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I'm about to install the SR-45 mod and Obbligatos in my Paramour IIs. I want to do them separately so I can judge the affect of each mod. Does anyone have any experience that would give me a ballpark figure on expected break-in time for each of these mods?
Thanks,
Gary
Vinyl and Film Forever
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I think it took about 2 weeks of breakin for my Obbligato caps.
"Remember, YOU are the only one who needs to be happy with the sound of YOUR SYSTEM."Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Just installed the Obbligatos in the Paramour II / 45 version. Once I feel they are broken in, I'll install the SR-45. Now off to build another Lenco.
Gary
Vinyl and Film Forever
hi Gary....I am also getting ready to do the SR45 conversion....are you already converted to the 45 tube or still 2A3 ?....what size obbligato caps are you using ?....when I did the upgrade I put in mundorf supreme 10uf and
a .1uf rel teflon...thanks -Al
Al,
I built mine as 45s in the original build. I also have a pair of Paramour I that I built as 2A3. I used 10 uf / 630 vdc Obbligatos. The boards are nearly done for the SR-45 mod. Just need to clean them up and double/triple check the components. Really just a matter of doing the demolition work to start the install, but I thought the Obbligatos would be a quicker task to do first. Also have a set of the Kommie Kaps to replace the coupling caps, but will save that for last. I understand those teflons take a long time to break-in.
Gary
Vinyl and Film Forever
thanks...I am getting the boards ready too...I figured I would upgrade most of the resisters since it seems they just threw together what every they could find with the assembly....after all why parallel or series the
resisters ?....got a mix of caddock (316k for the 156k series, 75k for the 150k parallel and 220r), riken for the 237r and a holco for the 237r and 5.5k and a tantalum for the 16.2r....may not make a difference but can't hurt...maybe the watts ?....good luck...keep me up to date -Al
When I built my first couple of Foreplays, I really didn't think much of the parts that went into them. I did a lot of substitutions for resistors and caps, especially the resistors on the C4S boards. In the end, a stock FP2 with anticipation ended up sounding much better. When I got down to it, the resistors in these kits are quite carefully selected. I also figured out that the power supply capacitors in many of these kits are actually some of the most expensive electrolytics you can find in that case size, short of Black Gates. The same goes for the kit wire, I just priced a couple of 100 ft. spools for myself, and I was absolutely shocked how expensive the teflon hookup wire is. Anyway, my point is, go ahead and experiment, but build it as stock as possible first so you know if you're making headway.
-Paul
hi Paul....thanks....thats great perspective from someone who's built their share of kits....much appreciated -Al
Hopefully you are considering power dissipation and voltage ratings when you are planning to make substitutions of, for example, two 1/2W resistors in series. Those resistors we just threw together are chosen with those parameters in mind as well as their material composition.
perhaps "threw together" was not the best expression for the efforts you made to develop this modification....but it is interesting that you are suggesting / recommending I consider power dissipation and voltage ratings while offering no details regarding the choices made for the circuits....or for example, how a caddock mk132 316k or caddock mk132 75k might be poor substitutions for some of the original resisters....can you provide some information behind the decision to parallel or put resisters in series ?
is your example indicating 1w is needed for the series resisters ?
Power dissipation across a resistor can be calculated by dividing the square of the voltage drop across it by the resistance. Resistors should be rated for at least 2X the power to be put through them, and PJ prefers 3X as a safety margin. You can use the voltages and resistances listed on the schematic to calculate the power dissipation requirement of the resistor as well as it's voltage rating. However I believe you will find the work has already been done for you on the SR45 schematic on page 4 of the manual. Power ratings for the resistors that are running relatively high dissipation are already spec'd on the schemo. Either it will not be easy or it will not be inexpensive, for example, to locate a 75K resistor rated for 6W and 5% tolerance. It may be far easier to find a reliable 150K 3W that can be paralleled. If you use a Caddock, make sure it can handle 6W of dissipation in that application.Voltage ratings must take into consideration the actual voltage that the resistor will see through the startup cycle. In the case of the Paramount circuit we use a resistor with 750V rating in one location, that being the 300K. Many resistors are rated for 500V or less and in these cases two 500V rated resistors in series can be used to handle startup voltage peaks that go above 500V.
From my reading of the schematic (which may or may not be correct)...The film resistors are placed in series (the 2x158k) because generally film resistors are rated for something like 250vDC or less, and these guys have > =320vDC across them collectively. You'll need to check the voltage rating for the Caddocks to see if they work here.
The wirewounds placed in parallel (2x150k) need a healthy rating, so the 6W rating noted. A Mills 12W would probably work here ratings-wise, but will it fit?
No matter what component we're talking about, it's always best to check voltage/ wattage ratings.
Regards,
John
thanks John...appreciate your input -Al
Thanks,
Gary
Vinyl and Film Forever
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