Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: ditdah on September 14, 2012, 12:23:54 PM
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Crack with speedball install. I could use some advise...direction...guidance.
I've gone through the entire install 3 times now and can't figure out my problem. I've done the following:
-reheated every solder joint
-verified connections as per the install instructions
---I connected terminal 4 on the transformer to 14U...as stated on page 19
-verified capacitor orientation
-verified LED orientation
-verified transistor orientation
Resistance checks (without power and tubes) were seemingly OK...except for the following:
Terminal 7 - 7.5K ohms
B3 - 7.9K ohms and rising...should be 2.9K ohms
B6 - 2.2K ohms and rising...should be 2.9K ohms
RCA center - 2.5K ohms...should be 90-100K ohms
...I assumed this to be possibly OK because of the speedball...so, I powered up.
Voltage checks (power and tubes installed)
Initial findings:
-output tube glows strongly...no glow at all from the 12AU7
-in every instance where there are LED's...1 of the 2 aren't lit up. The exception being the ones on the center pin of the 12AU7 socket...they both glow.
Terminal 1 - 65VDC and dropping...should be 75 VDC
Terminal 2 - 177VDC, rapid drop to 70VDC and dropping...should be 170VDC
Terminal 4 - 69.4VDC...should be 170VDC
Terminal 5 - 62VDC and dropping...should be 75VDC
Terminal 7 - 53.1VDC...should be 100VDC
Terminal 9 - 52.5VDC...should be 100VDC
Terminal 13 - 65.2VDC...should be 170VDC
Terminal 15 - found the resistor there sitting in melted solder! I had to stop and unplug at that point...something is obviously wrong.
Now, I've been through the instructions 3 times...rechecked everything...re-soldered...etc etc... I don't see where my problem is. Any suggestions? I guess my next step is to remove the speedball, install the 4 resistors and give that a shot...but I wanted to check in here first.
I just don't see how I could have gone that wrong on the install.
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ok...did a little looking around and there's another person here who has a problem with similar symptoms as I have. His post: http://www.bottlehead.com/smf/index.php/topic,2976.0.html
I see his LED issue is nearly identical to mine...and voltage readings are similar... I then found out...the metal transistors...I've installed them exactly in the wrong locations. I have the ones that should be on the small pcb installed on the big one...and VS. Question is...can that cause the melting solder I've experienced?
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You definitely need to fix the mixed up transistors. That may well solve the hot resistor.
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I've taken the speedball out of the circuit completely...installed the 4 resistors...and all resistance and voltage checks are perfect. Amp works great. So...that exercise was just to make sure I didn't destroy anything. I'm impressed it held up after melting like that. I'm guessing I may have shortened it's life a bit...but hey, all readings are just about bang on with the instructions.
I don't know what I was thinking when I installed those metal can transistors. Even though it's clearly marked in the instructions...I "assumed" they were all the same and just installed. I'll never assume like that again.
Now...how about some tips on removing those metal can transistors? I tried a bulb solder sucker...and that's just too damn hard to do. I tried some wick as well...worked to a point but I can't get those damn things out of there. Any suggestions?
Other than the time and money lost (mostly the time)...I'm not really heartbroken that the speedball isn't installed. The base kit sounds really good. It's dead quiet...not a hum, crack or anything.
I'm really enjoying floyd via an iBasso DX100 into some Beyerdynamics T1's.
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Now...how about some tips on removing those metal can transistors? I tried a bulb solder sucker...and that's just too damn hard to do. I tried some wick as well...worked to a point but I can't get those damn things out of there. Any suggestions?
Get a helper. Give your helper pliers to pull out each leg, one at a time as you heat and solder suck the pad.
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Well, lesson learnt...next time, leave enough room to put pliers under the transistors...so your helper can get a grip on each leg. :P
I'll give it another shot tomorrow when my patience has returned. Thanks Doc
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If they are flush to the board, personally, I'd probably just cut them out and desolder and remove one leg segment at a time then replace them with new ones. But, it can probably be done with some persistance, and some help as Doc mentioned.
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Well, lesson learnt...next time, leave enough room to put pliers under the transistors...so your helper can get a grip on each leg. :P
I'll give it another shot tomorrow when my patience has returned. Thanks Doc
It is also a good practice, for the future, to leave the leads on transistors long so that the heat doesn't get into the junction. Too much heat permanently damages the junction. A hot iron or a slow one can make the transistor useless.
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Appreciate the input about leaving more lead space...will do so next time around.
I left space between the pcb and transistor...just not enough for pliers to get into. I think I'm going to have to just cut them off as commented. I was already thinking about that honestly.
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Did the same thing with my transistors, taught me a good lesson. Read and follow the instructions step by step. Doesn't mean you won't make a mistake, but makes it less probable.
Cheers,
Shawn
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regarding getting those transistors out -- do you have a heat gun for heatshrink tubing? If so, you can make a heat shield out of a piece of aluminum foil with a hole cut in it just a bit bigger than the area of the 3 leads. Clamp the pc board in a vise, affix the heat shield you just made, grab the transistor with some pliers, and heat the 3 solder pads concurrently with the heat gun.
Also, one of those little 2-piece scribes can be used to get under the transistor.
Yes, the bulb solder suckers are almost useless, but the good spring-loaded ones with the aluminum body (weller makes a very nice one) can do a great job with a bit of practice.
As for mixing up the transistors on the speedball -- you're certainly not the first to do it, and you won't be the last either :-).
Good luck,
Jim
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All,
Appreciate the advise. All of which I'll look into...including the heat gun. I have a nice milwaukee heatgun...but as I found out last night...maybe too powerful. I destroyed the mesh stuff and it melted...and the heatshrink split on the power cord I was making! It's not pretty. I tell ya...had to wrap it all up in electrical tape...but it works just fine ;)
you know...just like with the speedball and the base crack kit. I was so happy I was doing such a good job...only for something to go wrong. Well, I'm over it...I'll have to find some way of correcting that some day.
mistake after mistake...man...makes me feel young again. hahaha...it's incredible what you forget over the years if you aren't doing this stuff all the time.
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Aluminum foil is your friend in that situation too :-). Just make a cone out of foil (like a dog would wear) and cover all the nylon mesh and just leave the heat shrink exposed. Works like a champ -- never melted any mesh since using this technique.
HTH,
Jim
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Much appreciated Jim. I'll try just that when I get my S.E.X. 2.1 in...I ordered a power cord kit for that as well. Hopefully I don't slaughter that one too! I'm confident and appreciate the tip!
Cheers,
Ken
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All,
Appreciate the advise. All of which I'll look into...including the head gun. I have a nice milwaukee heatgun...but as I found out last night...maybe too powerful. I destroyed the mesh stuff and it melted...and the heatshrink split on the power cord I was making! It's not pretty. I tell ya...had to wrap it all up in electrical tape...but it works just fine ;) . . .
I have a heat gun I bought 15 years ago, refurbished. I don't remember the manufacturer but it has two settings: Extremely Hot and Way Too Hot For Anything!
The Tech-Flex on my Bottlehead power cords have the same problem. I feel your pain.
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Some heat guns have extra tips you can put on to redirect the hot air. We have one that is wide and narrow. It lets us get pretty close to the top of the heat shrink without blowing too much heat on the Tech Flex
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I've got one of those wide, flat tips on my gun as well. I think it comes down to being much more careful where I'm directing the hot air. I wasn't initially aware that that mesh stuff would melt like that. I'm still curious about why the heatshrink split...I guess just too much heat. it split on the clear plug.
Well, on my next kit, I'll use some aluminum shielding as well as much more care about how I use the heat gun. I'm hoping for better results.
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I have not seen the heat shrink split. It will curl over right at the end if you don't heat it somewhat evenly.
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I noticed the curling as well. I was able to get that to smooth out, but that's when I ended up melting the mesh material. I'll use some aluminum foil or shield of some sort next time around.
On the hospital quality plug (clear plug) it split twice (clarification: the heat shrink split...not the plug). The first time, I was able to trim off the effected area and scoot up the unshrunk tube over the plug and start over. However, it split again. I also notice that the tubing crept down further away from the edge that it started...leaving behind about a half inch of that sealing goop. That happened on both plugs. I figured in all cases it was me...applying too much heat or something. Give me a day or so. I'll unwrap the electrical tape and take a shot and send it to you.
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Ive seen heatshrink split when it has a partial, lengthwise slit in it. Doesnt even have to be full length or all the way through. Makes sense because thats the best way to remove it. Honestly, Ive never had a problem with shrinking the stuff, including not melting techflex, using a Milwaukee heat gun on low (without a nozzle). But then again, I used boat loads of heatshrink in my work (used to shrink it with a wide nozzle torch). This was the bigger, thick, adhesive lined stuff for .500" - 1.00" cable and associated fittings. Anyway, just takes some doing to get the hang of it like anything else.
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Understood. I did not notice any damage, slits, cuts or otherwise before I started heating it. However...I didn't really look for that either. I was careful cutting...as I wanted a clean edge. I dunno...I think this can be chalked up to too much heat most likely. I've not worked with heatshrink this big before. Either way...it's an aesthetics thing. I'm not too bothered as this was my first go at it. I could fix it...maybe...but I won't even bother asking for more shrink tube. Would have been nice if it looked "prettier"...but I can live with it. I don't mind learning (relearning) as I go.
However...next project...it's going to have a pristine looking cable ;) ...now that I have some lessons learnt.
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I think Doc mentioned that he hadnt seen it split before. I was really just commenting on that. It very well could have just been too much heat. Based on your melting the sleeving and cracking the plug, it probably was. Like you mention, just consider it lesson learned. Good way to look at it. ;)
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I added a clarification to my comment previously...I didn't crack the plug... I only split the heatshrink and melted the sleeve where it joined the heatshrink. Just sayin...don't want you all to think I'm THAT bad :P
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You don't want to be known as Mr. All Thumbs.
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I've found that the shrink ratio of the tube has an effect, the higher the ratio the more prone to heat damage. I have had 4:1 and 3:1 split on me due to leaving the gun in one place to long.
Cheers,
Shawn
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I should have mentioned that, good point, keep the heat moving some kinda like blowdrying hair ... from memory. The only hair that I have to blowdry now is the Cats after a bath ;D
3:1 was what I used at work but that was industrial stuff, so thick and tough that it would blister without splitting ... unless it had a partial slit in it. The consumer shrink isnt nearly that tough but it doesnt need to be.
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Just found out how to attach pictures ;D
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...and the build...sorry for the quality of the pictures...not my strong point with a camera phone.
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There is yet another way to link pictures with no size limitations.
Lookie here at my FAQ Thread (http://bottlehead.com/smf/index.php/topic,2408.0.html).
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Appreciate that. :)
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Eileen sent me some replacement caps...and FAST! What great customer service!
Got the old caps out, installed new caps...and triple checked I had the correct ones at the correct locations ::)
Initial observation:
The 2nd small pcb to get installed...LED's do not light up. All other LED's light up.
Voltages
Terminal Expected Reading
1 75 90 and dropping
2 170 191.2
5 75 188 and dropping
7 100 120.1
9 100 184.8
13 170 188
15 185 201 (yay...not melted this time around)
19 0 87
20 206 0
A1 75 183
B1 75 82
B2 170 185
B3 100 116
B4 75 182
B6 170 184
B7 100 180
Anyone have any ideas? The Crack w/o speedball works perfectly...readings are all textbook. I've reheated all solder joints...don't think I could have installed anything else incorrectly. I've double checked all wired are connected to the appropriate areas.
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So, I'm checking the boards...this time, I'm checking components. Diodes, resistors etc. Since you all know I wasn't paying attention to the metal can caps...and assumed they were the same...give ya 3 guesses what I just found wrong.
...this time, I'm hoping it's the LAST problem and I get the speedball working!
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ok...2 incorrectly located/placed components removed and put in the correct location. This time, all diodes light up nicely.
All voltages are not textbook...but close and within 10%. ...minus 2. I get the following results at 2 terminals which confuses me since all other checks are close:
Terminal Expected Reading
19 0 87.6
20 206 0
...those readings remain consistent from the last check before I found out I had 2 additional components in the wrong place. Finally, measurements at the TRS jack show a very slow climb, then a sudden spike to about 21VDC...then a quick drop again to 0. The manual says 9VDC max... Strange...any suggestions?
I'd like some input before I plug this in and turn on some music.
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ok...little digging and I came up with:
-terminal 19 voltage check is irrelevant
-terminal 20 voltage check should be zero
-terminal 21 voltage check should be 206...
...seems this correction is noted on the board...again, me assuming...I thought the manual was correct as the correction was posted in 2010.
so, everything checks out...except the TRS jack voltage...which jumps to 21 for a very short time ...I'd say <1 sec...and drops to zero. Can't figure that yet.
I found another post: http://www.bottlehead.com/smf/index.php/topic,2946.0.html
It states: "...the two unused solder terminals. Connect both of those to ground (the terminal row closest to the chassis plate). The 1/4" jack supplied has a switching function built in, so when no headphones are plugged in, the output is shorted to ground, and thus the coupling caps at the output will charge without restriction."
When you plug your cans in, that connection is lifted and your music will flow through."
I haven't done that modification...should I? and why?
Question is...if everything is checking good, and no headphones are plugged in...how relevant is a quick spike to 21VDC on the jack going to be? it goes to zero pretty quick. What am I missing?
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Well, Just couldn't let it sit there ...I plugged in. ;D
I got a little popping and static when rotating the pot initially...and again after I tapped the knob on the pot. I haven't been able to reproduce that...but haven't powered down yet. Maybe it just needed more warming up.
I was worried about the momentary 21VDC on the jack...so left the headphones unplugged for about a min or so...then just plugged in hoping for the best. I may try to do that mod previously mentioned about the TRS jack grounding...on the 2 unused lugs. I'm out of time for this build for now...so I'll save that for next time I'm home.
What a day! I'm quite pleased with myself for sorting it out on my own (well, with the help of the forums previous posts)...and extremely pleased I didn't fry anything with the 2 mistakes I had made in component location.
The last problem I had found...the larger board called for 2ea 31.6 ohm resistors ...but I accidentally put one of the 237 ohm resisters there. Not sure how I had done that...other than they look identical to someone who hasn't bothered to check the resistance measurement or color code bands. Lesson learnt...check everything before installing next time and save myself a TON of time! Never take anything for granted.
Comments: I don't really notice the speedball upgrade being more quiet...my base install was already dead quiet. What I do notice, is more bass...more punchy I think. Very good clarity and separation overall.
Conclusion: I'm very happy with what I accomplished and the end results. I don't even mind the road getting there...I learned (relearned) some valuable things that I won't be soon forgetting...and that I'll apply to my next build. This is an excellent amp and I'm chomping at the bit to get my next one underway.
Thank you to those who gave me some great tips and advise. Much appreciated.
Doc and Queen...thank you for your support and for the outstanding kit!
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With Speedball the voltage at start-up seems to run higher. It's millivolts, not volts by the way. Manual states 9mV-DC with stock version. There is nothing in the Speedball manual that suggests the voltage is higher. I brought the question up after I installed Speedball. I measured 9mV DC after building stock and 22mV DC after Speedball upgrade and film caps. Another member measured 14mV. You should be fine if all your other measurements are in line. I have not yet connected the switched contacts to ground. I turn the amp on for 30 seconds or so before plugging in headphones. BUT, with headphones connected, that small voltage at startup would be even lower and probably non consequential. I just use extra caution and plug phones in after the 30 seconds. Grounding those switch contacts should remove that small voltage. But keep in mind that some folks use different headphone jack (like the Neutrik locking jack) that doesnt have the switched contacts. So, it isnt mandatory to ground those contacts. Crack was out for a while before the guys posted about grounding those contacts. Long way of saying that your 21mV at switch on should be fine and seems normal ... as long as it falls back to zero. Also, after it falls to zero, you may or may not have noticed digits on the meter rapidly jumping all over the place, too fast to keep track of unless maybe you have a peak hold function. This is also normal and, as Paul J. explained it, it is "leakage" from the electrolytic caps. Also normal and inconsequential.
I didnt notice Crack any quieter either after speedball. Mine was dead quiet in stock form. But I think some of that extra detail and/or clarity may be due in part to a quieter/cleaner background with Speedball installed. Eventhough the background seemed "black" in the stock build.
Anyway, sounds like all is good now. Happy to hear that you got her up and running. The problems you had just makes for a good learning experience for the future. Congrats and enjoy. Really sweet amp, Im still loving mine. Next up for you ... maybe film caps and tube rolling? ;D It can be hard to leave alone. I stopped at the film caps internally. BUT, I do have a pretty good stock of tubes to roll. I think that mods get more subtle once Speedball is in, and maybe film caps in place of the electrolytics for the output coupling caps. That's what seems to be reported by many. If you do have plans for future mods, enjoy it as it is for a while before doing so. But it sounds fantastic, even in bone stock form.
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Laudanum, appreciate the comments confirming my voltages. Also appreciate the correction :-[
I just may do the cap upgrade...it'll have to wait till I get home end of Oct...but till then I'll figure out which ones need replacing and with which ones.
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ramicio ... I checked the voltage with 300 ohm phones plugged in on turn on. I dont have a meter with peak hold feature. All I got was scrambling numbers that appeared very, very low in terms of millivolts DC. But I cant confirm an actual voltage. I just know that it appears to be much lower as it's been stated by the experts that it would be with phones plugged in. I know that there were/are forum members that did/do keep them plugged in. I dont keep them plugged, not only to be extra cautious but also because I have several cans in rotation and never know which I will be listening to. My rack isnt right next to the amp either and my evil cat would eat the cord if it were hanging down over the stand :o
ditah ... I was referring to the two, 100uf electrolytic output coupling caps as logical candidates for replacement with large 100uf film caps. But others have replaced caps in the power supply. PS resistor with a choke and so on. Check some of the builds in the Gallery forum, you'll see what I mean. 8)
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Sorry, yes NOT plugged in. My mistake. Thanks.
But I still dont have a definitive answer, just relaying what I measured, or tried to measure. I know that several members do/did keep them plugged in. I asked a related question after my build and got responses that said it was fine to keep them plugged in (before the switch mod was discovered). But I think the "cover your a**" answer would probably be to unplug them. Personally, I'd be more worried about the output tube going south on start-up than the very small dc voltage. But then again, the tube could go south any time.
I know, I know ... what a great help I have been ::) ;D
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In stock configuration the 2490 ohm resistor after the output cap is there to send the startup DC to ground. It should dissipate with a time constant of 1/2*Pi*R*C, or 0.6392 seconds. After a few time constants the DC will all be gone.
The magnitude of the voltage is dependent on the output cap's characteristics. Dan measured with the stock electrolytic. If you have upgraded to a film the resulting DC bleed through will be different. I don't know if it will be higher or lower but it will be different.
Two other factors here are the resistance/impedance of your headphones and their susceptibility to the leakage. Some headphones will weather the bleed through with no ill effects, others might burn out. That is why Bottlehead has erred on the safe side saying not to plug in the headsets till the amp has been on for 10 seconds or so.
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There is also the factor that the cathode voltage of the 6080 is 0 at startup, then slowly climbs as the tube warms up. With headphones plugged in (even 600 ohm ones), the parallel resistance of the 2.49K resistor and the headphone voice coil become very low, singificantly reducing the presence of this startup voltage. FWIW, Doc and I have both left our HD-800's plugged into stock and Speedballed Cracks during startup plenty of times without giving it a second thought.