Help for building CRACK with Speedball

[Doc B]

From the manual -

Don’t worry if your voltages are not exactly these figures. Line voltage variations and tube tolerance variations can change them by up to 10-15%.

 

[i luvmusic 2]

Again Thank You!

 

[i luvmusic 2]

I gotta admit patience will take you along way when it comes to building this KIT or possibly all sort of kits.I've checked and double checked each steps and i still managed to screw up few times i soldered where i should not be soldering and put wires on top where it should be in the bottom terminal,I looked at the manual several times when it comes to installing those Caps and Diodes I have one extra piece of #6 lock washer for the 9 pin socket i could not fit it in place due to the socket i used. It took me 12 hours to build the KIT but in the end all my testing it went really smooth no issue at all or maybe i was lucky.THANK YOU! Bottlehead for the nice manual and a excellent sounding AMP(CRACK)and all the support from all of you here.THANK YOU!

 

[i luvmusic 2]

Here is mine i'am not sure what kind of finish/look i want for the base so many nice looking base to choose from.
https://www.head-fi.org/content/type/61/id/1164239/width/500/height/1000/flags/LL

https://www.head-fi.org/content/type/61/id/1164235/width/500/height/1000/flags/LL

 

[Paul Birkeland]

Just for the tube heaters i'am thinking to disconnect those heater wires from the Crack transformer to lighten the transformer load maybe it will help to run cooler.In you guys opinion thus this make sense? Thanks!

The transformer may run a little bit cooler, but otherwise there will be no change.  IIRC, the PT-3 is rated to run with 3.5A of load on the 6.3V winding.  The stock Crack uses about 2.8A of that current.  On the high voltage side, the headroom is substantially higher.

-PB

 

[i luvmusic 2]

Thank You for the info!

 

[i luvmusic 2]

I need help for the MJE350 for Speedball PCB A&B the picture on the manual is deferent from what i received mine don't have the metallic side so i don't know which is the back or the front on my MJE350.The MJE350 markings are Fg D37 MJE350 and on the other side  there is a mark (A) on left top corner,Can anyone please tell me which side i have to orient the MJE350 on the A and B speedball PCB?Thank You!

 

[i luvmusic 2]

Another question about SB PCB A and B D1 and D2 is it connected in series?I soldered the 2 leads in between the two LED together.

 

[Paul Birkeland]

I need help for the MJE350 for Speedball PCB A&B the picture on the manual is deferent from what i received mine don't have the metallic side so i don't know which is the back or the front on my MJE350.The MJE350 markings are Fg D37 MJE350 and on the other side  there is a mark (A) on left top corner,Can anyone please tell me which side i have to orient the MJE350 on the A and B speedball PCB?Thank You!

The metal side is the side without writing.  (See the sticky about MJE350's)

 

[Paul Birkeland]

Another question about SB PCB A and B D1 and D2 is it connected in series?I soldered the 2 leads in between the two LED together.

D1 and D2 are in series. 

 

[i luvmusic 2]

THANK YOU VERY MUCH!

 

[i luvmusic 2]

Hi'
  Questions For those of you who installed Film Caps,Attenuator and the Speedball.I would like to do these upgrades but i have no idea Which one to do first i would like to install one at a time listen to it then do the next upgrade.Is it easier if i do the Attenuator followed By the Caps and then the Speedball?In what order did you guys installed your upgrades?looking at the underside of the amp it looks Like the Speedball will cover most of the terminal access.Thanks!

 

[JamieMcC]

I would suggest the order of speedball, attenuator and then caps

 

[i luvmusic 2]

Hi,
  I just need to finish my speedball MJE350 soldering and it will be ready for installations i got confused last night regarding the MJE350 orientation so i stopped.If i install the SB i still have easy access for most of the terminal connections for the Caps and attenuator without removing the SB? THANK YOU!

 

[JamieMcC]

Yes access is more limited but totally doable with the speedball installed and its always possible just to removed the speedball mounting screws after its all wired up and gently ease the boards over for a little better access if required. You will most probably find you don't need to.

Depending on the type of attenuator you plan to use take a look at the connecting wires some of the attenuators have the connections on the top and are quiet tall which may mean a couple of the original wires are tight for length and either require a little re-routing or replacing with longer ones to reach you will see in the pics below. Like the black wire that goes from the pot to terminal 3L page 22 of the manual is much easier to change if required without the speedball in place.

 

[i luvmusic 2]

So most likely everything will be a tight fit,by looking at your pictures the Attenuator is pretty close to the small PCB.Thanks!

 

[i luvmusic 2]

Hi,
  I replaced the pot with the attenuator and i have a concern about my resistance reading for T13 instead of reading up like how it was with the stock pot.Now it reads backwards then reads back up again.From 22 meg counting down then when it reach down to 40 ohms  it start to read up again up to 270 k and up.Is this normal if you used a attenuator?Thanks!

 

[i luvmusic 2]

I'am done soldering my Speedball but before i install it i want to make sure that i get this right.The metal tab for the MJE350 their should be no continuity between the heat sink or the bolt?Thanks! 

 

[Paul Birkeland]

The metal tab of the TIP-50 should have no continuity to the bolt or the heatsink.

-PB

 

[fullheadofnothing]

The MJE350 does not have a heatsink.

If you mean the TIP50, then yes, the metal tab should be electrically isolated from the heatsink.