[45triode]

here are some pics from the process:



tweeter backside fitted with dynamat extreme



duelund 12 ohm resistor and beeswaxed mundorf silver/oil (silver wire return yet missing here)



bybee large purifier on the plus input to the widebander

[45triode]

short update: about 200 hrs playtime so far and i am still disturbed by the new sound. the change in the crossover network seriously changes the tonal balance towards the highs. cymbals, snares, brass do sound much more realistic though, meaning they have the "bite" they should have. of course i also have a more attack driven sound now and subjectively more dynamic swing. so in that sense: mission accomplished.

problem is that the new network throws the druids off balance.

only after the changes did i realize how carefully ZU voiced this speaker´s HF according to the LF possible. i am now in serious need of a subwoofer to recenter the sound. i am curious why nobody else commented on this change. i have a yamamoto 45 amp, known for its lit-up nature, and i am "forced" to run it with a 245/280 tube set up, because in my system they have a mellower, more fluid and balanced sound signature than the usual vintage STs.

some might comment, that mundorf caps need double the break in time. we´ll see, but i doubt that it will change a lot. about the effect of the bybees i installed i cannot say anything. more highs always fool my ears into believing they hear a "clearer" sound.

bottomline: i need subwoofers. Badly.

[naggots]

I already have 2 mini methods so my comments were made with subs. For me the Druids need sub(s) but that depends on your taste/ears.
 
I've had the mundorf caps in for over 12mo now and they are verging on bright but never cross the line. I found the Zu Ash digital ic made a huge treble  boost over cardas neutral ref........ More than the Mundorf cap...... Or maybe because of ??

Anyhow I ordered the new Soul FRD from Zu to replace the mk408 FRD. Sean said you need the mundorf cap and a 10ohm resistor. The soul uses the Def2 tweeter network which is the same.

[NagysAudio]

Couple of observations... From experience, the Mills resistors sound better and are better built than everything else in the wirewound resistor category. There's absolutely no need to change the resistors in this speaker. Why spend $200 when you already have the very best that you can have?

Also, from the picture, I see that the inductor is glued to the back of the speaker magnet. Any crossover modification performed, *MUST* leave that inductor glue to the speaker. Or if the inductor is changed, then the new one *MUST* be the same size, design, and also glued to the same spot. Having the speaker magnet there changes the inductor's inductance. If one is to place the inductor elsewhere in the speaker, then the old inductor must first be measured with an LCR meter, while it's still attached to the magnet to see the correct value. If you guys are moving this inductor around, then you are significantly changing the crossover points and slopes and throwing the speaker off balance.

[lowtech]

Also, from the picture, I see that the inductor is glued to the back of the speaker magnet.

This is simply asinine.  Did they go out of their way to intentionally do this?

If you guys are moving this inductor around, then you are significantly changing the crossover points and slopes and throwing the speaker off balance.

Based on SoundStage's measurements, one could argue that any change to the balance might be an improvement.

[technobear]

This is simply asinine.  Did they go out of their way to intentionally do this?

Based on SoundStage's measurements, one could argue that any change to the balance might be an improvement.

It may have been mentioned before but that graph is total rubbish. Soundstage measured the Druid suspended in mid air, a position in which it's bass port cannot possibly work. The Druid needs a precise gap between the base and the floor to function correctly so the graph is nonsense.

I'm surprised by those who say the Mundorf cap tips up the frequency balance as that has not been my experience. I found the Mundorf cap just got rid of a lot of noise and hash thus making the Druid far more transparent.

As for the 'inductor' glued to the tweeter, there are no inductors in the Druid. The Mills wirewound resistors are non-inductive. They are deliberately dual wound in order to be non-inductive.

Those experiencing brightness may just be experiencing tweeter resonance in the 1 - 2 kHz range which can be quite fatiguing. Add a 47 ohm Mills wirewound across the tweeter terminals from plus to minus and this will go away.

[NagysAudio]

Go to page 2 of this thread, about half way down and look at that picture... What's that shinny copper looking thing? Looks like an inductor to me! If this inductor is moved to a different location, the balance will be off. Simple as that.

[technobear]

Go to page 2 of this thread, about half way down and look at that picture... What's that shinny copper looking thing? Looks like an inductor to me! If this inductor is moved to a different location, the balance will be off. Simple as that.

If you read on from there you will see that we are told by Zu that this is an older version of the crossover and should be replaced in its entirety with the single 1 uF cap and 12.5 ohm resistor.

[jameshuls]

There is NO inductor in the high pass filter of the MK IV Version of these speakers! A cap and a resistor is it...

Couple of observations... From experience, the Mills resistors sound better and are better built than everything else in the wirewound resistor category. There's absolutely no need to change the resistors in this speaker. Why spend $200 when you already have the very best that you can have?

First of all, where do you get the idea that people are spending $200 on resistors? I purchased Dueland resistors, which were $16 each, which brings me to the second point: Mills may be the best wirewounds (originally designed for indusrial use), but the Duelands are graphite (specifically designed for audio use):

Duelund Coherent Audio... resistors are specifically design[ed] for loudspeaker crossover use. Constructed from a graphite rod with silver terminals in a phenolic cylinder for protection. They have practically zero inductance, with a 5% tolerance. The special charcteristic about this resistor is that it displays a negative temperature coefficient. For example, when the voice coil of a speaker heats up, it's impedance rises. The DUELUND Graphite Resistor counteracts this by means of a decreasing impedance. The results are greatly improved dynamics from the driver.

Whatever the explanation, I feel that the addition of the Dueland resistor to the Mundorf Cap has improved the overall coherence/integration between the main driver and the horn tweeter. It has become smoother, with more with a more natural, "airy" sound.

So, despite what your graphs, specs and opinion based on zero experience either with the speaker and mods to the high pass filter might imply, these modifications make a significant impact (from this post, there seems to be a unanimous agreement that the change is an improvement), improving an already wonderful, if idiosyncratic, sounding speaker.

[face]

Mills resistors sound dark and colored compared to Duelund.  In series with a tweeter, there is no comparison.

[45triode]

After 400 - 500 playing hours the sound has surprisingly smoothed out. the modded druid is still brighter sounding than the original, but only recordings "hot" in HF are annoying (which they should be ). i believe this is a worthwile mod, not only does one gain treble, but more detail as well. after all i have to say, that i am satisfied and the hours of waiting for it to come on song paid off.

[naggots]

It amazes me that that stereophile graph keeps popping up. It's from a Druid mk2 with Audax tweeter and different FRD

Druid mk4/08  uses totally different drivers and high pass components.

Ignorance is bliss

For me the highs are cleaner and more forward but without tipping the sonic nature of Druid up too much, a definite improvement.

[Mozza]

I just wanted to post a tip for anyone interested in modding their Druids. I have a Druid MK IV (pre '08) which had a high pass filter consisting of a 1.0 uF Kimber Cap and a 12.5 Ohm Mills resistor. Having picked up a number of different 1.0 uF caps (Mundorf Silver/Gold in Oil, V-Cap TFTF and OIMP, Jantzen Superior and Silver Z-Caps and Obligatto) for coupling purposes in my various Hagerman projects I am working on, I thought it would be intersting to see how these caps might change the character of the Druid. As the Mundorf is said to be one of the best for speaker applications, I figured I might as well start with that one (not to mention, the Silver/oils are what Zu uses in the Presence and the Definition). A couple buddies, a couple hours and couple beers later, the job was done - the cap was soldered in with Mundorf silver/gold solder (with 8.5 % silver and 0.1 % gold). Upon firing up my melody 2A3 integrated and playing a few reference albums (has anyone heard Bon Iver - For Emma, Forever Ago? If not, check it out!) it was obvious there was a change. The highs were more pronounced, sparkly - off-axis listening improved greatly, and when in the listening chair, there was more life and air to the music. The soudstage also blossomed. However, there was also some stridency that was fatiguing. On went the radio for a week of Burn-in... Upon returning to the listening chair, the situation had improved. All the benefits, without the fatigue. These are definitely staying there, until I can afford some Duelands, that is! Overall, for about $200 and a few hours of work (if you're drinking beer and having fun maybe work is not the right word!), my speakers took a significant jump in performance. I guess Zu doesn't use these in the first place due to their cost - $200 worth of components probably means another $4-500 on the price tag, pushing the speaker into a price range that may impact sales, over what the improvements wrought. The only caveat - if your system is already bright, you may find this change takes things a bit too far, unless of course you change the resistor value to compensate. That brings me to my next mod - replacement of the Mills wirewound with a Dueland resistor - at about $30 for the pair it's hard to go wrong. I'll post again once it is complete!

Hi James

I seen your post thanks, I am very interested in doing this upgrade just wounded if you would mind emailing me a shopping list of everything I will need as I will be getting my local audio shop to do the work. Thanks in advance.

[Speedskater]

"Mozza" note that most of this thread is more than 5 years old. Some parts may not be available, the manufacture of other parts may be very different now than they were 5 years ago.

[Russtafarian]

Mozza, you can contact Zu directly.  They are really good about helping with upgrades.  If you want to DIY they will recommend part brands, values, and vendors.  Or you can trade in your current tweeter assemblies for tweeter assemblies with upgraded parts.

Russ