Eros is here... the build begins...

[ALL212]

Just a starter question...

The 47k resistors that are paired on the shunt regulator board are very large.  I've purchased some alternate 2w versions and both are much smaller.  Is 2w appropriate or should they be a larger value? 

Would a single 94 ohm 5w or larger wattage work instead?

Thanks!

 

[Doc B]

Why are you changing them?

 

[ALL212]

There are two more that were mentioned as possible replacement options - I figured I'd do these also.  Was just surprised at the size difference.

If it's better to go with the stock resistors I'm more than happy to do so to avoid blowing my new baby up.

 

[Doc B]

Who is suggesting replacing them, and what is their reason?

 

[Paul Birkeland]

The 47k resistors that are paired on the shunt regulator board are very large.  I've purchased some alternate 2w versions and both are much smaller.  Is 2w appropriate or should they be a larger value? 

These aren't in the signal path.  If someone suggested changing them, that someone isn't knowledgeable enough to make appropriate suggestions.  (PS - we provide really nice parts for the signal path already)

Would a single 94 ohm 5w or larger wattage work instead?

Doing this will very likely damage your power transformer, and at minimum blow the fuse almost instantly.  94 Ohms is a lot different than 94,000 Ohms.

 

[ALL212]

These aren't in the signal path.  If someone suggested changing them, that someone isn't knowledgeable enough to make appropriate suggestions.  (PS - we provide really nice parts for the signal path already)

I realize that but since there were more of them I just assumed...I understand where that gets me on most days.

Doing this will very likely damage your power transformer, and at minimum blow the fuse almost instantly.  94 Ohms is a lot different than 94,000 Ohms.

And that would be exactly as I would expect but my vision...and typing sometimes don't go exactly as my brain does.  I did mean 94k ohms.

 

[Paul Birkeland]

A single 94K/5W part will work, but will be an extremely tight fit into the board. A 94K Vishay PR-03 will fit and work fine.

 

[ALL212]

Who is suggesting replacing them, and what is there reason?

From this write up.  It is NOT suggested that these particular resistors be replaced.  I understand that.  But as long as I was purchasing a couple of them I threw in more.  I have no intention of blowing this up so I can easily install the original resistors to this board.

The coupling caps in the stock kit are 1.0uF Solens (though we may have shipped you 1.5uF's in their place).  This would be the most significant upgrade, and you could easily go much lower than 1.0uF, .47uF is a decent choice.

There's also a 0.1uf cap in the shunt regulator circuit that's potentially worth upgrading.  A 400V cap is OK here.

The 75K 1/2W and and 47K 2W resistors are also very much in the signal path, those could be upgraded, but be sure to use 1% parts or buy enough to match.

The 10.5k resistor, 0.030uF, and 0.010uF caps make up the RIAA network, you can find decent upgrades for those at Parts Connexion, but again, keep the resistors as 1% parts, caps at no more than 3% unless you can find a pair that measures closely.  For the 0.030uf cap, paralleling two 0.015uf caps tends to be easier to implement than finding a 0.030uf.

-PB

 

[Paul Birkeland]

Yes, there is a pair of 47K resistors mounted by the center 9 pin socket that are in the signal path.  The four 47K/2W resistors back on the board above the 12BH7 are highly isolated from signal current.

 

[ALL212]

Gentlemen - I thank you!

I'll put the originals on the board.  The 47k's I purchased are 1% and I can further match them for the center 9 pin.

 

[ALL212]

Here we go!

The parts.


Top Plate painted and populated.


Power Supply passed test.  I've removed a couple of components that I'm upgrading so that I can easily build the socket areas.

Heater wires completed


I found that if you put the caps in first with the fine wire they have it's easier to get the heater wires for A and C in after you have the caps in.

 

[BNAL]

Aaron,

Thanks for the advice about installing the resistors first. I just started my build and have only gotten to the power supply and shunt regulator boards.

What is on the ends of the heater wires?

Any other advice is greatly appreciated.

Brad

 

[ALL212]

Just heat shrink - it dresses up the ends and....maybe....keeps something from shorting to something someday. Vague at best, certainly not required.

For the middle socket - I put in the wires from socked D first following directions.  I had problems keeping the A and C heater wire in place while attempting to put in those tiny caps.  I backed out the A and C wire and placed the caps in leaving the leads long.  Then put the A and C heater wires back in again.  It was just easier as I could push the cap wires down with the heater wire as I went.  It worked for me.

I also found the length of the heater wire going to A and C was about an inch too long.  That could be just the way I put them in at B.  If you're careful it's easy enough to shorten them after you have B soldered down.

I'll take notes in here as I go.  I don't work on this every day.  It's when I'm motivated to do so.  I've found that trying to push through the higher difficulty kits is a very bad idea!

 

[BNAL]

Aaron,

looks like you are replacing the last electrolytic cap in the power supply with a film cap and the 270 5w resistor with a choke. Also, what caps in the signal path did you replace? Did you replace any of the resistors?

Brad

 

[ALL212]

I guess first the disclaimer...

Anything I change is my problem and certainly not under the recommendation of BH.  I don't expect others to like it, don't expect me to be able to explain why I did it.  It's just the way I did it.  If you decide to do it please investigate options and accept the responsibility of changing an already good kit and parts.

I've tipped each electrolytic cap with a small film cap.  Those might look familiar.  If you do this you'll have to figure out how to raise the power supply board about a 1/2" and still get the plate to sit on the base without hitting the surface under it.  I used slightly longer screws, an extra nut and some plastic washers so nothing shorts to the board.  It's not very elegant but it works.



I think everything on this board is stock except for the outside caps.  I have a fondness for Sonicaps.


These boards are stock - except the caps but there really isn't any reason to replace them.  I was on Mouser...added to my cart.  When I purchase these I buy more than needed and then match them.


RCA in/out's are Vampire CM1F/CB and fit the holes exactly as needed.

Ground post is a Cardas.  It just looks nicer.  I could not find this exact one but had it in stock.

The .01 film caps are replaced with Sonicap (hand matched)

The .03 film caps are replaced with two .015 Sonicap's (hand matched) each.

The 1.5 film caps are replaced with ClarityCap MR series .47uf.  I have some 1uf ClarityCap MR's on standby to try.

Last power supply cap is going full film with a Jantzen 100uf.  I had this one from a prior attempt at something...  :  Memory doesn't serve.

Resistor is out and the choke is in.  I'm putting that on some standoffs so I don't plug up the vent work.

Resistors - other.  Yes, I have purchased some replacements for those in the signal path.  The jury is still out on whether I'll use them or not.

Wire - I have my own favorite wire.  Stranded copper tined with silver.  Sometimes hard to work with as it's slippery stuff in the smaller gauges.

 

[ALL212]

Tonights work and warnings:

Page 47 maybe 48....49?  I cannot find where it says to solder the center pin of the D socket.  I almost missed it and when I was putting in the shunt regulator board I noticed I had not done so.  And did so right then and there.

Page 53 - Shunt Regulator grid stoppers.  Do not cut these short or you won't be able to mount the board.  If nothing else cut them a bit long but you'll have to be careful and insure nothing gets shorted out.  I had both cut the same length and I could not get the board mounted with the back one soldered in.  I removed it and cut another one just a bit longer.  The front one at the size I cut it just barely fit - another 1/32 and it would not have gone in.

I've passed the test on page 58!  8)

ONWARD!!!

 

[amritdesai]

Had same issue with pg 47 but it looked like the connection was soldered in the pictures so I went for it.

Looks awesome man. Sweet build!

 

[BNAL]

Aaron,

You have pulled out all the stops on the power supply. Can't wait to hear what you think.

The only change I'm making on the build is to change the EF86 to 6BR7s. I'm sure that I'm going to make other changes to the signal path after awhile.

The one thing that I'm doing different as compared to the manual is to solder components on the PCBs as I mount them on the boards. For me it is a pain having all the leads in the way. I solder them and clip them as I go.

Brad

 

[ALL212]

I looked over that change to go to 6BR7's but I've got three pair of EF86's so I'm sticking with them.

I also just add a couple components at a time to the board and solder as I go.  Trying to get through the porcupine is no fun!

Gotta admit I think this manual could be better written.  Too many times there is an entire paragraph and one check box to do 2 and sometimes 4 steps.  Could remove the T from each terminal notation and make it somewhat easier also.

Tonights work - no major issues I can think of.  Oh!  One easy change.  When going from C9 to 23L to the ground lug.  Just use one piece of wire all the way through and heat shrink it on the 23L to ground lug.  Much easy!

 

[Doc B]

Gotta admit I think this manual could be better written. 

I'd love to look over one of your manuals to get some pointers. If you wouldn't mind sending a PDF of whichever one you think would be the most helpful, I'd appreciate it. We are always looking for better ways to do things.