Bottlehead Forum
General Category => Technical topics => Topic started by: mp9 on October 23, 2009, 03:07:01 PM
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- i'd like to know what people here think of it and if it's worth buying?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300351726617&ssPageName=STRK:MEWAX:IT#ht_2042wt_808
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You do know that this is a balanced volume control. That is not for use with an RCA jack (unbalanced) input/output device?? If your system is unbalanced they have other devices that will work.
I have bought a few items from this seller. They have not been cheap but are not built cheaply.
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i have the XLR option but the more i think about it i'd rather not buy new interconnects any opinions on the following one?
http://cgi.ebay.com/Valab-23-Step-Attenuator-Potentiometer-100K-Stereo-Log_W0QQitemZ300355947359QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item45ee9c0b5f#ht_2259wt_808
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Personally I prefer the ladder style. I tried the dact series attenuator and I found the cheap ladder to sound better especially at low volume levels. I don't know if this is because the series attenutator runs through all those resistors at lower settings or if I'm just hearing things.
http://cgi.ebay.com/Assembled-Dale-23-Step-Attenuator-Volume-Control-100k_W0QQitemZ270311271326QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3eefceab9e (http://cgi.ebay.com/Assembled-Dale-23-Step-Attenuator-Volume-Control-100k_W0QQitemZ270311271326QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3eefceab9e)
The seller also has these as a kit.
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Great that's the kind of response i was hoping for and thank you i may try one.
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I'm using these and wish I had spent a bit more and gotten ones built with regular resistors rather than the surface mount (such as this http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110448818328&_rdc=1 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110448818328&_rdc=1)). The surface mount resistors are held in place only by solder and so when soldering wires on, the resistors can easily become disconnected. While I did get it to work, I found the experience very frustrating. I use only lead free solder with a higher melting point than lead/tin solders so this probably made it much worse.
--Chris
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I just want to be sure. Is the ladder attenuator is the same as VoltSecod's S5 (single series single shunt stepped attenuator)?
Here is his page. I'm asking is the "Standard Stepped," Shunt Mode Easiest Stepped" or "Single Series Single Shunt Stepped" attenuator what is being called a ladder?
http://www.siteswithstyle.com/VoltSecond/12_posistion_shunt/12_Position_Pure_Shunt.html
Above is VoltSecond's attenuator page.
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'Shunt mode easiest' looks like it is a normal series attenuator wired in shunt mode with a fixed input resisitor YYY. This could be done with a normal dact or sweetest whispers attenuator.
The ladder attenuator would be closest to the 'Single Series Single Shunt Stepped (S5)' attenuator. But in the ladder attenuator the input resistor YYY is also switched. There are 2 resistors for each step. This way the YYY and SSS resistors always add up to the total impedance eg. 100K. The S5 can be built with a single pole switch, but the ladder requires 2 poles for each channel.
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Thanks, I get it. And now I remember the S5 has a minimum and maximum impedance. I'd think not a good thing for the Seduction.
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Here is a link to a great calculator for customizing your own ladder attenuator. No need to settle for a standard 10 or 100k attenuator with standard 1 or 2 db steps. Choose your own impedance and your own attenuation steps. The calc will tell you which resistors to order. I tried using VS's calculator but got a little too confused (it happens alot).
[http://homepages.tcp.co.uk/~nroberts/atten.html (http://homepages.tcp.co.uk/~nroberts/atten.html)
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Wow, here is one I haven't seen before. New style of 21 step switch with SMD resistors. Very compact and only $15 shipped for stereo! If anyone tries these, let us know how they work.
http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-Potentiometer-50K-300B_W0QQitemZ120473999989QQcategoryZ3280QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26ps%3D63 (http://cgi.ebay.com/DACT-Type-21-Stepped-Attenuator-Potentiometer-50K-300B_W0QQitemZ120473999989QQcategoryZ3280QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26ps%3D63)
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Wow, those are cheap.
How's the quality/feel of those ladder types you linked to dmannnn?
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I've had them about a year now and haven't had any problems whatsoever. No switching noise and I'm pretty hard on volume controls. I bought 2 of the 2 pole blank switches for mono controls. Building them was a bit tedious to say the least.
The bodies are all plastic and they feel well built. The terminals are fairly malleable and can bend during shipping, but can be bent back easily. I haven't had one break. There is a good solid feel when switching, not springy like the standard sweetest whispers switches. You can actually take them apart and add or remove layers(poles) like a cake.
I am very taken with those Polish attenuators. I think they are called Khozmo's? They just look so cool, but I'm sold on ladder style attenuators over series attenuators. Unless the series attenuator is wired as a shunt, but then switching noise becomes a problem even with the better switches. If the switch breaks contact at all, there is no attenuation to the amp. This will cause some serious popping. The DACT attenuator (Elma switch) I had wired in shunt started making noise almost overnight. I think dust was getting into it. The dust out here in the desert is so fine, and when the wind blows 50 mph it will find its way into everything, no matter how tightly your house is sealed up.
I haven't tried the blue switches as shunt controls yet.
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... Unless the series attenuator is wired as a shunt, but then switching noise becomes a problem even with the better switches. If the switch breaks contact at all, there is no attenuation to the amp. This will cause some serious popping. ...
That does not happen if you wire the shunt attenuator as we do in the Foreplay III.
Historical note - this is derived from what was called a "ladder attenuator" back in the thirties; since then the meaning of that term has changed. I've never seen this variant elsewhere, though I can't imagine I'm actually the first to do it this way.
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. . .
[http://homepages.tcp.co.uk/~nroberts/atten.html (http://homepages.tcp.co.uk/~nroberts/atten.html)
Thanks, I bookmarked it.
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... Unless the series attenuator is wired as a shunt, but then switching noise becomes a problem even with the better switches. If the switch breaks contact at all, there is no attenuation to the amp. This will cause some serious popping. ...
That does not happen if you wire the shunt attenuator as we do in the Foreplay III.
Yes, when I use the term 'shunt' I am referring to the wiring that Voltsecond shows on his page (fig1.0). I don't really don't know how else to refer to that style of attenuator wiring. The standard FPIII wiring works great. When I first built the FP I thought it was just a standard series attenuator wiring. I can see now that it is a little different.
For some reason I found the wiring scheme on VS's page very intriguing so I tried it and liked the results (as long as the switch contacts are bombproof). I liked the idea that there was a direct connection from the input to the amp grid with only a single resistor in the path and the switched resistors only on the wire leading to ground.
I remembered a previous post where you stated that these newer styles were not actually ladder attenuators, so I just refer to them as 'ladder style.' I'm still not sure what a true ladder attenuator is.
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I think PJ is saying that there are a number of wiring schemes that can be called "shunt." VoltSecond calls the FP III wiring "Shunt Mode Pot Typical" and many use the "Shunt Mode Pot Easiest."
Also, the volume wiring in the FP III is one of many improvements that were made in that design revision to eliminate noise or problems that only some users had with the FP 2. The list is long and highlights the sophistication of this improved design.