Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Idiot seeks help with Hiraga
Idiot seeks help with Hiraga
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 25th August 2017, 02:37 PM   #11
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
Idiot seeks help with Hiraga
Not really, no. It's the simplicity, the well chosen and matched parts, the massive power supply that make it such a good amp.

Just out of curiosity, does your Cary amp have Cary branded tubes?
  Reply With Quote
Old 25th August 2017, 02:55 PM   #12
eduard is offline eduard  Netherlands
diyAudio Member
 
Join Date: Sep 2002
Location: Holland
Send a message via Yahoo to eduard
Hello,
A rather easy modification is changing the two 1K8 ohm resistor which are right above the soldering connection of the wires going to the output transistor. I did change them into 2 watt Allen Bradley 2Kohm or even 2K2 ohm. I changed them more than 30 years ago!! It is not the value change that gives the improvement but probably the bigger wattage and/or type of resistor. I did use the Shinko tantal resistors at that time as used in the original design.
A REALLY nice improvement would be replacing the two resistors in the power supply by two chokes like Lundahl LL1694. Look for the value of the resistors calculate how much there is running. Probably the choke will give a little bigger voltage drop but that is ok!
Greetings, Eduard
  Reply With Quote
Old 25th August 2017, 03:02 PM   #13
farflungstar is offline farflungstar
diyAudio Member
 
Join Date: Aug 2017
I use Shuguan black treasure series tubes and PSVane tubes. I think the Carys need a service to be honest. Surprised 10k of amps are being beaten by the Hiraga.
  Reply With Quote
Old 25th August 2017, 03:03 PM   #14
farflungstar is offline farflungstar
diyAudio Member
 
Join Date: Aug 2017
Quote:
Originally Posted by eduard View Post
Hello,
A rather easy modification is changing the two 1K8 ohm resistor which are right above the soldering connection of the wires going to the output transistor. I did change them into 2 watt Allen Bradley 2Kohm or even 2K2 ohm. I changed them more than 30 years ago!! It is not the value change that gives the improvement but probably the bigger wattage and/or type of resistor. I did use the Shinko tantal resistors at that time as used in the original design.
A REALLY nice improvement would be replacing the two resistors in the power supply by two chokes like Lundahl LL1694. Look for the value of the resistors calculate how much there is running. Probably the choke will give a little bigger voltage drop but that is ok!
Greetings, Eduard
Thanks - I'll look into that.

Last edited by farflungstar; 25th August 2017 at 03:18 PM.
  Reply With Quote
Old 25th August 2017, 04:06 PM   #15
eduard is offline eduard  Netherlands
diyAudio Member
 
Join Date: Sep 2002
Location: Holland
Send a message via Yahoo to eduard
Hello,
I did ask the people in Paris who were selling amps like the Hiraga if i could use a choke that was developped for another design. They said SURE.
Besides the LL1694 there is also the LL2733. It has more mH but also higher serie resistance. I think both Lundahl should be used with their two coils in parallel to reduce DCR.
Hifi collective in the UK has 2k2 AB 2 watt in stock. There could be resistors who could give a bigger improvement but i dont know which one. Maybe the audio note tantal 2 watt or the Mills mra 5. The AB are cheap. If you like the improvement you can decide to try other 2 watt resistors.
BUT i am alomost sure that AB resistors and two LL1694 will give more improvement than 4 audio note resistors.
Greetings, Eduard
  Reply With Quote
Old 2nd September 2017, 09:10 AM   #16
eduard is offline eduard  Netherlands
diyAudio Member
 
Join Date: Sep 2002
Location: Holland
Send a message via Yahoo to eduard
Hello,
It seems this thread is about to die soon.
There are not many people who tried Lundahl chokes like the ll1694 or ll2733 in solid state power amplifiers. If there is a choke used it will usually be a Hammond with something like 10 mH.
The original choke i bought in Paris was 200 mH. I also used it in a 20 watt Hiraga built for a friend.
A friend in Vietnam will finish his Nelson Pass amp with LL2733 choke input power supply. Choke input will need much more AC voltage from the transformer to get the right DC voltage for the circuit. So switching to choke input will need another transformer.
Hiraga amp seems to be sensitive to the quality of the power supply. These chokes will have infinite lifetime so i guess it is one of the best investments to make for this amp.
With choke input you will need another transformer and i would switch to 35/40 volt caps for the first cap. Would be wise to install a bleeder to assure a minimum current flow all the time. For the 30 watt Hiraga the cap right after the rectifier is used to close to its rating.
greetings, Eduard
  Reply With Quote
Old 2nd September 2017, 09:11 AM   #17
farflungstar is offline farflungstar
diyAudio Member
 
Join Date: Aug 2017
I'm getting my techie to take a look at this thread...
  Reply With Quote
Old 2nd September 2017, 10:11 AM   #18
eduard is offline eduard  Netherlands
diyAudio Member
 
Join Date: Sep 2002
Location: Holland
Send a message via Yahoo to eduard
Quote:
Originally Posted by farflungstar View Post
I'm getting my techie to take a look at this thread...
Hello,
I tried to get a closer look at your amp. The original one has one cap after the rectifier, then a resisistor and then two final caps. Because there is a + and a - side you will end up with 4 or 6 caps.
The ones i made use 6 caps and a choke instead of the resistor. If there is enough space inside your chassis it is easy to install!!
The original French 20 watt used 6 68000 F caps. The 30 watt i built used 2 68000F caps and 4 330000F caps.
If your caps are rated 40 volts ( i think they are) you could switch to choke input by adding a 40 volt cap on the + and - side . So both sides ( + and -) will have one choke, one cap with bleeder resistor!!, one resistor and then the two final caps.
The new cap can be something like 33000 F so you can mount it on the inside.
Like i wrote before with choke input you will need a new transformer! Of course you can start by replacing the original resistor by a choke. If you like it you can switch to choke input which will give a bigger improvement.
I have added Lundahl files so you can check if the LL2733 will fit.
Greetings, Eduard
Attached Files
File Type: pdf 1694.pdf (35.9 KB, 65 views)
File Type: pdf 2733.pdf (36.1 KB, 27 views)
  Reply With Quote
Old 2nd September 2017, 10:56 AM   #19
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
Idiot seeks help with Hiraga
Can you show us photos of the power supply?
  Reply With Quote
Old 2nd September 2017, 12:09 PM   #20
eduard is offline eduard  Netherlands
diyAudio Member
 
Join Date: Sep 2002
Location: Holland
Send a message via Yahoo to eduard
Quote:
Originally Posted by Pano View Post
Can you show us photos of the power supply?
Hello,
Are you talking to me?
I dont have the photos because i build this amp before the breakthrough of internet. But i can draw the circuit on a piece of paper and post a picture of that.
I remember well the discussion on paper and in real life about the right transformer. The French did not like toriodal transformers but preferred double c core or EI core. I remember seeing a dac built by Jean hiraga using R core transformer sold by Selectronic company in France but manufactured in India. Selectronic however did cease to exist.
One big advantage of choke input is that the transformer '' sees '' a much easier load to drive. So does the rectifier!
Greetings, eduard
p.s
★ J A C - M U S I C ★ EMISSION LABS TUBES ★ YAMAMOTO SOUNDCRAFT ★ NOS TUBES ★ You must like:
  Reply With Quote

Reply


Idiot seeks help with HiragaHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
new member seeks info. giblaut762005 Introductions 1 4th November 2013 02:20 PM
new member seeks info. giblaut762005 Parts 0 3rd November 2013 08:22 PM
new member seeks info. giblaut762005 Parts 0 3rd November 2013 08:07 PM
new member seeks info. giblaut762005 Parts 0 3rd November 2013 07:59 PM
Newbie seeks driver approval markg Multi-Way 10 19th October 2002 05:39 AM


New To Site? Need Help?

All times are GMT. The time now is 03:16 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki