Tube Rolling w/Crack
- Thread starter Dr. Toobz
- Start date
After a year without use i got my Crack back in working condition.
And for once i did a count of the tubes and with over 150 12au7's and many others i'm, once again, in for a long journey discovering the sound of different tubes.
But my love for Crack is mostly in the modding options for running all sorts of tubes.
I found a few ECC32's (1950's Mullard brown bases) and i'll try using Crack with those soon.
Any experiences with these? I think it should work in a standard speedball crack with R1 resistance for E80CC and the normal 1.5V bias? I also have the bias for 5687 build in to switch to?
Edit, now enjoying Bendix slotte graphite 6080 with Brimar CV491 red labeled(1950's).
And for once i did a count of the tubes and with over 150 12au7's and many others i'm, once again, in for a long journey discovering the sound of different tubes.
But my love for Crack is mostly in the modding options for running all sorts of tubes.
I found a few ECC32's (1950's Mullard brown bases) and i'll try using Crack with those soon.
Any experiences with these? I think it should work in a standard speedball crack with R1 resistance for E80CC and the normal 1.5V bias? I also have the bias for 5687 build in to switch to?
Edit, now enjoying Bendix slotte graphite 6080 with Brimar CV491 red labeled(1950's).
The ECC32 is a 6SN7 and should work with the stock Speedball.
That's the thing. It's not a 6SN7 equivalent. It might be close. But still different.
Please note the electrical comparison on the following website: https://www.tubeworld.com/ecc32ecc33.htm
Tube data: http://www.r-type.org/exhib/aad0139.htm
But my guess is that it indeed will work!
Might try tonight.
i'll measure 1 and 5 to see what the voltage is there (lets hope it comes in around 75V plate voltage).
Please note the electrical comparison on the following website: https://www.tubeworld.com/ecc32ecc33.htm
Tube data: http://www.r-type.org/exhib/aad0139.htm
But my guess is that it indeed will work!
Might try tonight.
i'll measure 1 and 5 to see what the voltage is there (lets hope it comes in around 75V plate voltage).
The mu values on that table are way, way off!Tom-s said:
The ECC32 does have slightly higher mu, higher Rp, and lower Gm, but the curves are pretty close.
It should be pretty close. You may see more like 85V.Tom-s said:
From a comparison standpoint, the Crack is already a bit heavy on the gain, so adding more isn't generally helpful to the amp (though no harm in trying).
vafan13 said:
Took me a while but I ended up with a Mullard CV4003 and IBM-branded 5998 at not-insane prices (relatively-speaking). The 5998 was a bit of a gamble, but no microphonics or noise issues, and it sounds great. I got the CV4003 first, so had a decent amount of time with that plus the stock 6080 before the 5998 went in.
I just pasted the curves into paint and you're correct. Setting the plate current for 2mA should be about right.Tom-s said:
InnerTube
New member
I have used several 6F8G tubes in the Crack with great success - especially the Tung-Sol. What a great sounding tube. In addition to the sound, the 6f8g runs quite cool. It hardly makes the plate warm while the 6080 makes the plate quite hot. I recommend adding this tube to the collection although it requires and adapter.
I have the same experience with these tubes.
More lush, spacious than your average 6SN7 tube.
IME they do tend to be a bit microphonic from time to time.
The VT-99 is indeed a great tube. I use them with square plate and round plate versions with the black glass.
Both are great. The round plate is supposed to be a bit better, but i can't hear that.
More lush, spacious than your average 6SN7 tube.
IME they do tend to be a bit microphonic from time to time.
The VT-99 is indeed a great tube. I use them with square plate and round plate versions with the black glass.
Both are great. The round plate is supposed to be a bit better, but i can't hear that.
InnerTube
New member
I have 8 or 10 of these tubes and have only had trouble with one of them. It causes substantial pops and cracks especially in the left channel. As good as these tubes sound I do not know why I listen to other tubes. Cool running is also a real plus. I wonder if this tube will be added to the crack list. Wishing you good listening, JS
Kitchener
New member
I wonder if this perhaps should go in the General Discussions subforum?
I'll risk it here and let the mods move it if I messed up.
I been tried out two types of 6SN7 valves in my Crack recently with an adapter (I'll be vague and say the adapter comes from a Bottlehead competitor, don't want to tread on any toes here).
But I'm so far most displeased with their performance.
They seem to be excellent antennaes for interference from pretty much everything in my office.
I keep my Crack pretty close to my computer and monitors, but the 12AU7 valves hardly pick up any interference.
-some slight high pitched whining if I move it around, but pretty much dead quiet.
Not so with the 6SN7s.
I've tried two USSR brown base 6SN7s and one RCA "smoky" valve, all are unbearably noisy.
-the RCA is busted anyway; loud popping when I wriggle the tube.
I thought maybe it was the adapter since it's kind of exposed, but I tried covering it in Sugru (not sure if that helps in the slightest though) and it made no difference.
Clamping my hands around the valves removes the noise, but I find it a little impractical in the long run.
Anyone else have the same experience?
I'll risk it here and let the mods move it if I messed up.
I been tried out two types of 6SN7 valves in my Crack recently with an adapter (I'll be vague and say the adapter comes from a Bottlehead competitor, don't want to tread on any toes here).
But I'm so far most displeased with their performance.
They seem to be excellent antennaes for interference from pretty much everything in my office.
I keep my Crack pretty close to my computer and monitors, but the 12AU7 valves hardly pick up any interference.
-some slight high pitched whining if I move it around, but pretty much dead quiet.
Not so with the 6SN7s.
I've tried two USSR brown base 6SN7s and one RCA "smoky" valve, all are unbearably noisy.
-the RCA is busted anyway; loud popping when I wriggle the tube.
I thought maybe it was the adapter since it's kind of exposed, but I tried covering it in Sugru (not sure if that helps in the slightest though) and it made no difference.
Clamping my hands around the valves removes the noise, but I find it a little impractical in the long run.
Anyone else have the same experience?
This is pretty typical of many of the adapters sold online.
Kitchener
New member
Seems like it from what I’ve read yes.
Bah, I can’t even tell the difference between different 12AU7s or 6080s.
Whatever difference I’ve thought I’d heard, turned out to be my imagination.
Im confident Bottlehead used the 12AU7 for a reason.
I’ll file the 6SN7 experiment under P for Pointless.
Bah, I can’t even tell the difference between different 12AU7s or 6080s.
Whatever difference I’ve thought I’d heard, turned out to be my imagination.
Im confident Bottlehead used the 12AU7 for a reason.
I’ll file the 6SN7 experiment under P for Pointless.
The driver tube in the Crack ultimately works best when it has the lowest possible gain, as well as being able to operate fairly well without a ton of voltage. The 12AU7 is just more available than the 6SN7, doesn't take up as much space on the chassis, and can't be plugged into the 6080 by accident.
The 6CG7 is a 9 pin 6SN7, and a minor change to the 9 pin socket wiring would allow its use (and the 7AU7 would then also work instead of the 12AU7).
The 6CG7 is a 9 pin 6SN7, and a minor change to the 9 pin socket wiring would allow its use (and the 7AU7 would then also work instead of the 12AU7).
Kitchener
New member
Might be a neat idea for some day down the line.
Maybe if I actually start noticing any difference between 12AU7s, I'll start wondering how other tubes might sound as well.
Right now I can't tell any of my three available 12AU7s apart (Mullard, Clear Top, Genalex Gold Lion).
So I'm going to give rewiring the socket a hard pass, I think.
I've read a couple of posts praising the soundstage of the 6SN7s so I figured an adapter might be an easy way to try them out for myself.
Some of you are pretty well versed in tube land, and this is all very subjective and dependent on the amp:
Would some of you say there are big, relatively speaking, differences in the sound between 12AU7, 6AU7, 7AU7 and 6CG7 tubes?
Maybe if I actually start noticing any difference between 12AU7s, I'll start wondering how other tubes might sound as well.
Right now I can't tell any of my three available 12AU7s apart (Mullard, Clear Top, Genalex Gold Lion).
So I'm going to give rewiring the socket a hard pass, I think.
I've read a couple of posts praising the soundstage of the 6SN7s so I figured an adapter might be an easy way to try them out for myself.
Some of you are pretty well versed in tube land, and this is all very subjective and dependent on the amp:
Would some of you say there are big, relatively speaking, differences in the sound between 12AU7, 6AU7, 7AU7 and 6CG7 tubes?
I you're looking for soundstage there's other nice additions to roll in a Crack.
With the pad in place in a Speedballed Crack there's a few cheaper options for great sound.
One to think of is the 6C8G tube. A NU or Tung Sol can be found for cheap. These are 6F8G's on the cheap essentially.
I prefer them to most 6SN7's. It's personal. Like with all tubes and "mods" to Crack, it's like different trying spicing for the same meal. Don't expect a world of difference when trying different tubes.
With the pad in place in a Speedballed Crack there's a few cheaper options for great sound.
One to think of is the 6C8G tube. A NU or Tung Sol can be found for cheap. These are 6F8G's on the cheap essentially.
I prefer them to most 6SN7's. It's personal. Like with all tubes and "mods" to Crack, it's like different trying spicing for the same meal. Don't expect a world of difference when trying different tubes.
Kitchener
New member
Oh boy those 6F8G tubes look cool.
I wonder if those eBay 6F8G to 12AU7 adapters are any good?
My gut says...nooo.
Maybe it would be cool to put an octal socket in place of the noval socket, but I don't have a Dremel so nah.
Besides I don't want to mess with the Speedball standoffs
I wonder if those eBay 6F8G to 12AU7 adapters are any good?
My gut says...nooo.
Maybe it would be cool to put an octal socket in place of the noval socket, but I don't have a Dremel so nah.
Besides I don't want to mess with the Speedball standoffs
