Jolida JD100 and JD100A,whats the difference?

Funny, I have a JD 100, and it has an articulate bass that goes very deep. There is no blacker than black. The stock 100 is as smooth as can get without getting boring. Yada yada.

There have always been tweak monks when it comes to Jolida. The voicing of the stock Jolida was a painstaking ordeal. Each element was carefully balanced, right down to the positioning of resistors and capacitors, before it's creators were pleased enough to put on the market.

When one replaces elements of the design, then the planned parts synergy is endangered. All the mods I listened to of the Jolida 600's machines were merely expensive failures.

What's more, the Svetlana is a decent tube, but is no match for many others on the market.

Without a doubt, 5751 tubes old stock. They are hard to find, but are relatively inexpensive. I've had much more expensive Telefunken and Mullards on board and the 5751 tubes bested them with greater extension, and detail. The midrange of these tubes are very clear and the background is black, with none of the 12AX tube microphonics.