Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: hpjun on February 09, 2016, 08:29:27 AM
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I messed up my install of the speedball, I have some waxy resin substance that is covering the connections of the board making a bridge (not sure if its conductive it came out of the soldier). I also am not sure if I installed the LED's right since I didn't install them upside down. Also I need more wire for the install. It was difficult before because my soldering iron was bad, now I have a good one.
What do you guys suggest I do?
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Looks like the center leg of the upper 2N2222A might need a touchup with the new iron. The flux residue doesn't look like anything to worry about. Touch up that transistor leg and anything else that might look shaky and try it again. If that doesn't work you might need to get those LEDs out and see which way they are facing.
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The "waxy resin substance" is flux. It is non conductive. But if you want to clean it off, a little isopropyl alcohol, a q-tip and a bit of light scrubbing usually does the trick.
I have successfully removed the diodes from the board without damaging them. I use a pair of needle nose pliers to gently grasp the LED. The solder connections on the LED are close enough that you can arrange the soldering tip and heat both connections at the same time. Once the solder liquifies simply pull the LED out of the board. It takes a little practice but this technique works great. Just don't force it. Once enough heat is applied the LED will practically fall out. If you accidentally break them replacements are available here. http://bottlehead.com/product/hlmp-6000-leds/ (http://bottlehead.com/product/hlmp-6000-leds/)
EDIT: Doc B. Beat me to it.
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Alright I'll see what I can do to touch it up. I don't want to mess the stock crack until I get the speedball looking good first.
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Removing the leds are tricky. I might just snip them off and order new leds. Is there a way to test the led direction from a multi meter? I have a lot of functions on my meter.
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Removing the leds are tricky. I might just snip them off and order new leds. Is there a way to test the led direction from a multi meter? I have a lot of functions on my meter.
You can look at the silver banded end to easily determine directionality.
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I remember when I installed the speedball it worked but it had channel imbalanced and sounded generally worse.
If the leds where incorrect there won't be sound right?
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If the leds are installed incorrectly they won't light and the voltages will be off. It will sound bad or most likely not work at all on the channel that is wrong.
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Well it's an hassle to reinstall the speedball just to check.
I already ordered 8 new leds I'll just pull them all off now and reinstall.
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I didnt change any leds they where already correctly installed since they lit up.
Installed the speedball and did the Voltage check and the values came out with in range so i gave it a listening test. I turned the volume about half and I hear buzzing in the left driver and when i turn up a little more the right driver has the buzz too but at a lower volume. Then i noticed the buzz is quietly audiable without headphones plugged in it's coming from the power supply area or the caps.
My music sounded Ok, except for the buzz. My crack was quiet before the speedball.
1 77
2 181.3
3 0
4 181.3
5 81.8
6 0
7 107.1
8 0
9 110.6
10 0
11 0
12 0
13 181.1
14 0
15 199
19 85
20 0
21 217
A1 81.6
A2 0
A3 1.53
A4 0
A5 0
A6 76.7
A7 0
A8 1.53
A9 0
B1 76.8
B2 180.7
B3 106.6
B4 81.6
B5 180.4
B6 110
B7 0
B8 0
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It's quite time consuming to go through a list of voltages and try to determine which might be in or out of spec. If you could post only the voltage readings that are out of spec, the terminal it was taken at, and what the manual says it should be we can usually come up with some suggestions little more quickly.
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2nd column is my measurements, 3rd column is the manual's measurements, 4th column is the difference in values, I also put in bold the big differences.
1 77 75 103%
2 181.3 170 107%
3 0 0
4 181.3 170 107%
5 81.8 75 109%
6 0 0
7 107.1 100 107%
8 0 0
9 110.6 100 111%
10 0 0
11 0 0
12 0 0
13 181.1 170 107%
14 0 0
15 199 185 108%
20 0 0
21 217 206 105%
A1 81.6 75 109%
A2 0 0
A3 1.53 1.56 98%
A4 0 0
A5 0 0
A6 76.7 75 102%
A7 0 0
A8 1.53 1.56 98%
A9 0 0
B1 76.8 75 102%
B2 180.7 170 106%
B3 106.6 100 107%
B4 81.6 75 109%
B5 180.4 170 106%
B6 110 100 110%
B7 0 0
B8 0 0
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Also the voltages are not balanced from right and left channels. I had that problem before speedball too.
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Those readings look like pretty typical variations from tube to tube, and they aren't really out of spec far enough to be a major concern. I think the best approach might be to go back over all of the new connections made from the PC boards to the tube sockets, since this noise seems to have appeared after those parts were installed. Buzzing usually indicates a ground connection that is not perfect. If you have some other tubes you might also try them to see if the noise goes away or changes in any way.
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Ok and the buzz sounds like the same kind of buzz from power supply. It's faintly audiable without headphones plugged in. I was thinking it might be picking things from the vibrations? I will do another resistance check and go over any soldier connections that are different and go over the ground on the speedball.
This is my second speedball install and it had similar problems before left channel had a buzz as well.
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You might try tightening up the power transformer mounting screws a bit. Sometimes that will eliminate the kind of mechanical buzz you hear.
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I tightened up the power supply to the chassis and noticed a small improvement. Before i had to turn it up to about half way 6 o clock to hear a buzz, now I need turn it up to about 7 o clock to hear the buzz. The nuts are really hard for me to reach and tighten since I don't have the tool for that size nut but I will keep trying and I'll buy some tools tomorrow.
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It was those long wires that ran from the rca input to the potentiometer! I noticed a good reduction in noise when I manually moved those wires farther away from the noisy powersupply. Is the powersupply supposed to be this noisy? Having the RCA inputs near the powersupply isn't an optimal design. I didn't do that good of a job braiding those wires though and probably would have made a difference. Knowing how bad the power supply can interfere with the sound just doesn't sit well with me. I feel like rerouting all wires carrying audio signals as far away as possible from the powersupply. Maybe I will drill 2 holes and install the rca near the potentiometer and away from the powersupply. Are there good ways of isolating the power supply noise?
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Rather than moving your RCA sockets you could replace the stock red white and black wires that run from them to the potentiometer with some high quality four core screened cable from Belden or Mogami as a number of other Crack builders have your only going to need a short length.
Or just re braid what you have and save some cash its dead easy to get a nice braid.
https://www.youtube.com/watch?v=qxJY4lna5q0 (https://www.youtube.com/watch?v=qxJY4lna5q0)
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The braided input wiring, and the tightly twisted filament heater wiring is done to reduce noise. If built exactly as shown in the manual the amp will be completely silent. Shielded input cabling is better again, but fine multi stranded cable like that is much more difficult to work with than the solid core wire supplied.
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Don't buy a different horse just because your stirrups are too long. Try braiding and positioning the wire as close as possible to the way shown in the manual before you decide to redesign the amp. Wire dress and solder joint integrity are very important to noise rejection.
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I'll try braiding them and then wrapping some grounded aluminum foil around the wires as a faraday shield.
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If it's magnetic field interference as you suggest, aluminum foil is not going to do much good. The braiding and proper wire dress and solder joints will have more influence.
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Ok doc, I am going to need a longer wire as tightly braiding them made it too short, going to radio shack later today.
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I bought some nice solid core copper wires from radioshack and did a really tight braid. I added aluminum foil shielding (see attached photo lol) not sure if it made a difference maybe I'll take off the aluminum and test someday. At max volume it's dead quiet, though I can feel a hint of 60hz harmonic hum, maybe I am hearing the phase or something but it's actually nothing, it would take measuring equipment to pick up on it.
I am currently happy with my crack, but the crack has gotten me addicted. I want to improve it further so do I upgrade the output capacitor? stepped pot? add a choke? tubes? Crackatwoa? What's the best upgrade path to take?
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What's the best upgrade path to take?
Once you price out some of the boutique part upgrades that some Crack builders do you might find that upgrading to a Crackatwoa kit is not that unreasonable. The circuit upgrades in the Twoa are some that you can't do to a stock Crack, and the improvement is significant. We will be hosting a Head Fi meet in late April and we plan to have a "tricked out" Crack and a Crackatwoa side by side for attendees to compare for themselves.
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Oh you guys should exhibit at canjam socal I am going there in two weeks.
Also my left and right channel voltages are a little off, is it because of tubes or is it my soldier connections? Should I buy an 12au7 tube just to check?
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I had a lot of enjoyment experimenting modding my Crack with bargain finds from ebay. You don't need to use expensive boutique parts.
£13 5x Film caps for output and last power supply (these look worth a try I've had good results with Epcos in the past)
£12 Triad C7X choke (cheaper on mouser)
£19 Valab 23 Step Ladder Type Attenuator Potentiometer 100K Log Stereo
£6 Teflon capacitors for bypassing the output caps
http://www.ebay.co.uk/itm/262044284465?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.co.uk/itm/Triad-C7X-10H-90mA-smoothing-choke-/171093411086?hash=item27d5f6450e:g:2pUAAOxyYSJR-35Y
http://www.ebay.co.uk/itm/Valab-23-Step-Ladder-Type-Attenuator-Potentiometer-100K-Log-Stereo-/252309543160?hash=item3abed218f8:m:msNfZ0JQ0HBEYro_BkTZXtg
http://www.ebay.co.uk/itm/0-047uF-500V-Matched-Pair-AUDIO-teflon-capacitors-K72P-6-/331575835775?hash=item4d3375bc7f:g:gi4AAOSwNSxVcwQV
Boutique version
£150 Caps Mundorf (their budget MKP range)
£12 Triad C7X choke (cheaper on mouser)
£125 48 step Khozmo stepped attenuator
£160 V-cap Teflon bypass capacitors
£447 for the Boutique parts vrs £50 for the budget option.
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Just about every Crack that I have fixed that was buzzing either had a loose capacitor or a loose ground wire. A loose cap won't change any of the voltages, but the low AC impedance that the cap provides is lost, which brings the noise floor way up.
The most common ground joint to give folks problems is where the black wires meet on the headphone jack.
-PB
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I noticed some faint ringing sound when I have the crack on for longer amounts of time. I start noticing the ringing sound for about an hour (could be earlier). I can even hear it without headphones, it's coming from the chasis, I lifted the board and put my ears closer to hear where it's coming from and it sounds like it's coming from either the volume pot or the speedball or the 12au7 area. It's very faint but it sounds like the type of sound a capacitor might produce when it discharges.
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Are the tube pins nice and clean? Is there any damage to a capacitor?
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The Caps don't look damaged, it only starts to ring when I have the crack on for a long time and when I turn it off it goes away. I'll inspect the pins and clean it if it looks dirty.
I also want to know what type of 12au7 I have. It says 12au7a and has no logo on it and doesn't have any indication of a brand name it seems like its just unbranded.
I am thinking of getting a telefunken or gold lion 12au7 to test out later on.
edit: attached picture to help identify my 12au7a, also the pins look dirty going to clean them.
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I cleaned the 12au7a and it sounded better not sure what channged but subjectively it sounded better, it could be bias. So I went ahead and cleaned the power tube as well. I might even get some small pipe cleaners for the sockets as well. I don't have an hour at this time to listen to the ringing but when post again if hear it later on.
edit:
Ok I hear that faint ringing now and it doesn't take an hour of warm up to hear it. It sounds like it might be from the power supply area or the capacitors.
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I also want to know what type of 12au7 I have. It says 12au7a and has no logo on it and doesn't have any indication of a brand name it seems like its just unbranded.
That's an RCA 12AU7.
Does the amp ring when powered up with no tubes in?
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I just removed both tubes and powered it on and it was silent.
It's safe to do this right? the speedball board doesn't light up with no tubes in.
When I tested earlier with the tubes in I put my ear close to the 12au7 and it was the noisy one. I hear a hissing, ringing and sometimes emi noise.
I think the problem might be the 12au7 tube.
I am going to get a telefunken tube.
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When I tap on the big power tube the ringing noise stops and then comes back later on. yep it's the power tube not the 12au7. but once it resonates the little 12au7 picks up on it and will resonate also.
edit: taping on the 12au7 also stop it from ringing but tapping the on big one is key though.
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Some people find that a silicone ring or two will solve the problem but a new 6080 is inexpensive and I'd go down that route first. If you can get another 12au7 from the same vendor at the same time that won't up the bill very much and you'll save on postage.
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Yesterday I decided to rewire the AC heater wire to the first power tube for optimal results, (I wanted a balanced and tight winding to lower the ac hum further).
I thought I did a good job so I turned it on (my mistake for not performing resistance check). none of the boards lighted up and one of the resistors was smoking so I turned it off really quick.
I did some measurements and got infinite ohms for terminal 7 and 9.
I checked resistance between terminal 4 and 5 was at 0 ohms (one probe on 4 and other on 5). I was wondering is terminal 4 and 5 supposed to be bridged? or did I do something wrong? I know I messed with the AC heater wires so the problem is around that area.
Edit: I think terminals 7 and 9 becomes infinite ohms when speedball is installed right? What about terminal 4 to 5 when probed I got 0 ohms. I don't want to risk turning on my crack for voltage checks, last time the 270k ohm resistors got really hot and smoked the wires (good clue for what's going on) and none of the boards lighted up. Not sure how to continue the resistance checks for speedball.
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bump, I'd like to get help on this.
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How exactly did you proceed when you rewired the AC heater wiring, meaning what wires did you disconnect and reconnect? This could be multiple issues as it sounds like you have a shorted front Speedball board and that may have happened due to a miswire of the redone heater wiring. Was the kit working with the Speedball before you redid the heater wiring?
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I thought I did a good job so I turned it on (my mistake for not performing resistance check). none of the boards lighted up and one of the resistors was smoking so I turned it off really quick.
This is almost always the mounting method of the TIP50C. If improperly mounted, it could cause the problems you're describing at any given time.
The AC wires that heat the tubes will not cause these kinds of problems unless you remove them and wire them to the incorrect location.
You'll need to carefully measure voltages for us to know what's going on. If you have a smoking 270 Ohm resistor, you could start by measuring the voltages with just the 12AU7 installed in the amplifier and not the 6080.
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My wires heater wires was soldiered properly and terminal 12 got touched up a bit I also rewired the connectors from terminal 6,7 connecting to 9,10. It might be terminal 12 that has an issue. terminal 4 was grounded to terminal 12.
Is terminal 4 & 5 supposed to be bridged? I took off the ac heater wire and measured terminal 4 to terminal 5 and still at 0 ohms. I just want to be sure about this because I don't want to short the power supply. Also terminal 4 and 5 are both grounded. Also I read that terminal 4 & 5 is supposed to have a fluctating reading since it's connected to the caps, I get 0 ohms instead.
I also noticed the 6080 tube has something loose inside that is rattling when I shake it, is it a broken tube?
I am a little scared to turn on my amp for voltage checks. I am mostly worried about terminal 4 and 5 please answer that question.
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There are no resistance measurements in the Speedball manual for reasons like this.
When you ask about terminals 4 and 5, do you mean on the 5 lug terminal strip at the front of the chassis, or power transformer terminals 4 and 5?
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Yeah the power supply transformers 4&5. The ac heaters for the tubes.
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Yes, one end is hard grounded, and the winding itself is several turns of thick wire, so it will also read as a short to ground.
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Everything works now.
I re-soldiered my connections and took out the power tube like you said, the mini board lights up. I put the big tube back in and everything lit up, did the voltage checks and it checked out. The audio is fine, I ordered an tungsol-6080 replacement power tube it sounds better than the stock sylvania 6080.