[HiFi FOR METAL]

PowerCon Does a few things that most connections cannot offer.

1. It has a twist and lock design that makes it impossible to jar loose, this means it has a more positive connection than IEC.

2. From what many manufacturers who design power products have told me it actually maintains power phase better than other products. Since power comes in +/-/ground it's phase can be corrupted. What that means it the 60Hz sine wave that power comes in is more in phase with itself. It is kind of like when you are using an antenna to get TV and the signal has ghosting effects. Obviously power phase need to be stable.

3. Its current bandwidth is far more stable and wider than IEC. You can get a 32 amp powerCon or a 20 amp. The benefit is that you won't be current limiting which is a good thing when it comes to audio products.

4. It also offers better +/-/gound isolation in it's design which helps to minimize noise. and interference. It also has silver plated connectors.

5. PowerCon also uses a low capacitance connection which improves signal speed and flow.

Here is some more info from the neutrik site.

Neutrik - Industrial - PowerCon® 32 Amp
Neutrik - Frequently Asked Questions

 

[FallenAngel]

Thanks, I have read up on it, but you do have to realize a few things.

1) I don't have problems with jarring loose power cables

2) Power lines are actually not +/- to ground, they are AC(hot) to AC(neutral) and switches 60 times per second. The ground is earth ground and not actually used for anything other than safety. A balanced power supply will reference ground, normal AC lines do not.

3) IEC is 10A or 15A; the Melos draws NOWHERE close to the limit

4) No argument there, the design is likely better

5) Uhm... yeah, sorry, that's bull. Neither connector will have absolutely any effect on the capacitance of the connection, there just isn't enough wire in close proximity to create that effect.

 

[HiFi FOR METAL]

I understand that you don't have a problem jarring power cables loose, but getting a positive connection does improve sound and IEC really has less of a positive connection, and less conductivity than powerCon. I also understand that the Melos doesn't run at 2OA, but having a wider current bandwidth including a 20A circuit does help with power, Sound staging is wider and dynamics are clearer. This is true even if the electronics receiving it are 15A. Since Current and voltage fluctuate and are reactive loads, things like resistance and capacitance effect how AC devices react. Having larger and more stable current above the demand of your components is a benefit. PowerCon does help with this as well. This is actually why products that operate on DC sound better because they aren't effected by current bandwidth limitations. All I ask is that you try it. Many manufacturers of equipment are starting to use this as their power supply connection simply because it does sound better. I mean it is only a 10$ solution, what would it hurt to try?

 

[dsavitsk]

Quote:

Originally Posted by HiFi FOR METAL /img/forum/go_quote.gif powerCon

The beauty of the name is that it has Con right in it.

 

[Uncle Erik]

Why not replace the resistors? A lot of people overlook them for caps, but I change them out in my restorations. Granted, most of the stuff I restore has ancient carbon comp resistors, but good precision resistors help things.


With one radio, I replaced the filters and recapped it, then powered it up every time after I replaced a resistor. A lot of radio guys stop after recapping, so I wanted to see if they made a difference. Each one made the sound clearer and more focused. I replace every resistor now.

The cost is marginal, but it ups the labor. Still, if you want to wring maximum performance, look into a set of 1%, 105 degree resistors with twice the power rating of the stock ones. YMMV, of course, but I've had good enough results to keep doing this.

 

[FallenAngel]

HiFi FOR METAL and dsavitsk: I really don't mean to get into a debate about this connector, it will be quite a ways down on my list of things to replace in this Melos as I have implemented a nice quality IEC socket with integrated line filter (which does have a measurable effect on quality of AC power). I might look into these types of Neutrik connectors for my balanced Beta22 build to send multi-channel DC from the PSU to the amp, but not likely for this build. Thanks for the recommendation though, I did read up on them.

Uncle Erik: I will very much consider replacing the resistors a little later, for now I want to "minimize the damage" of how the amp is designed and which parts are used currently.


Next up is the High Voltage regulators and high voltage caps.
Low voltage caps - so far I'm looking at Elna Silmic II or Panasonic FM.

 

[HiFi FOR METAL]

yeah, Most of the gear I have heard with the higher quality Vishay brand name resistors sound the best. In fact stepped ladder resister networks used for attenuation and volume control sound amazing on tube pre-amps. I also think Teflon caps are great as well, especially Auricap T. Solen caps are also good. Also you could replace the transformer with one from plitron it would probably be better than the one that is in there. Really there are a multitude of things you can upgrade. Personally I think it is about how it is executed. The execution is more art than science, but at the same time you have to account for all of the technical effects and measurements as well, not an easy task. One cannot just replace a resistor with brand name X and a capacitor with brand name Y and expect the heavens to open up, one really has to know how each thing will effect other things. It is sort of a balancing act.

 

[HiFi FOR METAL]

You could also try these. Hovland Company: Products: MusiCap Capacitors

 

[FallenAngel]

Well, I just got 6 Vitamin Q 1.0uF caps and they're unfortunately way too big to use for inter-stage without VERY creative mounting. Being the "can" type with no negative lead but just a solder spot on the end of the cap will also make it hard to isolate. I'll try to play with these, but if no possible, I'll just use a pair as input caps.

 

[FallenAngel]

Ok, two discoveries were made today

1) 1.0uF / 200V Vitamin Q caps are HUGE!
2) The Melos layout is STUPID! The input cap is on the other side of the input connection and runs right under the High Voltage regulators and around the board. I guess that's what the "Left Channel Mod" really is, not just the short jumper, but the input wiring which has a MUCH higher effect on lowering noise.

So, updated to update the build log. Today I replaced the input caps with 1.0uF Sprague Vitamin Q and routed the input wires straight to the position where they are used, not through an extra few sets of connections (lower pins of #28 and #70 on PCB). The background noise has dropped considerably to the point that I cannot really hear it even when I try (although I will experiment with other headphones later). These input caps really sounds wonderful compared to the crap they had before.

There is no room to use these as inter-stage coupling no matter what I do so I'll use something else for that position.

Updated Photo:

 

[dsavitsk]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif The Melos layout is STUPID!

Do be careful as you do this. I replaced all the caps in mine (an original SHA-1), and something started oscillating. I've never tracked it down, and it sits on the shelf in the closet -- though to be fair, that's where it sat for years before I swapped the caps. I don't have any use for it other than I wanted one so badly when the came out that I won't get rid of it now, even if it doesn't get any use ... or even actually work. Someday I'll look at it again.

 

[FallenAngel]

Thanks for the warning Doug; this being the first time I'm tinkering with a tube design, I've been acting about as cautious as a person doing their driving test for the first time with a cop in the car.

I have ordered parts to replace the high voltage regulators with HexFreds and all of the electrolytic caps with Nichicon UHE/Panasonic FM for low-voltage and Panasonic TS-HA for the high voltage. Values are taken from the SHA-Gold schematic (a little larger size than on my Maestro).

 

[FallenAngel]

Ok, I'm taking the next step in ordering caps to replace the 4 inter-stage 1.0uF caps (which are actually in parallel so they act as 2uF combined). My top choice for bang/buck is the Sonicap Gen 1 1.0uF/200V but I saw another pair of caps that caught my attention. There are two other caps that work inline with the theoretical negative input to the signal and run from Ground (signal ground, PSU ground, case ground, all same in this amp) - and connects to the Grid of one side of the tube just as the signal connects to the other Grid. Somehow this cap seems a little important and I'm wondering whether it should be replaced or not. Comments greatly appreciated as I'm completely lost in tube theory.

I'm also looking at changing the pre-amp output caps and really don't see why they would be rated at 250V. Looking at the schematic there is a 10uF cap bypassed by 0.1uF. I'm thinking Sonicap for both - Gen1 10.0uF/200V bypassed by Gen2 0.1uF/200V - as long as 200V is enough. Taking a measurement across that cap is impossible - I don't see any voltage! 0V!

Thanks

 

[nikongod]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Ok, I'm taking the next step in ordering caps to replace the 4 inter-stage 1.0uF caps (which are actually in parallel so they act as 2uF combined). My top choice for bang/buck is the Sonicap Gen 1 1.0uF/200V but I saw another pair of caps that caught my attention. There are two other caps that work inline with the theoretical negative input to the signal and run from Ground (signal ground, PSU ground, case ground, all same in this amp) - and connects to the Grid of one side of the tube just as the signal connects to the other Grid. Somehow this cap seems a little important and I'm wondering whether it should be replaced or not. Comments greatly appreciated as I'm completely lost in tube theory.

The cap which goes from the grid of the tube to ground (the other one should connect to signal input) is of questionable importance (quality wise). It is necessary as part of the phase-splitter, but is not DIRECTLY in the signal path. In my amp, I left this as the solen that was in there when I got the amp. I have not tried to replace this cap but SERIOUSLY doubt that it has much effect on SQ.

Replacing the actual signal input cap and interstage cap made a HUGE difference in sound. I upgraded from the solens, and was very pleased. With the craps (hehe) in your amp you should be absolutely amazed.
Quote:

I'm also looking at changing the pre-amp output caps and really don't see why they would be rated at 250V. Looking at the schematic there is a 10uF cap bypassed by 0.1uF. I'm thinking Sonicap for both - Gen1 10.0uF/200V bypassed by Gen2 0.1uF/200V - as long as 200V is enough. Taking a measurement across that cap is impossible - I don't see any voltage! 0V!

They DEFINITELY have voltage across them. They are between the emitters of the preamp mosfets and the outputs of the amp: It is probably 75-85V - it is the same as the voltage across any the BIG blue resistors on the bottom (towards the front of the case) between the 4 mosfets.

You can use 200V rated parts anywhere in the amp.

 

[fzman]

paralleling two identical caps in the signal path may not work out quite how you want it to -- it may cause a subtle blur that using dissimilar values in parallel may not create -- if you have the resources, try it both ways before you spring for the $$$ caps.

just my 2 cents worth....