Hi,
I have a Marantz PM6006 and have purchased their service manual. Currently I am 4 ohm speakers-1 inch seas h1189+ 5 inch SB acoustics (around 87 db) for desktop speaker in a 150 ft room and also using headphones. I have some electronic and soldering skill.
1. Currently I have increased the bias from stock 45ma to 90ma across each emitter resistors in the power amp sections and the amp is stable.
2. I know the amp itself has a "house sound", but I found it was a bit too forward and thin in the mids and synthetic highs and with a one-note, much weaker and muddy bass (Voltage gain much higher than Current gain?). Is it possible, with some component change (preamp section?) to voice the amp to a "straight wire with gain" + "well (better) defined and controlled instruments and soundstage" kind of voicing? I think I prefer 10% less voltage gain with a higher current gain across the bandwidth.
3. Can I remove the DC blocking capacitors if I first measure no DC on the input leg of the capacitor to ground? I appreciate if someone can direct me to these caps as I want to be sure.
4. Are there any benefits if cap value of C6011, 6013, 6012, 6014 and C6019 (page 7); C5011, 5012 (page 9) (one channel) is increased? Any recommendations?
5. On the volume board (page 9), can I remove C5001 and 5009 as on question 3? Also can the diodes be upgraded? or simple circuit changes as I have read that the HDAM design is not the best?
6. I have read somewhere that the auto-standby circuit which activates on no sound from speakers can be disabled by removing two jumpers as this circuit is noisy, can someone direct me to the correct ones.
7. I am also using tone controls. Any suggestions as to the op-amps in the amp that should be upgraded? LM49720?
8. Any upgrades from the digital section as I am planning to purchase a Schiit Eitr to connect via usb to a computer. This connection is not asynchronous usb connections, is it?
9. Any bottlenecks or better design ideas in this amplifier (simply DIY tasks?)
Any other suggestions are most welcome.
Thank you.
I have a Marantz PM6006 and have purchased their service manual. Currently I am 4 ohm speakers-1 inch seas h1189+ 5 inch SB acoustics (around 87 db) for desktop speaker in a 150 ft room and also using headphones. I have some electronic and soldering skill.
1. Currently I have increased the bias from stock 45ma to 90ma across each emitter resistors in the power amp sections and the amp is stable.
2. I know the amp itself has a "house sound", but I found it was a bit too forward and thin in the mids and synthetic highs and with a one-note, much weaker and muddy bass (Voltage gain much higher than Current gain?). Is it possible, with some component change (preamp section?) to voice the amp to a "straight wire with gain" + "well (better) defined and controlled instruments and soundstage" kind of voicing? I think I prefer 10% less voltage gain with a higher current gain across the bandwidth.
3. Can I remove the DC blocking capacitors if I first measure no DC on the input leg of the capacitor to ground? I appreciate if someone can direct me to these caps as I want to be sure.
4. Are there any benefits if cap value of C6011, 6013, 6012, 6014 and C6019 (page 7); C5011, 5012 (page 9) (one channel) is increased? Any recommendations?
5. On the volume board (page 9), can I remove C5001 and 5009 as on question 3? Also can the diodes be upgraded? or simple circuit changes as I have read that the HDAM design is not the best?
6. I have read somewhere that the auto-standby circuit which activates on no sound from speakers can be disabled by removing two jumpers as this circuit is noisy, can someone direct me to the correct ones.
7. I am also using tone controls. Any suggestions as to the op-amps in the amp that should be upgraded? LM49720?
8. Any upgrades from the digital section as I am planning to purchase a Schiit Eitr to connect via usb to a computer. This connection is not asynchronous usb connections, is it?
9. Any bottlenecks or better design ideas in this amplifier (simply DIY tasks?)
Any other suggestions are most welcome.
Thank you.
Philip C
Sorry if I have asked too many questions on my earlier post. Perhaps I should rephrase in a simpler way: How to reduce voltage gain in the preamp stage (on Volume board)?
Thank you.
Sorry if I have asked too many questions on my earlier post. Perhaps I should rephrase in a simpler way: How to reduce voltage gain in the preamp stage (on Volume board)?
Thank you.
> I know the amp itself has a "house sound"
As far as I can see, this box _IS_ a "straight wire with gain".
Have you *measured* it as being un-flat?
_I_ don't even see anything I dislike.
As far as I can see, this box _IS_ a "straight wire with gain".
Have you *measured* it as being un-flat?
_I_ don't even see anything I dislike.
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