Just built a Hagerman Cornet 2 phono pre

[45144]

This sounds great and I only have 2 hours on it.

An externally hosted image should be here but it was not working when we last tested it.

Here is a photobucket link:

Cornet 2 Photos by cytovette | Photobucket

 

[acceler8]

Very nice! I like the wooden sides! I've used mine an awful lot. http://www.diyaudio.com/forums/analogue-source/190055-cornet2-tube-phono-preamp-completed.html

 

[vinylkid58]

That's a nice looking build.

jeff

 

[andyr]

I'm just finishing off a Cornet 2 build and would appreciate some advice re. transformer primray connections.

Can either of you confirm that, for the specified Hammond T370BX transformer, for 240v (according to the table on the "Constructor: Powersupply" diagram):
* Blue is connected to one of the pair of tags on the PCB marked 'L'.
* the other 'L' tag has no connection.
* White is connected to one of the pair of tags on the PCB marked 'N'.
* the other 'N' tag has no connection.
* Brown & Black should be connected to the tags marked 'S'.
* the tags marked 'O' are not connected to anything - these are for 'parking' the 4 remaining wires (the striped wires, for 240v), which are marked as 'NC' in the 240v column in the table.


Thanks and regards,

Andy

 

[45144]

I'm just finishing off a Cornet 2 build and would appreciate some advice re. transformer primray connections.

Can either of you confirm that, for the specified Hammond T370BX transformer, for 240v (according to the table on the "Constructor: Powersupply" diagram):
* Blue is connected to one of the pair of tags on the PCB marked 'L'.
* the other 'L' tag has no connection.
* White is connected to one of the pair of tags on the PCB marked 'N'.
* the other 'N' tag has no connection.
* Brown & Black should be connected to the tags marked 'S'.
* the tags marked 'O' are not connected to anything - these are for 'parking' the 4 remaining wires (the striped wires, for 240v), which are marked as 'NC' in the 240v column in the table.


Thanks and regards,

Andy

Jim Hagerman has a forum here with real experts:

Hagerman Technology

I would post my questions there.

I can tell you that the tranny wiring directions were spot on for me (USA 120v)

 

[andyr]

Jim Hagerman has a forum here with real experts:

Hagerman Technology

I would post my questions there.

I can tell you that the tranny wiring directions were spot on for me (USA 120v)

I guess what I'm asking is ... where Jim says "NC" in his table of different mains voltages on the "Constructor: Powersupply" diagram - does this mean "connect to the 'O' tags on the PCB"?


Thanks,

Andy

 

[picowallspeaker]

usually NC is Not Connected

 

[amandarae]

I guess what I'm asking is ... where Jim says "NC" in his table of different mains voltages on the "Constructor: Powersupply" diagram - does this mean "connect to the 'O' tags on the PCB"?


Thanks,

Andy

Yes.

An externally hosted image should be here but it was not working when we last tested it.

 

[andyr]

Yes.

An externally hosted image should be here but it was not working when we last tested it.

Thanks, Abe. I thought that was the case but I wanted to make sure before switching it on! After all, 240v AC is a serious voltage - unlike your wimpy 110v!!

IMO, he should've used 'O' in his instructions - instead of 'NC' (since they are connected!).


Regards,

Andy

 

[andyr]

Just something you may wish to try, gentlemen ...

I haven't listened to it yet but I did connect up the mains and switch it on - without letting the magic smoke out!

When I connect up a mains trannie, I always make sure the primary is oriented the right way round*. Jim's instructions (at least, for a 240v mains supply) to connect the 'Blu' wire to the Active tag on the PCB and the 'Wht' wire to the Neutral tag ... do not, in fact, deliver the 'correct way' - you need to reverse these.

* Google the BoundforSound article (repeated on other websites) about correct mains orientation of transformers - AIUI, it comes about as a result of parasitic capacitance of the transformer's primary (whatever the hell that is! . Using Jim's orientation, I measured around AC 140v between mains earth and the chassis; reversed, the DVM read <2v. (NB: I am assuming all 370BX trannies are manufactured identically - which I suggest is a reasonable assumption. )

The BoundforSound article - and BTW, Clark Johnsen (the guru of absolute polarity) - claim that the lower voltage reading between the chassis and mains earth delivers the better sound.

NB: the mains cord needs to have a 'cheater plug' on its end, so the IEC earth tag on the component - and the chassis - is 'floating'. You get the 'mains earth' reference by sticking one of the DVM's probes into the earth hole in a wall socket.


Regards,

Andy

 

[mucool]

Finished my Cornet2



Did the woodworking inhouse. Wanted a better look than the hammond/lansing cases. Used copper sheet for mounting the PCB. No hum/buzz. Sounds great.
Have a low end Audio Technica turntable, so the difference was very apparent straight away. Bass improved. Need more burning in and listening time to enjoy this.
This was my second audio diy project (first was a millet headphone amplifier).
The circuit board for Cornet was amazingly easy. Thanks everyone for inspiring me to build one.