wow thats a great find !!!
put it in a good chassis with more bias and heatsinks !!!!!!
i am sure you wont be dissapointed !!!!
0.5A is a bit low i found a big difference in sound (obviously) when i cranked the bias to about 1.6-1.8 amps the only downside i can see with this amp is wasted heat !!!!
-Dan
put it in a good chassis with more bias and heatsinks !!!!!!
i am sure you wont be dissapointed !!!!
0.5A is a bit low i found a big difference in sound (obviously) when i cranked the bias to about 1.6-1.8 amps the only downside i can see with this amp is wasted heat !!!!
-Dan
Alternative output transistors?
Hi guys,
I'd like to build an amp based on the Hiraga 20W design and I've managed to find some of the originally spec'd input/driver transistors but what are your recommendations for the "best" replacements for the output devices?
How about OnSemi's MJ15003/4 or MJL0281/0302 or MJL1302/3281?
Any advice would be much appreciated!
Thanks,
Steve
Hi guys,
I'd like to build an amp based on the Hiraga 20W design and I've managed to find some of the originally spec'd input/driver transistors but what are your recommendations for the "best" replacements for the output devices?
How about OnSemi's MJ15003/4 or MJL0281/0302 or MJL1302/3281?
Any advice would be much appreciated!
Thanks,
Steve
Hi Steve,
I would suggest that MJ15003 istoo slow (fT 2.0MHz) andthe capacitance is 1000pF,
The MJL0281 and MJL3281 are better choices the MJL0281 is the best out of the three in terms of speed / capacitance.
I would suggest using the toshiba 2SC5200/2SA1943 pair as the capacitance is much lower. another option would be Sanken 2SC3264/2SA1295
Hope this helps
-Dan
I would suggest that MJ15003 istoo slow (fT 2.0MHz) andthe capacitance is 1000pF,
The MJL0281 and MJL3281 are better choices the MJL0281 is the best out of the three in terms of speed / capacitance.
I would suggest using the toshiba 2SC5200/2SA1943 pair as the capacitance is much lower. another option would be Sanken 2SC3264/2SA1295
Hope this helps
-Dan
Hi Dan,
First time for me on this forum, but i am also planning to build an Hiraga on steroïds like yours. Allready have almost all the parts.
I have a question about the 1K8 biasresistors.
On the Class-A amp site they mention that you should increase the value of it by a couple of hundred ohms when the voltage rises. In case of the 30 watt Hiraga 2K4 max instead of 1K8.
In your case whe go from 21 volts to (+/-)34 volts.
Shouldn't the resistor be much bigger than 1K8 ?
Jurjen.
First time for me on this forum, but i am also planning to build an Hiraga on steroïds like yours. Allready have almost all the parts.
I have a question about the 1K8 biasresistors.
On the Class-A amp site they mention that you should increase the value of it by a couple of hundred ohms when the voltage rises. In case of the 30 watt Hiraga 2K4 max instead of 1K8.
In your case whe go from 21 volts to (+/-)34 volts.
Shouldn't the resistor be much bigger than 1K8 ?
Jurjen.
Boxmaster said:
Hi Jurjen,
In my signature line there is a link which has details of what i changed and also the performance measurements.
JohanH said:
In this design the transistors should relatively fast 2.0MHz will not be sufficient. the circuit has inherant roll of much lower than this however faster transistors tend to have lower capacitance resulting in better/faster performance and they are easier to drive
- hope this helps and makes sense.
-Dan
Driving Apogees Ribbons?
Hello members,
I would like to build this amp for my mid/ High Range Ribbon (Apogee Duetta).
It's crossed over at 450 Hz, with a slope of 24 dB.
I guess concerning power, this amp would suit fine. But what about the ribbons` Z; It's around 2,6 ohm, so quiet on the low side.
Do you think the Hiagra can handle this load?
Thanx for clarification.
Olaf
Oh, Dan, your amp looks great, hope you don't mind me doing copy cat. I like to see this big towers on the top
Maybe in red, like le monstre...
Hello members,
I would like to build this amp for my mid/ High Range Ribbon (Apogee Duetta).
It's crossed over at 450 Hz, with a slope of 24 dB.
I guess concerning power, this amp would suit fine. But what about the ribbons` Z; It's around 2,6 ohm, so quiet on the low side.
Do you think the Hiagra can handle this load?
Thanx for clarification.
Olaf
Oh, Dan, your amp looks great, hope you don't mind me doing copy cat. I like to see this big towers on the top
Maybe in red, like le monstre...
Hello Dan,
no it's constant (it's a ribbon and R is nearly equal Z)
For an amp with low damping factor, this linearity in impedance is an easy load (no dips ore peaks).
Might be the problem, that it is so low.
I hope le class a is able to drive this, 'cause I really like to build one
Have a nice time
Olaf
no it's constant (it's a ribbon and R is nearly equal Z)
For an amp with low damping factor, this linearity in impedance is an easy load (no dips ore peaks).
Might be the problem, that it is so low.
I hope le class a is able to drive this, 'cause I really like to build one
Have a nice time
Olaf
20w Hiraga
good day,
i have built the 20w hiraga 3yrs ago, in my opinion excellent sounding amp in ss design, I found the schematics at Geoff Moss's website. "The Class A amp Site". Only problem is finding the parts, it took me too long to collect the parts than building it, but after I finished the project, its truly rewarding,. I dont use the original power supply, instead I use the capacitance multiplier design. For a DIY amp in ss class A, truly the Hiraga 20W exceeds my expectation.
regards,
efren
good day,
i have built the 20w hiraga 3yrs ago, in my opinion excellent sounding amp in ss design, I found the schematics at Geoff Moss's website. "The Class A amp Site". Only problem is finding the parts, it took me too long to collect the parts than building it, but after I finished the project, its truly rewarding,. I dont use the original power supply, instead I use the capacitance multiplier design. For a DIY amp in ss class A, truly the Hiraga 20W exceeds my expectation.
regards,
efren
Hello
I built mine with the same power supply . At first I tried large capacitors 1F /channel but I was not satisfied with the sound .
After I used capacitance multiplier power supply , the sound got much-much better .
The truth is for the capacitance multiplier I use for the large caps 60 000uF . Of course U need soft starter because the large capacitor will destroy the power transformer .
Another big improvement I replaced the output and the driver transistors .
I had the orig NEC output and driver transistors but not my taste , to soft bass and not much control over the speakers . It sounded like a old tube amp , slow , to soft , a bit muddy .
Now much-much better after all those changes .
It is important to use as short wires between the PC board and the power transistors as possible and use only solid wires .
Now I try build the Zenquito in bridged and in balanced mode (it use lateral mosfet output) and com pair with the Class A .
After Jean Mark that is a improvement over the Class A . I will see , of course I keep the Class A amp in case that better .
Now I built the ProFet (also from Jean Mark) which is much better than the Class A .
Of course I use better parts Caddock resistors , PIO capacitors , 999.9 solid silver wire .
But all together the Class A was better amp than the Aleph 30. At least for my taste .
The bias must be over 1.5A /channel ,and with the capacitance multiplier power supply I do not use electrolytic on the PC board , just Russian Teflon capacitors with Dale resistors .
Regards
I built mine with the same power supply . At first I tried large capacitors 1F /channel but I was not satisfied with the sound .
After I used capacitance multiplier power supply , the sound got much-much better .
The truth is for the capacitance multiplier I use for the large caps 60 000uF . Of course U need soft starter because the large capacitor will destroy the power transformer .
Another big improvement I replaced the output and the driver transistors .
I had the orig NEC output and driver transistors but not my taste , to soft bass and not much control over the speakers . It sounded like a old tube amp , slow , to soft , a bit muddy .
Now much-much better after all those changes .
It is important to use as short wires between the PC board and the power transistors as possible and use only solid wires .
Now I try build the Zenquito in bridged and in balanced mode (it use lateral mosfet output) and com pair with the Class A .
After Jean Mark that is a improvement over the Class A . I will see , of course I keep the Class A amp in case that better .
Now I built the ProFet (also from Jean Mark) which is much better than the Class A .
Of course I use better parts Caddock resistors , PIO capacitors , 999.9 solid silver wire .
But all together the Class A was better amp than the Aleph 30. At least for my taste .
The bias must be over 1.5A /channel ,and with the capacitance multiplier power supply I do not use electrolytic on the PC board , just Russian Teflon capacitors with Dale resistors .
Regards
@Efren and Gabor;
your support my opinion, that it's a good sounding amp.
But my original question is still unanswered.
Will it cope with a load arround 2.6 ohm?
I suppose I just have to try, since I don't know a person who did it.
Some time ago I was thinking of building a chipamp for this purpose, but alot of people told me, this won't be a good match with the ribbon; To low impedance. By looking at the chipamp datasheets I agreed with them.
I suppose it'll work, well let's see.
Thanks for your input.
Olaf
your support my opinion, that it's a good sounding amp.
But my original question is still unanswered.
Will it cope with a load arround 2.6 ohm?
I suppose I just have to try, since I don't know a person who did it.
Some time ago I was thinking of building a chipamp for this purpose, but alot of people told me, this won't be a good match with the ribbon; To low impedance. By looking at the chipamp datasheets I agreed with them.
I suppose it'll work, well let's see.
Thanks for your input.
Olaf
taotao,
Good day, not so sure about 2.6 ohm load, but i am using 6 ohm ONKYO AX37 bookshelf speakers, in my own view it will work, much more if you double the output devices and provide them with their own load resistor much like the JLH that drive electrostatic speakers that drive 2.0 ohm load. Find out more about it at "The Class A Amp Site" by Geoff Moss, the site thats dedicated to the JLH class A amp., its a great site.
Best regards,
Efren
Good day, not so sure about 2.6 ohm load, but i am using 6 ohm ONKYO AX37 bookshelf speakers, in my own view it will work, much more if you double the output devices and provide them with their own load resistor much like the JLH that drive electrostatic speakers that drive 2.0 ohm load. Find out more about it at "The Class A Amp Site" by Geoff Moss, the site thats dedicated to the JLH class A amp., its a great site.
Best regards,
Efren
Thank you Efren and Gabor.
Dan, I'm going to use 2sc5200 and 2sa1943 as output trans, since they are easily obtainable here.
I still don't know the replacement for the Input and Driver Stage.
Maybe you can suggest me some (I overlooked the thread, but didn't become wiser concerning this )
Dan, can you provide me some matched pairs, I would be glad.
If not, I have to think about matching the input trans. I read it's necessary, well so I have to do it.
Just have to look for a howto guide, I'm not an expert (I'll find here in this forum).
Also, DC protection is a must. Westhost will be my friend ...
Thank you.
Olaf
Dan, I'm going to use 2sc5200 and 2sa1943 as output trans, since they are easily obtainable here.
I still don't know the replacement for the Input and Driver Stage.
Maybe you can suggest me some (I overlooked the thread, but didn't become wiser concerning this )
Dan, can you provide me some matched pairs, I would be glad.
If not, I have to think about matching the input trans. I read it's necessary, well so I have to do it.
Just have to look for a howto guide, I'm not an expert (I'll find here in this forum).
Also, DC protection is a must. Westhost will be my friend ...
Thank you.
Olaf
HI tao tao
For the input please use the original , that would be the best choice for there . Is hard to find parts but some people still have .Try to much them !
For driver please use MJE15030/31 is much better than the original Hiraga uses .
For output please use MJ15024/25.I believe the best choice .
I tested many different output transistor at least 10 different transistors , I had the original NEC to but after I tested the MJ's I sold the original on Ebay . For me the Toshiba gave to soft bass not to talk about there are most Toshiba fake. Yes is stamped as Toshiba but nothing to do with Toshiba corporation .Toshiba does not produce these transistors more than 15 years .
The MJ15024/25 is in TO3 metal case it can take more heat than the TO247.
You can go to ON semi website , register and order samples .
It is possible to order 5PC from each output or driver transistor and 25PC from small signal transistor up to 25PC .Up to 10 different type of transistor , U need to pay only for the shipping .
Please use very short wire to connect the power transistor .For the input U can use longer wire .There is no need for preamp .
Use the modern PC layout , if I find them I will post it for you .
Regards
For the input please use the original , that would be the best choice for there . Is hard to find parts but some people still have .Try to much them !
For driver please use MJE15030/31 is much better than the original Hiraga uses .
For output please use MJ15024/25.I believe the best choice .
I tested many different output transistor at least 10 different transistors , I had the original NEC to but after I tested the MJ's I sold the original on Ebay . For me the Toshiba gave to soft bass not to talk about there are most Toshiba fake. Yes is stamped as Toshiba but nothing to do with Toshiba corporation .Toshiba does not produce these transistors more than 15 years .
The MJ15024/25 is in TO3 metal case it can take more heat than the TO247.
You can go to ON semi website , register and order samples .
It is possible to order 5PC from each output or driver transistor and 25PC from small signal transistor up to 25PC .Up to 10 different type of transistor , U need to pay only for the shipping .
Please use very short wire to connect the power transistor .For the input U can use longer wire .There is no need for preamp .
Use the modern PC layout , if I find them I will post it for you .
Regards
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