Tuesday, 1 March 2011

Clarity and direction.

After the first initial session with the DT880 and the MiniMax, I ran them through a whole range of music as burning in. This included everything from the full works of Handel's Messiah, to the entire works of Coldplay and Muse. After 10 hours of burn-in, I sat down for another session. Cued up was my now standard testing and auditioning mix. This has a range of music styles that I listen to, and am quite familiar with. I will elaborate on the playlist at a later date.

The result after the first burning in session - bass has firmed up, balance is even better and treble is more articulate. This has made dramatic improvements to the stock cans. The bass that was quite recessed and thin has opened up. The high end has definitely got more definition and clarity. I would say that the mid-range has seen as dramatic improvement as the lower and higher registers. There is no harshness in the sound, and I would not call it ‘boring’. The sound is now closer to my HD650, which has over 500 hours of use. To compare with the HD650, the bass is more controlled, and highs more clear, but the midrange is not as engaging. I can hear now, what others on the Internet have been saying about the differences between the HD650’s and the DT880’s. It does come down to a matter of taste. But any more critical analysis has to be done after at least another 100 hours of so with the DT880’s.

Through using the MiniMax in the last few days, has highlighted a few points of difference with the Crack. Once you get used to it, the MiniMax does sound pretty awesome and is enjoyable thoroughly. But in a direct comparison between the two, I'd have to say that the Crack with Speedball wins comfortably. It is shame that I am having a few issues with the Crack at the moment, but a quite weekend is what is needed to check and test. But I am looking forward to using the Crack again.

Another decision was to abandon the Yamamoto HA02 and the custom Crack build for the time being. With other priorities, it is probably not the best to invest in more headphone amps. Instead, a concerted effort will be made to complete the D3a amp and the ST70 upgrade/new build from K and K Audio (link). So looking forward to coming days and weeks, when I will post more information and progress updates for the two amps. The ST70 project really shouldn’t be considered a ST70, as it uses a brand new driver board and different output transformers. The only similarity is that it uses a KT88/EL34/etc type tube in a push pull arrangement and it also uses the ST70 spec transformer. To complete this amp, I have purchased a ST70 replacement power transformer, and made an order for a pair of Softtone/ICL RX-40-5 (link). Looking through the web page, they look to be a very good performer. The fact that it shares the same footprint as the Tango FX40 makes any future upgrading a snap.

In terms of speaker projects, that has been on the back burner for the last few years, I want to revive it with mating the ST70 clone build with an open baffle speaker. Recently ordered a pair of Fostex F200A for a very good price (in small part due to the excellent Australian dollar!) and this joins my collection of full range drivers. This collection currently made of; Fostex FE207, Lowther DX3, 8” Saba Alnico Green cones and Jordan JX92s speakers. This forms the range of speakers that will be compared in an open baffle speaker. With the ST70 design having around 8-10W, should be plenty to drive the more inefficient JR92s and the F200A. Currently in my head is an open baffle speaker with replaceable baffle panels to allow quick switching and storage of speakers. The baffle design in mind is a U frame. Overall dimensions are; 440mm wide by 940mm high and a side depth of 180mm. This will have 2 identical front baffles, each at 400x400mm, which can be user replaced. In the central part separating the two removable baffles would be rail to allow for tweeter placement. There will also be a fixing point at the top to allow for alternate tweeter placement. This would form a speaker frame/carcass that can allow me to change and match different speakers in different configurations. This could form my primary speaker that can be tweaked and changed easily. Expect more to come with some initial sketches and simulations.

One last item on the wish list is to review my previous posts and clean up the grammar, spelling and links, and make sure everything is working and makes sense. Hopefully this will make this blog more readable, enjoyable and relevant.

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