Hiraga 20W class A

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sergiu2009

sergiu2009

Member
Joined 2011
knutn said:
Is there an english translation of the article in post 795? http://www.diyaudio.com/forums/solid-state/193-hiraga-20w-class-80.html#post4246265
Click to expand...

There isnt any translation for this article...This is the schematic (the 30 watter) that i have used primarly for my version of amp (mine has 38watts@1.65A@+-27Vcc) and our colleague danieljw used it with success in his 58w@35Vcc@1.65A class a Hiraga version...
This article reffers to a newer batch of better output transistors wich permits higher power at the output, to be more precise, exactly 30w.. It says that the older, original pair 2sa627/2sd188 is obsollete.
It also says how the newer pair of transistors have better heat dissipation, better Cob, lower rbb, higher wattage and voltages and better overall heat stability. It also shows you how to calculate the maximum working poit of the output transistors for a given Ual (Vcc).
And it describes at the end of the article some listening impressions: the differences between the original pair form article number 15 and these new trannies is translated in a better tonal equillibre, overall better sound (a ricer sound), and a significantly better clarity in the bass==bass-medium region. The hights and medium are more engaging and more precise and the hights are thready (file with accent on the e) and detailed..
And it also says that the PSU have changed. The PSU now has 24Vcc, 4pcs of 330.000uFa prefiltrage for the amps, 2 pcs of 68.000uF high ripple for the input of the psu and two resistors of 0.22ohm/25W.
At the end of the article Hiraga states that the difference between the old versions and this newer 30w version is not about the wattage differences instead it is in an improved subjective definition in the clarity department in all the large bande spectre and a better overall homogenity wich made the 20 watter reputation renewed for..
It also gives an example in biamplification where this 30 watter was used and it says that the punch in the lower spectrum and the overall energy delivered in the Onken enclosures was extraordinarry and out of the box..
I have translated and made a short debrief of the article that you have posted in your link..
I agree that is better to know french and understand it right from the article than from a translated and adapted one.
Cheers
Sergiu

PS: i have the article listed.. ;)
 
G

gaborbela

Member
Joined 2005
sergiu2009 said:
Hello,
Finally in back home from a long journey trip for my job..
Here are some of my thoughts when i made my variant of this amp:

"For drivers i tested the following pairs:
a)2sa1837/c4793
b)2sa1220a/c2690a
c)2sa1930/sc5171
And found the followings:
a) the best pair, with a very precise sound, very good soundstage, pleasant mids, very good imaging, low,punchy bass and tight, extended hights and beautifull overall sound;
b) too fast pair because of the hight FT, flat soundstage (didnt have presence), tight bass but abit soft, the hights where not impressing and the mids where at the same level as the bass and hights so nothing impressing here.
The sound was focused but was hard to distinguish the instruments and effects and because these trannies where too fast it was hard and exausting to listen to the amp. It wasnt pleasant at all.
c) same as the b) variant;
Conclusion: altought all the above pairs where better aprox in all aspects compared to the original drivers used, Cob an FT, it seems that this amp doesnt love drivers with FT faster than 90-100 Mhz altought the CoB is better than the original ones....
I used as output pair 2sa1943/2sc5200 Toshiba NOS for tests.
The source: ipod 5.5 classic@80gb@Wolfson DAC chip moded to Rockbox for FLAC format support.
Speakers: modified Tento closed enclosures rated at 40w sinus and 8 ohms from an Kashtan mag.
The music (in Flac format):
* luminary-amsterdam (smith and pledged remix); -- depht of field, vocals, effects;
*julio iglesias-crazy;-- vocal and for the big trompet (dont know the name in english);
* katie melua- nine million bicicle;--guitar, flaut, violin, vocals;
* sting-fragile;--- mandoline, dinamics, vocals, depht of field;
*dave brubeck-take five; dinamics, rithm, timbre;
*mantovani and his orchestra- limelight and moulin rouge;-- soundstage and precision;
*above and beyond--full concert film live from Porchester Hall (not FLAC; it is dirrectly from youtube@1080p); sound stage, sound stage and vocals;
I made the listening tests for 3 days from 8AM to 24:00PM continous listening to the same mellodies over and over again.... I think that after i'll finish the tests i will not want hear again those mellodies..
So my friend i think that MJ15034 and his complement and the 2sa1837/c4793 and other good pairs with COB lower than 40pF and FT lower than 100mhz is best for this amp."
If i remember clear this was exhausting... For a precise difference between the batches of different transistors you have to listen to the amp allot (same mellody, over and over and over again...) and choose what you like best.
Cheers
Sergiu
Click to expand...

You should try MJE15034 & 35 or 15030 & 31 from ON Semi, to me that was the best, all do I used ON Semi MJ110## power device..
I tried several Toshiba for drivers, on the end I chose the ON Semi..
 
sergiu2009

sergiu2009

Member
Joined 2011
gaborbela said:
You should try MJE15034 & 35 or 15030 & 31 from ON Semi, to me that was the best, all do I used ON Semi MJ110## power device..
I tried several Toshiba for drivers, on the end I chose the ON Semi..
Click to expand...

Hi Gaborbela,
I know. Daemon and Danieljw told me to try them. I have a budget rised for these pairs (20pcs+20pcs for better matching) but will not buy them yet because my amp is closed now and freshly painted... :D
Now i restarted my other project in progress from here: http://www.diyaudio.com/forums/planars-exotics/69450-diy-ribbon-speaker-different-kind-53.html. I need to finish this first and after this i will start my listening tests on the amp again.
For the output i use Sanken matched 5% range pair 2sa1492/2sc3856 wich blew away the toshiba pairs that i had and some mj4281/4302A, soundwise speaking... :)
Have you tested the Kubota regulator for the input or cap multiplier?
I have a separate passive PSU comprising in a separate trafos and a CRCRC filter of aprox 50.000uF per input for each channel and havent tested a voltage reg or cap multiplier in this point..

In the future i want to test the Kubota, Salas low voltage shunt and Mr.Evil cap multiplier here..

Any impressions or thoughts here?

Cheers
Sergiu
 
Last edited:
sergiu2009

sergiu2009

Member
Joined 2011
knutn said:
Thank you very much, Sergiu.
And I must say I am very impressed by your job.
Click to expand...

Thanks. My amp hadnt worked from the start because of a bad PCB so i had allot of modifications done and learned allot.
In the end (second attempt) i used the originall pcb with some modifications made to acomodate my needs and with the knolledge acumulated from the first attempt i adjusted the amp from the start and tested different components in time and opted for the ones that i liked most, and i am glad that i learned this way. The hard way is the better way somethimes... ;) :D
Cheers
Sergiu
 
damon1983

damon1983

Member
Joined 2013
sergiu2009 said:
Thanks. My amp hadnt worked from the start because of a bad PCB so i had allot of modifications done and learned allot.
In the end (second attempt) i used the originall pcb with some modifications made to acomodate my needs and with the knolledge acumulated from the first attempt i adjusted the amp from the start and tested different components in time and opted for the ones that i liked most, and i am glad that i learned this way. The hard way is the better way somethimes... ;) :D
Cheers
Sergiu
Click to expand...

ESL supported.:eek::eek::eek::D
 
obscurus

obscurus

Member
Joined 2013
sergiu2009 said:
Hi Gaborbela,
I know. Daemon and Danieljw told me to try them. I have a budget rised for these pairs (20pcs+20pcs for better matching) but will not buy them yet because my amp is closed now and freshly painted... :D
Now i restarted my other project in progress from here: http://www.diyaudio.com/forums/planars-exotics/69450-diy-ribbon-speaker-different-kind-53.html. I need to finish this first and after this i will start my listening tests on the amp again.
For the output i use Sanken matched 5% range pair 2sa1492/2sc3856 wich blew away the toshiba pairs that i had and some mj4281/4302A, soundwise speaking... :)
Have you tested the Kubota regulator for the input or cap multiplier?
I have a separate passive PSU comprising in a separate trafos and a CRCRC filter of aprox 50.000uF per input for each channel and havent tested a voltage reg or cap multiplier in this point..

In the future i want to test the Kubota, Salas low voltage shunt and Mr.Evil cap multiplier here..

Any impressions or thoughts here?

Cheers
Sergiu
Click to expand...

I built one chanel of the Hiraga 20W with some modifications to origin schematic. My PSU is 40kuf + cap multiplier (dadod mosfet version) + 20kuf.

I used
- KSC1845/KSA992 for input (with higher bias than origin schematic).
- 2SC4883 / 2SA1859 for driver
- MJL4281 / MJL4302 for output
- PSU Votage = 32 in and 26 after cap mul.

I think sound is quite balance, nature, good bass but with a little less in treb area.

For driver, I think we better look at hfe-ic and try to choose transitor which have hfe linear until 40ma. I only try 2SC4883 / 2SA1859 and it sound good to me so I just move forward.
 
A

AndrewT

R.I.P.
Joined 2004
The a1859/c4883 looks to have similar performance to the mje15034/5 from ONsemi.
I don't think hFE vs Ic is a problem. it holds up well to beyond 1Apk.
It also has very good drive @ higher Vce eg. 20W @ 40Vce DC and 30W @ 40Vce 100ms and 35W @ 35Vce 100ms. This 1A @ 35Vce for a bass thump is good.

But the fT is only 60MHz. This is only available from Ie = 120mA to 1200mA. I think you could get a transistor that is slightly less robust that is double the speed. That may prove to slightly change/improve performance.
 
obscurus

obscurus

Member
Joined 2013
AndrewT said:
The a1859/c4883 looks to have similar performance to the mje15034/5 from ONsemi.
I don't think hFE vs Ic is a problem. it holds up well to beyond 1Apk.
It also has very good drive @ higher Vce eg. 20W @ 40Vce DC and 30W @ 40Vce 100ms and 35W @ 35Vce 100ms. This 1A @ 35Vce for a bass thump is good.

But the fT is only 60MHz. This is only available from Ie = 120mA to 1200mA. I think you could get a transistor that is slightly less robust that is double the speed. That may prove to slightly change/improve performance.
Click to expand...

Thanks for your information, it did clear some of my doub. fT of 2SC4883 is 100Mhz but 2SA1859 is 60Mhz.

Do you already have some transitor names in yoour mind? It will save me some finding time?
 
damon1983

damon1983

Member
Joined 2013
AndrewT said:
The a1859/c4883 looks to have similar performance to the mje15034/5 from ONsemi.
I don't think hFE vs Ic is a problem. it holds up well to beyond 1Apk.
It also has very good drive @ higher Vce eg. 20W @ 40Vce DC and 30W @ 40Vce 100ms and 35W @ 35Vce 100ms. This 1A @ 35Vce for a bass thump is good.

But the fT is only 60MHz. This is only available from Ie = 120mA to 1200mA. I think you could get a transistor that is slightly less robust that is double the speed. That may prove to slightly change/improve performance.
Click to expand...

60 MHz, 100 MHz, 600 MHz, maybe 3 GHz will better? I don't know, what we doing: Hiraga's Class A AMP or Intel i7-4770K?..:xeye::confused:
 
cumbb

cumbb

Member
Joined 2005
The Hiraga Class A is a four! stage complementary (-parts)-pp-design. You could change and test and try your live along transes or parts or values - never it will sound clean, clear. But the Hiraga does sound much better than every big commercial complementary-pp stuff,-)
 
Ian Finch

Ian Finch

Member
Joined 2010
Paid Member
cumbb said:
The Hiraga Class A is a four! stage complementary (-parts)-pp-design.....
Click to expand...
No, it is not a four stage amplifier. Maybe you think 4 cascaded active devices means 4-stage?

a20w_1024.gif
 
Ian Finch

Ian Finch

Member
Joined 2010
Paid Member
stevenrotterdam said:
Anyone have an opinion about using MJL 1302 and 3281 as outputs? According to Farnell these are high quality audio transistors.
Click to expand...
Most modern, high quality devices are developed specifically for the needs of class AB amplifiers where a high gain-bandwidth product is necessary for the large amounts of negative feedback needed to remain stable while eliminating audible crossover distortion.

Whilst there is nothing wrong in using high quality transistors like the obsolete MJL1302/3281 in class A amplifiers for the ultimate low distortion performance, there really is no practical need in home DIY use and older, 1-4 MHz Ft silicon can still be fine in class A amplifiers. People using the JLH 10W amplifier will attest to how good it sounds with even ancient 2N3055 power transistors :) That is also true for feed-forward designs like Quad's 405, 306, 606 and 909 models, class S, and even Technics SEA, SUV series etc. too
 
cumbb

cumbb

Member
Joined 2005
My focus is on complementary-parts-steps. These sound much different, have much different characters (and cascodes, darlingtons and others get the influence in noise, in, at moment not regarded, distortions - every alteration of the signal - of all - involved active too - parts). The sum of (very much different) parts decide on how clean. The Hiraga, i did tuned some, I did build some, is a rumbling thing. Much fun, but never a clean tone.
 
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