Brainstorming Purifi 1et400a amps

[Bill poster]

Can the op amps be rolled?

 

[Oneminde]

Any OP-Amp can be rolled. If they are hard soldered, just un-solder and put in a socket.

 

[Bill poster]

Any OP-Amp can be rolled. If they are hard soldered, just un-solder and put in a socket.

Thanks, yes wondering if they are hard soldered like the 3e 3255

 

[Oneminde]

Both Purifi and Neurochrome hard solder the OP-Amps... had to check when you asked the question

 

[wealas]

The purifi modules have a hardware and software mode so you can run them without a controller.

 

[Oneminde]

I got a reply from Tom at Neurochrome.

Sent message:

Just a followup on the Purifi adapter board for your universal buffer. We have an ongoing debate on how to make the thing work. From our limited perspective, the amp modules need control which the buffer alone probably(?) don't deliver but is found on the Purif EVAL1 board, so the talk was/is how to "hijack" the EVAL1 board to make things happen. A custom solution would be much better. But since our knowledge is way more limited than yours, I figured I would give you a heads up and perhaps you could find a few minutes and drop a comment or two in the thread.

Answer:

I don’t think the amp modules need control, but in the input boards I’ve designed for OEMs in the past, I’ve always connected the control lines of the amp to those of the SMPS. Might as well take advantage of the shutdown and such for over-temp, etc.

Tom

 

[bassnkeys]

2 Questions

The purifi modules have a hardware and software mode so you can run them without a controller.

Does the module change modes when the bypass is used?
Also, since it seems there is gain obtained from the control board doesn't that make it a type of pre-amp as opposed to buffer?
Thanks,
Dave in MN

 

[JimM]

Arild it appears you have built the Purifi EVAL 1, would you give us your impression of the sound of the amplifier? What speakers are you driving and what preamp or DAC are you using? After all the music is what we looking for. Any information would be appreciated.
Jim

 

[Oneminde]

Arild it appears you have built the Purifi EVAL 1, would you give us your impression of the sound of the amplifier? What speakers are you driving and what preamp or DAC are you using? After all the music is what we looking for. Any information would be appreciated.
Jim

While we wait for a possible reply from Arild, did you check this review ?

Eigentakt demonstrator amplifier

 

[Oneminde]

Regarding Neurochrome universal buffer. Since the internal buffer can be bypassed completely, then all we would need to do is use the N.buffer as the front end and allow the signal to go through it before entering the Purifi EVAL1 board. So, that would mean an adapter board isn't really needed... correct ?

 

[U101222]

I am trying to figure out via the user guide which section is the buffer, so question is if its bypassed by:

And the Neurochrome buffer could use the Salas SSLV1.3 UltraBiB shunt regulator as the PSU

Can it be sourced already built?

 

[U101222]

Any OP-Amp can be rolled. If they are hard soldered, just un-solder and put in a socket.

Well, in this case however it is a discrete opamp, if I am not mistaken. So you would have to replace a bunch of circuitry.

 

[Oneminde]

Salas might have some for you, contact him.

 

[Oneminde]

Well, in this case however it is a discrete opamp, if I am not mistaken. So you would have to replace a bunch of circuitry.

Hard soldered simply mean the pins are soldered to the PCB instead of installed in a socket. So not discrete JFet circuit which is different.

 

[JimM]

Just did thanks.
Jim

 

[JimM]

Arild I guess while telling us about the other items I questioned you about would you also give us some information on some of the following.
1. Did you have any problems ordering and receiving the EVAL 1.
2. Where did you purchase the SMSP 1200 A400.
3. Any problems connecting the P.S. or assembly of your amp.
4. Any suggestions on cases, assembly, or parts to purchase, would be greatly appreciated.
5. A build guide would really help.
Jim

 

[JimM]

I have a Benchmark DAC2 HGC of which I have driven a Benchmark AHB2 set to the 22dbu 9.8 VRMS balanced input setting, from the HGC DAC with 0 db attenuation settings which is 24dBu or approximately 12VRMS with good results. So, I may be able to drive the EVAL 1 set to buffer bypass.
Jim

 

[Oneminde]

Benchmark AHB2

Out of curiosity:

1. AHB2 vs. NCore ?
2. Why Purifi if you have AHB2 ?

 

[U101222]

I am trying to figure out via the user guide which section is the buffer, so question is if its bypassed by:

And the Neurochrome buffer could use the Salas SSLV1.3 UltraBiB shunt regulator as the PSU

There are jumpers to bypass the buffer. Then the input is directly routed to the amp boards.

It seems that the SALAS is only "proven" to work attached to the secondaries of a transformer, not sure after a SMPS. I would like to use only SMPSs to keep size and weight low. So a little SMPS followed by a DC-DC converter, such as a dual TRACO with +-15V should work, and then a little CLC filter to kill the HF noise and smooth the residual ripple (which is at around 100mV). I would probably not do more mostly because I would not feel that comfy putting, say, another regulator with the little tantalum and 2 resistors to further clean everything.


Roberto

 

[U101222]

Regarding Neurochrome universal buffer. Since the internal buffer can be bypassed completely, then all we would need to do is use the N.buffer as the front end and allow the signal to go through it before entering the Purifi EVAL1 board. So, that would mean an adapter board isn't really needed... correct ?

Correct. The EVAL1 board would be the adapter board, in a sense