best SUB for 132-070
- Thread starter calman46
- Start date
kevzep
Its all about the Music
Okay, so its in the front end most likely.....
What is the frequency of the hum? I know this was asked before....fundamental frequency being 60hz, then there could be harmonics of that 120/240 perhaps...this may help narrow it down to one area...
Did you replace the multi-caps?
Its a low frequency hum gets less when I turn down the bass. I don't have the knowledge to tell you that . I did all the electrolytic caps. Increase the 80uf to 100uf
I talked to McIntosh and the MJ50003(c_dk) is the sub they use. Maybe the 024 are just to much for amp , it does play loud ,at half volume .
I talked to McIntosh and the MJ50003(c_dk) is the sub they use. Maybe the 024 are just to much for amp , it does play loud ,at half volume .
Its playing to loud and now one channel is lower than the other,not much but you see in VU's and hear it (the imaging is off) Its seem to have a different problem every time I turn it on. I think hum is just the amp cranking . I have to check the new volume pot on the Mx114 maybe I put that in wrong, I do get some static and the sound you get when you unplug a live mic. Its does this when I turn it fast. I replace a lot parts on these two units, needs some tweaking now .
kevzep
Its all about the Music
There will be no audio difference you could detect just by listening with the 024's its all to do with amplifier stability.....It wont play any louder just because of the different outputs....
Okay, so if you swap the inputs around going into the 2505 does the problem remain in the same place or does it move when you swap the inputs around? I it changes with the inputs moved, its in the preamp....
Have you got an ipod or something with a level control to plug straight into the 2505? We need to eliminate things, so lets just work with the 2505 first....
kevzep
Its all about the Music
While you are finding out whats going on, just use a source directly into the 2505, work in the pre-amp later when the 2505 is sorted.....
Sounds like you may have to go through and triple check your work and the component values used....
The MC 2505(stand alone) is fine a far I can tell ,the noise I hear at full gain sounds like the amp working. This amp plays loud . The MX114 has at least one worn out input jack on the main and maybe one phono. I get microphoincs when I touch any of the pots ,chassis , and I/O jacks on the MX114. The same microphonics is present on MC2505 only when the MX114 is turned on . Maybe bad jacks on the 114? or could it be the filter caps I replaced ? I'll look around see what I can find
Check the jacks. Clean them up. Sometimes they are lightly corroded and give those symptoms.
Regarding the 024 transistor - in all my Mc2300s, many, many side-by-side comparisons have been made in every possible scenario, old vs. new driver cards, transistors, etc., and the 024 by far sounds the best. I have no idea why this is, but everyone who has heard my Mc2300s say the one with the 024s sounds the best.
The 003s make it sound a bit tinny - and it runs like a champ on the 024s. I don't care that Mc says the 003 is the replacement - because in fact, that's exactly what the 003 is - a replacement, though not an exact one. They just don't make the old ones anymore. So the 003 and the 024 are 'replacements' and it's a matter of taste. The 003 sounds different, though not good to me.
Regarding the 024 transistor - in all my Mc2300s, many, many side-by-side comparisons have been made in every possible scenario, old vs. new driver cards, transistors, etc., and the 024 by far sounds the best. I have no idea why this is, but everyone who has heard my Mc2300s say the one with the 024s sounds the best.
The 003s make it sound a bit tinny - and it runs like a champ on the 024s. I don't care that Mc says the 003 is the replacement - because in fact, that's exactly what the 003 is - a replacement, though not an exact one. They just don't make the old ones anymore. So the 003 and the 024 are 'replacements' and it's a matter of taste. The 003 sounds different, though not good to me.
kevzep
Its all about the Music
If you can hear a difference thats great.....
All I am saying is for less experienced people fitting non recommended replacement semiconductors who do not understand the risks involved or the equipment or experience to watch the performance of the amp for instability or self oscillations and the likes....I think it wrong to advise to fit those non recommended parts....
I have used 15024's and I was not able to get the amp to go unstable, so I am satisfied, i am also satisfied my technical training and knowledge can support experimenting in this way....
However, I am not going to advice lesser experienced guys to go down that road unless I am ABSOLUTELY sure it is safe....
Its not the output transistors making the amp play like that, those 15024's actually have less hfe (DC Gain) than the 15003's for a start.....
Its not the transistors....
It seems to me you have some problems in the pre-amp. I am not familiar with the pre, so maybe someone else will chime in with some advice.....