I have seen a lot of K1000 in the "Headphones for sale/trade" forum the last few months and often I see buyers asking if it's a bass heavy/light version or sellers advertising it as bass heavy/light. No, I don't want to say it's falsly advertised, they probably believe it is bass heavy/light from what they read. What's more, they may even be right.
That same question kept me busy as well a while ago and I almost ended up buying a second K1000 because of that. I know, you're sorry about my wallet.
Now I remember finding an old thread about the matter or a discussion in a longer thread, almost certainly here on HF, by doing a search here or on Google since I found that sometimes results in finding old threads on HF I didn't find by using the search function here. I can't seem to find it back though. It might even have been info I collected from multiple threads.
Anyway, what I understood from it was that people eventually came to the conclusion there probably is no bass heavy or bass light version. First low SN were believed to be bass heavy, then certain series of SN, low as well as high were found to be bass heavy/light and finally the bass heavy/light difference was considered uncerrtain or non existant. I haven't found any direct comparison between the two so called different versions with the same amp though.
So, in my opinion based on testing my K1000 with different amps (all I have/had in my profile except from the iCube) and what I read on HF I think bass heavy or light perception depends on the amp used with the K1000. My K1000 has a serial number in the 8k and is in no way shy of bass when powered with an appropriate amp. Some amps don't have the power to drive it loud enough, some do but don't make it shine (lack of bass, lack of body in lows and mids among other things) and some get it right.
Now I wrote this post hoping to start a thread that might be helpful to all those people who are intereted in buying a K1000 and falsely/rightly believe that there are two versions of the K1000.
I hope this doesn't become a discussion about the right amp for the K1000 since we have enough of those already.
I would love it if people post in this thread either know where to find the info I once found or have tried different K1000 on the same amp and can prove me right or wrong.
