#1
Yo!

So I just bought new tubes for my 6505+ (I've asked a question in the 6505+ official thread, not answered so I'd appreciate it if you checked it out!)!
I bought the amp used a long time ago and the guy said it had original tubes. I now opened up the amp and saw that yep it had the original ruby power tubes. HOWEVER! The pre-amp tubes were JJ's? They come in stock with JJ's????

Now to my point. I bought all JJ's for the amp, so should I even change the pre-amp tubes? The amp is 3 years old. Do fresh pre-amp tubes sound better than old ones? I know that power tubes should be changed every couple of years before they actually (possibly) break down. How about pre-amp tubes? And should I keep the old pre-amp tubes somewhere as back up tubes or something, or should I just get rid of the ooold tubes?

And yeah, the question in the official 6505(+)/5150(II) thread is about the bias of the 6505+ so it would be greatly appreciated if anyone could check that out too!

Thanks!
#2
if you have the tubes then yeah change them out and save the old for backups.
#3
You should always have spares for everything. At least one spare preamp tube. If you think the ones in it are dying you simply swap in the spares and you know for sure. Usually just one preamp tube will croak at a time, hence why you can get away with a single spare. It's simply a matter of systematically trying it in different spots and listening to it. Power tubes however, you should have a full set spare.
Gilchrist custom
Yamaha SBG500
Telecasters
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Cathbard Amplification
My band
#4
Allright ok. But how often am I supposed to swap them? Like (with both pre- and power-) am I supposed to wait until it totally dies?
#5
No, you can do it any time you feel like it. I swap around preamp tubes just for fun.
"hmmmm, it feels like an Amperex day today."
If you're sus on a tube you just stick in your spare and you'll know straight away if it was necessary.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#6
Quote by Cathbard
No, you can do it any time you feel like it. I swap around preamp tubes just for fun.
"hmmmm, it feels like an Amperex day today."
If you're sus on a tube you just stick in your spare and you'll know straight away if it was necessary.

So should I swap back the old JJ's? as they still worked and didn't sound broken even after 3,5 years.. And the old and new tubes were JJ's so that wouldnt be a difference.
#7
It's not uncommon for preamp tubes to last for many years, even modern ones. It's up to you which ones you keep as spares and which ones you use. Keep whichever ones you think sound best in there.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#8
JJs are stock in the preamp for most if not all 6505 series amps IIRC. but the power tube differ between ruby and JJ stock.

for example. my 6534+ has 4 Ruby EL34s, and came that way stock. my buddy on the other hand, got 4 JJ EL34s with his 3120 stock. they all sound good though
#9
Ruby what? Ruby valves can be anything, they just rebrand things. You have to look at the whole code not just the EL34 bit.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#10
Quote by fc89konkari
So should I swap back the old JJ's? as they still worked and didn't sound broken even after 3,5 years.. And the old and new tubes were JJ's so that wouldnt be a difference.

You are over thinking this. You don't have to replace preamp tubes unless they die or you are looking for a tonal change. It doesn't sound like the old ones died. It seems you were happy with the tone. Yes, having spares is good. You can either leave the new ones in and keep the old as spares or put the old ones back in and keep the new ones as spares.



just listen to Cathbard. He is Tube Lord.
#12
Ruby codes aren't as easy to decode as Groove Tubes but afaik those ones are Chinese Shuguangs. Surprise surprise.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#13
But yeah it would be pointless to keep the new ones in if they sound the same? Then I'd just be using them and I'll find myself with 2 sets of not-full-life tubes. Instead the old ones could start wearing out in some time (years I guess) and then I can replace 'em with full-life-brand-new-tubes.

btw my Ruby tubes are 6L6GCM-STR. Wonder what those are?
#14
Quote by fc89konkari
But yeah it would be pointless to keep the new ones in if they sound the same? Then I'd just be using them and I'll find myself with 2 sets of not-full-life tubes. Instead the old ones could start wearing out in some time (years I guess) and then I can replace 'em with full-life-brand-new-tubes.

btw my Ruby tubes are 6L6GCM-STR. Wonder what those are?

you are still over-thinking it.

you could flip this whole conversation around and ask yourself why you bought all new preamp tubes if you didn't need them. If you had started a thread asking what to do about preamp tubes I would have told you to buy one JJ 12AX7 and one JAN Phillips 5751. Experiment with the 5751 in V1 and the Phase Inverter.

i don't buy preamp tubes unless one dies or i'm looking for a tonal change.

for argument sake - let's say you have 6 preamp tubes in your amp and none of them are dead. They all work fine. Now some of those may last another 10 years and some of those may last another 10 minutes. Then - you decide to buy 6 more preamp tubes. You now have 12 total. You technically are in the same position you just have more of them. Some could last 10 years, some could last 10 minutes. Point being new production preamp tubes are not the greatest anyway - it is all a shot in the dark.

it will not make any difference if you leave the old ones in or put the new ones in

personally, I'd return 4 of them and get 2 - 5751s, a Penta Labs 9th Gen, and a Tung Sol or Sovtek.

Or all NOS
#15
^ thanks for the advice!

The whole thing was basically my own stupidity. I didn't bother checking what tubes my 6505+ already held. I assumed they were some stock tubes (which they were) by a renamer like ruby or something, but they were JJs infact :O what you gonna do.. my own fault.

The good thing is that with the new power amp tubes I'm absolutely loving my tone. The only possible change would be doing the bias mod. I don't know how to do that, or if I can do it myself. Thats the 1 question that I'd really want an answer for. Someone who knows whether (and how) I could do it, could answer here or in the 6505+ official thread where I asked it already.

thanks!
#16
the bias mod is answered in that thread probably 5 - 10 pages back. Summer time. Otherwise, go to rig-talk.com or google.com and search on 6505 bias mod. There are several good ones out there.


PS: It's not stupidity. You had the money - now you've got extra JJs. You are set for a very long time on preamp tubes. The stupid people are the ones that do not buy spares and come on here asking about what to buy because their amp doesn't work.

Swapping some preamp tubes around cost like $12 for the spare, $0 in effort, and can save you tons of money and time down the road.


*we need a new 5150/6505 thread*
Last edited by 311ZOSOVHJH at Oct 28, 2011,
#17
allright thanks

I don't know about the places you guys buy tubes from but I love my local tubestore (I live in Finland). They charge 9 euros for a JJ 12AX7 and what comes to power tubes, the JJ 6l6GC cost me 22,5 euros per tube. They charge a couple euros more than others but thats because they have tested them buy running them on an amp for 24 hours and they always come as matched pairs/quads and have 3 month warranty.

Love it