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ALL212 · 5112

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Offline ALL212

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on: September 11, 2016, 07:22:36 AM
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!

Aaron Luebke


Offline Doc B.

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Reply #1 on: September 11, 2016, 08:48:46 AM
Why are you changing them?

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline ALL212

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Reply #2 on: September 11, 2016, 09:05:45 AM
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.

Aaron Luebke


Offline Doc B.

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Reply #3 on: September 11, 2016, 09:52:47 AM
Who is suggesting replacing them, and what is their reason?
« Last Edit: September 21, 2016, 04:43:12 PM by Doc B. »

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Paul Birkeland

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Reply #4 on: September 11, 2016, 10:00:02 AM
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.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ALL212

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Reply #5 on: September 11, 2016, 10:02:27 AM
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.

Aaron Luebke


Offline Paul Birkeland

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Reply #6 on: September 11, 2016, 10:05:56 AM
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.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ALL212

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Reply #7 on: September 11, 2016, 10:10:46 AM
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

Aaron Luebke


Offline Paul Birkeland

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Reply #8 on: September 11, 2016, 10:13:20 AM
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.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ALL212

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Reply #9 on: September 11, 2016, 10:15:50 AM
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.

Aaron Luebke



Offline BNAL

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Reply #11 on: September 21, 2016, 05:16:33 PM
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

Brad Nalitt
Iron Upgraded S.E.X. Amp 2.0
Foreplay III
Quickie w/PJCCS
Eros Phono
Blumenstein Orca Speakers, Baby Benthic Subs
S.E.X.y Speakers W/FT17H Horn Tweeters
Thorens TD 125 MkII W/ Shure M97xE JICO SAS Stylus


Offline ALL212

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Reply #12 on: September 22, 2016, 12:55:58 AM
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!

Aaron Luebke


Offline BNAL

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Reply #13 on: September 22, 2016, 05:49:15 AM
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

Brad Nalitt
Iron Upgraded S.E.X. Amp 2.0
Foreplay III
Quickie w/PJCCS
Eros Phono
Blumenstein Orca Speakers, Baby Benthic Subs
S.E.X.y Speakers W/FT17H Horn Tweeters
Thorens TD 125 MkII W/ Shure M97xE JICO SAS Stylus


Offline ALL212

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Reply #14 on: September 22, 2016, 11:26:43 AM
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.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi905.photobucket.com%2Falbums%2Fac253%2Fall212212%2FIMG_1770_zpsby61ngjl.jpg&hash=cd401a5cfba83a826138640a3a62fbec302cc2b0)

I think everything on this board is stock except for the outside caps.  I have a fondness for Sonicaps.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi905.photobucket.com%2Falbums%2Fac253%2Fall212212%2FIMG_1768_zpswsd8hjp1.jpg&hash=c4083a4012634a9bf950b089dd50fe194f304277)

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.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi905.photobucket.com%2Falbums%2Fac253%2Fall212212%2FIMG_1767_zpsnri7mb6x.jpg&hash=9758984760b8b2e1919be542fc75fb2df6490aae)

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.

« Last Edit: September 22, 2016, 11:31:46 AM by ALL212 »

Aaron Luebke