Stuart
I have Rightmark, but I the PC it runs on is old and slow, and only has a 16/44K card. The card is on the upgrade list, but not near the top.
Had a call from your B-I-L last week, he got your parcel, so I should get round there at some point and see if he's got everything! 🙂
I have Rightmark, but I the PC it runs on is old and slow, and only has a 16/44K card. The card is on the upgrade list, but not near the top.
Had a call from your B-I-L last week, he got your parcel, so I should get round there at some point and see if he's got everything! 🙂
testing
Al,
A good 44k/16bit soundcard is enough to test midband distortion down to 0.02% and signal to noise to 90db, so it's worth giving it a shot. I used a loopback cable to judge and pick the best of the sound cards I have. I ended up getting 96k/16bit then used an attenuator on the output of the amp that matched the gain of the amp, ie input and output voltages were close to identical. Finally I adjusted the level of the sound card for max output with no 'clipping', got some good readings for my zen and aleph, no reason why it can't be done for the krell, just haven't got around to it...
Thanks for dealing with the BIL, he should have everything he needs, if not you know where to find me...
Stuart
Al,
A good 44k/16bit soundcard is enough to test midband distortion down to 0.02% and signal to noise to 90db, so it's worth giving it a shot. I used a loopback cable to judge and pick the best of the sound cards I have. I ended up getting 96k/16bit then used an attenuator on the output of the amp that matched the gain of the amp, ie input and output voltages were close to identical. Finally I adjusted the level of the sound card for max output with no 'clipping', got some good readings for my zen and aleph, no reason why it can't be done for the krell, just haven't got around to it...
Thanks for dealing with the BIL, he should have everything he needs, if not you know where to find me...
Stuart
Hi Guys,
May I ask a couple of questions?
First, as I have said, I bought a couple of the original boards. Will the output boards that Al has made work with the older boards?
Also, what are the best output transistors to use? I have quite a few different transistors that I have aquired from OnSemi over time. I see that NUTTTR has used some T-03's. I have some MJ15003/4. Will those work?
I also have the MJL 21193/4's.
Thanks, Terry
May I ask a couple of questions?
First, as I have said, I bought a couple of the original boards. Will the output boards that Al has made work with the older boards?
Also, what are the best output transistors to use? I have quite a few different transistors that I have aquired from OnSemi over time. I see that NUTTTR has used some T-03's. I have some MJ15003/4. Will those work?
I also have the MJL 21193/4's.
Thanks, Terry
The output boards will work with any T0247 output devices with the standard OnSemi/Motorola BCE pinout, so should be compatable with just about any similar amp.
Both types of trannie will work, but T03s will need to be hard wired, it's not difficult. Have a look at the pics that Stuart and I posted earlier.
Both types of trannie will work, but T03s will need to be hard wired, it's not difficult. Have a look at the pics that Stuart and I posted earlier.
Regarding the output devices.
I asked the same question a few pages ago. You can look there for some answers. Maybe this will already help you a bit further.
My question
Cheers
I asked the same question a few pages ago. You can look there for some answers. Maybe this will already help you a bit further.
My question
Cheers
transistors...
Hi Terry,
The mj15003/4 are the original transistors and work perfectly. I have also used the mj21193/4 and they work perfectly as well, essentially they are more recent versions of the originals, the same or better in datasheet parameters, but still relatively slow. I didn't do any back to back comparisons for sound quality.
That said, pinkmouse used the very latest on-semi transistors for audio, the mjl4281 and it's complement and found they sounded better than the mj15003/4...
Stuart
Hi Terry,
The mj15003/4 are the original transistors and work perfectly. I have also used the mj21193/4 and they work perfectly as well, essentially they are more recent versions of the originals, the same or better in datasheet parameters, but still relatively slow. I didn't do any back to back comparisons for sound quality.
That said, pinkmouse used the very latest on-semi transistors for audio, the mjl4281 and it's complement and found they sounded better than the mj15003/4...
Stuart
Cool,
I have the MJL4281s as well. If they are better I might give them a try.
All together, I have
MJL4281A
MJL3281A
MJL21193
MJL21194
MJL1302A
MJL4302A
MJ15003
MJ15004
Which would you guys suggest as the best to use?
So are the output boards something that will make things easier/better?
If they will work with the boards I have purchased, can I buy just the output boards?
Thanks so much for all the help.
Blessings, Terry
I have the MJL4281s as well. If they are better I might give them a try.
All together, I have
MJL4281A
MJL3281A
MJL21193
MJL21194
MJL1302A
MJL4302A
MJ15003
MJ15004
Which would you guys suggest as the best to use?
So are the output boards something that will make things easier/better?
If they will work with the boards I have purchased, can I buy just the output boards?
Thanks so much for all the help.
Blessings, Terry
still4given said:
Hello Terry, the two boards I shipped you are the same two I am building up now. There are output boards attached for the Positive and Negative rails. They just have to be snapped away from the main board. There really is no need to buy more output boards, unless you want an Uber amp?
Regards
Anthony
Coulomb said:
Thanks Anthony,
I didn't know if the boards I was getting from you had the output boards or not. I saw that some of the ones on the website didn't.
Which output trannies are you using?
Thanks, Terry
Terry,
Since you have them, I'd use the mjl21193/4 outputs. At least until more people have tried the much faster, newer 4281/2302 parts. Phyically they fit both the original and pinkmouse output boards, are very robust and basically just nice audio power transistors.
If a bunch more people with the right test equipment use and prove the newer parts are completely stable, and actually sound better, switching them out won't be that hard.
Stuart
Since you have them, I'd use the mjl21193/4 outputs. At least until more people have tried the much faster, newer 4281/2302 parts. Phyically they fit both the original and pinkmouse output boards, are very robust and basically just nice audio power transistors.
If a bunch more people with the right test equipment use and prove the newer parts are completely stable, and actually sound better, switching them out won't be that hard.
Stuart
still4given said:
I have a Plitron 750VA 30-0-30 which should be plenty for 70 Watts.
Anthony
jacco vermeulen said:
Hi Jacob,
Do you have a special switch for switch between your various amplifier?? If you have a convience switch how is it wired??
jacco vermeulen said:
Hi jacco,
I am happy to help if necessary, but won't OnSemi send samples to you? They sent me 10 different transistor models in quantities of 25 each for just $11.00 to cover shipping and handling. That's 250 transistors.
If you can't get them it would probably be cheaper for someone who lives on your "Side of the Pond" to send them to you.
Let me know.
Blessings, Terry
still4given said:
Let me rephrase the question :
Terry, can i have some classic devices from you in 20 years from now ?
I have no idea if OnSemi gives samples overhere, i buy the stuff i desire.
If they send you those devices in series of 25, how are they making money ? Selling it to gits like me, i guess ?
I have 4 creditcards, the regular procedure is that i pay the bill.
I dont use a switch.
pinkmouse said:
Al,
10kHz square wave has primary (10k) and all the odd multiple components (30k, 50k, 70k .. etc. ad infinitum). The sharpness of the "corner" of 10kHz square will be formed by very high order residuals (in 100's of kHz and MHz range), which are blocked by input filter anyway.
I can't hear any of these, don't know about you 🙂
It is also possible that ultra fast devices add some of their own (ringing) and "fill" the corners of the shape. The (single) compensation pole in KSA 50/100 was designed with devices originally specified. You may find that with faster outputs a more aggressive compensation might be in order.
Try the amp with something reactive, like 2uF in paralel to say 4 ohms and compare squarewaves again. My 2kHz shape shows minimal ringing (only about 1.5 - 2 cycles discernible on the scope). This is more like real world load the amp will see, especially if you like electrostats. The excessive ringing in this case WILL be heard as upper range "glare", keeping in mind how well resolving electrostats are there.
Bratislav
PS I like the idea of using latest semiconductors, like everything else they are likely better designed/researched/manufactured. I just want to throw in some caution