We've been discussing for some time what we would do to improve the Crack circuit if we had more real estate and a little bit bigger budget. PB has been building and testing various ideas over the past few years and this summer we decided it was time to pick the best bits from those experiments and combine them with some other tricks we have developed for other kits along the way.
One big consideration was that this kit was to fit between the Crack and the Mainline in terms of price. We wanted to keep the price below $700. Yes, the S.E.X. kit fits in that price range, but there seems to be a devout following of high impedance headphone specific OTL amps that we wanted to address, and thus this alternative offering. With that in mind we decided that the biggest benefits would be from a more sophisticated power supply and the ability to upgrade to our very special stepped attenuator as used in BeePre (and in a slightly different form in Mainline). We also know that our customers like to have multiple switched inputs, so we include three.
And so Crack-a-two-a is a premium version of the direct coupled Crack circuit, with the C4S active loads of the Speedball incorporated and also shunt voltage regulation in the form of two 6AQ5 tubes along with a bigger power transformer. There are three pairs of RCA input jacks and a volume and balance control. The standard potentiometer controlled volume/balance setup will be upgrade-able to a coarse and fine stepped attenuator very similar to the BeeQuiet attenuator used in the BeePre preamp and a similar style used in our most premium Mainline headphone amp. Like Crack this amp is intended to be used with high impedance headphones (200 ohms or higher) like Sennheiser HD600/650/800, Beyerdynamic 250 and 600 ohms headphones, etc.
The chassis is twice as big as the Crack chassis and along with fitting in the extra inputs, shunt regs and attenuator components there is plenty of space for those humongous output coupling caps everyone wants to add to their build.
Crack-a-two-a sonics? Compared to the Crack the shunt regulation gives a slightly more quiet background and a sense of better bandwidth and control. The balance control allows one to compensate for the tolerance variations in the volume pot that create imbalance at low volume settings in some Crack builds. Upgrading to the stepped attenuator is as big an improvement in the OTL circuit as we have found it to be in all of our other circuits that incorporate it - the presentation is more resolved and more natural, particularly vocals.
This kit doesn't replace Crack in the lineup. Crack is just too great a value for the dollar to let it go. The intent here is to offer a higher level of performance potential than one could ever squeeze into the Crack chassis or price point, while keeping well below the cost of the more premium Mainline kit. With this in mind the introductory price will be $599 with the stock volume and balance pot configuration. The attenuator upgrade will come out in the future and will be priced similar to those offered for our other kits. Life is not interesting without many choices, and this is another really interesting one.
Here's a link to the new web page in our online store:
http://bottlehead.com/product/crack-a-two-a/
« Last Edit: August 04, 2015, 05:33:29 PM by Doc B. »
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.
