vsat88
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Not a problem. You will love your preamp if you clean the switches and re cap it . I have done two so far. Two more to go.
Kenwood Basic C1 Preamplifier Restoration/Upgrade
- Thread starter Leestereo
- Start date
Harvestor
Addicted Member
Too bad I don't live in your neck of the woods because I would Pay you to do my C1 and M2a ... though I am already impressed with how they sound together.
harvester, while I haven't heard an updated c1, my c2 improved noticeable after some minor updates. I'd suggest getting a c2 and sending your c1 off for an update.
BTW, I can't imagine having 4 c1 preamps. I think I have enough preamps for all my power amps but not 4 of the same brand/model. even my mark iiis have different driver boards on 2 of them (and I have a bunch of the dynaco monoblocks).
BTW, I can't imagine having 4 c1 preamps. I think I have enough preamps for all my power amps but not 4 of the same brand/model. even my mark iiis have different driver boards on 2 of them (and I have a bunch of the dynaco monoblocks).
vsat88
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I really do this for a hobby not for others besides my friend here in town. Just a small shop out back of my house. @Leestereo would be your contact or DRM (personal opinion, no affiliation) . Daniel Mattis at "https://drmaudio.com/"
Both are experts. Mr. Mattis sells kits to re cap all the Kenwood Basic series amps and pre amps. I have a C1 I use in the shop, a C2 I use as a back up, A C2 that I restored and sold and a C2 to do up for my friend in Columbus. That is the four count BTW. I am running a C2 now as I have my Sumo Diana on my workbench for a restore, in fact did the parts order today from Mouser ( no affiliation) . As far as the switches in the C1 they are not a problem at all to clean/lubricate. On the C2, Ha Ha, those are a different animal.
C1bob
New Member
Hello All,
Having done the mods to my C1, I have recently paired it with my modded Quad 405-2, this amp has a sensitivity of 1.5v, but when using it with the C1 the volume is just too high when the volume knob of the C1 is at the 9 O'clock position. It's unusable the beyond 9 O'clock.
R41/R42 were changed to 56.2K in the mods, would a change back to the original 1.2K improve things?
Thanks for any help.
Bob
Having done the mods to my C1, I have recently paired it with my modded Quad 405-2, this amp has a sensitivity of 1.5v, but when using it with the C1 the volume is just too high when the volume knob of the C1 is at the 9 O'clock position. It's unusable the beyond 9 O'clock.
R41/R42 were changed to 56.2K in the mods, would a change back to the original 1.2K improve things?
Thanks for any help.
Bob
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vsat88
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Hope @Leestereo can chime in on this one..I see R 41 and R 42 in the voltage regulator powering two op amps and in the original schematic I see them as 4.7 not 1.2k ohm ??? Hope someone stops by to help.
zaskarx
Active Member
Hifi engine lists the Quad 405 mk2 as having an input sensitivity of .5v, so that could be about right. I recently restored my C1/M1 pair with the same load resistor mod and my normal listening position is just past 9 o'clock, source CD player, with 90db sensitivity speakers. The M1 has an input sensitivity of 1V. Do you have a scope and dummy loads to test where on the volume pot the amp starts to clip? On my pair it was just past 2 o'clock into an 8 ohm load, which seems pretty typical. Unfortunately, I didn't listen to the C1/M1 pair together prior to the restore given that the M1 was in such poor condition so I'm not sure if it changed. Hope that helps.
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Hopefully not resurrecting a dead thread, but I have a C1 that I just received, but the shipper broke the shaft off the Bass control pot. Can anyone point me towards a replacement part? All I know is that it's a 20kohm linear 6 pin pot. Otherwise I'm in the dark. Any help is appreciated.
vsat88
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No, this thread will never die. We keep posting here. In fact as far as I know the OP is still posting and helping others with the C1 Kenwood basic preamps. I would not be of much help as I do not have one of the pots that you need. Silly to say but have you looked on ePay ? They have parts on there all the time. If not then one of the dudes here may have one. Wish you luck.
https://www.ebay.com/itm/2x-Potenti...hash=item3d8da861b7:m:mcOEJfjYq5E56h6wO50mvHQ
No Affiliation
https://www.ebay.com/itm/2x-Potenti...hash=item3d8da861b7:m:mcOEJfjYq5E56h6wO50mvHQ
No Affiliation
vsat88
Like my Bluetooth ?
Bought another C2 BTW @Leestereo . I am a sucker for cleaning those switches...This one has a balance control that works !
Redone90
New Member
Thanks so much for the responses! Both me and my local repair guy are searching for a suitable replacement. I was unsure about the Chinese units from the internet, but somewhere on this thread someone replaced theirs. If they've got a good one, that's be great to know! I've emailed DRMaudio, we'll see if he's got a suggestion. Thanks again!
simpsonsons
New Member
Hi
Hope i am not resurrecting an overly dead thread
I have a dead c1 I am trying to bring back to life.
My first question is -> why can the replacement capacitors have a higher capacitance than the older ones? I thought going up in volts is OK but not capacitance. Just curious why that is OK in this situation.
Any idea where to get a replacement transformer? Unfortunately mine is quite dead. Or how to source an equivalent replacement.
Thanks!
Hope i am not resurrecting an overly dead thread
I have a dead c1 I am trying to bring back to life.
My first question is -> why can the replacement capacitors have a higher capacitance than the older ones? I thought going up in volts is OK but not capacitance. Just curious why that is OK in this situation.
Any idea where to get a replacement transformer? Unfortunately mine is quite dead. Or how to source an equivalent replacement.
Thanks!
ye olden caps had wide tolerances like +80%/-20%, modern day, through better techniques are +/-20% so going up say 50%
is no big deal and is covered in the circuit design which catered for +80%. Generally increasing the capacitance of filters/storage
should provide (audible?) sonic improvement with less ripple and low level response.
Change from LM4562 to OPA2134 in tone circuit.
The LM4562 had lots of detail, tones were crisp/sharp though sound stage was a little 2 dimensional.
The OPA2134 had softer tones, lost a bit of detail however had deeper sound stage and a non-fatiguing sound.
Base went noticeably lower (Zoe Keating cello draw). Played through a yamaha CA-1000 in "class A" as
power amp, thought the OPA2134 closely match the CA-1000 pre but with wider base response.
The C1 represents excellent value for those wanting to get into separates, about the same as the yamaha C-40.
Short of the CX-1000 and electrocompanient 1a but a good unit.
2c?
The LM4562 had lots of detail, tones were crisp/sharp though sound stage was a little 2 dimensional.
The OPA2134 had softer tones, lost a bit of detail however had deeper sound stage and a non-fatiguing sound.
Base went noticeably lower (Zoe Keating cello draw). Played through a yamaha CA-1000 in "class A" as
power amp, thought the OPA2134 closely match the CA-1000 pre but with wider base response.
The C1 represents excellent value for those wanting to get into separates, about the same as the yamaha C-40.
Short of the CX-1000 and electrocompanient 1a but a good unit.
2c?
simpsonsons
New Member
Thanks!! Makes perfect sense about the tolerances I should have realized that I was so fixated on getting exact replacements.
Well hopefully I can find a replacement transformer which..... might be impossible or prohibitively exspensive
Well hopefully I can find a replacement transformer which..... might be impossible or prohibitively exspensive
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