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disarmamant
19-09-2019, 11:51
Just finished this pre-amp. Hypnotize DC B1 Jfet buffer with a MM phono stage using the Elliot Sound Products PCB and Burr Brown OPA2134 jfet audio opamps.

Individual transformers for phono stage and buffer.
Shunt regulated dual power supply for the phono stage.
50K stepped attenuator.
Elma source selector switch.
Adjustable brightness power indicator led.
Aluminium case, 3mm thick top and bottom panels.

https://dl.dropbox.com/s/qn83fpxolqbtzdp/front%20whole.jpg?dl=0
https://dl.dropbox.com/s/2evnfx0ytf573dk/Hypnotize%20board.jpg?dl=0
https://dl.dropbox.com/s/dca2ebia1eynigi/inside%20whole.jpg?dl=0
https://dl.dropbox.com/s/eztcha1cio1f0am/controls.jpg?dl=0
https://dl.dropbox.com/s/gmbbk0u601haer4/Back%20connections.jpg?dl=0
https://dl.dropbox.com/s/wd7g6z0e2en197a/ESP%20board.jpg?dl=0
Bigman80
19-09-2019, 12:16
Just finished this pre-amp. Hypnotize DC B1 Jfet buffer with a MM phono stage using the Elliot Sound Products PCB and Burr Brown OPA2134 jfet audio opamps.

Individual transformers for phono stage and buffer.
Shunt regulated dual power supply for the phono stage.
50K stepped attenuator.
Elma source selector switch.
Adjustable brightness power indicator led.
Aluminium case, 3mm thick top and bottom panels.

https://dl.dropbox.com/s/qn83fpxolqbtzdp/front%20whole.jpg?dl=0
https://dl.dropbox.com/s/2evnfx0ytf573dk/Hypnotize%20board.jpg?dl=0
https://dl.dropbox.com/s/dca2ebia1eynigi/inside%20whole.jpg?dl=0
https://dl.dropbox.com/s/eztcha1cio1f0am/controls.jpg?dl=0
https://dl.dropbox.com/s/gmbbk0u601haer4/Back%20connections.jpg?dl=0
https://dl.dropbox.com/s/wd7g6z0e2en197a/ESP%20board.jpg?dl=0Doesn't that look tidy!!

Lovely work.
Pepperamip
19-09-2019, 13:29
Top class build there. Is that one of them valab stepped attenuators?

Sent from my CLT-L09 using Tapatalk
disarmamant
19-09-2019, 14:30
Top class build there. Is that one of them valab stepped attenuators?

Thanks. Yes it's one of the Valab jobbies.
smangus
19-09-2019, 15:44
Very nice build :), how's it sound?
disarmamant
19-09-2019, 18:22
Very nice build :), how's it sound?

Thank you. It sounds really good.

The phono stage is particularly good, very low noise. I have used Rod Elliot’s phono design before and it deserves the positive reports it gets.


Sent from my iPad using Tapatalk
Rosewind
19-09-2019, 19:44
Great-looking unit! I have one of your earlier builds of the B1 - I believe with the same phono board. Too bad that I haven't been able to make my Benz Micro Gullwing SLR sing with my Partridge 977 SUT - also one of yours, by the way. All the mm-stages that I have used with that combo has sounded off and strangely bland (EAR 802/Croft Riia R/Pass B1). Did you ever build a Pass B4 buffer, by the way?
Bigman80
19-09-2019, 19:49
Great-looking unit! I have one of your earlier builds of the B1 - I believe with the same phono board. Too bad that I haven't been able to make my Benz Micro Gullwing SLR sing with my Partridge 977 SUT - also one of yours, by the way. All the mm-stages that I have used with that combo has sounded off and strangely bland (EAR 802/Croft Riia R/Pass B1). Did you ever build a Pass B4 buffer, by the way?You need a good Valve phonostage.
Rosewind
19-09-2019, 20:05
Ha! Been there, done that. Not with the EAR 516 and Quad ESL 57s, though.
EDIT: I wouldn't mind a listen to a line stage version of the Pass B1 "hypnotize", or a Pass B4 buffer, which should be excellent.
Bigman80
19-09-2019, 20:15
Ha! Been there, done that. Not with the EAR 516 and Quad ESL 57s, though.
EDIT: I wouldn't mind a listen to a line stage version of the Pass B1 "hypnotize", or a Pass B4 buffer, which should be excellent.Can't beat a well built DCB1 IMO.
disarmamant
20-09-2019, 18:56
Too bad that I haven't been able to make my Benz Micro Gullwing SLR sing with my Partridge 977 SUT - also one of yours, by the way. All the mm-stages that I have used with that combo has sounded off and strangely bland (EAR 802/Croft Riia R/Pass B1). Did you ever build a Pass B4 buffer, by the way?

I have not built the B4 buffer, is that a Nelson Pass design? The Pass Labs B4 is an active cross over isn’t it?

Sorry to hear that your Benz does not sound right through the Partridge 977’s. How are you using the transformers? Are you trying to load the primary or secondary windings to match the cartridge?


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Rosewind
20-09-2019, 19:08
Martin. Let me PM you about the Partridge.
You build some stunning kit! I only wish I had a DIY skill set.
Rosewind
22-09-2019, 17:44
Edited

Re: B4 pre.

I stumbled over a post on PFM comparing a B4 build with the Pass B1 pre. Assumed that it also was a Pass build but I think I must have been wrong. The B4 pre in question is indeed Piglet's Dad's build on PFM. Just found the relevant threads.

Just answered your PM by the way.