Tips for buying used Vinyl needed


I see there is a learning curve to buying used vinyl, can you please offer your wisdom and experience? In my recent attempts at buying used vinyl I have learned not to buy from someone who has stored their collection in the garage, dusty, moldy, and urine smells are gnarly. I am starting to look closer now that I have brought some home from my local shop and noticed imperfections in the vinyl itself, resulting in pops. Finding thirty and forty year old records in good condition is not as easy as I thought it would be.
bigwavedave
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Completely agree with Jazdoc - in fact it is early stereo you should avoid. Until they got it right there was an over-exaggerated "hole in the middle" image to stereo which is quite annoying to listen to. I much prefer mono for most early jazz.
I've tried to get into mono recordings, but I just can't. I'm sure there are many that sound great, but it just doesn't sound enjoyable to my ears. I didn't mean to start a stereo/mono argument, just wanted to point out that if you don't want mono, then you have to pay close attention to albums. To each his/her own.
I seek out and listen to mono recordings for the same reason I look for 78s - there is a large body of music available in these formats that you just won't find on stereo recordings. But unlike most 78s, mono LPs actually sound great. But in order to achieve the best you need to use a good (not necessarily expensive) mono cartridge. I won't go into a detailed explanation here - there are many, many previous posts that discuss this in detail.
There is a wealth of great info here. One thing I am a little surprised no one has mentioned is the fingernail test for scratches on used LP's. Gently run your fingernail across the scratch - if you can feel it, you will certainly hear it, and do not purchase the LP. If you can't feel it, this is not a guarantee that you won't hear it, but there is a good chance that you won't.

I have found this fingernail test to be much more reliable than visual inspection. Many times I have cleaned an LP that looked fine visually and then turned out to have groove damage that was not visible, even looking at it after I knew the location of the damage.

Visual inspection will also almost never reveal whether or not an LP has a great deal of surface noise from the pressing. I can't tell you how many times I have been disappointed by the RCA "shaded dogs" in this particular respect. Sometimes an LP was just pressed badly, and no amount of cleaning will fix it.

Speaking of cleaning, I agree that a RCM is a must. I also highly recommend the AIVS fluids - I have had some very good results using their three-step process.