Can't say I did. My stock Crack was pretty damn good with absolutely zero issues. My biggest issue was when I rebuilt the Crack and had a flaky solder at at T13 which is one of the legs of the final PS cap. That made the Crack sound flat and is why I believe the last PS cap influences the...

Based on my understanding, higher capacitance may lead to more bass, but the Crack is already pretty well optimised, thus most of the uF above 220uF may not have any effect (other than the caps taking longer to discharge). There is some math on the Bottlehead forum which will allow you to...

My first mod was the VA Labs attentuator. When I received it, the PCB was installed upside down. Luckily by looking at pictures of other builds I realised what the problem was and PB on the Bottlehead forums was very helpful in explaining how to check for in, out and ground. I was a bit nervous...

  I have not tried any other tubes, but I believe common consensus is that once Speedball is installed, the difference between tubes is much smaller than before. Although that being said, there is a tube-rolling thread on the Bottlehead website so you could read through that...

    Based on the above post by Warren and since you mostly listen to balanced anyway, I would wager that the upgraded power supply would not represent a major improvement to your listening experience. I would also be very surprised if the upgraded power supply made a major difference to the...

That is a beautiful build. Out of curiosity, do you use 14U or 22L for the ground? I think I see a ground wire going past the back of the transformer, so it looks like 14U, but I am not 100% certain from the photo.

I have found this piece that actually recommends adjusting volume on your PC rather than the amp - http://bitperfectsound.blogspot.lu/2013/03/digivol.html   There may be some channel imbalances with some of the pots in the Crack. The Bottlehead suggested solution is to turn down the PC volume...

I would get a thread going on the Bottlehead site and post some pictures. The guys there are pretty good at the troubleshooting.   I have never had humming, so never needed to investigate potential causes for that. However, here is a helpful ground path check that can eliminate some potential...

A little late for this advice now for you, but perhaps others may find this helpful. I always advise installing the standoffs right at the beginning of the normal Crack build. Remove them each time you need to solder in their vicinity and then replace them. Makes cable routing a lot easier.  ...

No. Build the stock Crack first. If you run into any issues, the first troubleshooting step is to remove the Speedball.   Only thing I would recommend is putting the standoffs in place. Inserting the standoffs after having built the Crack can be tricky. I prefer to do this in advance.  ...

You can find bad solder joints by doing the chopstick test, namely taking a chopstick (any non-conductive object will do) and systematically giving all solder joints a push or shove. If you listen to your headphones, you will usually hear a crackling noise to indicate something is loose. I would...

Yes, being shocked by electricity is no fun and realising how I stupid I was even less. Being shocked from the caps discharging is even worse. Before I start working on the Crack nowadays (and especially during voltage checks), I always check to ensure that the PS caps have discharged before I...

Even if you switch off your power at the wall, I believe it only switches off live (could be neutral - I can never remember). Thus, as long as the Crack is plugged in you run the risk of being shocked. The only way to avoid that risk is to a) unplug the Crack completely, b) switch the power off...

Well said Doc - my top plate is left as is and I see no need to paint or clearcoat it. I still occasionally marvel at just how beautiful the brushed aluminium can look.   krikor - painted aluminium has the issue with corrosion. Steel tanks have almost no issue - not sure at all, but I think...

Yeah, in hindsight I realise my post does not address what the question was really about. Aluminium oxidises pretty quickly, so by the time anyone receives a top plate that is what it will look like for the rest of its life, unless you of course damage it.   OT - Untreated aluminium scuba...

Aluminium does "rust", but it is not the same as iron that rusts https://answers.yahoo.com/question/index?qid=20061025141908AAhtPFu.

You will notice that both skeptic and I advised mounting the Speedball standoffs during the Crack build. With my initial build, I blocked the screw closest to the terminal strip which made getting the standoff really difficult and would have placed some stress on one or two solder joints.  ...

You should absolutely build it stock first - if you run into any issues with your build removing the Speedball to troubleshoot is unavoidable.   The only thing I would do is place the standoffs around the nine-pin socket to ensure that your wires are routed appropriately. Just note that you...

I received my Mad Dogs 3.2 on Monday and have been listening to them at work since then. WOW - great sound even straight out of the iPhone. When compared to my hot-rodded Crack with DT770s there is less bass-slam, but otherwise it beats that combo in everything else. Comfort is exceptional...

The EHP-O2Di and JDS O2+ODAC are essentially the same. JDS is based in the US and EHP in the UK. If you are in the US, get the one from JDS Labs. If you are in the EU, get the one from Epiphany Acoustics. If you are based elsewhere, then you need to evaluate shipping and customs to determine...

  It really depends on the output level of your source. Seems that there is quite a lot of variance between different models / manufactures due to the "loudness wars".   Unless you need to turn it up to the point where distortion gets introduced, no need to worry about this.

Nah, those are baby caps...  For manly caps, have a look at http://bottlehead.com/smf/index.php?topic=4775.msg45699#msg45699.   They are pretty big though, but are 270uf / 400V. The 220uf Jantzen is not much smaller. I could have gotten a 200uf / 250V Mundorf MCap which is a little smaller...

Thank you, however, I can't claim this as an original idea. I got my inspiration from two Bottlehead builds - links are http://bottlehead.com/smf/index.php?topic=6855.0 and http://bottlehead.com/smf/index.php?topic=2349.0.   The wire comes from Tube Depot...

Modded the PSU - Details are over on the Bottlehead forums (http://bottlehead.com/smf/index.php?topic=7945.0).   Some pictures of the modifications:      

Well, the top plate is also used for grounding, so I assume you want to make it from something that conducts electricity.