i hope this one makes someone excited

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Offline Bill Epstein

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Reply #30 on: October 16, 2015, 08:59:06 AM
"Now, after rolling in the rack you need 8" spikes you can drop and lift it off of the rollers."

I'll have you know that's a $60 Ikea TV stand! When I complete the JEL 76 Line Stage maybe I'll spring for something that will hold it and the two amps. Right after the brake job, 4 new tires and a power steering pump  :P

(https://darklanternforowen.files.wordpress.com/2014/01/jelsc-linepre1-b.jpg?w=670)

The last of the parts arrived today and I'm looking forward to it after hearing Steve's but truthfully, I've just come from listening to Count Basie and the Kansas City Seven, the one with Freddie Hubbard, Lockjaw Davis and JJ Johnson and I'm blown away, Foreplay and all.

I did indeed use the Valab you linked and had a look recently at McandMar's Dale version. Dales are nice but It's very true that there are about 4 positions that get all the use and upgrading those Xicon Rs would make more sense. Not Dales, tho'. I'd go for AN Tantalums or nude Vishays.

VPI Traveler/ZYX R50
Cinemag 3440 AH
Steve Brown Caravaggio Phono
Foreplay 2.1
The Twins: 55 Watt Mullard 5-20 KT-88 mono-Blocks
4 Pi Speakers


Offline 2wo

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Reply #31 on: October 16, 2015, 04:54:35 PM
The way the volume control is drawn. Sure that is correct?...John 

John Scanlon


Offline Bill Epstein

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Reply #32 on: October 17, 2015, 01:24:05 AM
The way the volume control is drawn. Sure that is correct?...John

LOL...I just caught the wrong way arrow. Thanks for pointing that out.

VPI Traveler/ZYX R50
Cinemag 3440 AH
Steve Brown Caravaggio Phono
Foreplay 2.1
The Twins: 55 Watt Mullard 5-20 KT-88 mono-Blocks
4 Pi Speakers


Offline Paul Birkeland

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Reply #33 on: October 17, 2015, 01:56:32 PM
LOL...I just caught the wrong way arrow. Thanks for pointing that out.
What wrong way arrow?  That's a fairly normal diagram for a pot.
(https://startingelectronics.org/beginners/components/potentiometer/potentiometer-symbols.png)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Joppa

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Reply #34 on: October 17, 2015, 02:19:41 PM
The input has an "out" arrow. Makes sense if the arrow is labelled "to input RCA jack"  but not if you see it as an indication of signal direction. That's the only thing I see.

Paul Joppa


Offline ee

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Reply #35 on: June 02, 2016, 06:57:33 AM
The tune up is coming along pretty good. I did place new 100k resistors across in/out of vol pot. Vol pot is now single Valab series stepped attenuator. I really like it. Vol is not twitchy like it was before.
My mental state is being messed with by cap 1 and cap 2 of power supply though. I ordered 220uf as the original value spec'd. The new ones showed up measuring 190uf each. Should I let this bother me and replace them or parallel some, or it's fine and no performance issue. I mean it is foreplay but i don't want a performance issue. haha
Thanks
Eric

Hey guys just some additional clarification about the resistor that goes from the selector to vol pot input from previous message I wrote. When I received the foreplay it had the the 100k resistor going from the selector to the input of the pot and across to the output lug also. This is how I have done mine just copying the previous setup. No manual.
Is that the correct wiring? It sounds good just wondering if I should really just have the 100k resistor going from selector to volume pot input only. Does it being soldered to both lugs input and output do anything because the input and output is continuous within the pot anyway? I would then place 20k resistors to ground if I think it needs it for volume control as Grainger suggested. I would mess around with it but it's in place, works, and the solder ports on the valab won't take much abuse of soldering and unsoldering under my hand. I can easily remove what is essentially a jumper wire from the valab input to output if that's what needs to happen.
I attached a photo of the original build with one of the channels going from selector to vol pot showing it soldered to the input lug and then going across to output lug if the pic helps.
Second photo is with valab in. In the photo-  input with vishay resistor is furthest away, ground middle with black wire, output is closest in pic showing the jumper going from input to output.
Thanks all
Eric

Bottlehead Stereomour 2a3
Fostex FE206En in Vulcan (BIB BLH)
VPI Scout 1.1 with classic platter
Lyra Delos
Manley Chinook phono pre
Creek Destiny 2 CD
Audio Art Power Cables


Offline Paul Birkeland

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Reply #36 on: June 02, 2016, 07:53:28 AM
When I received the foreplay it had the the 100k resistor going from the selector to the input of the pot and across to the output lug also.
A 100K resistor between selector and the input of the pot would be a good way to pad the preamp down.  When you say "and across the output lug also", I didn't see that in your photos, but making that connection would turn the pot into a shunt element, which would offer finer control at very low volumes.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ee

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Reply #37 on: June 02, 2016, 10:55:01 AM
Ok sounds good. I tried to fix the picture a bit to show the resistor connecting from selector to outer lug (input) and then middle lug (output). Thank you for your explanation.
Eric

Bottlehead Stereomour 2a3
Fostex FE206En in Vulcan (BIB BLH)
VPI Scout 1.1 with classic platter
Lyra Delos
Manley Chinook phono pre
Creek Destiny 2 CD
Audio Art Power Cables