[cyto]

Hi All   

My first post here, for my birthday this summer my wife is getting me a new phono preamp and I prefer to build one. Although I work in the medical field I was a licensed TV repairman in the 70s (tube days) and still tinker a lot, so doing the build won't be much of a problem. After looking at just about everything available I have decided on the Cornet2.

I am currently using a Musical Fidelity V-LPS that I upgraded the caps and op amps(opa627) on and using a Pyramid power supply. I was wonder what I can expect soundwise from the Cornet2, comparatively speaking?

Also, what brand of tubes tend to work best with this design?

What do the dimensions of the box end up being?

The rest of my system:
Yaqin MS-20L integrated tube amp
Technics SL1200-M3D turntable with Cardas tonearm wire and RCA jacks
Audio Technica AT120E cart
Emotiva ERC-1 Cd player
1987 Klipsch Heresy II signature edition speakers with H3 woofers and external crossovers
two Martin Logan Dynamo 300 subs

Thanks 

David

[Phil_S]

Can't help with the Coronet question however I strongly recomend you upgrade the 120e to at least the 125LC.  We have the same table and modifications.  The difference was like night & day for less than $100. 

[cyto]

Phil,
I have never heard the 125LC, I had an AT440MLa and didn't like it so I sold it.

Does the 125LC sound similar to the 440MLa?

[galyons]

The circle is fully stocked with a multitude of posts about building, tube choices and customization.  Just search for Cornet2 and read away!

Cheers,
Geary

[Phil_S]

That's a tough answer for me as 1) I've never heard the 440MLa and 2) my system appears to be a bit on the dark side.  My amp is an HK Citation 12 unmodified that I've been running for 40 years.  Speakers are OHM Walsh 100's M3 in M2 cabinets.  They get down to 30Hz in room.  If your issue w/the 440 was that it was a bit bright then I'd shy away from the 125LC.

Happy Hunting! 

[Tone Deaf]

You won't regret choosing the cornet.  It just sounds right.   Jump in dude.

[poty]

I am currently using a Musical Fidelity V-LPS that I upgraded the caps and op amps(opa627) on and using a Pyramid power supply. I was wonder what I can expect soundwise from the Cornet2, comparatively speaking?

The design is a mix of traditional simplicity and several novels, so you should definitely try.

Also, what brand of tubes tend to work best with this design?

IMHO, the tube set is a matter of personal taste. Here in the forum there are a lot of opinions about that.

What do the dimensions of the box end up being?

Chassis is 8"x12"x3" + on top of the chassis there is the transformer 3" high + some feet... Personally me is not a proponent of such (case) design, but sometimes it worth to try sound even if the appearance is not so bright.

[cyto]

Thanks for all the replies 

Phil that is exactly why I sold the 440, with the horn loaded Klipsch speakers my system runs on the bright side anyway.

poty I agree on the appearance, it looks fine but I would prefer something I can slide in a rack, not a deal breaker though.

It looks like Cornet2 vs Groovewatt vs Jolida JD9, each has it's + and -.

I REALLY like have a pc board for the Cornet2, the only downside is that it won't slide in a rack.

Doing p2p wiring on the Groovewatt scares me because I may be building a "hum generator"

The JD9 will need upgrades so I would have to get a used one at a good price for that to make sense.

Thanks again for the help, the ball is in my court now   

[poty]

poty I agree on the appearance, it looks fine but I would prefer something I can slide in a rack, not a deal breaker though.
...
I REALLY like have a pc board for the Cornet2, the only downside is that it won't slide in a rack.

You have all the information in the manual for the kit to assemble it in any box you like. Your box can be even quieter, because you can make longer distance to the transformer and wire the RCAs directly to corresponding parts on the board.

[cyto]

You have all the information in the manual for the kit to assemble it in any box you like. Your box can be even quieter, because you can make longer distance to the transformer and wire the RCAs directly to corresponding parts on the board.

So the tubes and transformer could all be inside of the box? I wonder if anyone has built one like that?

[WGH]

You can use a lower profile box but need to drill larger holes for the tube sockets.



The Cornet2 circuit board is mounted upside down so there is a limit how short the box can be, it depends on how much stuff you pack into it. The Mundorf caps need 1-1/2". If you include the FT-3 bypass caps like I did (highly recommended) then you need the standard size box (or a wider, longer one). Although it is hard to tell from the photos, the rectifier tube is only 1/4" shorter than the transformer so you wouldn't gain much by relocating it.



Wayne

[galyons]

So the tubes and transformer could all be inside of the box? I wonder if anyone has built one like that?

http://www.audiocircle.com/index.php?action=gallery;album=1848

I really didn't care about whether it would "slide in a rack" or not.  I wanted a very solid, enclosed, quiet build. The phono pre is dealing with minute signals.   I  also wanted ample room to modify.   The extra real estate has allowed me to replace some of the PS electrolytic caps with PIO's.  IMO, mechanical integrity, isolation and damping are as important as the components to build up the board.

You are missing a tremendous amount of knowledge and experience n this circle if you don't search.

Cheers,
Geary

[poty]

Although it is hard to tell from the photos, the rectifier tube is only 1/4" shorter than the transformer so you wouldn't gain much by relocating it.

It depends on how far you are going to go in modifying the layout of the power supply part. Lets just imagine what we can do:
1. Divide the box into two compartments: signal and power supply.
2. Move ALL power supply circuits (except LED driver circuit R104-R108, Q100-Q101, D100) from the PCB to the power supply compartment. It allows us to save the height relocating the rectifier tube also (and you have the option to mount it horizontally). In doing so we also move all power AC to the isolated compartment. All transformer wires should go directly to corresponding circuits (input IEC socket, rectifier tube, bridge...) not PCB.
3. The high voltage part (R100-102, C101, C103, V100) is very simple and can be easily made point-to-point with only moderate precautions like make ground wires short and star-connected. Of course you can also save the C103 on the PCB.
4. The heating voltage part is simple too, but I'd replace it with regulated one. There are a lot of PCB-based and point-to-point layouts. The only problem - 6.3V AC is not enough for common regulated PS, so you have 2 options: either use LDO regulators or add small-power 9V transformer and common regulators. The regulated power supply gives us more flexibility and stability and eliminates the need for selection the right value for the power resistor (R223).

[cyto]

I ordered the Cornet2 half kit today. I am going to stick with the original design and layout (except for signal caps), when something is well designed changing things rarely make an improvement, usually the opposite.

Thanks everyone