, a well-designed discrete amp will likely have much better performance and this offering would sound very very tempting.
  Reply With Quote
Old 24th June 2010, 08:13 PM   #14
diyAudio Member
 
Join Date: Jan 2002
Location: Cheltenham
Any updates on the progress of Legato?
  Reply With Quote
Old 25th June 2010, 03:31 AM   #15
diyAudio Member
 
Russ White's Avatar
 
Join Date: Jan 2005
Location: Nashville, TN, USA
Send a message via Yahoo to Russ White
Just waiting for the production boards to arrive.

I have been listening to the prototypes for weeks now, and tweaking and testing and getting things just the way I want. I hope you find it worth the wait, but that wait won't be much longer now

The board is very flexible.

You can even use small signal FETs if you like. I have had great luck with BS170/250.

Also the boar clearly shows where to jump and which parts to omit to skip the optional class A buffer. I would not do that. I have found it works best with the buffer.

Here is a pic of the coming board.
Attached Images
File Type: jpg pcb_silk.jpg (471.0 KB, 1149 views)
__________________
Less pulp more juice Twisted Pear Audio.
  Reply With Quote
Old 25th June 2010, 08:34 AM   #16
Spev is offline Spev  United Kingdom
diyAudio Member
 
Join Date: Jun 2005
Location: uk
Nice, can't wait. Cash is waiting and finger is poised to buy now!
  Reply With Quote
Old 25th June 2010, 07:28 PM   #17
diyAudio Member
 
Join Date: Jan 2002
Location: Cheltenham
Thanks Russ. Do you have measurements ... THD, PSRR? Also, I'll likely be driving a pair of transformers for bal-SE conversion, so low output Z is important to me. Can it get down to around 25 ohms per phase?
  Reply With Quote
Old 27th June 2010, 11:40 PM   #18
diyAudio Member
 
Russ White's Avatar
 
Join Date: Jan 2005
Location: Nashville, TN, USA
Send a message via Yahoo to Russ White
Hi Spartacus,

The best I can do is tell you how it simulates and sounds right now. The THD is amazingly low for having no feedback.

Here is the simulated FFT at 20khz it only gets better as the frequency gets lower.

I have many hours listening to it now. The noise floor is surprisingly low for a discrete cct. When I put my ear to the cone of a full range driver with the DAC directly coupled to a balanced power amp with about 20db gain I can't detect any noise at all.

The sound is really really awesome. It is so awesome that I am torn between it and IVY-III. I never expected this.

The output impedance is well under 1ohm. And the drive capability is about 20ma. I have used it driving 600ohm headphones with ease. But I am not sure I would drive a load less than that. It could be done with some tweaking.

Cheers!
Russ
Attached Images
File Type: jpg FFt20khz.jpg (126.8 KB, 1020 views)
__________________
Less pulp more juice Twisted Pear Audio.
  Reply With Quote
Old 29th June 2010, 12:50 PM   #19
diyAudio Member
 
Join Date: Jan 2002
Location: Cheltenham
Impressive THD there, and of course that 5th harmonic won't be heard above 4KHz anyway.

Is the output Z from the balanced buffers or just the opamp?
  Reply With Quote
Old 29th June 2010, 01:06 PM   #20
diyAudio Member
 
Russ White's Avatar
 
Join Date: Jan 2005
Location: Nashville, TN, USA
Send a message via Yahoo to Russ White
The output impedance I mentioned is at the balanced outputs. As well as the FFT I posted is measured (in simulation) there.

I can tell you that it definitely sounds like the simulation is not at all far off.

The output at the BAL/SE converter is 21 ohms if you decide to use the indicated output resistors. But it can be much lower if you like. Just jumper at those spots. The resistors are there to help the opamp drive capacitive loads with stability if they exist. I honestly don't use the BAL/SE section much. Almost all my gear is balanced.
__________________
Less pulp more juice Twisted Pear Audio.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Buffalo DAC+IVY+OPUS+Dual PS for sale huskydawg9 Swap Meet 13 6th February 2010 03:33 AM
Buffalo DAC, IVY, LCBPS pdrie Swap Meet 2 24th July 2009 04:44 PM
Twisted Pear Buffalo/IVY/LCBPS/LCDPS Hacker Swap Meet 6 26th February 2009 05:57 PM
FS: TwistedPair Buffalo DAC+IVY+LCBPS VT67 Swap Meet 3 23rd February 2009 11:38 PM
Twisted Pear Buffalo Dac and Ivy modules - built - for sale phrarod Swap Meet 3 17th January 2009 03:25 AM


New To Site? Need Help?

All times are GMT. The time now is 02:46 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2