[Rattle]

The ECC802, both the original and modern production, were ruggedised long-life low noise 12AU7/ECC82 variants. Huge big long plates, versus the much shorter plates in most 12AU7.

The JJ ECC802s is my favorite tube in the Crack. It's just very well balanced; not too dry or wet, not too sharp or soft, a wonderful all rounder. Plus, it's relatively cheap, and will last for years.

[EDIT] I just realised that I'm still using the same tubes from the Crack link in my signature. 13 years and I keep coming back to the exact same combo!

Thanks for the info I think I'll grab one of these tubes. My crack has no SB but after reading your DIY thread I'm thinking of having my crack decked out a bit more in the future. Just have a blue velvet put and output caps for now. Is there any need or advantage to gold pins vs regular pins ?

 

[CaptainFantastic]

Crack is like an antenna for BS. Cell phones routers anything with wifi. It's usually the input tube picking up interference. I recently installed a tube shield for the front socket. Made a huge difference for me... I can still hear my cell phone if I hold it over the amp though lol that's quite normal. I wouldn't even bother with a crack near a PC as a source to be honest.

Yes, I get the same if I move my phone within 50 cm of it or so and there happens to be an incoming call or message, but I hardly ever feel the need to do bring my phone that close. Otherwise mine is perfectly quiet with the phone <1 m away and the router 1.5 m away. Unless the tube is noisy, the amp is perfectly quiet in my experience.

I don't have other OTL amps, but I had the WA3 a while back and it behaved similarly, although a few of my tubes were microphonic in it whereas they are quiet in the Crack.

 

[NaN93]

Is it connected to a computer? My computer is a horrible source of noise for me. I have to use an ifi iDefender between my computer and DAC to get rid of it.

it was connected to my dac, which at that time was the topping e30, and the dac connected to my pc.

Crack is like an antenna for BS. Cell phones routers anything with wifi. It's usually the input tube picking up interference. I recently installed a tube shield for the front socket. Made a huge difference for me... I can still hear my cell phone if I hold it over the amp though lol that's quite normal. I wouldn't even bother with a crack near a PC as a source to be honest.

Does this happen with all tube amps?

I concur, the Crack input tube is definitely prone to interference. When my Crack was close to my router, I could hear the WiFi beacons as constant ticking! An input tube shield definitely helped.

But it's also worth noting that some tubes are much worse than others. For example, of new production tubes, noise through my JJ ECC802S is barely audible. Whereas several New Sensor (Tung Sol, Genalex) were *really* bad.

What is the tube protector?

I had to move my router upstairs to stop my interference. I still get a bit. With my cellphone.

What is the tube protector?

Yes, I get the same if I move my phone within 50 cm of it or so and there happens to be an incoming call or message, but I hardly ever feel the need to do bring my phone that close. Otherwise mine is perfectly quiet with the phone <1 m away and the router 1.5 m away. Unless the tube is noisy, the amp is perfectly quiet in my experience.

I don't have other OTL amps, but I had the WA3 a while back and it behaved similarly, although a few of my tubes were microphonic in it whereas they are quiet in the Crack.

It's a shame to hear that, I think I'll stay away from a tube amp for now, since my cell phone is very close to my desk, as is the Wi-Fi.

 

[CaptainFantastic]

It's a shame to hear that, I think I'll stay away from a tube amp for now, since my cell phone is very close to my desk, as is the Wi-Fi.

Maybe you misunderstood the measurement? 50 cm is not much. You just have to keep your tube amp on one side of the desk and the phone on the other, like either side of the monitor and you're 100% fine. Pretty simple. I thought I was making an argument FOR the Crack.

 

[Rattle]

it was connected to my dac, which at that time was the topping e30, and the dac connected to my pc.

Does this happen with all tube amps?

What is the tube protector?

What is the tube protector?

It's a shame to hear that, I think I'll stay away from a tube amp for now, since my cell phone is very close to my desk, as is the Wi-Fi.

Some tube amps are more susceptible to this than others. I'd have to so no to the question does this happen with all tube amps. However if you're using a "PC" as source you will be susceptible to all kinds of noise from the PC USB connection or others if you are all Single ended. Grounds loops and other electrical noise. Best to go all balanced if you are going to be using a big power desktop PC as a source. Not to mention a room filled with wifi routers and the like.

 

[Beefy]

What is the tube protector?

I bought this one: https://www.thetubestore.com/shield-for-9-pin-tube-socket

 

[NaN93]

Maybe you misunderstood the measurement? 50 cm is not much. You just have to keep your tube amp on one side of the desk and the phone on the other, like either side of the monitor and you're 100% fine. Pretty simple. I thought I was making an argument FOR the Crack.

I must have misunderstood the measurements, the space that the components that emit or receive signals should have seems reasonable.

I bought this one: https://www.thetubestore.com/shield-for-9-pin-tube-socket

Thank you, so weird haha.

 

[Shroomalistic]

Up and runnin finally. I had a few hicups along the way. It sounds amazing. Well worth the troubles. Time to sell the darkvoice!!!

 

[NaN93]

Up and runnin finally. I had a few hicups along the way. It sounds amazing. Well worth the troubles. Time to sell the darkvoice!!!

how long did it take you to put it together?, it looks very good

 

[Shroomalistic]

being the blind old man i am, first I didnt realize there was 2 different size of caps so when I went to put in the smaller ones I had one big and one little. When I swapped them out to the right ones I ended up putting one of the power supply caps in backwards and fried a bunch of parts. I blame my kids, I was trying to assemble this with my 4 kids loose in the house. I then had to order a few replacement caps and resistors. UPS decided to crush the box along the way and I belive they just reboxed it and sent the same stuff to me. So i ended up with 2 shorted resistors and had to wait for those replacements. Then to find out i got sent a bad 12au7 with the set and had to get bottlehead to send me a new one and had to wait for that.

So long story short it took almost a month to get it done but that was my fault mostly.

 

[Shroomalistic]

Are these tubes decent (clear top rca 12au7a)
https://www.ebay.com/itm/144800240553?hash=item21b6c453a9:g:qpYAAOSwsR5hmEs1
I ordered 2 of them cause they were decent price, they are brand new looking and still in the unopened box.

 

[sp79]

Are these tubes decent (clear top rca 12au7a)
https://www.ebay.com/itm/144800240553?hash=item21b6c453a9:g:qpYAAOSwsR5hmEs1
I ordered 2 of them cause they were decent price, they are brand new looking and still in the unopened box.

Did you get those tubes, if so how are they, how does the sound differ from the stock/supplied tubes?
I just finished getting the Crack together, no SB in it, yet.

 

[SHIMACM]

Hello everybody!

I made the adaptation of my Crack to use 6sn7 as default in the valve driver.

As a result I'm having problems with distortion in the sound, especially when I turn the volume up from medium to high.

I did the Resistence test and this is the result:

1 - random from 40 to 70
2 - random from 40 to 70
3 - 0
4 - random from 40 to 70
5 - random from 70 to 120.

6 - 0
7 - 2.9
8 - 0
9 - 2.9
10 - 0

12 - 0
13 - random from 40 onwards
14 - 0
20 - 0
22 - 0

B3 - 2.9
B6 - 2.9

Red RCA pin - 90
Black RCA pin - 88
Earth RCA - 0


And these are the results of the voltage test:

1 - 59.6
2 - 190.4
3 - 0
4 - 191.3
5 - 57.1

6 - 0
7 - 99.5
8 - 0
9 - 98.2
10 - 0

Follow the photos of the wiring to see if anyone can detect any errors.

Two details to report:

The 22.K 1/2w resistors have been replaced with 22k 1w resistors.

Wiring from the volume pot to the RCA inputs is 1.5mm stiff copper wire. I did not find a replacement wire like the one in the Kit to put in place.

I changed the wire because I had to lengthen it because my project is to use two 8-pin sockets (which are already installed on the board) to feed two 6j5 and also install two film capacitors in place of the two output electrolytic capacitors. That's why the wire is loose to accommodate these adaptations underneath it.

 

[SHIMACM]

I managed to solve the problem. The magic is back!

 

[Galapac]

I managed to solve the problem. The magic is back!

Can we see it now with the tubes plugged in once you got it wired up?
Will it have enough power?
I haven't seen a Crack with four sockets.
You could use a Dremel to cut those long screws down.