Interested in hearing about tube rolling experiences with the Orchid and other MHDT dacs, namely, the specific comparative sonic characteristics of the various 396a, 5670 and other compatible tubes used in the output buffer. My only experience is with the WE396a that Linear Tube Audio installed in my new Orchid.
Unfortunately I missed out on that deal. They were low on them and I had to buy it separately. I got one of the last couple. Certainly worth the cost of admission! Seems a bit richer sounding and less digital.
I am the person who introduced the idea of using 6922/ecc88 family tubes in mhdt DACs, in the head-fi forum. As stated you need an adapter. I took a flyer on the idea after experimenting with every 5670 compatible variant tube. There were certainly great and meaningful differences among them but I evaluated the trade-offs between them as too constricting. Happening upon an adapter lit the bulb.
It's surprising that it works so well, because in the mhdt DACs, that output buffer position has the 6922 operating with a B+ around or slightly under 25v. Very unusual. But sometimes that works and in this case you give up nothing to get plenty. Going back to Havana Balanced ten years ago, through Atlantis, Pagoda and Pagoda Balanced, my preferred 5670-compatible tubes were Bendix 1964 production 6385, and Bendix or Hytron 2c51. The Tesla NOS equivalent was in the same realm. They pushed these DACs to be meaty, vivid and natural. But something was given up, a little, in elasticity and nuance.
The ecc88/6922 delivers everything good about the best 5670 compatible tubes, gives up nothing, then adds more. You'll hear big gains in soundstage dimensioning. Music is dynamically unleashed, spatially liberated and tonally more authentic still than what you expect from mhdt. Bass is deeper where appropriate, more fully realized and textured. In voice you hear more of the whole human pipe, less restriction to the throat. The whole presentation is harmonically more complete, vivid yet relaxed, natural. I use CCa and CV2492 tubes. Siemens and Valvo NOS 6922 work well too.
213cobra... Interesting post. I own the new MHDT Orchid and am currently using a Western Electric 396a. Do you know if a 5670/396a to 6922/6DJ8 tube socket adapter requires any circuit alterations in the Orchid? Petrhaps a question for MHDT.
I have followed the recommendation made by 213cobra and have now rolled an Amperex made in Holland 6DJ8 into my Orchid. I know my new tube has not burned in at all yet.But out of the box I am hearing what he has predicted. I'd describe the change as a more fully fleshed-out tone. I suppose what that means for me is that the already very good midrange of the Orchid has filled out even more. The female vocal I just listened to has more depth and sounds warmer and more beautiful. Really looking forward to the sound improving as this tube burns in.@213cobra Thanks for the recommendation!
I should have mentioned that I'm using the 5670/6DJ8 tube socket adapter available on-line. It did not require any circuit modifications. Also, now that I'm a couple of hours in, and listening to some orchestral music, the new tube continues to provide a more fully fleshed out timbre. I'd describe it as the note fundamentals are fuller and a tiny bit more realistic, though I don't know how that is possible.
RE: the link you provided. According to the description, it's for a device that already uses a 6992. However, the adapter pins need to be for a 5670 device (i.e. Orchid), and the adapter top accept a 6992.
He asked for 5670 to 6922 which is what I gave him, I didn't see the reverse on their website; that aside here is a link that grannyring posted short while ago under the MHDT Orchid vs Amber 3 Forum for a site that he said his buddy found the adapter at for his Orchid
The Orchid takes 5670 tubes. The adapter needs to convert 5670 pin configuration to 6922 pin configuration. What I am looking for a HIGH QUALITY pin adapter, not just any old adapter, that is, one with quality components and construction. I am aware of the adapters cited. In other words, what I am hoping for is feedback on adapter quality. Perhaps the ones cited fit the bill, I just don't know. In general, there is a lot of junk out there.
“I'm using the 5670/6DJ8 tube socket adapter available on-line. It did not require any circuit modifications...”
This is just a curiosity question. Is the adapter just “adapting” the pin outs or also compensating for the differences between the two tubes’ electrical characteristics? According to the tubes’ data sheets, there are some differences between their characteristics that could theoretically result in different sonics but that could be at the expense of stressing other components in the circuit, or the tube itself. I’ve heard of anecdotal examples where folks have used a “wrong” tube but liked the sonics results better.
Not many sets of Torx go down to the t8 size, most stop at t10. Fortunately I had a more complete engineering set that went to t8. I know you can buy the t8 torx on eBay if you cannot find a set with one in it.
Since I installed a 6922 adapter (from Garage 1217), I tried various flavors of the 6dj8/6922/7308 family. Hence, I'm selling my NOS 396a tubes, including WE JW396a, Tung Sol, GE and the rare 1970 Tesla Military pinched-waist flavors.
I know the 'normal' route is to throw money at a problem or spend more with an upgrade. However I found out many years ago with my Havana dac that after a pretty short break in of 50hrs or so the 6H3P Russian tube has all the clarity, bloom, bass slam, and midrange of any tube I've tried. Very cheap yet sounds like a million bucks....easily beat my Tung-Sol, Ratheon etc. They found a permanent home in both my Havana and my Orchid.
Best thing is, since they are so cheap I don't feel bad leaving them on, even when I am away.
Ok, interesting information. I have tried many different flavors of 5670 tube, some obviosly better than others, however, I will never go back to that tube after adapting the socket to emply the 6922. What a glorious difference that made in every respect compared to the stock tubes.
Best 5670 to 6922 tube adapter is made by Garage 1217 (garage1217.com). Superior to every other adapter that I have seen. However, please note: the pin holes are tight and therefore the tube pins must be straight in order to facilitate placement.