Well, it was just a question of time to make an update to the VT-25 DHT preamp. I wanted to try the BSH111BK as lower FET as shown below:
The result is visible on the frequency response. It does have an improved FR and the bandwidth gets up to 800kHz on same testing conditions. If you increase the HT to 280-300V you can increase the anode current to 30mA which should be good as well.
I love the sound of this stage driving the 4P1L PSE output stage. It has a deep bass as well as clear treble. Dynamics on the system are fantastic. 
The bass on my system is fantastic now. Stronger than with previous setup. That is what you get when you marry low ra (4P1L pair) with a high-quality OPT.
I have a pair of pre-soldered BSH111BK boards (which are painful to solder) so I will give them away on a first come first serve basis
Weather is really nice today in London, so I’m going out right now…
Such great work Ale. I would love that pair of boards. Happy to pay for them as well.
Dear Ale,
Iam inetrested in the pair of pre-soldered boards. pls send me your offer.
Enjoy sunny London with your family . We have a blue sky in Gdansk as well.
Happy to see you’re still working on that preamp. That BSH111BK seems the way to go for higher currents than BF862. I started to check what are the “realistic” operating points using filament bias (meaning reliable set up) in that case.
Another nice article! Great work. Thank you.As driver, you prefer the VT-25 to the 4P1L?
Ale – great update. I always enjoy reading about your adventures. I wanted to ask whether or not the BSH111BK needs the protect zeners that you show in the schematic. According to the BSH111BK datasheet, it already has ESD protect diodes built in. So are you being extra careful or are the diodes just a holdover from previous builds using devices like the BF862 which don’t have internal protection diodes?
Thanks,
—Gary
Thank you for your feedback! The diodes in the schematic which aren’t numbered are built-in on the FET, with exception of the VDS zener of course
Now this sounds nice Ale.
Am I too late to get boards ? Lol
Heard 10Y amplifier on my Phillips 12 inch full range 97db sensitivity speakers
made by TATIC audio, they bew away 300B and 2A3 ampifier easily. 10Y is not a nie sounding tube, it is a right sounding, no colour, no lies.
That is when I fell in love with it.
If you have any boards to sell, I would be willing to buy them.
Also, I have a spare pare of those ticonal Phillips drivers12inch, would exchange them for a amp or preamp
Hi Vladimir, good to hear you like the 10Y, fully agree.
You can order PCBs in the “For Sale” section of the blog. Thanks
Hi bARTOLA/aLE, so sorry to bother you but I really need your help.Im not an EE but Im willing to learn and all this is so much fun but I,ike now,sometimes feel helpless. I’ve spent heaps on a 10Y Ultrapath preamp with Tango NP-126 OT.
It played nicely,like..very nice and then by accident I introduced Slagle AVC instead of Alps res. pot and I literallyhad to call the ambulance to saw my jaw up. Holy Jesus…this is what I was looking for and this is efortless.. Now I got a BIIIG PROBLEM…wanting to upgrade few things I was reading a lot and using AI and read this: “Upgrade 1…to remove cathode bypass capacitor///that one and 3 resistors are connected to “central tap” and then to ground bus wire…if doing so I had to up the value of Ultrapath cap which was 10uF and without bypass.cap now has to be 47-100uF. I had only 22uF film cap and didnt remove bypass cap .The sound Im not too thrilled about and Im hearing cracks n pops..THEN AFTER READING SOME MORE I READ THAT TANGO NP-126 IS NOT A GOOD OT FOR 10Y TUBE !!! MY BAD LUCK So close but so far. It’s undersized, max DC current is 20mV which is middle operating point of 10Y tube so no headroom. I attached link to a local BlogSite, post 8 is the schematic of preamp as is now and post 15 is the collection of explanations why all this is not good and some solutions, main one being to switch to Parafeed design.
Thomas, Im kindly askig you to take a look or give advice or both on how to reconfigure existing preamp best possible way.
I didnt have space for Coleman regulators. HV is Kubota board with GZ34 tube. Fillament supply is a version of Neurochrome design.System is Wiim Ultra streamer into Slagle AVC into 10Y preamp into MarkLevinson 27.5 pwr amp( input imp. is 50k ohms shunted by 1.5nF) into KEF 107(with Raal 70-10D ribons)…so preamp needs to have low impedance to match ML amp and it needs to keep the DHT character. What would you do? My situation is…Id like to use components already installed and to configure it in a best possible way with a moderate budget.
Which is your best sounding 10Y preamp topology/configuration? Same question for 10Y WOT as Id like to keep the Tango if possible if that is a good move…how to proceed, what to add and what to scrap in which configuration.
I got only 1 box. Everyone PLEASE ADVISE based on your experience. This is the link with schematic as is now (post 8) and my Internet research which led me to these conclusions (post 15):
https://www.diyaudio.rs/topic/1139-teflon-zica-awg-22-za-ozicenja-pojacala/page/6/