DigiPete

JP, I've got the Choir SUT H-7 and its fabulous. Using it with my Airy 3x, on the lower gain setting and it works just fine. Playing it through my Conrad Johnson Premier15 MkII phono with teflon caps upgrade. I had the standard bobs cinemag before that, this SUT clearly outclasses it, and the rig sounds much better (dynamic , resolving, 3d) and quieter than when I was using the CJ phono stage alone. A chap in England (Martin Taylor, whose review of this unit is linked to from the Choir website) bought the Choir Audio H-7 based on my review over at Art of Sound forum, and he is very happy with it too. http://www.adventuresinhifiaudio.com/01/07/2011/the-choir-audiohashimoto-sut-h7-moving-coil-step-up-transformer/

I use the Herbie's Supersonic Record Stabilizer to good effect A molded and hand-machined non-magnetic composite of fluorocarbons and metallic particles formulated for use with Herbie's turntable mats to enhance overall turntable performance. Stabilizer is not a clamp or conventional record weight it's designed to add a moderate amount of virtual mass to the record without clamping. 163.5 grams (5.8 oz.)

Choir Audio has some killer Hashimoto transformer boxes, the perfect way to run a low output MC....

Guns N' Roses -- Appetite for Destruction 180gm Vinyl

Cool!

Beautiful table. The SME V is a great arm, but it is held back the the tonearm cable SME supplies with it. I built a nice cable from OHNO cryoed silver and it made a noticeable difference for the good. Cheers Pete

I am waiting to see if anyone can get the original DynaFet group buy boards working, not going to invest in another DynaFet board at least until it becomes apparent all attempts to get a reliably stable group buy board have been abandoned. That said, I would rethink a new DynaFet group buy board, as the a second group buy board may run into the same stability issues as the first attempt. I would like to see several successful builds of a prototype DynaFet before I would consider investing

vinyl is tweaky by nature!

the vinyl infection is spreading

Some brief impressions of the Choir Audio Hashimoto HM-7 based SUT. Lifted this pic off their website, and it is actually of my unit. The fit and finish is top notch. I opted for the Cardas Silver outputs, since John at Choir Audio mentioned that he prefers them, and that the WBT connectors have been having quality problems. I burned the SUT in for 100 hours using the Granite Audio MC burn-in CD track. Disconnected the CD player, reconnected the phono cable, and voila, time to listen. My previous SUT was the Bobs Devices Cinemag, a well respected and reviewed unit, and rightly so. I noticed right off, a more refined sound with more resolution/transparency and detail in the treble and mids, especially low level details. A bit wider and deeper soundstage. Plenty of deep bass and dynamics, but no bloat, and no bass roll off that I can detect, or treble roll off for that matter. Plenty of color and musicality and super quiet. A nice step up from the Cinemag. Truly an audio bargain at $1500. Not sure what I could get that would better it by any margin for any price. My search for phono stage components is over. I built myself a phono cable to go from the SUT to my phono stage. At first I tried some normal RCA ICs I had, and they killed the sound, lost frequency extension and dynamics and transparency. So I got some OHNO UPOCC Silver 28g teflon cryoed wire from Take Five Audio, along with some silver braid shield and Eichmann bullets. Turned out very nice sounding, comparable sounding to my Grover phono cable I am using from the SME V tonearm to the SUT. I burned the cable in along with the SUT and CJ phono stage for the 100 hours. The CJ got a teflon cap upgrade and only had about 200 hours on it, and I hear that those caps need about 400 hours break in, so I figured an extra hundred hours of wear on the tubes was worth it. Anyway really enjoying my system now. I would heartily recommend the Hashimoto HM-7 SUT in conjunction with the MM inputs to your favorite phono stage for a fantastic sonic experience. Cheers Pete

Just pulled the trigger on this: Choir Audio SUT using the Hashimoto HM-7 After using a Bob's Devices Cinemag step up transformer unit for a few weeks, I am convinced I like SUTs in my setup. So I did some reading and have concluded I can get close to top end SUT performance with this unit, for a reasonable price. I should get delivery in 2-3 weeks. I'll report back what I hear. Nice thing is they offer a 30 day in home try out period. Some details from the website. Frequency Range: 10- 80K Hz Insertion Loss: < 1.5db Loading/Gain: 2-7 ohms + 29dB / 7-40 ohms + 23dB RCA: Cardas Pure Silver Contacts (the wbts are no longer offered due to quality issues, this also dropped the price of the unit to $1499 ) Internal Wiring: 99.999% Oxygen Free Silver plated Copper with Teflon jacket / WBT Silver solder Selector Switches: All contacts are constructed from Silver with Gold plating Recommended Preamplifier Load Impedance: 47K Ohms Enclosure Formed Mumetal shielding Internal Enclosure dampening Dimensions: 6.00" W X 8.5" L X 5.00" T Weight 4lbs The SUT-H7 uses the ultimate Hashimoto HM-7 transformers, allowing the highest level of details and nuances to be extracted from a cartridge's performance. Please make sure that your source is up to the task as the HM-7 is very revealing and will uncover any weak links in your source components. But, if your system is up to the task, then you are in for an unbelievable level of performance and presentation with the H7. A pic of the lower level model

maybe try him on Head-Fi or HeadWize?

Anybody contact J4CBO, surely he has the eagle files since he designed the boards are these it?:

The Clash - Combat Rock Vinyl

Steve Miller Band - Fly Like an Eagle Vinyl

ouch! Keep forging on! Let me know if I can help. Does Kevin have any advice? Pete

I see oscillation in your input waveform in the second picture. Your signal generator may be injecting the noisey waveform, which is amplified and output. maybe I am not interpreting the image correctly?

It would be good if you have all 4 output devices on that board going for your RMAA test If you could check the final configuration for both 150ma and 75ma bias at low gain approx 5-6, that would be great

great stuff. I'm just a board stuffer, so I'll let you guys do the heavy lifting to figure this stuff out.

Yes I have two Dynahi PSUs which are powering my Dynamite. I plan to swap out the Dynahi boards with DynaFet boards I have a spare dynahi psu board if you need one, I think. OF course its hard to find the regulators on that board now a days

Great work Chris! Glad you are figuring this stuff out. So the board with 4 output devices draws 375ma at 150ma bias; so that should be x2 for stereo, and x4 for balanced, correct? Should be no problem for my dual Dynahi PSUs. A gain of 5 or 6 would be good to try out, as that is what I plan to run. Look forward to your final parts recommendations. PS I have output devices matched by Marc, since I will only use half the devices for my 4 ch amp, I can spare them if you need. Cheers, Pete

Kirkland Hefeweizen

Pars, I was going to use half the output devices as well, according to Kevin's original schematic. Not driving K-1000s so that should be fine. Pete

Java Delight House Blend

Steely Dan - everything must go 96/24 DVD-A