Hello everyone,
I,m going to build a class D amplifier with Purifi's 1ET-400A modules operating in HW mode. I will use a linear PSU and a tube based input buffer. I have a question regarding the description of pin 32 on J3 connector. In the user's guide, TABLE 7, it states the following: "PSU off control signal (SW Mode), or Amplifier Disable (HW Mode) – pull low to enable Amp". Can anyone please explain me what shall I do with this pin? How shall I connect it?
Thanks in advance
vassilis
I,m going to build a class D amplifier with Purifi's 1ET-400A modules operating in HW mode. I will use a linear PSU and a tube based input buffer. I have a question regarding the description of pin 32 on J3 connector. In the user's guide, TABLE 7, it states the following: "PSU off control signal (SW Mode), or Amplifier Disable (HW Mode) – pull low to enable Amp". Can anyone please explain me what shall I do with this pin? How shall I connect it?
Thanks in advance
vassilis
When connect to gnd the amp is on, when open the amp is off. I use relaycontact of 20sec startup delay for tubepreamp to turn amp on.
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-3#post-7046086
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-3#post-7046086
Almost what I want to do. It looks amazing!
Actually, I build a "long tail pair" as input buffer and phase splitter. Two 6H6 (one "bottle") per channel, loaded with resistors and a 10M45 depletion FET as a CCS at the tail. Input shall be single ended.
Thank you very much for your assistance.
Is there any specific reason that you have chosen the μ-follower instead of simply loading the tubes with resistors?
Vassilis
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The mu-follower has low impedance you need for driving the.2k input impedance of the 1et400a. It has great PSRR and very low distorsion and because of the higher gain I could use some feedback to lower impedance further and lower distorsion.
The PCB I made you can also use for srpp stage and much more other tubes.
https://www.diyaudio.com/community/...c85-6922-6dj8-etc-mu-follower-or-srpp.388295/
The PCB I made you can also use for srpp stage and much more other tubes.
https://www.diyaudio.com/community/...c85-6922-6dj8-etc-mu-follower-or-srpp.388295/
Finally,I decided not to use any active input buffer. I will use an input transformer 1: 1+1 and I my preamplifier is powerful enough and with sufficient low output impedance as to drive the "Purifi" adequately. The preamplifier is an Aikido with 6922 input tube two 10M45 depletion mode MosFets in the place of current sourced output cathode follower tube, at 25 mA.
In case you do not have read my other thread about (un)buffered 1et400a, look here for unbuffered connection board.
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-8#post-7254111
Ronny
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-8#post-7254111
Ronny
