1st time DIYer - tales of my build - questions in 1st post

[Laudanum]

Those Alpha pots are really inexpensive.  They often dont track well at low volume but they sound fine (to me tin ears).   Not many reports of bad ones here but it's not uncommon for them to be noisy just as you describe.  Ive used them in other projects before and have had a noisy one (crackling and static).   I probably have 1/2 dozen stashed away.   Follow Graingers advice on the pot.  Bottlehead will send you a replacement if needed.   
You could also consider something like the Alps "Blue Velvet" (conductive plastic type).   They track really well even at the bottom of the range and they sound fine and are quiet.  Good pot for the price but a little tricky to solder because of the pin terminals instead of lugs.  They are made for through-hole mounting.  Under $15 at Mouser.  $25 give or take at most audio parts sites.  Just something to consider of you want an inexpensive upgrade in the future.

Im curious as to your Beyers being ok?  I see you edited your post but I know you had posted that you plugged them into another amp and they didnt sound right and you were concerned they were damaged.   I assume they are ok.   Crackling and static from a noisy pot shouldnt hurt them in and of itself.  Of course, if the volume was up far enough I imagine it could.  But anyway, just wanted to check to see if they were ok.  I love my Beyers and they are great on Crack   

[wullymc]

Thanks guys for your suggestions.

I think I will resolder the pot and see if it is okay.  When doing the listening test if it starts to crack and pop I will try the method of pushing down and pulling out.

Unfortunately, my headphones are not doing well.  When I was preparing the cmoy they said to use a cheap pair to test.  I should have used that strategy with the Crack.  I am going to keep going with the cheap pair and see where I go from there.

The Alps pot sounds interesting.  In looking around it seems like a lot of people have done that upgrade.  I am very novice and don't know what wires go where.  I do have a helping hand so I think I could solder it first and then attach it to the chassis later.....well another option.

Thanks again.  I truly appreciate the help.  I figure I am getting there.  I was getting excited but I have to think of this as the challenge.  I find for the most part the build wasn't that bad.  I had a few problems, but with going slow it is coming together.  I think the more difficult part has been the testing.

[Grainger49]

Check FAQ #6 for help on installing an Alps pot:

http://www.bottlehead.com/smf/index.php/topic,2408.0.html

[Laudanum]

Thanks guys for your suggestions.

I think I will resolder the pot and see if it is okay.  When doing the listening test if it starts to crack and pop I will try the method of pushing down and pulling out.

Unfortunately, my headphones are not doing well.  When I was preparing the cmoy they said to use a cheap pair to test.  I should have used that strategy with the Crack.  I am going to keep going with the cheap pair and see where I go from there.

The Alps pot sounds interesting.  In looking around it seems like a lot of people have done that upgrade.  I am very novice and don't know what wires go where.  I do have a helping hand so I think I could solder it first and then attach it to the chassis later.....well another option.

Thanks again.  I truly appreciate the help.  I figure I am getting there.  I was getting excited but I have to think of this as the challenge.  I find for the most part the build wasn't that bad.  I had a few problems, but with going slow it is coming together.  I think the more difficult part has been the testing.

Sorry about the phones.  If new, you may be able to exchange them defective.  Im not suggesting that you "lie" to the dealer.  Just that some have a no questions, unconditional return (Amazon comes to mind as an example)  so it would depend where you got them, and, of course, if they are indeed new and within the refund/exchange period.

The Alps pot is indeed easier to wire before installing.  The FAQ covers the wiring and I believe they just wire up exactly like the stock pot.  It's really not hard.  I just crimp the wire to the pin first so I have positive contact and then normal soldering.  I use a lighted magnifier as my eyes arent getting any younger but it really isnt difficult at all.  You're in Canada, right?  Parts Connexion has the Alps for $18.  Probably cheaper for you there over saving 4 or 5 dollars from Mouser in the States and paying the extra shipping. But first things first. Regarding the stock pot, I was suggesting that it is possibly just a bad/noisy pot.  Not sure resoldering will help but it's worth a shot.

[wullymc]

Thanks guys,

I will try the resolder today.  If that doesn't work I think I will buy a Alps pot.  Does it make a big difference?

Thanks for the partsconnecXion suggestion.  I am looking at the page.  I have a question though since there are about 8 of them.  I wouldn't buy the motorized or mono ones but what one would you suggest for the stereo ones?  They have 10k, 50k, 100k, and 250k.

[Laudanum]

100K, same as stock value.   Sound wise, I probably couldnt hear a difference, or not enough to buy on that alone (some can).  But it's smoother, it tracks much better, most noticeable at lower volume.  With the cheaper pots, especially at low volumes, left and right channels can be uneven, volume wise.  And, it's quieter, no static or crackling as you turn the pot which can also sometimes be a problem with cheap pots, both when new and when they get some use.   There is also the TKD pots if you want to spend more money.  The most popular one is a little less than $100.  Also conductive plastic and Im sure its better but Im confident that my ears wouldnt hear a difference.  Speaking purely for myself, Im confident that the difference in price would be better spent on, for example, film output caps or tubes or put toward Speedball.  YMMV of course. 

[wullymc]

Thanks!!!


I just finished resoldering.  I remembering missing the ground closest to the chassis and going back and soldering it trying not to hit the other wire.  I think I probably got half good solder that would intermittently break away.

I have been listening at 12-1 for about 10 minutes and can't hear any cracking or popping.  Hopefully this has fixed the problem!

I will do a lot more listening tonight to see if I can get it to do it.  Hopefully I won't succeed!

Thanks again!  I will update later.  Take care...Dave

[Jim R.]

Dave,

Sure sounds like you found the problem to me.  As the amp heats up solder joints can expand and if it is a bad joint, that can indeed do what you heard.

Nice job!!

-- Jim

[Laudanum]

Good to hear!

[wullymc]

thanks guys,

I have just listened to about 45 minutes of music switching another the volume from 7 - 2 trying to see if I can get it to crack and pop.  I wasn't able to make it.  This is good news!  I graduated to using my AKG 518 ($50 headphones) and they still work!

I have noticed that when I take out my headphones there is a little bit of a pop or such when I take out the headphones at the end of a listening session.  The volume is at 0 when I do so.

Also, when I take out the headphone tip it is extremely hot.  Is this normal?

Am I using the amp correctly regards to connecting and disconnecting headphones?

Method A:

1.  Turn on amp with no headphones and volume at 0.
2.  Wait 30 seconds or more then connect headphones with volume at 0.
3.  When done listening to music turn volume to 0 and disconnect headphones
4.  Turn off amp.

or should I do this:

Method B:

1.  Turn on amp with no headphones and volume at 0.
2.  Wait 30 seconds or more then connect headphones with volume at 0.
3.  When done listening to music turn volume to 0.
4.  Turn off amp.
5.  Disconnect headphones

Thanks very much.  Just don't feel like ruining another pair of headphones.

Take care...Dave

[Laudanum]

Sure sounds like you got it figured out.     
I turn amp on, volume at 0.  Wait 30 seconds or so, plug in phones.   I generally turn volume to 0, turn amp off and then unplug phones.  But I do get a turn off snap/pop occassionally although not a bad one.   I asked about something related to this, changing headphones while amp was on and of the Bottlehead guys suggested that it should be fine.  So either way should be ok.  I would just use whatever method produces the least snap-crackle-pop for you.   

Those small snaps and pops shouldnt hurt the phones but a large enough one could, or sustained  noise could.  I dont know electronic/electric circuits all that well but those type of transients (I believe that is the right word) can be much higher in amplitude than the music signals coming in and are amplified accordingly ... which is beyond what the drivers in your headphones can take.  Probably what happened with those crackling and popping noises you heard before you found and fixed the cold solder joints at your pot.    Im sure it will serve as a good learning experience, although a farily expensive one.   Sorry to hear that it happened, and still hoping to hear that you were able to exchange the phones or get them repaired.

Regarding the hot plug tip,  logically this would seem normal.   The amp gets hot so anything metal inside the amp would get hot and that would unclude the metal headphone plug.  I have never checked mine but Im sure it's a hot as the amp is.   Maybe others will have a different take on this but it just seems logical.

[wullymc]

Thanks Desmond,

You have been most helpful.  How long have you had your Crack?

I have just been listening again.  I get a pop when I insert the headphones after powering on (after 1 minute warm up time).  I have done the headphone jack mod for the initial voltage spike.

I will try the power down before taking out the headphones.

I might post the power up/power down headphone question in a separate thread because I don't think a lot of people are reading this one.  I would like to get a concensus.  I would hate to ruin some more headphones.  I am hoping something good will come of the ones that I damaged.  I will let you know...

I am looking forward to eventually checking out some tubes to swap out the originals.  This will be fun!

Thanks again for your help.  Take care...Dave

[Laudanum]

I've had mine for about a year now.  I havent done the start-up voltage mod yet.  I dont think I get a pop when I insert the phones but I cant even recall if they are usually on my head when I plug them in.  I'll check next time and let you know.

[wullymc]

Okay,

so I have been listening some more with my amp and I think that I have got it sorted out.  I have another pair of DT880 600ohms so I think that I will wait another week before plugging them in.  I am a little bit gun shy.

Now I though that I would finish this thread off by giving some lessons learned for new builders, those who are mostly novice.

Here they are:

-  print a hard copy of the assembly manual
-  print and read the manual corrections, make markings in the manual for corrections
-  highlight where it says "solder" in the manual
-  read the manual a couple of times before beginning
-  go to youtube and watch videos of introduction to soldering
-  split up the manual into workable chunks.  3 pages a night worked well for me.  About 1 week to build then.
-  read old threads of problems people reported after assembly - learn from them
-  follow manual carefully and respect the installation positioning of caps & resistors.
-  before soldering review that the word "solder" is there where you are in the manual.  I have soldered and then have had to go back to reheat the solder to put another wire through.
-  test using cheap headphones!  You don't want to ruin your $300 + headphones.
- most importantly Have Fun!  The building process is not that difficult, it is more the problem solving that could get stressful.  Use the forum here.  There are great people willing to help you out.

Good luck!

Next I will try to post a few pictures of my build.

[Pluck]

Okay,

so I have been listening some more with my amp and I think that I have got it sorted out.  I have another pair of DT880 600ohms so I think that I will wait another week before plugging them in.  I am a little bit gun shy.

Now I though that I would finish this thread off by giving some lessons learned for new builders, those who are mostly novice.

Here they are:

-  print a hard copy of the assembly manual
-  print and read the manual corrections, make markings in the manual for corrections
-  highlight where it says "solder" in the manual
-  read the manual a couple of times before beginning
-  go to youtube and watch videos of introduction to soldering
-  split up the manual into workable chunks.  3 pages a night worked well for me.  About 1 week to build then.
-  read old threads of problems people reported after assembly - learn from them
-  follow manual carefully and respect the installation positioning of caps & resistors.
-  before soldering review that the word "solder" is there where you are in the manual.  I have soldered and then have had to go back to reheat the solder to put another wire through.
-  test using cheap headphones!  You don't want to ruin your $300 + headphones.
- most importantly Have Fun!  The building process is not that difficult, it is more the problem solving that could get stressful.  Use the forum here.  There are great people willing to help you out.

Good luck!

Next I will try to post a few pictures of my build.

Thanks for this - I've followed the thread with interest as my Crack arrives today and I'm a first time DIYer!  Do post pics of your build - I'll be doing likewise when mines done.

N