Now the new version is comming --> iAMP100. The stereo OPS unit for single pair transitors, just transformer is required.
The board will ''take'' on board BJT and the Mosfet transitors, board has:
-main PSU
-preamp PSU +/-15V with short circuit protection
-speaker DC protect
-over temperature protect
-speakers 10s delay ON
-speakers fast OFF -->after trafo is switched OFF
-you can use single relay or two separete relays
-BJT or FET-hex output transistors
IPS boards are 60mm x 70mm which is enough to fit in most of the simple amplifiers (including sony ta777es if you will have a parts).
The special tool will help to bend the transitor legs
Excellent configuration with snap-on IPS boards! Very PRO
Big THANKS lads.
I must say that I am very suprised with irfp240/9140 pair, they sound lovley. On the paper (measurements) they are a bit behind BJT's but at the listening tests they rocks.
Bias spreader with red LED keeps the bias very solid all the time. I have some 2SK2013/2SJ313 (for drivers) and 2SK1530/2SJ201 so I will try to make it more SONY look like OPS.
Regards Peter
I must say that I am very suprised with irfp240/9140 pair, they sound lovley. On the paper (measurements) they are a bit behind BJT's but at the listening tests they rocks.
Bias spreader with red LED keeps the bias very solid all the time. I have some 2SK2013/2SJ313 (for drivers) and 2SK1530/2SJ201 so I will try to make it more SONY look like OPS.
Regards Peter
Attachments
We have fans for HexFET's and Bipolars !
Anyway what was the final circuit you used ?
Did you by any chance try the Quasi Hexfet circuit also ?
Cheers.
Hi Borys,
Have you used the uPC1237 chip for protection ?
You forgot to post the power amp circuit you used here. Is it posted somewhere ?
I have a board from eBay for the TDA7294 which has the uPC1237 for protection. Apparently one pin ( pin1) isn't used. Many users seem to skip this pin. Isn't hard to implement.
Have you used the uPC1237 chip for protection ?
You forgot to post the power amp circuit you used here. Is it posted somewhere ?
I have a board from eBay for the TDA7294 which has the uPC1237 for protection. Apparently one pin ( pin1) isn't used. Many users seem to skip this pin. Isn't hard to implement.
ashok
Tche output stage schematic is bellow, very simple and basic as 90% of the amplifiers. Bellow resistor values for mosfets IRFP240/9140.
I have around 10 differend IPS boards (bellow a bit modyfied apexaudio A9 IPS).
The protection is splitted in two circuits, first one is for temperature protection and is based on shmidtt trigger (comparator with histeresis), protection is cutting the speakrs off at 80deg and switching them back on at 65deg (depend on the resistor value).
The second part is DC detector + delay ON, just a few trannies. I have never used uPC1237, I can learn more when using fully discrete version.
The next generation of the main board will have same as above plus full short circuit protection (same as in i-PSU) , so hopefully it will be bullet proof.
Regards
Tche output stage schematic is bellow, very simple and basic as 90% of the amplifiers. Bellow resistor values for mosfets IRFP240/9140.
I have around 10 differend IPS boards (bellow a bit modyfied apexaudio A9 IPS).
The protection is splitted in two circuits, first one is for temperature protection and is based on shmidtt trigger (comparator with histeresis), protection is cutting the speakrs off at 80deg and switching them back on at 65deg (depend on the resistor value).
The second part is DC detector + delay ON, just a few trannies. I have never used uPC1237, I can learn more when using fully discrete version.
The next generation of the main board will have same as above plus full short circuit protection (same as in i-PSU) , so hopefully it will be bullet proof.
Regards
Attachments
Thanks Borys.
The uPC1237 is easy to implement but not so easily available locally. There are some others similar to it. However I also use discrete circuitry to control the output relay. For the thermal cutout I used a thermal relay which doesn't have much hysteresis like yours. But I do have some chassis mountable thermistors which could be used that way with some circuitry.
Which type of input stage sounds best in your opinion ? When I used your original circuit it did sound very good. I had found that LATFets sounded slightly better at HF but a shade lighter in the bass as compared to bipolar devices. Will try out the Hexfets as soon as it's possible.
The uPC1237 is easy to implement but not so easily available locally. There are some others similar to it. However I also use discrete circuitry to control the output relay. For the thermal cutout I used a thermal relay which doesn't have much hysteresis like yours. But I do have some chassis mountable thermistors which could be used that way with some circuitry.
Which type of input stage sounds best in your opinion ? When I used your original circuit it did sound very good. I had found that LATFets sounded slightly better at HF but a shade lighter in the bass as compared to bipolar devices. Will try out the Hexfets as soon as it's possible.
I know that upc1237 is hard to get so I didnt bother with it.
The IPS board I like most is the tube one VSHA and CFP-Madness. Both simple and working good boards.
I have the same experience with latFETS, bass-wise they need to be paralleled to get good resaults.
Basicly I like simple not over complicated circuits - for some reason they sound the best for me.
Regards Peter
The IPS board I like most is the tube one VSHA and CFP-Madness. Both simple and working good boards.
I have the same experience with latFETS, bass-wise they need to be paralleled to get good resaults.
Basicly I like simple not over complicated circuits - for some reason they sound the best for me.
Regards Peter
excellent ops card. im glad i found it, thanks.
i've been wanting to make a class ab version of krell ksa50.
what do you think about mating the BG1's output stage to diamond differential input of KSA50?
(or is it balanced ltp?. i don't know what the technical term for that is. seems to be called many things. same input is also found on leach amp)
i've been wanting to make a class ab version of krell ksa50.
what do you think about mating the BG1's output stage to diamond differential input of KSA50?
(or is it balanced ltp?. i don't know what the technical term for that is. seems to be called many things. same input is also found on leach amp)
Can I use bc550c instead of 2sk246 and bc560c instead of 2sj103? I actually added that. For this scheme
Jc2 preamp https://www.diyaudio.com/community/attachments/jc2-2-1-pdf.1093894/
Jc2 preamp https://www.diyaudio.com/community/attachments/jc2-2-1-pdf.1093894/