Tube Rolling w/Crack

I got a huge box of tubes off the Facebook marketplace for $50 last summer (mostly NOS RCA and GE) and seeing as I just finished my Crack, I thought I'd see if I could roll some tubes. Been unable to find any power tubes that are equivalent. I found an RCA 9AU7 tube. Clear top. The original tube is a 12AU7, but would this still be okay to run? If so, what's the quality difference between this tube and an RCA 12AU7? I'm still digging through this box hoping to find a 12AU7, but no luck yet.
 
The 9AU7 is the same as a 12AU7 except it's expecting either 9V or 4.5V to heat the tube instead of 12.6V or 6.3V for the 12AU7.  If you plug that tube into the Crack, it will glow very brightly and live a very short life.
 
Paul Birkeland said:
The 9AU7 is the same as a 12AU7 except it's expecting either 9V or 4.5V to heat the tube instead of 12.6V or 6.3V for the 12AU7.  If you plug that tube into the Crack, it will glow very brightly and live a very short life.
Click to expand...

Damn. Well I decided to try it out. Huge step up from the Sylvania tube that the crack came with. Almost no tube noise at all. Also much more balanced. With the stock tube it felt like the image wasn’t as centered as it should be - slightly right channel dominant. Def gonna look into the 12Au7 RCA now.
 
You can put it in the amp and turn it on, but it will blow the fuse immediately.  That is tube is nowhere near compatible.

This post has a reasonably comprehensive list of compatible tubes.
 
Hey Kill_Surf
I hate to sound like a dick but you just got your amp up and running reliably, replacing tubes willy nilly will quickly lead you back
into trouble again.
Use the amp for a while and enjoy, while doing so, do some research and get a basic understanding of tube requirements and circuit theory. I would hate to see you get yourself into trouble and have to possibly replace a transformer or other components that could be destroyed.
Just saying.
 
Thermioniclife said:
Hey Kill_Surf
I hate to sound like a dick but you just got your amp up and running reliably, replacing tubes willy nilly will quickly lead you back
into trouble again.
Use the amp for a while and enjoy, while doing so, do some research and get a basic understanding of tube requirements and circuit theory. I would hate to see you get yourself into trouble and have to possibly replace a transformer or other components that could be destroyed.
Just saying.
Click to expand...

I only tried the 9AU7. I've just had this big bin of tubes sitting in my closet and unfortunately didn't find any that would work with the Crack. No offense taken btw.
 
Paul Birkeland said:
Tube World has been around a very, very, very long time.
Click to expand...

Oh good! There website seemed pretty impressive to me as did their selection, advice and measurements posted.
I've ordered from a few others also recently. I just finished my Bottlehead crack. Listened for a few days and rolled a few tubes already. Putting in the speedball now.
I have ordered the following tubes so far:
-5963 RCA Cleartop NOS 1971 (11.2/14.4ma)
-12AU7A Amperex Globe Logo Holland NOS 1970 (11.8/12.8ma)
-ECC82 12AU7A NOS NIB Mazda made in Czech (14.6/14.6ma)
-CV4003 Mullard boxplate wrinkle glass NOS (9.6/9.6ma)

Tubes I own:
Sovtek 6AS7G
Sylvania JAN 6080WB (came with crack kit)
Gold Lion ECC82 12AU7 platinum grade
Sylvania 5963 (came with crack kit)

I started off with the stock tubes mentioned above and was not very thrilled with the sound. Had me wondering what I had just put all that effort towards. So i rolled to the Sovtek 6AS7G and was immediately impressed. It pairs very nicely with the Sylvania 5963. Next I rolled the Gold Lion in, that sounded much different from the Sylvania, but definitely not in a bad way. I can post better impressions later. I'm waiting to find a single GEC 6AS7G or Bendix 6080 but they are so expensive! I'm just going to find my favorite preamp tube with the Sovtek for now. I think I'm most excited to hear the CV4003 mullard and the Mazda 12au7.


 
Do also be sure that all your solder joints are 100%.  The amp will sound pretty bad if you have cold joints, and rolling tubes and hearing enormous differences is sometimes an indicator of cold solder joints.
 
Because it's price is very high compared to NOS probably.
Here a 6N13S / 6H13C that's also out of Russia, looks and sounds good imo and saves you a lot of money.

https://www.ebay.com/itm/6N13S-6-13-6AS7G-RUSSIAN-100-TESTED-TUBE-NOS/283678599033?hash=item420c8fe779:g:4TsAAOSwoG5Z8FWl
 
I feel with today's current prices of tubes $60 is almost considered the lower end for cost. I swear damn near all the tubes I've looked up recently have been $70-400 that most people recommend on here. It's a sad day for the wallet.
 
Just to let you know. I have a fair amount of (on internet crazy expensive) tubes.

The price of a tube has little to do with the actual sound quality.

In my Crack i use my current favorite setup (since a few months) that cost me 12€ total.

I paid maybe 10€ for a CV2984 GEC power tube on a local antique market and 1€ each for a CV6/7193 (+-half 6SN7).
Most pricey part of this tube setup was the adapter needed from ECC82 to 2x 7193 at +-30€.

https://www.head-fi.org/threads/crack-bottlehead-otl.476650/page-650#post-15242293



 
The Sylvania 6080wb and the mullard cv4003 are a great pairing for the hd6xx/hd650. It's rich and full sounding. Sounds good with everything. The 6080wb really brought that rich sound compared to the sovtek 6as7g. The sovtek really opens the soundstage up with more air, details and highs that are allowed to sing.
The other pairing I liked for my own preferences is the sovtek 6as7g with the Mazda 12au7a. Compared to the other preamp tubes I rolled in the Mazda with the right power tube is some good stuff! Soundstage is a bit wider, more micro details start to stand out, the highs are so good! Along with controlled and punchy bass.
I really love hearing background details and an open airy sound. I'm hoping to purchase some more power tubes soon to be able to find the perfect one for my tastes. I am a bit worried the hd6xx are not going to give me the detail retrieval Im hoping for. I'm hoping at least I can get them closer to my tecsun caogen headphones.
 
Tom-s said:
Just to let you know. I have a fair amount of (on internet crazy expensive) tubes.

The price of a tube has little to do with the actual sound quality.

In my Crack i use my current favorite setup (since a few months) that cost me 12€ total.

I paid maybe 10€ for a CV2984 GEC power tube on a local antique market and 1€ each for a CV6/7193 (+-half 6SN7).
Most pricey part of this tube setup was the adapter needed from ECC82 to 2x 7193 at +-30€.

https://www.head-fi.org/threads/crack-bottlehead-otl.476650/page-650#post-15242293
Click to expand...

OMG....10€ for a CV2984 GEC  :o  It's a huge advantage living in Europe.

When I visited Germany last Christmas, I found GEC tubes rare and expensive on eBay.de as well, no advantage to eBay.com at all.

Maybe I should have spent some time to locate some antique market when I was there...too late now  :'(
 
legion1capone said:
Is the Svetlana winged c 6H13C and the sovtek 6AS7G the same tube?
Click to expand...

Not too sure about that.

I do own several 6H13C's. You can post some pics of their innards here, and people here can check if they're the same.
 
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