Tube Rolling w/Crack
- Thread starter Dr. Toobz
- Start date
Paul Birkeland said:
Curious about tube rolling.
So when you plug in a 6SN7 tube and adapter to replace the 12AU7 tube on a stock Crack with Speedball, you don't need to make any other changes?
Someone said you need to change the resistors on the speedball. Is that true, or is it as simple as "plug and go"?
Thanks.
A 6SN7 (w) will work just fine with the stock speedball setup. No need to change resistors.
The 0.6 amp heaters are ok for Crack. Max is 3.5 amps for all tubes together. Output normally uses 2.5A.
That said, the ECC32 is not an exact 6SN7. See: https://www.tubeworld.com/ecc32ecc33.htm
It works fine in the stock speedball Crack, though the E80CC resistor change helps to optimize the voltages.
The ECC32 is unobtanium and overpriced. Tried a few, and they are somewhat suspect to hum from the PT.
They do sound great, but can't recommend them for the price. Do mind the 0.9A heater current.
I've tried many 6SN7 and variants and they all work fine with Crack.
Right now using RCA 6as7g with 5692, also not a 6SN7 but close enough and functioning perfectly in Crack.
Also bit pricey for Crack, but extremely well build. If i ever build a tube amp for my car, this i'd use.
From my personal experience, don't buy expensive tubes. Better learn a thing or two by making modifications to your Crack and save the money for a better amp. The best Crack is not a S3X and a Mainline is in a entirely different league.
The 0.6 amp heaters are ok for Crack. Max is 3.5 amps for all tubes together. Output normally uses 2.5A.
That said, the ECC32 is not an exact 6SN7. See: https://www.tubeworld.com/ecc32ecc33.htm
It works fine in the stock speedball Crack, though the E80CC resistor change helps to optimize the voltages.
The ECC32 is unobtanium and overpriced. Tried a few, and they are somewhat suspect to hum from the PT.
They do sound great, but can't recommend them for the price. Do mind the 0.9A heater current.
I've tried many 6SN7 and variants and they all work fine with Crack.
Right now using RCA 6as7g with 5692, also not a 6SN7 but close enough and functioning perfectly in Crack.
Also bit pricey for Crack, but extremely well build. If i ever build a tube amp for my car, this i'd use.
From my personal experience, don't buy expensive tubes. Better learn a thing or two by making modifications to your Crack and save the money for a better amp. The best Crack is not a S3X and a Mainline is in a entirely different league.
Thank you very much Tom-s for your detailed explanation and insight into the 6SN7 tubes! It's very helpful.
Very glad to know that 6SN7 is as simple as "plug and go". I built my Crack w/speedball with great care. It sang amazingly for me from the moment it was completed. So really don't want to screw it up accidentally when changing something like resistors on the SB circuit board.
I haven't really looked into tube rolling yet. Just quickly looked up the 6SN7GT tubes the other day, and found lots of them could be outrageous in price.
Do you have any good value 6SN7 tubes to recommend (i.e. sound good but do not break the bank)?
Very glad to know that 6SN7 is as simple as "plug and go". I built my Crack w/speedball with great care. It sang amazingly for me from the moment it was completed. So really don't want to screw it up accidentally when changing something like resistors on the SB circuit board.
I haven't really looked into tube rolling yet. Just quickly looked up the 6SN7GT tubes the other day, and found lots of them could be outrageous in price.
Do you have any good value 6SN7 tubes to recommend (i.e. sound good but do not break the bank)?
Regarding the additional heat caused by doubling the current for 6SN7, it could be a problem for a Crack without Speedball, because the wirewound resistors under the heat sink might generate excess heat. However, with the removal of wirewound resistors during Speedball installation, there won't be heat from the 2 wirewound resistors anymore, hence it is no longer a problem to Crack with Speedball, right?
Not sure whether my poor reasoning on the possible heat issue is correct or not?
My knowledge in electrics is very limited.
Not sure whether my poor reasoning on the possible heat issue is correct or not?
My knowledge in electrics is very limited.Cool.
I don't remember where I read it, but someone reported the wirewound resistors under the heat sink became very hot and wires next to them turned brown after rolling in a 6SN7. So I was kinda concerned about 6SN7 tubes. But it's okay now. Thanks very much.
Hopefully I won't get into the trap, or at least not too deep into the trap. We'll see.
I don't remember where I read it, but someone reported the wirewound resistors under the heat sink became very hot and wires next to them turned brown after rolling in a 6SN7. So I was kinda concerned about 6SN7 tubes. But it's okay now. Thanks very much.
Hopefully I won't get into the trap, or at least not too deep into the trap. We'll see.
Maybe he used a really dead 6SN7 or had other issues with the amp.cddc said:
Paul Birkeland said:
Hi Paul,
You are definitely an expert in tubes. I think most of us here do not possess the knowledge like you do to find out the target tubes from these rebranded ones, while you can easily tell them apart just by the look and structure of them.
If you do find some good deals on 5998/6520/421A/6AS7G tubes or other good tubes for Crack from eBay or other places (rebranded or not), can you post them here? I think lots of Crack users here would be very interested.
Thanks a lot!
I would recommended talking to Jim at vacuumtubesinc.com, or Jim at McShane Design.
It takes a ton of time to sort through all the listings on eBay!
This is a pretty decent listing:
https://www.ebay.com/itm/4-PCS-CSF-6080WA-6AS7G-Chinese-6N5PJ-TUBE-VALVE-french-made-one-of-the-best/173722865320?hash=item2872b08ea8:g:HSoAAOSwwTla~7iv
It takes a ton of time to sort through all the listings on eBay!
This is a pretty decent listing:
https://www.ebay.com/itm/4-PCS-CSF-6080WA-6AS7G-Chinese-6N5PJ-TUBE-VALVE-french-made-one-of-the-best/173722865320?hash=item2872b08ea8:g:HSoAAOSwwTla~7iv
I know this advice won't be for everyone but here goes...
I realized that the world of tubes is so enormous that I had to do something to limit what I'd consider buying. So my filter is that I only buy tubes from the year I was born. It makes the shopping process quite a bit less time consuming. And it's also fun to learn how to understand the codes on tubes. Surprisingly easy to find tubes from the year of my birth (in the 1960s).
My favorite so far, and I absolutely can't believe I found one, is a Burroughs 2399 (Made by Tung Sol but quite rare and sounds fantastic!)
My 12AU7 is by LaRadiotechnique...another fairly cool brand.
I realized that the world of tubes is so enormous that I had to do something to limit what I'd consider buying. So my filter is that I only buy tubes from the year I was born. It makes the shopping process quite a bit less time consuming. And it's also fun to learn how to understand the codes on tubes. Surprisingly easy to find tubes from the year of my birth (in the 1960s).
My favorite so far, and I absolutely can't believe I found one, is a Burroughs 2399 (Made by Tung Sol but quite rare and sounds fantastic!)
My 12AU7 is by LaRadiotechnique...another fairly cool brand.
Rule no.1. buy cheap. ;D
Get a cool coke shaped bottle for Crack.
The output tube i recommend to try (prefer it over RCA 6as7g) is the Russian 6N13s https://www.ebay.com/itm/382880263018
Pair it with some locally found Ecc82/6sn7.
A Tungsram E80CC is a nice tube in a speedballed Crack.
https://www.ebay.com/itm/142545441812
Edit: La Radiotechnique is a Philips tube. Ecc82 was made in the Suresnes Philips factory, like ECC40.
Get a cool coke shaped bottle for Crack.
The output tube i recommend to try (prefer it over RCA 6as7g) is the Russian 6N13s https://www.ebay.com/itm/382880263018
Pair it with some locally found Ecc82/6sn7.
A Tungsram E80CC is a nice tube in a speedballed Crack.
https://www.ebay.com/itm/142545441812
Edit: La Radiotechnique is a Philips tube. Ecc82 was made in the Suresnes Philips factory, like ECC40.
Paul Birkeland said:
These French 6080s seem to be a great deal. Thank you very for the link.
I will also give Jim a call sometime. The problem with vacuumtubes is that they list tubes and prices on their website even thou they probably do not have most of them. So it is really hard to find tubes from them unless you give them a call.
I would e-mail him, that gives him the time to get everything together without the time crunch of being on the phone.cddc said:
-PB
attmci
New member
Nope, you have to use a 6SN7GT to 12au7 adapter. So the heat is not a problem here.cddc said:Cool.
I don't remember where I read it, but someone reported the wirewound resistors under the heat sink became very hot and wires next to them turned brown after rolling in a 6SN7. So I was kinda concerned about 6SN7 tubes. But it's okay now. Thanks very much.
Hopefully I won't get into the trap, or at least not too deep into the trap. We'll see.
Have you read this?
https://bottlehead.com/smf/index.php?topic=663.465
These are great drivers for Crack (bent ones):
https://www.ebay.com/itm/CBS-5814A-Pairs-Black-Plates-3-Pairs-available-5814-12au7-ecc82-/202623303320
Same seller that Paul (very cool find on the 6080 BTW) linked to earlier has a listing for Mullard CV4003. Super popular for the Crack. Although a little on the expensive side, still cheaper than most, usually see these around $99.
https://www.ebay.com/itm/Mullard-ECC802S-M8136-12AU7WA-ECC82-box-plate-small-shield-UK-made-TUBE-VALVE-/173814424654
https://www.ebay.com/itm/Mullard-ECC802S-M8136-12AU7WA-ECC82-box-plate-small-shield-UK-made-TUBE-VALVE-/173814424654
