Hello,
Long time ago the company that did sell the stuff necessary to make these circuits published in a french magazine by jean hiraga did also sell 200mhenry chokes to replace the resistor in the power circuit. This is more then 20 years ago. This choke was constructed for a single ended transistor design with one powerfet and an output transformer. So people begin asking could i use this choke for the 20 or 30 watts hiraga design? The two models available in the shops would use a double c- core transformer. For the kit of the 30 watt hiraga a 500va ordinary transformer was available. The model i did buy did use 68000mf in front of the choke and four 330000MF (2 for+ 2 for_) All six were 25 volts and after a few years one of the 68000mf did start leaking. They were used very close to their max. working voltage The 330000 were especially made for the hiraga design and were very expensive. The chokes did look very ordinary and were cheap for the improvement they did offer. Their dc resistance was about 1 ohm. Maybe if i would still be in my hiraga era i would try to go for a choke input version but that should be done with an impregnated or potted and shielded choke probably because of the hig current involved( 1.5A for the 30 watt) Maybe there are companies that have a choke in their list that could be used for running a small comparison and after that one could ask them to make one perfect for this design. Greetings, eduard
Long time ago the company that did sell the stuff necessary to make these circuits published in a french magazine by jean hiraga did also sell 200mhenry chokes to replace the resistor in the power circuit. This is more then 20 years ago. This choke was constructed for a single ended transistor design with one powerfet and an output transformer. So people begin asking could i use this choke for the 20 or 30 watts hiraga design? The two models available in the shops would use a double c- core transformer. For the kit of the 30 watt hiraga a 500va ordinary transformer was available. The model i did buy did use 68000mf in front of the choke and four 330000MF (2 for+ 2 for_) All six were 25 volts and after a few years one of the 68000mf did start leaking. They were used very close to their max. working voltage The 330000 were especially made for the hiraga design and were very expensive. The chokes did look very ordinary and were cheap for the improvement they did offer. Their dc resistance was about 1 ohm. Maybe if i would still be in my hiraga era i would try to go for a choke input version but that should be done with an impregnated or potted and shielded choke probably because of the hig current involved( 1.5A for the 30 watt) Maybe there are companies that have a choke in their list that could be used for running a small comparison and after that one could ask them to make one perfect for this design. Greetings, eduard
Hello,There has been a 50 watt kaneda design that did use the same choke 200mhenry 2,5A as my old 30 watt hiraga It is a pity that you probably have to adjust your chassis to use these coils.
Because you have some extra voltage maybe you could make a choke-input with a choke with more mhenry to get the voltage down. I never did try that with a transistor design but i did gain a lot with tube circuits. But it has to be a potted one because it will probably vibrate a lot when there is so much current running. If you did not actually listen to it you can do some things in advance to make the use of chokes easier.
I remember that replacing the two 1800 ohm 0,5 watt resistors supplied in Paris by 2 watt Allen Bradleys or was it Mills did make a big improvement.
Hiraga did pay a lot of attention to chosing the right components
But it is long time ago that i did spend time reading about it. It is a pity that outside Europe there aren't many people that can read his articles. The first ones on this hiraga amp were published in 1979. there has also been a cd rom available with copies of the magazines called l'audiophile. The original magazines were allready hard to find when i did start collecting them. Nice to see that this design still draws a lot of global attention. Greetings Eduard
Because you have some extra voltage maybe you could make a choke-input with a choke with more mhenry to get the voltage down. I never did try that with a transistor design but i did gain a lot with tube circuits. But it has to be a potted one because it will probably vibrate a lot when there is so much current running. If you did not actually listen to it you can do some things in advance to make the use of chokes easier.
I remember that replacing the two 1800 ohm 0,5 watt resistors supplied in Paris by 2 watt Allen Bradleys or was it Mills did make a big improvement.
Hiraga did pay a lot of attention to chosing the right components
But it is long time ago that i did spend time reading about it. It is a pity that outside Europe there aren't many people that can read his articles. The first ones on this hiraga amp were published in 1979. there has also been a cd rom available with copies of the magazines called l'audiophile. The original magazines were allready hard to find when i did start collecting them. Nice to see that this design still draws a lot of global attention. Greetings Eduard
Yes i have the full CDrom set it i think it is well worth getting if you want to build some hiraga stuff.
I cant read french but the diagrams and pics are useful.
the link to a translated version with most of the info is here:
http://www.tcaas.btinternet.co.uk/hiraga.htm
-Dan
I cant read french but the diagrams and pics are useful.
the link to a translated version with most of the info is here:
http://www.tcaas.btinternet.co.uk/hiraga.htm
-Dan
Hello,
I have both the magazines and the cd-rom. Both contain loads of information on some very good designs. I think the shop in Paris still exist but because of the internet people did start buying their stuff elsewhere. The diy scene in France is still alive but i think it is less vivid and enthousiastic compared to the era when i did discover it.
The l'' audiophile magazine did cease to exist long time ago and the other magazines were getting more and more commercial.
Allthough i did start using tube amps now i am still curious about the opinions about using chokes in a hiraga amp. I remember that there were 2 groups of people in france . One would say it is better to get the biggest transformer and smaller electrolytics . The other group would state the opposite. I would say 500va and 2 big chokes. If i am right the dc resistance of the chokes i did use was just below 1 ohm. I think using a choke with a resistance of a few ohms may be not giving a big advantage. Maybe a special order BIG choke can do a good job. I would certainly try that if i was still playing with this amp., This kind of choke would not be to expensive to make but i think it has to be potted and shielded.
The original Hiraga did use sic safco for the 20 watt version and cef ( special order) for the 30 watt version which did have very low internal resistance, capable of delivering lots of amperes and constructed more rigidly then the usual mallory stuff. Nowadays these parts are getting smaller so maybe using a big number of small ones might be a good idea.
The sic safco had series like the co38/co39 ( long life) tfrs ( tres faible resistance serie) The cef were ufrs ( ultra faible resistance serie) ( faible means low in this context and tres is very )
greetings, Eduard
I have both the magazines and the cd-rom. Both contain loads of information on some very good designs. I think the shop in Paris still exist but because of the internet people did start buying their stuff elsewhere. The diy scene in France is still alive but i think it is less vivid and enthousiastic compared to the era when i did discover it.
The l'' audiophile magazine did cease to exist long time ago and the other magazines were getting more and more commercial.
Allthough i did start using tube amps now i am still curious about the opinions about using chokes in a hiraga amp. I remember that there were 2 groups of people in france . One would say it is better to get the biggest transformer and smaller electrolytics . The other group would state the opposite. I would say 500va and 2 big chokes. If i am right the dc resistance of the chokes i did use was just below 1 ohm. I think using a choke with a resistance of a few ohms may be not giving a big advantage. Maybe a special order BIG choke can do a good job. I would certainly try that if i was still playing with this amp., This kind of choke would not be to expensive to make but i think it has to be potted and shielded.
The original Hiraga did use sic safco for the 20 watt version and cef ( special order) for the 30 watt version which did have very low internal resistance, capable of delivering lots of amperes and constructed more rigidly then the usual mallory stuff. Nowadays these parts are getting smaller so maybe using a big number of small ones might be a good idea.
The sic safco had series like the co38/co39 ( long life) tfrs ( tres faible resistance serie) The cef were ufrs ( ultra faible resistance serie) ( faible means low in this context and tres is very )
greetings, Eduard
Hello,
He also did scan the second volume of magazines. I just did buy the first cd-rom because some issues of the old volume were not available any more. Especially if you read French ( i do ) it is well worth the investment. Especially in the early eighties they were allready busy with things that did start drawing attention outside with the introduction of the internet in every household. The language-barrier did keep it inside France for a long time. Some europeans did make regular trips to Paris to buy parts but the person running the shop was annoying every one.
BUT i think there is enough information on the internet at this time to build a hiraga amp . A lot of parts are not so easy available anymore and if you want to build it the way hiraga intended it you will have to spend a lot of money for the caps. The 30 watt version i did buid did have at least half of the investment in the 4 330000 mf electolytics, 2 chokes, 2 68000mf caps and the 500va transformer. In the most recent pricelist i have got that dates from 1994 the component list for the 8 watt design by hiraga also spends more than 50% for the powersupply.This dates from 1994 but in the eighties they did also sell 16 and 25 volts caps instead of the 40 volts. Soon they did begin using car batteries in parallel with the caps and there was even a version that would have a charging system involved so during listening there wasn't a live wire connection at all. We are talking about the early eighties here. So better get these 2 cd-roms and a dictionary and be surprised. Greetings, Eduard
He also did scan the second volume of magazines. I just did buy the first cd-rom because some issues of the old volume were not available any more. Especially if you read French ( i do ) it is well worth the investment. Especially in the early eighties they were allready busy with things that did start drawing attention outside with the introduction of the internet in every household. The language-barrier did keep it inside France for a long time. Some europeans did make regular trips to Paris to buy parts but the person running the shop was annoying every one.
BUT i think there is enough information on the internet at this time to build a hiraga amp . A lot of parts are not so easy available anymore and if you want to build it the way hiraga intended it you will have to spend a lot of money for the caps. The 30 watt version i did buid did have at least half of the investment in the 4 330000 mf electolytics, 2 chokes, 2 68000mf caps and the 500va transformer. In the most recent pricelist i have got that dates from 1994 the component list for the 8 watt design by hiraga also spends more than 50% for the powersupply.This dates from 1994 but in the eighties they did also sell 16 and 25 volts caps instead of the 40 volts. Soon they did begin using car batteries in parallel with the caps and there was even a version that would have a charging system involved so during listening there wasn't a live wire connection at all. We are talking about the early eighties here. So better get these 2 cd-roms and a dictionary and be surprised. Greetings, Eduard
Hello,
I think that would be a good idea to do. It won't be easy to read some of the articles because their use of words can be a little poetic. But a lot of technical words look alike and i think that there are online dictionaries available too. Allthough some words related to audio cannot be found in any dictionary paper in oil capacitor is un condensateur papier huilé. While reading you should make your own little technical dictionary. Good luck, P.s visit this link and you will see some French audiophiles gathered in a club. I did join too but it did somehow cease to exist. Not a lot of life going on there
Eduardhttp://perso.orange.fr/franck.doucet/index.htm
I think that would be a good idea to do. It won't be easy to read some of the articles because their use of words can be a little poetic. But a lot of technical words look alike and i think that there are online dictionaries available too. Allthough some words related to audio cannot be found in any dictionary paper in oil capacitor is un condensateur papier huilé. While reading you should make your own little technical dictionary. Good luck, P.s visit this link and you will see some French audiophiles gathered in a club. I did join too but it did somehow cease to exist. Not a lot of life going on there
Eduardhttp://perso.orange.fr/franck.doucet/index.htm
danieljw said:
Very good looking Dan! Not tempted to peel and polish your caps?
I have the original outputs for this amp (SA627/SD188) but have committed them to the K10A. An intensive search of my junk pile of vintage circuits may reveal a few of the others used in the original.
I'm sorely tempted to build this one.
Attachments
Hello, These metal power transistors were indeed the ones used in the first hiraga 20 watt version. Because they were no longer available at a certain time they have been replaced by a pair did allow a higher dissipation, so the power supply voltage was increased and because of that there were some minor changes in the circuit values as well. Later the same thing did happen because of the non-availability of the drivers. Greetings, eduard
MJL21193 said:
Very good looking Dan! Not tempted to peel and polish your caps?
I have the original outputs for this amp (SA627/SD188) but have committed them to the K10A. An intensive search of my junk pile of vintage circuits may reveal a few of the others used in the original.
I'm sorely tempted to build this one.
and these 705/745 jobies were used in Otala's HK770 and few others
hehe - HK770 - two pairs of these , for 60W/ch ...........
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