New Posts  All Forums:Forum Nav:

Attenuator talk - Page 2

post #16 of 125
Quote:
Originally Posted by n_maher View Post
I can never figure out what the heck I need to order from Dantimax to build a simple, rotary encoder controlled balanced attenuator.
RelVol3 and either Control1 or Control2, depending on whether you want to use a VFD display or not. You can power it with an AC wall wart, or perhaps Standby1 or Standby2 if you want a e24 type functionality.
post #17 of 125
Quote:
Originally Posted by dsavitsk View Post
IResistive attenuators, no matter how well made, are always detrimental. But, a well implemented TVC or AVC actually improves drive capabilities as you attenuate
well-said.
post #18 of 125
Quote:
Originally Posted by dsavitsk View Post
<snip>
I might point out, too, that the attenuation method used is a huge step up from a resistive attenuator which throws away signal as heat and mucks with impedance. Resistive attenuators, no matter how well made, are always detrimental. But, a well implemented TVC or AVC actually improves drive capabilities as you attenuate.

-d
Aren't transformers, regardless of expense and materials used, still at least somewhat non-linear? Much more so than a resistor? It seems that whenever I see transformers being used, that they are rather expensive, and get more so with silver wire (Kondo?) and probably lots of other stuff I'm not even aware of. Of course I guess we aren't talking about a price comparison with an Alps Blue either
post #19 of 125
Well, in my case I went from resistive attenuator -> gain stage -> coupling cap, to just a transformer after my gain stage. dsavitsk talks about this in his write-up linked a few posts up... definitely the best exposition on the subject I've seen.
post #20 of 125
Thread Starter 
Quote:
Originally Posted by dsavitsk View Post
The whole point of DIY (among the other whole points of DIY) is that you can build gear just for you -- you don't need to adhere to manufacturer conventions, or do things how they were always done. Instead, you can figure out what works for you and implement it. The whole notion that one's own amp would need 48dB worth of attenuation simply says that the amp has some design problems.


And yes, I understand that some people use multiple phones and sources, but in that case, maybe a switch to switch between High Z and Low Z, or some sort of gain adjustment might be useful.

I might point out, too, that the attenuation method used is a huge step up from a resistive attenuator which throws away signal as heat and mucks with impedance. Resistive attenuators, no matter how well made, are always detrimental. But, a well implemented TVC or AVC actually improves drive capabilities as you attenuate.

-d
Agree completely - different phones, different sources, different users (at least in my house), and then IFF something should get _sold_, well, what is good for me rarely translates, or guarantees a bad transaction.

I really like the TentLabs solution - and, since my skills lag everyone else, is the 4 input for balanced? If so, fabulous. That said, JT (from what I have heard) is a bit finicky on source - would this seem to be also?

Finally, I simply prefer a 48 step resistive to 23 step resistive - especially where it is true I only use 5 spots or so on a stepper, it is not always the exact 5 spots preferred.

Besides, I struggle enough making amps work, much less dialing in their gain to match the attenuation.

We'll see what Goldpoint comes up with - maybe it is not mechanical resistive at all.
post #21 of 125
It seems as the tentlab's volcontrol has 4 separate pairs of unbalanced RCA inputs, each sharing the same relay circuit, so I don't think it would work for balanced stereo.

I could be wrong though, and it wouldn't hurt to ask them directly.

The RelVol3 + VolControl(1-3) sold at dantimax I think would be a good alternative for a balanced attenuator though.
post #22 of 125
Quote:
Originally Posted by pabbi1 View Post

Grit (rk27)
Unobtanim (rk40 log taper)
Isn't the Rk40 the same as the RK27, just a motorised version? (or "motorized" for my American friends ^^ )
post #23 of 125
Quote:
Originally Posted by rogerlike View Post
Isn't the Rk40 the same as the RK27, just a motorised version? (or "motorized" for my American friends ^^ )
nope.

Its a totally different beast. In any type of cage-match the RK40 takes the RK27 and makes it its female dog. sadly the RK40 has not been built for quite a few years, and is accordingly hard to come by.
post #24 of 125
There is also the issue of different levels in the music. I have some albums which are +/-10 dB hotter than other albums, which, considering the fact that there is even more variation in the sensitivity of my various headphones, means that there is no way I could make 23 steps work to my satisfaction.

Quote:
Originally Posted by Pars View Post
Aren't transformers, regardless of expense and materials used, still at least somewhat non-linear? Much more so than a resistor? It seems that whenever I see transformers being used, that they are rather expensive, and get more so with silver wire (Kondo?) and probably lots of other stuff I'm not even aware of. Of course I guess we aren't talking about a price comparison with an Alps Blue either
What, you mean fancy stuff like cobalt laminations? Yeah, transformers can get pricey.

Rogerlike, the Alps RK40 is much larger than the RK27, and better made. Also, it is black, thus the nickname, Black Beauty.
post #25 of 125
Quote:
Originally Posted by nikongod View Post
nope.

Its a totally different beast. In any type of cage-match the RK40 takes the RK27 and makes it its female dog. sadly the RK40 has not been built for quite a few years, and is accordingly hard to come by.
D'oh

RK27 Motorised = Blue Beauty
RK40 = Black Beauty

I think? This is what I get for trying to discuss something I know nothing about :P
post #26 of 125
Quote:
Originally Posted by nikongod View Post
nope.

Its a totally different beast. In any type of cage-match the RK40 takes the RK27 and makes it its female dog. sadly the RK40 has not been built for quite a few years, and is accordingly hard to come by.
Indeed the RK40 is superior in everyway to the RK27. I once happened upon 4 of them about to make a poor helpless RK27 their lunch.



Now, about Doug's point about gain matching. Part of the issue for me is that the source material that I listen to varies wildly and levels can be all over the map. I've had several instances where switching between CD's resulted in a 50% volume difference. No way a 6 or 12 step adjustment is going to be able to cope with that. I also use several different sources that each have a different output level, further muddying the waters. Finally, I've got amps that I use for both speakers and headphones where when listening to headphones I might hover in the 9 to 10 o'clock position and require fine adjustment but when I switch to speakers I'm in the 3 to 4 o'clock range.

And don't autoformer type attenuators still require a switch and have a limited number of positions?
post #27 of 125
Quote:
Originally Posted by rogerlike View Post
D'oh

RK27 Motorised = Blue Beauty
RK40 = Black Beauty

I think? This is what I get for trying to discuss something I know nothing about :P


http://cgi.ebay.it/Potenziometro-vol...05126001r14920
post #28 of 125
Quote:
Originally Posted by n_maher View Post
Indeed the RK40 is superior in everyway to the RK27. I once happened upon 4 of them about to make a poor helpless RK27 their lunch.
wow, that is awesome. OK now carry on...
post #29 of 125
Quote:
Originally Posted by n_maher View Post
And don't autoformer type attenuators still require a switch and have a limited number of positions?
yes, but they way they attenuate is different.

Rather than just throwing signal away (slipping the clutch to get something with 1 highish gear going...), they act like many gears in a transmission. I dont think that the fact that there are switches in the signal path is that big of a deal: the problem is that there are resistors in the signal path wasting signal.

I think another important thing is that he runs an output transformer (or auto-former) in most of his amps. This also counts for a LARGE amount of "total gain" reduction in open-loop tube amps. With multiple output taps, you could get by with an attenuator with only a few positions and a variety of headphones.
post #30 of 125
Ari,

I'm not at all concerned with the switch being in the signal path, my thought was more running along the lines of the fact that with a TVC or whatever you're still limited to using a mechanical switch and the affordable versions of those are generally limited to 24 positions.
New Posts  All Forums:Forum Nav:
  Return Home