umph

[quote name='Ancient Mariner' timestamp='1326297974' post='1495108'] Not entirely. Some years back when I was much more active building amps we had a debate about this on 18watt.com. I had a few pairs of valves sitting around and decided to experiment using liquid nitrogen that was available at work. The first valves I tried were some Sovtek 6L6s which were a bit dull sounding. Both valves from the pair sounded similar, so I marked one up and treated it, first freezing to -80'c, the immersing in LN2 for a couple of days in a small volume dewar vessel, which was allowed to run dry and gradually warm up (slow warming is part of the annealing process). To test whether the difference was real or not I had my wife swap various valves around in a single ended amp I'd made while I was out of the room, and to make it a little more fun, we included an EL34 and a 6CA7 too, along with the pair of 6L6s. In each case I was able to identify which valve was which, and differentiate the cryo treated 6L6 from the other as well as the EL34 and 6CA7. What difference did it make? In each case, and with every valve I treated afterward, it made the valve a bit brighter and a bit more open, and the effect remained after several hours of use. Some valves were affected more than others, with the biggest difference in the 6L6s and EL34s I tried, very little difference in some Ei EL84s, National 12AT7s and Sovtek 12AX7s. IMO the value is in brightening a dull valve, if that is a problem for you, but it will not make a modern valve sound like a NOS Mullard contrary to some claims. Larger power valves seemed to benefit more than small valves. One other thing was interesting: none of the nay-sayers were willing to accept that a difference was possible, and none of the guys in the UK were willing to take part in a blind controlled study where they tried valves before (to check a pair sounded the same) sent them to me for treatment & I sent them back for re-testing. edit for spelling. [/quote] Did you do any measurements with gear?

cryo treatment is snake oil. theres been a resurgance in valve popularity lately so i think they'll be sticking round for a while yet. Can't imagine neo will be vanishing either

you got a new face panel for it and got ridda the green? how rude

free listing atm ;p

[quote name='matt_citizenbass' timestamp='1325718876' post='1486751'] Watch it The thunderverb through bass isn't AMAZING. It's mainly there to cover the top end that the AD200b doesn't cover (bass basically all cut) [/quote] should use his soundcitys, only soundcity is real. Or if you're in sheffield come borrow some manly amps off me

to me ;o

eww orange

[quote name='shizznit' timestamp='1325673220' post='1485821'] I am very much a solid state fan. Main reasons... 1. Reliability 2. Portability 3. Price Reliability - When a tube goes it's always when you least want it to. 9/10 in the last 5mins of a soundcheck or second song into the set! Portability - Have you ever picked up an Ampeg SVT-2 head and carried it up a flight of stairs? Try that and then do the same with a Markbass LMIII. Price - The D-class market is very good value for money and the quality of the products out there is getting better and better every year. Companies like Genz Benz and Markbass are developing very nice D-class/Tube hybrid amps that sound great. [/quote] if your solidstate amp goes wrong you have to bin it! much worse in my eyes

no personal experience with them but 808's are really good valves so it should sound nice

[quote name='Amazoman' timestamp='1325284286' post='1481870'] The tech is a top man, highly recommended. It was John Chambers from Champ Electronics in Nottingham. I did have a problem originally with the power tubes which was caused by a cracked tube and air getting inside. This had the effect of taking a second tube out as apparently they work in pairs. When those tubes were replaced and biased John found a small black line of (I can't remember what he called it!!) material that was linking two of the power tube bases together on the board and causing one tube to discharge all of its volts into another. This he cleaned off and everything power wise was fine. All of this was checked using an oscilloscope and meters. There was no need to look at the preamp stage for any of this repair. He said it looked like the amp had been worked on before and this material should have been cleaned away and was the root cause of my original problem. He did this work as I waited and watched, absolutely fascinating. He kept inviting me to look through his workbench magnifier to see exactly what he was talking about. With regard to 'was this hum there before he worked on it' I expect so but I don't actually know because the amp developed the problem with the power tubes within half an hour of me taking ownership of the amp. (See previous post). [/quote] John is my mentor and a top amp tech, i thought it might've been him when you said he suggested kt100's! He's loving the shuguang atm

[quote name='Amazoman' timestamp='1325265493' post='1481543'] I am an absolute novice with regard to valve amps and the characteristics of the different valves. The stock valves that come with the AD200 are 6550's. From what I have read they do start to break up and give that gritty driven sound quite early on when driving the gain when compared to KT88's. When I spoke to the amp tech about this and that I was after a smoother tone, and as I was having it revalved anyway, he suggested KT100's. His reasoning was that they are very similar to a KT88 but in his terms a little beefier I assume he meant more robust, The tone that I am getting from them is just what I was looking for but I'm not driving them hard as I said in a previous post I am only using the amp in the bedroom currently so I certainly don't want any masonary falling down. Just a final question in the pre amp stage the amp takes two ECC83 and one ECC81. I can get the ECC83's locally and save on posting but not the 81. Could I put 3 ECC 83's in as their characteristics look to be the same when I've searched the internet. The 83 are high gain the 81 medium gain thats the only difference I can find. [/quote] 81's can push more current than 83's. You may find the drive will suffer on your amp. An 83 is at its limit driving a quad of kt88's. In other words grab a nice NOS 81 off ebay

kt100 is basicaly a tougher version of kt88, it's still pretty similar though. Best way to troubleshoot the noise would be to pull valves starting with the input valve until the noise goes then do some valve swapping till you find a quiet one.

[quote name='solo4652' timestamp='1325254040' post='1481350'] I must say I was a bit surprised. I thought he could at least have had a look and then gone through the repair/replace options. As soon as I said it was a Line 6 he lost all interest. He'd already half lost interest when i said it was solid-state and not valves. [/quote] i'd've said the same in his position. Line 6 amps aren't easy to work on. It'll be almost the same price to buy a new one. Basically you don't troubleshoot with line 6 amps you send them to be rebuilt or put them in the bin

sell me the 200 ;o or do a trade and i'll make you a smaller amp?

You can get head switching devices that put one amp on a load while the other goes to the speaker.

get a kappalite and retune the ports. Would be a sound plan to me

you shouldn't be asking these questions the other bassist should be

[quote name='obbm' timestamp='1324510262' post='1475182'] Nope still too much. Now if it had all the schematics as well then that would be different matter. [/quote] what are you after?

[quote name='andydye' timestamp='1324475385' post='1474687'] That's a great price isn't it? Not far from me too... [/quote] DIBS

Gut shots of the mark one please I'd recomend going NOS and trying out phillips, JAN and mullard valves. edit; Mil spec and bigger plates are good for what your after