So, balance works fine? I forget whether you said you HAD bypassed it or THOUGHT you had.
Kenwood Basic C2 Preamplifier Restoration/Upgrade
- Thread starter vsat88
- Start date
So, balance works fine? I forget whether you said you HAD bypassed it or THOUGHT you had.
OK gentlemen the verdict is in. It is the way it is supposed to be. Henry brought his spare C2 over and we checked it all out. The volume position is the same on both when playing the same material at the same loudness level. My C2 being refurbished, new caps, new op amps and all sounds better of course but the loudness of the music is the same at the same levels on both. So, I was chasing a ghost I created up here in this pea brain again. I second guess my self way too often.
NCSUZoSo
New Member
Hey guys/gals!
Excellent thread with some great information on the C-2. I recently put discrete op-amps in for the flat amp and I think the EQ amp is the other location that can fit discrete op-amps. I used review samples from Burson Audio, V6-OPA-D "Vivid" Op-amps. Then in the tone control spots I used their compact V5i-D Op-amps. I also replaced diodes 11, 12, 13 & 14 with 16V Zener diodes to bring the op-amp total voltages from 36V down to a more normal 32V.
My only issue is the fact that on the tone control for treble, only if you take it to 9 or higher does it really open up. Either 2 frequency selections do about the same thing. It is like the treble control is useless until you almost max it out.
Is this a symptom that anyone recognizes? A treble control that only works if you max it. Otherwise the whole pre-amp takes some of the sparkle out of the top end.
You can see my photos and more info here at my website: http://hallmanlabs.com/2018/05/12/o...2-basic-pre-amp-gets-a-burson-audio-facelift/
Excellent thread with some great information on the C-2. I recently put discrete op-amps in for the flat amp and I think the EQ amp is the other location that can fit discrete op-amps. I used review samples from Burson Audio, V6-OPA-D "Vivid" Op-amps. Then in the tone control spots I used their compact V5i-D Op-amps. I also replaced diodes 11, 12, 13 & 14 with 16V Zener diodes to bring the op-amp total voltages from 36V down to a more normal 32V.
My only issue is the fact that on the tone control for treble, only if you take it to 9 or higher does it really open up. Either 2 frequency selections do about the same thing. It is like the treble control is useless until you almost max it out.
Is this a symptom that anyone recognizes? A treble control that only works if you max it. Otherwise the whole pre-amp takes some of the sparkle out of the top end.
You can see my photos and more info here at my website: http://hallmanlabs.com/2018/05/12/o...2-basic-pre-amp-gets-a-burson-audio-facelift/
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Sorry to be so long in returning any answer. I never had any trouble with the bass or trebel controls on any of my C2's . All of those seemed to work just fine before and after a restore. I only completely went through the one C2 the C1 and other C2 I have not done much to. The balance control can g et flakey on the C2 otherwise I think it as good of a pre as any and better than most. I saw a bit of smoothness appear after my build that I didn't hear before otherwise I really didn't hear a major difference. I could have ran it forever the way it sounded before the build and not had a problem with the sound. 30 plus year old parts inside made me want to update it and that was originally the idea of going in, at least for me. While I was in and by reading the other threads about the C1 and C2 here on AK gave me the idea that I should go ahead and do some more and really fix it up nice. I would also like to say that I may not be the one to answer too much on your question as I almost never use a trebel or bass or loudness control on any pre amps that I use in my system so I might not notice something like that as much. I do not think changing caps or an op amp would make the difference that you spoke of about having to crank the controls up so high to get a response. My volume control seemed that way but I proved that there was no difference there by putting another C2 in the same system and getting the same response from it with the volume control on the 2 nd one. On another note in order to go with all USA made equipment I bought an Sumo Diana. Oh what a beauty. It matches my B@K 442 amp perfectly, separate power supply and everything... 500.00 dollars later, I don't think it sounds one bit better than the C2....
NCSUZoSo
New Member
I believe I misrepresented the problem in the way I described it, let me try again.
The tone controls work correctly throughout the control it changes the tone. What I was trying to say was in the last 10% of the treble control when I push it between 9 to 10 (either 3kHz or 6kHz) it's like something opens up at that range only. It's harder to hear this in my Audeze EL-8 open-backs vs. using my Wharfedale Diamond 220 bookshelf speakers (where it's obvious as night and day when it happens). It's almost as if the controls have an EXTREME log curve, more like an exponential curve actually. Could it be the boost or cut in dB level throughout the range that is the problem? If anyone needs me to measure something, I can do it.
I can roll the highs out if I run the control to the left (as expected), so I know the tone control is working overall. Perhaps they intentionally did this for people who really want that treble boost? Can some people with the C-2 please check if you notice the same thing?
Begin playing an acoustic or mainly vocals album, turn the treble control to 3kHz (usually the easier of the two to tell this is happening) and begin to slowly turn the control to the right stopping around 7-8. Then continue to turn it all the way to 10 and see if you notice what sounds like a high frequency lift/spike that occurs between 9 to 10 on the control.
I am working on a review for the Burson Play v2.0 with all V6-OPA Classics (5 of them) and this is a little off topic, but does anyone have a good place/thread suggestion to ask for help on getting accurate audio measurements like SNR, DR, THD, Noise Floor, Jitter, IMD, etc.
The tone controls work correctly throughout the control it changes the tone. What I was trying to say was in the last 10% of the treble control when I push it between 9 to 10 (either 3kHz or 6kHz) it's like something opens up at that range only. It's harder to hear this in my Audeze EL-8 open-backs vs. using my Wharfedale Diamond 220 bookshelf speakers (where it's obvious as night and day when it happens). It's almost as if the controls have an EXTREME log curve, more like an exponential curve actually. Could it be the boost or cut in dB level throughout the range that is the problem? If anyone needs me to measure something, I can do it.
I can roll the highs out if I run the control to the left (as expected), so I know the tone control is working overall. Perhaps they intentionally did this for people who really want that treble boost? Can some people with the C-2 please check if you notice the same thing?
Begin playing an acoustic or mainly vocals album, turn the treble control to 3kHz (usually the easier of the two to tell this is happening) and begin to slowly turn the control to the right stopping around 7-8. Then continue to turn it all the way to 10 and see if you notice what sounds like a high frequency lift/spike that occurs between 9 to 10 on the control.
I am working on a review for the Burson Play v2.0 with all V6-OPA Classics (5 of them) and this is a little off topic, but does anyone have a good place/thread suggestion to ask for help on getting accurate audio measurements like SNR, DR, THD, Noise Floor, Jitter, IMD, etc.
I was still having some intermittent problems so I removed this switch and took it apart. It was very dirty inside and I spent some time with CRC, q-tips, toothbrush, and finally an eraser which finally got it clean. The problem I have now is those little copper clips fell out and I am not exactly sure how they go back in./ Does anyone have a good picture of how these should be?
Do you have the 8K filter button pushed in? If so, you're setting up a 12dB cut and then trying to boost with the tone controls. Not going to work well.
Hi everyone, looking for 2 knobs same for tape and input selectors and one small knob from same size group of 4 knobs on the left side of my kenwood basic c2 pre-amp and also the miniature potentiometer that control the headphone volume control, any kind help will be greatly appreciated! Thanks! Ali
Missed this post, sorry.
Do not mix up the switches side for side. Remember one is five position, one is four. Make sure they go back where they came from.
The contacts are in the same position on both switches. The base with the contacts in place will only fit one way. They either fit in the plastic part, or they don't. I hope this is helpful. Jim.
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On ePaY right now . As far as that headphone pot. Good luck. They are hard to find.
Phaceless56
Active Member
THD the Knobs are Aluminum with plastic inserts so best of both worlds I have one question you are not really going to purchase or not a Basic C2 based on the knob material are you they sound awesome and I personally enjoy modifying them
Phaceless56
Active Member
I don't think its paint maybe powder coated I'm not sure
Phaceless56
Active Member
My Knobs are actually
Trellium-D
live long and prosper
Trellium-D
live long and prosper
These amps sound very good and you can find them at a pretty decent price on ebay. If you find a way to remove the black paint and polish the aluminum I'd like to see how it comes out. Are you talking about removing the paint from the face plate too? What are you going to do about the lettering?