market value of my gears

There are examples of the Marantz and Jadis models that are up for sale (or auction in the case of the 8B) here at Audiogon right now, so you can see what people are asking for them.

Your JA200 is considerably older than the one being offered, which should be taken into account in determining your asking price.

The McIntosh 225 and 240 are not especially rare, so I suspect that a little Googling would turn up recent asking prices.

I don't think I've ever seen an MC3500 offered for sale, but fwiw a 2012 valuation of $12K is cited in this reference. Not sure if that is for one or for a pair, though :-)

Regarding the Orion bluebook which was suggested above, I have no knowledge of how realistic their current valuations are for vintage tube gear. But I can tell you that the 1991 bluebook which I have absurdly undervalued most examples of collectable vintage tube equipment, relative to their true worth at that time.

All of them in mint and original conditions.

Keep in mind that the value of classic vintage tube equipment such as this is extremely sensitive to cosmetic condition. Very little equipment from the 1960s or thereabouts is truly mint. Any minor scratches, speckling of chrome, discoloration, etc., will reduce value considerably. If the serial numbers of the 9s are not close, that will reduce value somewhat. If one of them is the blue chassis version and the other the brown chassis version (as opposed to both being the same color), that will mean $thousands off.

Finally, willingness to ship internationally can make a considerable difference in how much pieces like this will bring.

Good luck!
-- Al

Audiogon Bluebook prices are based on the average of actual sales, and often seems pretty close to what I see a lot of used equipment selling for. Original Marantz 9's for example are listed at well in excess of $6,000.00, certainly not lowball.

Gbart, I suspect that figure is for one mono Marantz 9. A pair of them that have the same color chassis and are fairly close in serial number would be worth considerably more than twice the value of a single unit.

"Considerably" meaning at least several thousand dollars more than twice the value of a single unit. I am basing that on my own experience selling a pair during the 1990's, and on input I received at that time from a highly respected expert on these things, while factoring in some allowance for price escalation that has occurred since.

Regards,
-- Al

I think you should donate all the gear to my favorite charity, me.

Jbl 375, I would check the sold section of EBay would give you the best info possible. I buy and sell quite a bit of this stuff. Bob