Valve replacement time...some opinions please?

[Gazjam]

Had a couple of scary moments with my valve amp of late and so I'm replacing the valves.

I've already replaced the power valves. Had them in for a couple of years and a some of them are not glowing properly so suggests something bad waiting to happen...
Replaced those with a new matched Quad of the same Genalex Gold Lion KT88s.
Heard a few different sets of power tubes in my amp (even the fabled Svetlana winged C's) and to me these sounded the best.

I'll wait until I get the new KT88's run in then take a view on whether I'd get any improvement with replacing the 12AU7/12AX7 pre valves.

Out of curiosity, what makes more difference to the overall sound of the amp, Pre or power tubes?
I've read power tubes need replacement more than Pre?
That true?

Any suggestions as to good 12AU7/12AX7 replacements (If I need 'em?)
The Gold Lion Ecc83/83 versions get great write ups, thinking to get these?
http://theartofsound.net/forum/showthread.php?19237-Genalex-valves


thanks. :)

[Ali Tait]

The pre valves can often make more of a difference than the power valves IMHO. Usual suspects apply re. NOS, depends how much you want to pay I guess. I can send you some to try if you like?

[Gazjam]

Would you?
That'd be great Ali, just to see the effect different pre valves can make.

Cheers! :)

[jandl100]

Yup, I agree that pre valves can make more difference, and yes, they tend to last a lot longer than power valves and have less reliability issues.

I like the sound of TAD 12AX7, they are cheap, too. Open, explicit and detailed. Lovely things if you like that sort of sound. :)

I have a pair I can lend you if 2 is enough, Gaz.

[Ali Tait]

Would you?
That'd be great Ali, just to see the effect different pre valves can make.

Cheers! :)

No bother, let me know what the amp uses and pm your address and I'll send a wee selection out.

[Ali Tait]

BTW, yes, the pre valves will last a lot longer. An often quoted figure for a PP amp is 2000 hrs for the power valves. Good NOS driver valves will give 10000 hrs or more. Last donkey's years in other words.

[vouk]

Hey Gary,

I tried out a few ECC83/12AX7 back in the day on my Pathos in Power monos; the Telefunken (smooth plate) were my top choice but had very good results with Gold Lion and Mullard (re-issue) ones; to my mind though, the Sovtek (LPS) is somewhat of a bargain considering its low price.

[Gazjam]

Cheers John, tempted to try the Sovtek (LPS) as they are not too spendy.

[Gazjam]

Got the new matched Quad of Gold Lions in this morning, fired them up.

Ooh, amp sounds quite different, a lot more punch, more detail coming through.
Guess the old ones were slowly getting past their best?
Straight out the packet a nice upgrade, how long though till they burn in properly?

Thanks.

[vouk]

Got the new matched Quad of Gold Lions in this morning, fired them up.

Ooh, amp sounds quite different, a lot more punch, more detail coming through.
Guess the old ones were slowly getting past their best?
Straight out the packet a nice upgrade, how long though till they burn in properly?

Thanks.

60-80 hours at most, ime.

[Gazjam]

cool.
Thanks.

[The Black Adder]

Hi Gary.

Have you seen these? These are highly recommended.

http://www.tubemonger.com/Mullard_CV4035_NOS_NIB_1961_Prem_CV4004_Whyteleafe _p/2050m.htm

:)

[Gazjam]

Have a loan of a few different pre valves to try inclusing some Mullards. :)
Letting the KT88's bed in for a bit then I'll have a play with the pre valves.

How much are those Mullards Joe, cant see from the site?

[Ali Tait]

150 dollars per valve. Yikes!

[loo]

Hi Gary , I don't know what amp you have but remember to keep an eye on
Your kt88 's bias for the first 100 hrs also re check after swaping the driver tubes
Cheers
Paul

[Rush2112]

Hi Gary, Paul is on the money with bias settings not sure what adjustment is available to you on your amps but when I had Lumley Reference M120 mono-blocks it was a part of my regular checks and yielded excellent valve life from the Sovtek 6550's.

Regards,

Mark

[Ali Tait]

You'd need to with those from what I've read, Lumley ran the valves rather hot...

[Ali Tait]

Have a loan of a few different pre valves to try inclusing some Mullards. :)
Letting the KT88's bed in for a bit then I'll have a play with the pre valves.

How much are those Mullards Joe, cant see from the site?

Tried any of the pre valves yet Gaz?

[Gazjam]

Hi Gary , I don't know what amp you have but remember to keep an eye on
Your kt88 's bias for the first 100 hrs also re check after swaping the driver tubes
Cheers
Paul

Thanks Paul, Mark.
The amp has individual bias pots, checking every few days.

Bias set at 45mv..some sites say though the 88's need to be run hotter?
No info on the amp itself, was a 2nd hand buy, albeit a fantastic one. :)

[Gazjam]

Tried any of the pre valves yet Gaz?

Not yet Ali, letting the new power valves bed in for a bit.
Checking out the Pre valves during next week.

Will be interesting! :)

[The Black Adder]

Have a loan of a few different pre valves to try inclusing some Mullards. :)
Letting the KT88's bed in for a bit then I'll have a play with the pre valves.

How much are those Mullards Joe, cant see from the site?

Hi Gary.

They are quite expensive $150 but they are the best of the best because they were made for hard wiring. Tubemonger have had some bases made for them. I've tried numerous valves including the mullard yellow print, CV4004's and these babies surpass them for sure.

If they are too much then try a Mazda, Amperex or the CV4004.

[Ali Tait]

That's the thing though Joe, they may well be best in your particular application, but not necessarily in others, and it's a lot of money to take a punt. In any case, I've lent Gaz some nice valves to try, Mullard, Amperex, Telefunken etc, so at least he's got the chance to try a selection to see what's best with his particular amp. Should give him an idea of which direction to go.

[The Black Adder]

ok... just throwing my thoughts and experience in.

[Ali Tait]

Aye, don't get me wrong, I've no doubt they are great valves, but it's just my experience that a particular valve can sound different depending on the amp/ circuit it's used in. :)

[Gazjam]

Will have a play next week.

big thanks to Ali to let me try different ones in my amp.
Good guy... :)

http://www.youtube.com/watch?v=Z_UGD7AazMI

[Ali Tait]

:lol::lol:

Brilliant!