L'Amp: A simple SIT Amp - Page 91 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd April 2012, 06:48 AM   #901
diyAudio Member
 
OlavHaal's Avatar
 
Join Date: Oct 2010
Location: Haugesund
Hi Juanitox!

Nice suggestions - will try most(exept fishing in the COLD Norwegian rivers this time of year - did much of that earlier in life- my family owned a little bit in a nice river).

One thing I forgot - I have two amps(monoblock) with 2 400 watt and 15 - 20 Caddock 50watt different resistors! Enough for a while.
But I will order the spare 2SK82 and the 100000 mF and wait with the Hammond(very heavy and expensive postage).

And I have to take my 2 week offshore-schedule in Telecom from 5 April - then my youngest daughter is into the confirmation middle of May.
So to avoid your prognosed divorce - and not having to stay in the cold river, fishing red-meat salmon - I try build in small amounts 1 hour pr day. And my boxes is mostly OK now - so I will solder resistors and such after 20 april. But also according to my family`s plans(or else.....)

Really looking forward to that day when the first stage is finished - last night I listened to Ryan Adams/Ashes and Fire. On my B1/classdD Amp - and it was like the band was playing in my house.

Wonder how can anything be even more lifelike......

Thanks Juanitox and everyone for suggestions.

Best

Olav
  Reply With Quote
Old 3rd April 2012, 07:05 AM   #902
generg is online now generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
Olav,

Here you pay 35 € for postage fee and about 120€ for two hammonds 193v

Tube-Town Online-Store - Hammond Drossel 193V ha193v
__________________
and the First Wtt is......a really First Class PSS Idea
  Reply With Quote
Old 3rd April 2012, 07:20 AM   #903
generg is online now generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
Thumbs up Rethinking

Quote:
Originally Posted by ilimzn View Post
I have also developed and prototyped one of my own, but this is now being completely re-thought and re-designed, since new data and devices have become available to me.
Hi ilimzn,

Thank you for the private insight, so you have a really long history with these parts and I am happy you can contribute some ideas to this thread or a thread of your own.
I hope you do not hesitate a too long time to give us some impression of your prototypes....... after rethinking all!
__________________
and the First Wtt is......a really First Class PSS Idea
  Reply With Quote
Old 3rd April 2012, 08:42 AM   #904
diyAudio Member
 
OlavHaal's Avatar
 
Join Date: Oct 2010
Location: Haugesund
Hi again to all!

This guy has made many SIT`s - some nice - some are strange and complex! Ilimzn may have tried some of them.

And maybe you all probably has seen them before.

Evolve Power Amplifiers

Best

Olav
  Reply With Quote
Old 3rd April 2012, 09:55 AM   #905
ilimzn is offline ilimzn  Croatia
diyAudio Member
 
Join Date: Feb 2005
Location: Zagreb
Quote:
Originally Posted by generg View Post
Hi ilimzn,

Thank you for the private insight, so you have a really long history with these parts and I am happy you can contribute some ideas to this thread or a thread of your own.
I hope you do not hesitate a too long time to give us some impression of your prototypes....... after rethinking all!
Although I have been 'into SITs' for a long time, most of my experience outside the actual behavior of the parts, is related to much more complex (perhaps needlessly complex) amplifiers, some of which do not really use the SITs to their full advantage. My prototype was a push-pull hybrid, but I have since figured out a better topology to use, and found a different part that may have some advantages which may even be peculiar amongst SITs. Now, if there was only time...

As for the SITs not being utilized with theri particular triode-like advantage, it may be due to the fact that they appeared when engineers were already taught that tubes were a thing of the past, and semiconductors were the future. I would guess that not having dealt with triodes, many would have missed the point of a SIT.
In fact, I can give you an example - Sony has a small VFET/SIT, 2SK63/79 (same part, different case) which they used in some of their amps in the phono section, as the second stage - the first being a special low-noise BJT that operates on very low currents. In this design the SIT was really only used as a FET due to it's high input impedance, to interface with the megaohm output impedance of the previous stage. It also provided a reasonably low output impedance for a two-stage amp - but lacked in gain (it's a design with RIAA network in the feedback loop), because of SIT mu. They could have easily used a largeish JFET and got better results, but there was no such part being made in-house. Paradoxally, this part was ONLY used in that position before they stopped making it, so it was never really used 'properly'. Modifying the design with a small MOSFET in it's place (now commonly available) signifficantly improves on the original.
  Reply With Quote
Old 3rd April 2012, 01:41 PM   #906
suburra is offline suburra  Italy
diyAudio Member
 
Join Date: Aug 2009
Quote:
Originally Posted by Salas View Post
Detail for applying the sense terminals for Marco & you. Try to keep the loop area (sense wires enclosed area) minimal. Tightly twisting their most length is welcome if feasible. Their gauge can be relatively thin. Choose that next to C1 K117GR for about 3.15mA IDSS.
Thank Salas, will do

Marco
  Reply With Quote
Old 5th April 2012, 08:49 AM   #907
protos is offline protos  Greece
diyAudio Member
 
protos's Avatar
 
Join Date: Mar 2002
Location: Athens+Addis Ababa
Ilimzn thanks for all the info.
I think the point about variability in the parameters due to the power supply fluctuations points to the need either for a current source or a regulated supply as ilimzn noted (or both).
Ilimzn mentioned something about the high capacitance of mosfet ccs being not ideal for the sit. The ccs with the semisouth r100 is better in this regard since I see that it has half the capacitance of i.e. the irfp240. Correct?
What about a simple programmable ccs based on the LM338 regulator? It is not fashionable but would it sound as good as a single fet? Or does the ccs not contribute so much to sound quality?
__________________
``The author always assumes that when power is applied , the amplifier will explode or ,at the very least, catch fire.´´
Morgan Jones, Building Valve Amplifiers.
  Reply With Quote
Old 5th April 2012, 12:08 PM   #908
diyAudio Member
 
Join Date: May 2001
Blog Entries: 5
  Reply With Quote
Old 5th April 2012, 12:17 PM   #909
generg is online now generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
Quote:
Originally Posted by Michael Rothacher View Post

Have nice Easter Holidays Mike!

I have 7 different input caps In front of my SIT.......they all sound different....not easy to decide......I will switch to and fro til I can't do anymore....
__________________
and the First Wtt is......a really First Class PSS Idea
  Reply With Quote
Old 5th April 2012, 08:50 PM   #910
generg is online now generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
I tried Panasonic ECQ, Ero1813MKT, Obbligato gold, Russian KP75 paper oil, Cornell Dubilier KP, Elna Silmic always 10uF......
And I compared with my BJ2 to get a similar or better sound balance and in this Bj2 are two Elnas, one in the negative input and one going to the upper Semisouth.
So the result was programmed .......the Elna Silmic as input cap for the SIT gave the same sound of course....
You will laugh......
The Cornell KP had the most impressive attack and accuracy but was to sharp over the time, the Russian made wonderful colors but was a bit to soft...
The Panasonic was very balanced.... The ERO too soft, the Obbligato was the loudest and had a very big image with much bass and highs, but all the film caps sounded a bit tamed against the Elna...

My last film cap try will be the Clarity caps Nelson used in BA-3 and maybe in SIT-1 ....
They are ordered and I will see...Have all nice Easter days!
__________________
and the First Wtt is......a really First Class PSS Idea
  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
L’Amp: A Simple SIT Amp: Part 1 Michael Rothacher diyAudio.com Articles 22 5th October 2013 09:25 AM
SIT Amp Article Out Now Variac Site Announcements 0 2nd December 2011 07:55 AM
Srajan has the 1st SIT amp for Une dégustation vizion Pass Labs 131 14th November 2011 11:41 PM
SIT-Preamp VladimirK Solid State 36 27th August 2011 08:36 PM
New SIT - old problem StevenOH Parts 2 13th June 2008 10:46 AM


New To Site? Need Help?

All times are GMT. The time now is 08:48 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