Agree they cannot replace electrolytics back when the article was written. However, the link you provided to the large Eaton bank that may not be a true statement anymore. The datasheet does not provide discharge curves but the fact they can provide 20A of continuous current with an ESR of 22mohm will outperform even the best electrolytics! At that point, you are basically meeting battery performance. I have been in the industry >25 years and the supercapacitor technology has come a long way!
Hello Craig,
I noticed too the specs changed for the better.
There are some attempts to use smaller capacity supercaps for digital gear. But some people there seem to get into trouble because when power down their digital gear with several types of power supply the one using supercaps will contain to much '' juice '' . This prevents the complete collection of interconnected digital gear to properly switch on/of so to say.
When using the part which i linked to a few post ago you probably need some kind of soft start. And if you switch of will you let the two banks of caps fully drain or will you put a switch between the circuit and the caps and let the caps stay connected to the transformer all the time??
Greetings, Eduard
I noticed too the specs changed for the better.
There are some attempts to use smaller capacity supercaps for digital gear. But some people there seem to get into trouble because when power down their digital gear with several types of power supply the one using supercaps will contain to much '' juice '' . This prevents the complete collection of interconnected digital gear to properly switch on/of so to say.
When using the part which i linked to a few post ago you probably need some kind of soft start. And if you switch of will you let the two banks of caps fully drain or will you put a switch between the circuit and the caps and let the caps stay connected to the transformer all the time??
Greetings, Eduard
Hello Ralf,
Did you ever read the article by Jean Hiraga about thermal distortion. His idea is that the transistor should be at a constant temperature to sound at their best. Probably because le Monstre is class A it will be pretty constant even if it is just a little bit above room temperature.
When i had the 30 watt i mounted the drivers isolated but on the same piece of aluminium to keep them at identical temperature before that if i created extra airflow by '' waving '' with a door close by DC at output would change.
After installing the piece of aluminium on the drivers DC would stay stable.
With the Le Monstre and a moderate dissipation one could use a bigger heatsink and mount one channel on on heatsink. I dont know if le monstre is more sensible for dc on the output.
When switching on you dont blow any fuse or are you using a big R in the CRC filter. If i remember well the R in le monstre was 8 ohm, it had to be to achieve proper filtering. Of course with a proper choke you can achieve the same and with a little care better filtering and end up with a DCR lower than 8 ohm.
Probably the latest supercaps are better than the car caps.
If i remember the reason why the supercaps where used some decades ago was not something like low ESR but just the effect they had on the stability of the dc voltage.
We will have to wait for Nilton to hear his ideas about Le Monstre with choke input.
Greetings, eduard
Did you ever read the article by Jean Hiraga about thermal distortion. His idea is that the transistor should be at a constant temperature to sound at their best. Probably because le Monstre is class A it will be pretty constant even if it is just a little bit above room temperature.
When i had the 30 watt i mounted the drivers isolated but on the same piece of aluminium to keep them at identical temperature before that if i created extra airflow by '' waving '' with a door close by DC at output would change.
After installing the piece of aluminium on the drivers DC would stay stable.
With the Le Monstre and a moderate dissipation one could use a bigger heatsink and mount one channel on on heatsink. I dont know if le monstre is more sensible for dc on the output.
When switching on you dont blow any fuse or are you using a big R in the CRC filter. If i remember well the R in le monstre was 8 ohm, it had to be to achieve proper filtering. Of course with a proper choke you can achieve the same and with a little care better filtering and end up with a DCR lower than 8 ohm.
Probably the latest supercaps are better than the car caps.
If i remember the reason why the supercaps where used some decades ago was not something like low ESR but just the effect they had on the stability of the dc voltage.
We will have to wait for Nilton to hear his ideas about Le Monstre with choke input.
Greetings, eduard
craigtone,
the bad quality stems from the large capacitance to volume ratio. What is of great use is the addition of large value polypropylene capacitors to cover the important high frequency range. A couple of uF is not much.
Low rather than constant.
A small capacitance to volume ratio implies high ESR. In this context, stability is inferior.
the bad quality stems from the large capacitance to volume ratio. What is of great use is the addition of large value polypropylene capacitors to cover the important high frequency range. A couple of uF is not much.
Low rather than constant.
A small capacitance to volume ratio implies high ESR. In this context, stability is inferior.
under the big heatsinks there are non heareable additional 120mm fans for even more cooling
the driver transitors actually have heatsinks glued.
and even the 1 Ohm resistors have heatsinks because of high bias
Update on Speaker Load Handling.
I used to have a pair of Sonus Faber Venere 3.0 and the monstre handled them "OK", it was very detailed but lacked control at all frequencies and really never managed to get a handle on the lower frequencies. This is compared to my standard ref KSA150.
I recently swapped the Sonus Fabers for a pair of KEF Reference 205 which are a much more complex load, that doesnt work at all with either of the low/high power Audio Research I tried (C30/vS110), they really just sounded crap. The KSA150 was amazing, but here is the killer, the Monstre found new levels of detail and an incredible bass control that is at least 90% of the KSA150, I mean this thing sounds incredible on a complex load.
I know @eduard is going to hate this- the KSA is still my go to, but the Monstre (16v) is really really close, even with techno and EDM which I listen to alot (as well as classical, jazz, classic rock, modern rock etc.). If you have a pair of speakers that don't work with valves/tubes, try the Monstre.
I am not even going to try and explain the difference in cost of the two amplifiers.
To anyone put off by the low power of this amp, dont be, it is a fantastic project!
I used to have a pair of Sonus Faber Venere 3.0 and the monstre handled them "OK", it was very detailed but lacked control at all frequencies and really never managed to get a handle on the lower frequencies. This is compared to my standard ref KSA150.
I recently swapped the Sonus Fabers for a pair of KEF Reference 205 which are a much more complex load, that doesnt work at all with either of the low/high power Audio Research I tried (C30/vS110), they really just sounded crap. The KSA150 was amazing, but here is the killer, the Monstre found new levels of detail and an incredible bass control that is at least 90% of the KSA150, I mean this thing sounds incredible on a complex load.
I know @eduard is going to hate this- the KSA is still my go to, but the Monstre (16v) is really really close, even with techno and EDM which I listen to alot (as well as classical, jazz, classic rock, modern rock etc.). If you have a pair of speakers that don't work with valves/tubes, try the Monstre.
I am not even going to try and explain the difference in cost of the two amplifiers.
To anyone put off by the low power of this amp, dont be, it is a fantastic project!
A couple of days ago I replaced the references in the regulators in my Le Monstre, instead of the LM329 I made four Walt Jung LED references for 6.9V. I am very pleased with the result, the change in the sound was immediately felt, there are more details in the sound, the highs are more fluttery, the bass has a kick and it is more controlled.
Unfortunately I don't have the equipment to measure the noise of the regulator because it is below the sensitivity of my oscilloscope, but after the change in sound it is immediately clear that the new LED reference is better than the popular LM329.
Unfortunately I don't have the equipment to measure the noise of the regulator because it is below the sensitivity of my oscilloscope, but after the change in sound it is immediately clear that the new LED reference is better than the popular LM329.
Attachments
Something like that.
Le Monstre replaced the JLH69 a little over half a year ago and since then something has been improved though not as much as on the JLH69.
I changed the output and driver transistors, and inserted non-inductive 0.5R resistors, and now these new LED references in the regulators.
I am very satisfied with the sound, I listen from classical to electronic music and it works great with everything.
amp reg
Le Monstre replaced the JLH69 a little over half a year ago and since then something has been improved though not as much as on the JLH69.
I changed the output and driver transistors, and inserted non-inductive 0.5R resistors, and now these new LED references in the regulators.
I am very satisfied with the sound, I listen from classical to electronic music and it works great with everything.
amp reg
Attachments
I found this Hiraga forum now.
I am building my second version of the Hiraga amplifier right now.
Designed my own pcb with KiCad to get the design I want.
All input transistors are tied together for example.
Almost finished now but missing the 2SJ74 jfets, delivery problem.
Waiting for 10 ordered sj74 to get 2 matched pairs with my waiting 2SK170´s.
My first version is using the BC550c and BC560C, TIP3055, but this amplifier is original.
Using TX2575 resistors, Mundorf 30W resistors and 2x85Ah AGM batteries in this version.
I have 2 inputs, one AC input with a 2,2uF Miflex huge capacitor and one DC coupled input if you know how the output is from the source.
Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.
I am building my second version of the Hiraga amplifier right now.
Designed my own pcb with KiCad to get the design I want.
All input transistors are tied together for example.
Almost finished now but missing the 2SJ74 jfets, delivery problem.
Waiting for 10 ordered sj74 to get 2 matched pairs with my waiting 2SK170´s.
My first version is using the BC550c and BC560C, TIP3055, but this amplifier is original.
Using TX2575 resistors, Mundorf 30W resistors and 2x85Ah AGM batteries in this version.
I have 2 inputs, one AC input with a 2,2uF Miflex huge capacitor and one DC coupled input if you know how the output is from the source.
Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.
Last edited:
Of course, I can send the Gerber file, but I have to adjust some minor glitches I discovered when I started assembling the components.
The mounting hole to the Mundorf 1ohm resistors was a bit small.
I would please like to finish the project to see if all is ok first.
Discovered the 2sk170 and 2sj74 Y-grade with IDSS 1,3mA is very hard to find.
Stuck right now missing them.
I have GR grade but this is not optimal because I have to replace the 1Kohm resistors due to the higher IDSS current.
Like 520 ohm and I do not want to buy any more TX2575 resistors because they cost about 20$ each with customs and VAT from US.
The side effect is also a drop in gain in the input stage of about -5dB.
Anyone know where to get the Y-grade jfets?
Transistormosfet.com has the 2sk170y but I am not sure to trust the site/company.
The mounting hole to the Mundorf 1ohm resistors was a bit small.
I would please like to finish the project to see if all is ok first.
Discovered the 2sk170 and 2sj74 Y-grade with IDSS 1,3mA is very hard to find.
Stuck right now missing them.
I have GR grade but this is not optimal because I have to replace the 1Kohm resistors due to the higher IDSS current.
Like 520 ohm and I do not want to buy any more TX2575 resistors because they cost about 20$ each with customs and VAT from US.
The side effect is also a drop in gain in the input stage of about -5dB.
Anyone know where to get the Y-grade jfets?
Transistormosfet.com has the 2sk170y but I am not sure to trust the site/company.
Both 2SJ74Y and 2SK170Y are not available anymore. The G's become's rare, the B's are limited. The Pchannel is not available actually. In the Pass-section there's are topic about replacements, but it is a meager yield. You should have checked this before designing your board.
Lowering the value of first stage drainresistors lowers the open loop gain too with 6dB. One should do a full open loop calculation (or simulation) to see if there's enough margin.
Also the transconductance is higher of the G's and B's (if available) and this can push the design near its limit. Divirting a part of the drain currents through fixed current sources in parallel with the drainresistors (say enough to keep the 1kΩ's) to the rails is only possible when both sides are controlled and of the same value (an extra control circuit is needed). This will make this nice simple design way more complex, and no guarantee it will sound as good though.
Lowering the value of first stage drainresistors lowers the open loop gain too with 6dB. One should do a full open loop calculation (or simulation) to see if there's enough margin.
Also the transconductance is higher of the G's and B's (if available) and this can push the design near its limit. Divirting a part of the drain currents through fixed current sources in parallel with the drainresistors (say enough to keep the 1kΩ's) to the rails is only possible when both sides are controlled and of the same value (an extra control circuit is needed). This will make this nice simple design way more complex, and no guarantee it will sound as good though.
Thanks for the information.
I am currently researching Service Manuals för some vintage Hifi amplifiers containing the Y-grade jfets.
Found Teac A-70 so far with 4 piece of 2sk170y in the parts list.
Will continue to search old hifi components.
How hard can it be to find them
Also sent mail to some vintage hifi dealers in Sweden to see if they have some parts or hifi components.
I am currently researching Service Manuals för some vintage Hifi amplifiers containing the Y-grade jfets.
Found Teac A-70 so far with 4 piece of 2sk170y in the parts list.
Will continue to search old hifi components.
How hard can it be to find them
Also sent mail to some vintage hifi dealers in Sweden to see if they have some parts or hifi components.
