[ronpod]

My spouse gave me the Hagerman half-kit Clarinet including the Lansing chassis a little in advance of Christmas so I could build and burn-in just in time for Christmas cheer.






This was a particularly good time because several of the parts vendors were having reduced pricing on some of the more expensive options. Parts Connexion offered 20% off the Mundorf SIO caps which I followed tubesforever's suggestion and placed a pair on the output and a pair on B+ which took up some real estate.

Also, I still had the Russian FT-3 caps from the group buy still in wooden shipping rails just awaiting a project such as this:

so I strapped them in what extra space I could find. The FT-3s are in parallel to the Mundorfs.

I decided to order the TX2575 resistors for all "signal path" locations to match my Cornet2 build.

But this time I used PRP resistors where I had used KIMAMEs in the Cornet.

I ordered the 4A 600V Fairchild "Stealth" soft recovery diodes (HexFreds) from Michael Percy Audio.

My experience with these diodes is similar to that of tubes in that I placed a shunt shorting jumper across R313 to get a stabilized tube heater potential of 6.01V.

I previously has a rag tag bunch of interconnects so I ordered parts from Percy Audio to DIY some ICs. A representative pair are seen in the above photos. The ICs started as 28ga. solid silver wire in cotton sleeve that were gently twisted around a cotton rope and wrapped with Teflon plumbers tape. Eichmann Bullets were used for RCAs. In the unshielded version, I could assess the emissions emanating from the stereo components. The Hammond transformer on the Cornet2 was a major noise creator. I disassembled the Hammond TX and fished out the "grey" wire that was not really contacting the TX case. So I star grounded to the Cornet2 chassis ground lug. That reduced the radiated noise in the immediate environment dramatically. I did the same to the Hammond transformer on the Clarinet.
I also decided to wrap the interconnect cable with shielding braid with a single ended grounding wire. These modifications quieted the system to an amazing low noise floor.

The system is burning in. I had previously noticed that the left channel from the Cornet2 was slightly "muted" and cable swapping indicated that it was the Cornet. I found the problem. When I had soldered in the Russian FT-3s across the Mundorf SIOs, a single strand of wire made contact with the surrounding ground trace on the PCB. I somehow missed this in my initial installation.  So now the system is sounding very nice but it needs some time before the real joy emerges. I will keep you posted.

Merry Christmas the everyone! Enjoy your holidays.

Ron.

[Bill Epstein]

Merry Christmas to you and all.

Glad to know you're enjoying your Clarinet. How about sharing some details on that grey wire fishing? Opening the Hammond scares me a bit.

[ronpod]

Bill,

Only the case on the primary side needs to be lifted. The grey wire is very accessible once the primary side cover is uncovered. It's quite easy.

Ron.

[Bill Epstein]

Another question. I've been planning to shield the input and output wires that travel across the Aikido circuit boards. Would you suggest using the shield as ground, or just connecting it to ground at the output eyelet along with the ground wire and leaving it open at the RCA?

[alpa6]

Very nice!

[ronpod]

Hi Bill,
I subsribe to the school of tackling problems in small steps. If you are hearing noise or spurious signal induced through your input/output wires, you can use this as an experiment to understand what components are the root cause. The reason I do this is that air is a wonderful dielectric that imparts so little modification to the sound. If the problem component can be corrected, that fix may be perferable. I would sheild the wires in steps. First use a "floating" sheild and listen if that solves most the problem. If not, then star ground to the source. I try to avoid grounding at both ends the avoid ground loops. Jim Hagerman's circuit boards uses this strategy extensively. YMMV


alpa6 - Thanks for the compliment.



Merry Christmas to you and your family,
Ron

[ronpod]

I modified the hole punch for the rectifier tube from 1.375 in DIA to 1.50 in DIA to accommodate a NOS Mullard GZ34. I also punched out the Cornet2 to accommodate another one. The GZ34 is a very slow start tube and has a metal base that requires the slightly larger hole for clearance. This tube adds very good bass response.

I also decided to purchase Telefunken 12AX7s and 12AU7s to roll and compare the the Mullards and Amperex Bugle Boys. My tube source told me to buy now because another substantial price increase is coming. I immediately noticed that NOS tubes were much less noisy than the used tubes I was using (trying to economize). Now I realize that the tubes are the first place that upgrading seems to matter. The rest of the circuit modifications are much less effective then the tubes. But the combination of good tubes and circuit components is very satisfying.

Happy Hollidays,
Ron.

[tubesforever]

Outstanding work on your Clarinet.  Give this baby about 100 hours to cook those Mundorf SIO caps.  They are outstanding caps in my system.

BTW, I hope everyone listens to your suggestion of grabbing the grounding wire on the Hammond transformer.  When you do that, it is easy to reverse the bolts so the nice end is facing you instead of the bolt end.  Or you could use cap nuts on the ends to make for a nice finished look. 

Bringing the gray wire down is important as I will mention below.  However on my Hammonds the wire is black and you can find it easily because it has a eyelet end for easy grounding.  I cut this wire, splice it to a longer wire and take that to the star location of the Clarinet or C2 earth ground.

This is more important than some might think.  Over time if that tranny shorts, the shortest path to ground will be the earth ground and not your body touching the case. 

Safety first everyone!

Second, you can shield internal wires but I have not found this to be helpful for emi noise.  It will reduce rf is you are in a high rf environment.  I like to twist all the wires and shield them if they are longer than a couple inches in length.   

I am running a .82uf SIO and a .22uf teflon on the final output of the Clarinet.  It worked so nicely that I could remove the 0.10uf teflons on the Clarinet B+. 

If you are running all 0.10uf teflons, then I would probably recommend using a pair at the B+ as Ronpod has done.  They are easy to pull out if you find them distasteful. 

Happy Holidays Ronpod.  Your wife is a definite keeper....does she have a single sister????  Just wondering....

[Bill Epstein]

I'll be looking for that wire on my Cornet, thanks to Ron. I wish I could do that on the Aikido but I spent almost an entire day getting the tranny bolted to the side of the case and it ain't ever coming out! I wonder why it comes hidden in the case? Not knowig about it, I always ground one of the mounting bolts.



BTW, have you noticed the newest 370s have a toothed locking cap nut on one bolt end?

Still have to buy a transformer and case for the Clarinet; that will have to wait for my tax refund. Should be interesting to compare the two pre-amps.

Merry Christmas or Happy Chanukah, everybody.

[ronpod]

Merry Christmas everyone!

Bill - The screw with the toothed locking nut on the 370 transformer is the screw that the grey wire eyelet is internally attached to. I was not convinced that the eyelet was making good contact through the paint of the tranny chassis when I opened each of the trannys in the Cornet2 and Clarinet. That might be why there was a dramatic noise reduction when I soldered a wire extension that was subsequently attached to the grounding lug by the input RCA connectors.

Tubes - Thanks for your numerous earlier posts that provided most of the information and building tips that allow a wonderful experience in DIY modding.

Jim - This is the second component kit of yours that I have built and both of them powered up and worked immediately! The circuit design and instructions are well conceived making the build straight forward. These components are an excellent addition to my system!

The music is an intergal part of my family's Christmas experience.
Wishing you all the best of the season!
Ron.

[ronpod]

Here are some larger, fuzzier pictures:

[tubesforever]

Bill, as long as you are taking the bolt with the star washer and taking this to your earth ground then you are properly protecting yourself.  That should make for a quieter and happier transformer.

RonPod.  You need to fill us in on what you've listened to? 

I want to know how it sounds in comparison to your other preamp / linestages you have used over the years.

For me, everything sounds better through the Clarinet.  The single ended triode operating in a series resistor push pull configuration is absolute ear candy in my system. 

I have never been happier!

Happy New Year everyone!

[analog97]

I'm still troubled a tad by some hum with my Cornet2, so these posts about grounding the 370BX tranny have got me curious.  I wonder if that would be beneficial in my rig. Geez, I am one of those guys who really dislikes ripping something apart once it's built!!  In my 30 years experience, that darn hum problem with vinyl playback is just the hardest problem of all to solve.  That's always been my Achilles Heel in getting my noise floor down. 

[denverartist]

I am with you, analog97. I still have that touch of hum. I did not want to tear into the Cornet2 but finally did, found the internal ground wire inside the Xformer. No change at all, after running it to the main ground on the rear of chassis. Then I also changed my power cord (hard wired, no IEC connector).

Tried different tubes obviously, resoldered many joints. No change. Now I am looking at the heater circuit, new parts there. And will be using an Adcom "AC Enhancer" 515 power conditioner because I think my house AC is bad. Of course that would not be the fault of the Cornet2. I am wondering if DC is getting through my AC line - there are several DIY solutions to block DC.

What does sound great? -- my new (slightly used) AT OC9 cartridge, run through an old Ortofon headamp. The improvement is incredible. Now THAT is what vinyl is supposed to sound like.

Cheers to all,
Pete

[analog97]

Denver,

I don't want to get off topic too much, but the hum problem is something I am not necessarily faulting the C2 for.  It seems that all the problems with signal amplification, extra wires, head-amps, SUT's etc in order to play vinyl just gang up on the final product.  My CD's, SACD's, home theater sound NEVER have that hum.  Doesn't matter what I try, I always fail to completely get rid of it.  That said, I am VERY pleased with the Cornet2.  I just always hope someone will say..."hey, I know what the problem is".....but, they never do.

Happy Holidays to all who make this a better place.  There are a ton of very helpful and friendly guys on this site.

[alpa6]

I don't get hum or really the hum i get is so small i never hear it unless i put my head right next to my woofer.I do get tube rush.But not bad tube rush until im way over 50% volume.
What i get is a buzz.My clarinet wiped out a jj tube in 8 hours.It wiped out a well worn eh tube in 48.That buzz just comes back.
Im now looking to buy some nos american tubes.I am thinking this might be the long term fix.
The buzz when it kills my tubes is audible and annoying.
Im thinking of getting a european gz34 while i'm at it too.I have read they were all just rebadged mullards so i figure why not get one.
It's  a very good sounding unit.No way around it but i think my unit will work with certain nos tube's.Any of you have this problem?

[analog97]

What i get is a buzz.

I really don't know the difference between a buzz and a hum.  I don't hear a "bzzzzzz", but some may construe it that way.  I think I hear something in between....

[alpa6]

For me a buzz happens in my midrange speaker.A hum is a 60hz tone that is in my woofers.

[denverartist]

I've bought 3 Mullard 5AR4s on eBay in the last few months and paid $12, $15, and $32. I find the tubes that the sellers mis-label, so get under the radar and save.  I need a few because my Quicksilver mono amps take 2 apiece.

I just solved hum on an old Scott amplifier by replacing some heater circuit caps, so thought I would look closer at my Cornet2 heater circuit. If diodes were overheated during the soldering process, could that make them "leak" or cause hum downstream?
Yes, the whole vinyl thing is prone to hum and buzz, so many places it can work it's way in insidiously.

ronpod: not trying to hijack your thread! Your build is superb.
- Pete

[ronpod]

Happy New Year, Everyone!

I, too, have concern about the nature of noise in the system. I have been running the "new" Clarinet constantly during my awake hours for the last 6 days. The Clarinet and the new interconnects are undergoing a burn-in period. The system sound is changing enough to confirm that burn-in is real IMO.

The Clarinet is an excellent addition to the system that I am VERY happy with. Right now I have the Cornet2 and an Oppo DV-983H DVD player connected to the input with the third channel with no connection. When I switch between these inputs, the DVD player and the channel with no connection are dead silent until the volume control on the Clarinet is turned up to about the 3 o'clock position (nearly all the way). When the Cornet2 is selected, tube rush noise is evident and, as the volume is increased, a slight hum reveals itself. As I have reported earlier in this thread, I have been working on, and continue to work on reducing the hum. Whether it is a hum or a buzz may be an important distinction that I am not sure I can entirely distinguish. But this quest of noise reduction has been fruitful in moving down the noise floor.

A large reduction in noise occurred when I replaced my "economic" used tubes with NOS Telefunkens. The 12AU7 Telefunkens in the Clarinet were very quiet except for an intermittent ring. The ring was not volume dependent or input dependent. So it was evident that the ring came from the Clarinet. Tubesforever wrote that he experienced similar ringing that was solved by tube selection. So I tried swapping the tube positions and the ringing went away.

The Cornet2 is now the major focus of noise reduction. I have noticed that when I place my hand on the transformer, the Cornet TX is hotter then the Clarinet's. There is one more tube in the Cornet than the Clarinet so this may be the reason. But, I have a notion that heat is equated with noise (entropy). The first stage tube in the Cornet may be the most critical position for a low noise tube. Isn't this a reoccurring theme throughout the archives of this chat site? I've tried a GE, Mullard, Amperex Bugle Boy, and Telefunken 12AX7 tube in this critical spot and the the Telefunken is clearly the lowest noise winner in my system. Unfortunately, the Telefunken is also the most expensive. However, apart from the noise, each tube has interesting sound characteristics that could appeal to different tastes. The GE was used, noisy and used for component burn-in so its sound was not expected, nor performed to the standard of the others. The Bugle Boy added a liveliness to the music that is fun and beyond the laid back sound of the Mullard and Telefunken. I would likely be happy with the Bugle Boy if I could find one (they seem to be harder to find) with lower noise. The Mullard has a full, well behaved, maybe even lush sound that is pleasant that I would also be happy with if the Telefunken was not so quiet. But because the Telefunken is so quiet with a reputation of having a long life with little drift, this is my choice (today).

The laying of hands was an interesting experience. When I placed one hand on the Clarinet transformer, I could move my other hand over various components and places around my system to induce noise. I took this as a way to identify what items may benefit from further modification. I did a similar test with the non-shielded interconnects as written previously. When the noise increased when my hand or the cable was in close proximity to any item, that item was suspect. The shielding of the interconnects was very important in my system. These shields are connected only to the source ground lug. When I lift these connections a definite rise in hum occurs, so I am encouraged that something good is accomplished. In terms of the most critical interconnect, it seems to be the IC between the SUT and the Cornet2. The SUT can be quite noisy if not properly grounded. I have tried to examine my grounding system to determine where the center of the star grounding is. It appears to be the shield of the Cardas tone arm cable from the turntable at the SUT input. This arrangement provides my system the lowest noise floor so far (but is subject to further testing) and creates the largest hum when disconnected.

I have become very happy with the metal-based Mullard GZ34 rectifier tube. It was worth punching out the chassis to a 1.50 in DIA hole to accommodate it. It takes about 10 seconds for the red LED to turn green, so I feel much better about running expensive tubes. I have not done extensive measurements of the heater voltages so I am not sure how different the heater potential is. The GZ34 is reported to provide slightly more current then some of the other rectifier tubes. Am I correct to assume this?

The Clarinet sound may not exist. Just a clean amplification of what I imagine to be true to the source. A funny thing about the vinyl reproduction; the surface noise is not as noticeable as before. Either the music is more dynamic or the signal-to-noise has increased or the quality of the music has improved to the point of making surface noise superficial. Thrashed vinyl even sounds better. I bought the Beatles White Album for a buck at a garage sale that was trash but it almost sounds passable now that the Clarinet is in the system (sorry, but no lead to gold type of miracles). This is great for those old original jazz albums that have great sound but have been played (and played). It is difficult to explain the wonderful sound that comes from the Clarinet together with the Cornet2 without lapsing into overused verbage. It has become exceedingly difficult to lay a vinyl record on the turntable and become preoccupied by something other than the music. The first thing I do when waking up in the morning is to turn the Clarinet and the Cornet2 on to get them "warmed up."

The Clarinet and the rest of the system is still burning in. So more later...

May you all have a prosperous new year.
Ron