impedance problem with rebuilt scintillas

[ulrich]

I own a pair of Scintillas. They were 1/4 ohm version in 1 ohm mode.
They worked truly great with Rowland Coherence II and two Rowland model 8 amps in biamping mode.
Last year I had them refurbished by Rolf. Complete 1 ohm version xo rebuild.
1 ohm bass foils, all ribbons new, Auricaps for MR, Mundorf s/o for Tweeters, original Graz inductors, Mundorf zement high load resistors, Cardas binding posts, Nordost 2flat interior wiring.
A labour of love. Pics of the xo are on Rolfs homepage (Bergwinkelaudio).
Purity and imaging are great now, but ...
Impedance has dropped.
Measuring with a Fluke Ohmmeter, it is 0.8 Ohm on bass.
System now lacks drama, impact, power, bass control, highs get strained when louder.
So I am afraid, impedance is perhaps now TOO low for my model 8s.
I do love these speakers.
I do love my Rowlands.

Well, what to do?
Is there a way to raise impedance without changing sonics?
Other inductors?

Yours cordially Ulrich

[K2.NL]

Hi Ulrich,

Measuring low impedances is a tricky thing. Are you sure you've used the right procedure/equipment?

0,8 ohm is very odd. Graz 1 ohm ribbons measure 0,86-0,88 ohm and the original inductors resistance is about 0,11 ohm. So you should measure an impedance very close to 1 ohm. Bad contacts are not likely as well as that would have raised the impedance.

Do both bass sections by the way measure the same?

My best guess is that the Mundorf resistors are not up to the task. Stanley tried out various resistors in his Scintilla xover. I don't remember all of them, but I know he tried out Caddocks and Duelunds. They didn't work in his situation. In the end he ordered the upgraded version of the original ohmites at North Creek and is very happy now.

It is by the way amazing how much this little resistor in the treble section can influence (read: degrade) the entire sound spectrum when it is not up to its task. I've heard on several occasions at Stanley's place how large the impact of this resistor to the quality of sound is.

If the Mundorfs are not up to their task, they might have functioned properly in the beginning. Maybe now they have degraded so much that you start noticing the bad effect to the quality of sound.

In my stock Apogee xover 4 ohmites were put in parallel to produce the 1,25 ohm resistor. Stanley now uses 6 of them in parallel and Arjan recently was advised by George to put 8 of them in parallel.

Kees

[K2.NL]

And of course check all the internal soldering very good. Also the terminals!!!

[ulrich]

Hi Kees!
Thanks for your comment! I think I sent you pictures of the rebuilt xo. I would be surprised to find a defective soldering, as all was built extremely well.
Those Mundorf resistors will be replaced by Graz foil resistors.
Did you compare Ohmites with Graz foil resistors?
Both bass sections (measured at the Cardas speaker posts) measured 0.8 ohms.
Ulrich

[Graz]

I am in contact with Ulrich about this

Take care - Graz

[K2.NL]

Hi Ulrich,

Yep you sent me the pictures of your xovers, I remember them well. The xovers looked great. Inductors, capacitors and internal foil connections in your xovers I don't expect to be responsible for the problem that you describe. The Mundorfs are the only components I'm not familiar with. My best guess is still that something is wrong with them.

We haven't tested the Graz-foil resistor but no doubt it will outperform the Mundorfs and any other resistors I can think off. The foil resistor I expect to be in theory the best way to go for minimal distortion combined with very good power handling. Like the foil resistor in front of the Scintilla midribbon which I believe is highly responsible for the IMO more musical performance of the Scintilla compared to that of its bigger transformer-coupled brother, the Full Range.

I would not be surprised that the problem is solved as soon as the foil resistors have taken over the function of the Mundorfs.

The fact that both channels measure equally low (0,8 ohm) probably is a good indication that nothing wrong with connections in the xover. We used several equipment/methods to measure the low impedances of ribbons and components in the xover. I repeat that it is difficult to measure exact values. Not sure about the equipment we used that gave the best results anymore, but it is was not ordinary stuff...

Cheers,

Kees

[ulrich]

Quite some time has passed since then.
When delivering speakers, Rolf had told me NOT to photograph the right bass panel, not to send pics to Graz, bass foil installation was called suboptimal and promised to be replaced in the near future. He asked me to pay the full amount NOW, as he needed the money. I did. I trusted him.
Hm.
This replacement was never done. In the beginning Rolf asked me to wait, lots of work, this&that Apo to restore....
Later Rolf always told me it is SIMPLYANDONLY my amps fault. Hm.

I was totally fed up with Rolf telling me its my amps not beeing able to run Scintillas.
They had done that before.
Well: Right Scintilla was lacking bass compared to left Scinnie, also dynamics. Both was lacking overall in my system.
I was not listening to music anymore, as it was NO FUN.
Maybe something was wrong with both speakers, certainly something was wrong with the right speaker.

I decided to send the Scinnies to someone who COULD fix it.
I asked Graz.
Graz recommended Frank Ferlesch of Switzerland.
So we proceeded.
I sent Scinnies and AMPS to Suisse...
Frank found a tear in the right bass foil. Rolf had "fixed" this shortening out a part of the bass foil...
So impedance HAD dropped, a part of the foil was not driven ... no wonder sonics sucked.
Rolf and Frank had a phone call. Rolf admitted to know about that...
Frank found more mistakes....resonance tuning of bass foils was completely f***ed up. Both speakers.
Some of these mistakes I have been asked not to share...
Frank should comment that, I think.
I asked Rolf to refund 1000 of the 8000 I had payed for his faulty labour. That would have covered only transports to/from Suisse.
He simply hung up the phone.
More detail of this story in the German "analog forum". Those of you speaking German should read it there.

I do wish to apologize to all here who read my posts lauding Rolf, Bergwinkel Audio, his work. Maybe this made you choose Rolf doing your restoration. This thought makes me angry.

Paint job was great, the reworked Scinnies looked stunning.
Rolf made new struts for the base plate, this was done fine. Rigid, solid.
Treble/Midrange ribbons were installed correctly, I presume. Right channel ribbons have slightly more "hang", which might be due to transportation to Suisse. I do not know and wish to be fair.
BUT.
All this makes me think that he is NOT capable to install bass foils properly and tune them.
All this makes me think that he is not really understanding this speaker´s construction and way of working.
To say that I am disappointed of his way to handle his faulty labour is a gross understatement.
I am disappointed too, as I had trusted him.

Graz has removed Rolf from his installer list.
You may ask how/why Rolf ever was on that list of official installers....and was not removed before he took my money for inadequate work.
I think Graz should comment here.
I do NOT wish to complain to Graz, as he was the one who helped me when I did not know what to do. It was Graz who offered his help before I even asked. It was Graz who sent parts to Frank for free. Parts R had told me he would install, parts I had payed for to R, parts R never installed...
I wish to thank Frank.
Many thanks to both of you, Frank and Graz.

Scinnies are back now. Break in time was very long. Dynamics and bass and drama and fun are back now!
Resolution, imaging are simply great.
But most important, the fun in listening is back, the emotion.

Cheers, Ulrich.

[artm]

Ulrich,

What a story! I would like to comment:

1. The only fault on your behalf is the delay in exposing the bad work of Rolf and the impact it may have had to anyone else using Rolf's services. You acknowledge this so that's that. Whether Graz had some input on this time frame is understandable. In the end, the uncensored commentary is welcomed.

2. I appreciate exposing an inept Apogee installer as I have felt that members here would support an installer to no end, faults and all. If in fact Rolf's inability in this area is not new but has been present for some time, I wonder what value we can place on the opinions of those who lauded Rolf in excess.

3. Of course, well done to Graz for stepping up and salvaging this situation at his expense.

Best of luck with the new gear.

[Vansloneker]

Ulrich deine Geschichte tut mich wirklich Leid für sie. Ich bin mir sicher dieses Arschloch hat dich komplett überrascht und überfallen sonnst hättest du nie seine scheiß akzeptiert.
Great jobs of Frank and Graz to get you out of trouble.

[Groove-T]

Hi Ulrich

Abouth comment from me, i will make my technical rapport to you within a few days.
You are free for translating it into english and post it here or where ever you like, no restrictions from me.

On one side, i met Rolf a few years ago and he invited me at his home and was very gentle like a friend.
Now, in the last few month many things happened behind the curtains and i found that Rolf did some things, i never will and never would do , so the situation for me is not how like it.

I will keep my mouth closed, until i have green light from graz.

Im not so good in politics like in apogee woofer fixing and tuning

What i can say about impedance:

If a woofer (no matter if it is a cone or foil or whatever) is in resonance, his impedance rises, since he does the job with lesser electrical energy for the same acoustical output level. This is simple physic.

Thats one reason why i am warning everyone to tighten the adjusment screw to fight the buzz, the second one is that a fully tightened woofer can crack , what means it is dead and to be replaced.
And the third reason is that the magic apogee sound is no more so much magic.

[artm]

Now, in the last few month many things happened behind the curtains and i found that Rolf did some things, i never will and never would do , so the situation for me is not how like it.

I will keep my mouth closed, until i have green light from graz.
.

You are wrong! You are keeping secret information that would be helpful to anyone considering doing business with Rolf.

Why? Because it may damage the Apogee brand? Ridiculous! What we have here is nothing more than an unscrupulous vendor of a manufacturer's product. Surely we don't blame the manufacturer or the brand for that? If you do you're an idiot.

This is exactly what I was referring to above: keeping things quiet in this utopian place YOU call Apogee.

Ridiculous!

[Groove-T]

The problem is, the situation is not cleared, and i dont want to introduce more trouble.

If somebody is catched by police, he is not guilty until the judge decided he is. At least here in switzerland.

Thats the part i keep my mouth.

About Rolf i can say, he is no more certified installer, because he obviously made some mistakes.
So if people read this and are somewhat intelligent, they will see by themself, that they shoud make use of a certified installer.

And i can say for sure, he made really not a good job with Ulrichs woofers. In any aspect which is important.

[Graz]

There is both an on-topic and greater topic to this story, and I am under legal instruction to keep to the on-topic of this as much as explanation requires.

MY SINCERE PUBLIC APOLOGY TO ULRICH IN THIS MATTER.

Ulrich knows this was a nasty surprise for me too, when it happened. He has been a tolerant, kind and constructive client, better than one could expect in his circumstances, and a pleasure to work through this mess with to a solution.

Positive. Ulrich - as you know I am beyond happy that your speakers are delivering the results you (rightfully) expected from the start. My sincere thanks to Frank (Hifi BURG, Switzerland) for his timely, accurate response. Well done, my friend and associate of 11+ years.

To be honest when I found out about this situation it made me a bit sick. Apology and urgent rectification were my first thoughts, and what would have been the normal line of rectification had been closed in a VERY abnormal situation (with Rolf) - something that I had only found out about 6 days before. To those ends the two closest Apogee Acoustics endorsed Installers to Ulrich were considered, their proximity and current workloads assessed, and the speakers went to Frank (Apogee Acoustics Installer for Switzerland). Once there the detailed analytical tests and subsequent strip down followed, assessments were made by Frank and myself (Frank taking pictures and acting as my local eyes). Several disturbing anomalies were found, and a parts list was made for rectification, and new parts sent to Frank on an expedited service. Reduced impedance, inactive panel areas, inaccurate bass installation, tuning and bass circuit errors, wrong TW xover parts, amongst others and a dangerously low 0.7 ohms bass panel reading. Rectifications were made to the speakers in accordance with requirements in Franks workshop using new bass panels, and other new parts previously sent to Rolf (when acting as Installer) that strangely had not been fitted to Ulrich's speakers - parts I later found out had been used in another application...

The problems found explained clearly why the amplifiers Ulrich had used for years had problems driving them when returned by Rolf - leading to steering to buy Rolf and Armin's Weiteck amplifier as the solution. Rolf didn't answer his phone any time I called to discuss Ulrich's problem, and never returned calls.



On January 18th this year I found out something that affected former Installer Rolf Mooz and his partner Armin Weidner's status as our Installer-Agents for Germany. Something personally so very disturbing, costly and absolutely heartbreaking for me (I don't use this lightly). Consequently they were given 24 hours to respond to questions/allegations, and following a phone call with Rolf were removed from the Installer-Agent's list on the Apogee Acoustics site due to several breeches of their agency. This happened on January 19th 2011. At this time I was not aware of client problems. Despite this complete severance Rolf's Bergwinkel Audio internet site has continued to misleadingly advertise they exclusively use "GRAZ APOGEE ACOUSTICS CNC parts" on their main welcome page until a few days ago - infuriating to me and beyond my control. The whole Bergwinkel web site has since disappeared in the last week.

All Installers make occasional mistakes (me too), and I stand behind them with parts, encouragement and instruction at all times to make the clients experience a good one. Rolf has made such mistakes and I have helped him through the years so as this didn't impact on clients - no worries. Ulrich's Scintilla's had several mistakes and the usual feedback and dialogue with Rolf was not in place as Rolf was deeply engaged in activities (unknown to me at the time) that ultimately kept him from communicating with me. A reject blemished bass panel was fitted to Ulrich's Scintilla's despite an instant replacement having been sent out by me immediately I was informed by Rolf. I assume this replacement was deemed needed elsewhere...

I was not made aware of any problems with Ulrich's Scintilla's despite Rolf's associate having an unusually detailed consultation with me regarding the speakers, deep in all aspects of the work. I honestly had no cause to believe there were problems, until told by Ulrich - 6 days after Rolf had been removed from the Installer list.

I am very accessible for both Installers and clients and my aim is to repair classic Apogee Acoustics speakers to better than new status. For over a decade this has been my professional life, and I do take my work obligations very seriously and understand the product properly. I often, almost always contact clients for feedback and always welcome this - good or bad. People with problems with work should contact me if they feel they have reason to criticise the Installer-Agent's work - or cannot reach agreement with their Installer. Without fear of rejection out of hand by me. I do not take lightly that people are dealing with me largely on 'faith" to restore their speakers properly either here or via an Installer, and am always ready to mediate if/where required.

I have also since (last few weeks) had pictures sent of another client's speakers returned to them extensively damaged whilst in Rolf and Armin's control, repairs commencing during the time Rolf and his partner was acting as Installer-Agents. This is another story though. Clients with similar situations or problems should contact me asap - I want to help.

Many who know me understand there is a deeper story with Rolf and are aware of it. To be honest I am still close to disbelief and full of disgust for the big picture here! We are in a legal dispute with Rolf and Armin over several premeditated malicious actions on their behalf, and until those are resolved I have been advised I should restrict my comments to clients cases dispassionately, despite my personal feelings to speak from the heart!

Bottom line. Installers not on the list are no longer Installer's, no longer able to supply or be supplied with our GENUINE parts, or be backed up with our support, advice and service.

ROLF MOOZ & ARMIN WEIDNER as of January 19th this year are no longer our associates and were removed from the Installer list. As they only ordered our parts on a case-by-case basis they carry no old stock of ours, and will not be supplied new stock.

People located in Germany requiring Apogee repairs should contact long term Installer-Agents Frank (Switzerland) or Henk (Netherlands) to arrange a genuine repair using our GENUINE parts and methods.

http://www.apogeeacoustics.com/installers.html

Sincerely

Graz

http://www.apogeeacoustics.com

[artm]

never mind...

[Vansloneker]

I know of only one person who has been granted by the owners to make use of the brand name 'Apogee' or 'Apogee Acoustics'.

[converse320]

Haven't been here for a while. I checked out Ralph's website to see what on earth is going on and was so surprised by this. Really sorry this has happened Graz, just terrible. Best of luck with the lawyers, and hope you have a speedy resolution.

[Ralph]

Haven't been here for a while. I checked out Ralph's website to see what on earth is going on and was so surprised by this. Really sorry this has happened Graz, just terrible. Best of luck with the lawyers, and hope you have a speedy resolution.

With respect, I hope you meant, "Rolf's website" ....

Ralph (not Rolf)

[converse320]

Oh dear. Yes you are quite right, I meant Rolf's site. Sorry.