Kenwood Basic M1 Amplifier Goodwill Find

Discussion in 'Dollars and Sense' started by noprayer, Jan 23, 2007.

  1. noprayer

    noprayer For The Dying

    I found a Kenwood Basic M1 Power Amp at Goodwill today that is in good shape except for 1 missing connector for one of the B channel speakers. it cost me 15 dollars and i was wondering if anyone here has had any experience with these. It is supposedly 100 watts per channel into 8 ohms with a pretty low total harmonic distortion. Any opinions would be appreciated. (I will post a few pics tonight)
  2. wineslob

    wineslob Wiping out white van

    Nice find, and a pretty decent amp.:thmbsp:
    If memory serves, it is a 100w/ch amp.
  3. nbourbaki

    nbourbaki Active Member

    I believe theophile uses a Kenwood Basic M2 as his bass amp.
  4. Gibsonian

    Gibsonian AK Subscriber Subscriber

    I had the Basic M1D, which is rated 125w/channel. I thought it did best in the upper frequencies, mine seemed a bit bass shy.
  5. Boonaroo

    Boonaroo Well-Known Member

    I have had a number of the Kenwood Basic components over the years. M1A M1d, M2a, C1 C2, but I have never had either of the first generation amps. The M1 and M2 had what Kenwood called Dynamic Linear Drive amplification. If I recall correctly, you have to have 2 speaker cables running from the amp to the speakers. You may want to find a manual for it, because I believe that it has to be wired properly to you speakers or you won't get the best performance.

    I currently have a Kenwood Basic M1d with the C2 pre amp. I have it hooked up to Polk SDA 1c, and I am very pleased with the combination.

    You may want to consider looking into the Kenwood Basic pre amps. The C1 is very cheap and plentiful. A C2 might set you back $75 in good condition.

    Let us know how it is working out for you.
  6. noprayer

    noprayer For The Dying

    I have an old Sony tuner/pre combo that i like the sound of so i think i will give that a try first. After taking a gander at the insides it looks like it's going to need a fair amount of cleaning before i give it any kind of workout. I'll keep you posted.
  7. noprayer

    noprayer For The Dying


    Here are a few photos.

    Attached Files:

  8. Damage

    Damage Super Member

    Well, that isn't what I expected the insides to look like. I figured they would look like the inside of my 880SD integrated.

    Attached Files:

  9. redcoates7

    redcoates7 redcoates7 Subscriber

    I had an M1D for a while and was dissapointed to find that the outputs were all "power packs" like in the KA-880 and a lot of their newer gear...

    The M1 on the other hand...discrete outputs, Sigma Servo, that's one heck of a nice machine! And for $ deal!

    Make sure you connect both the A Speaker outputs and the Sigma Servo outputs to your main makes a big difference in the bass response!

    Nice find...
  10. Damage

    Damage Super Member

    I believe that the M1A uses the power packs. Other than that, they are very similar in looks. The KA-880SD has the Sigma Drive also, but not the external connections.
  11. restorer-john

    restorer-john Super Member

    Interesting design- it looks like the amp may use two rails and the second set of output transistors may switch a higher rail voltage in for peaks. The output transistors appear original but the TO3P trs are way over spec for just drivers. Also the two sets of different value caps points to either two rails or a separate supply for the driver stage. Would be interested to see a schematic if anyone has one.
    Should sound pretty good- amazing for $15!!!
  12. nielsvanm2

    nielsvanm2 AK Subscriber Subscriber

    I picked up a VGC M1 and C1 for 50 cdn a while ago, but haven't found a permanent home for them yet. So, with the Sigma drive, you just run speaker wire to the speaker from the output, and then back from the speaker to the Sigma outputs?

  13. theophile

    theophile Pheasant Plucker. Subscriber

    OK guys.
    Hello all,nbourbaki was right I use a Kenwood Basic M2 as the bass amp in my system.I used to use a K B M1 as the treble amp before I bought the Yamaha B-2.
    With the understanding that I've never used the M1 for any frequency below 800Hz,I'll say it's a nice amp.It's not an eye-opener(for that you've gotta go to the Yamaha B-2:yes:),but it's respectable sounding.
    The sigma-drive function (available on the "speaker A"outputsonly,not "speaker B"),requires two sets of wires to be run to the speakers.One set of wires come from the normal "speaker A" outputs,the other set run from the shaded "speaker A" outputs.The wires run from the sigma outputs need to be of a slightly smaller gauge than the wires run from the non sigma outputs.
    Make sure that you keep "+"normal with "+" sigma or you'll f*** things up.
    Have fun with your amp.:yes:
  14. Damage

    Damage Super Member

    They are both switching designs. Not sure of the specifics.
  15. thedelihaus

    thedelihaus Questionable Morels Subscriber

    How's this "sigma" work, and what's it really do?

    sounds interesting...
  16. theophile

    theophile Pheasant Plucker. Subscriber

    According to Kenwood's literature on these amps you've described what the "DLD"(Dynamic Linear Drive)feature embodied.They said that the idea was that there was a very high sound quality/low power stage which handled low power requirements.This was backed-up by a higher output stage which kicked-in as required.
    The idea of the Sigma Drive function was that via the "Sigma Sensor" terminals the negative feedback loop(NFBL) could include the contribution of the speaker wires(?plus the passive crossover,plus the voice coil wire?)into the compensation mechanism of the NFBL.
    Like I said the Kenwood Basic M1 didn't set the world on fire above 800Hz,but I got some very nice sounds out of it.
    I'm still using the Kenwood Basic M2 as the bass amp(below 800Hz)in my system,and it's a very accomplished performer in that role.The M2 has a level of bass subtlety here which I've never heard anywhere.But of course in the context of my system,it stands on the shoulders of giants(Yamaha PX-2,Kenwood 700C(EW),Yamaha B-2,Altec Valencias).
  17. FunkNOOBiest

    FunkNOOBiest New Member

    Hey guys, I just scored a M1 and C1 for $60cdn. This thread has been a huge help in understanding what I was looking at. I'll admit I know little to nothing about this stuff but the GF's got me watching Craigslist for some audio equipment for her soon to open dance studio. Couple questions for you Cerwin Vega speakers I may use this amp to power have a 1/4" mic style connector. I'm guessing these "banana" plugs will work to the back of this amp? I know I can just clamp the wires but I like the idea of clean plugs. Also if I go this route... to still take advantage of this Sigma Drive you are talking about, could I just clamp a jumper between the shaded and non-shaded terminals and then run a banana style pluged cable to the speakers???

    Sorry for the noobness of these questions but your help would be appreciated!

    Ced :eek:
  18. theophile

    theophile Pheasant Plucker. Subscriber

    Man,that connector on the rear of the CVs,opens-up a real question about the Sigma Drive.
    Let's face it.At the speaker-end of things the 'Non shaded' and the 'shaded'(Sigma) wires are attached to the same speaker terminals.
    Whether or not the resistance of the speaker wire is necessary to prevent trouble(ie was integral to the correct operation),and connecting the terminals on the rear of the amp would be a problem?
    I can't answer that. :no:
    Whenever I used the Sigma hook-up on my Kenwood M2,I followed Kenwood's lead and made the diameter of the Sigma wires smaller than the non-Sigma wires.I figured there must have been a reason why they appear that way in all the diagrams relating to Sigma Drive that I have ever seen. :scratch2:
    I wouldn't fool with it too much.Capiche?
  19. FunkNOOBiest

    FunkNOOBiest New Member

    Hmmm... I'm thinking the same thing. Prob shouldn't mess with it. Although I wonder if using an even smaller guage jumper (as recommended or smaller) would reduce the risk of problems.

    Banana connector is the right term for the amp's terminals? Anyone know if they make a 1/4" mic style cable with 2 sets of banana plugs???

    Thanks for the reply.

  20. redcoates7

    redcoates7 redcoates7 Subscriber

    OK, So if you're going to connect the CVs to the Kenwood, just make sure that you run the two pairs of speaker cables from each channel of the amplifier to a 1/4" jack on the's totally OK to use a lower guage cable for the Sigma Servo connection

    Amp L+-----------\
    ----------Speaker Left+ on 1/4 Jack
    Sigma Left +------/

    Amp L- -----------\
    ----------Speaker Left - on 1/4" Jack
    Sigma Left - ------/

    The 1/4" plug is just an easier way to quickly connect and disconnect the cables in a pro speaker rig. They use the sam type of speaker cable as a standard binding post

    SO, be careful that when you buy 1/4" jacks (or premade cables), you purchase Speaker Cables, and not instrument cables

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