Re-installing a brass nut on my LP Studio.

[Simon Barden]

Orange do the cheapest and most versatile valve tester that I know of, but it's still expensive and worthwhile only if you do a lot of amp servicing. Don't know what the valve supply situation is like in Australia, but there area a couple of UK suppliers (probably more but these are the biggest outlets) that pre-test the valves and match them up, often into low, medium and high gain sets. It's often variations on the standard valves that end up having the lowest microphonics or highest gain. A valve spec for a 12AX7 valve means it should have a maximum gain of 100, but often ends up less. And even the same manufacturer's valves will have a variation in actual gain. Here's a site I just found that does a good comparison of the different available types of 12AX7s. https://www.amplifiedparts.com/tech-...ent-made-tubes

Worth noting how many of the different brand's offerings are all the same Chinese-made valve, with the same electrical and sound characteristics. So you may as well find the cheapest brand you can find if you decide to try one of those valves.

[DrNomis_44]

Orange do the cheapest and most versatile valve tester that I know of, but it's still expensive and worthwhile only if you do a lot of amp servicing. Don't know what the valve supply situation is like in Australia, but there area a couple of UK suppliers (probably more but these are the biggest outlets) that pre-test the valves and match them up, often into low, medium and high gain sets. It's often variations on the standard valves that end up having the lowest microphonics or highest gain. A valve spec for a 12AX7 valve means it should have a maximum gain of 100, but often ends up less. And even the same manufacturer's valves will have a variation in actual gain. Here's a site I just found that does a good comparison of the different available types of 12AX7s. https://www.amplifiedparts.com/tech-...ent-made-tubes

Worth noting how many of the different brand's offerings are all the same Chinese-made valve, with the same electrical and sound characteristics. So you may as well find the cheapest brand you can find if you decide to try one of those valves.

Cheers for the website link, I downloaded a copy of the pdf of the comparison table, I've decided that I'm going to see if I can order three of those 12AX7/B759 - Genalex Gold Lion, Gold Pin valves, I know that they are a bit expensive but so is my Marshall amp, and I reckon it deserves some decent preamp valves to get it to sound it's best, so I'm prepared to spend the money.


I tried creating an account with that website (amplifiedparts.com) but it won't let me log in even if I use the exact username and password I chose when I created the account, so, I'm going to try ordering the new preamp valves from Evatco since I was able to successfully create an account with them, the new preamp valves will end up costing me about $160.00 all up but I'm not really too worried about that at all.