Schaller KV-50

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Re: Schaller KV-50

Postby Muziekschuur on Sun Aug 10, 2014 2:27 pm

I have a working Schaller Sound Echo....... And a KV40. I'm not as skilled as you.
The heads from the echo should not touch the drum... But be very close....

The KV40's belt is broken. So I should fix that. The echo sound IS a working one. Tho since purchase (June 2014) I have not yet fired it up. I allso have the matching KV35.
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Re: Schaller KV-50

Postby Muziekschuur on Sun Aug 10, 2014 2:37 pm

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There was allso a volume pedal option on the KV40. Where you can connect a DIN 3 pin connector running towards a volume pedal. I have that pedal too.... (Thanks ebay).

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Re: Schaller KV-50

Postby Racing on Sun Aug 10, 2014 3:49 pm

Yep.
Believe i´ve seen some of your equipment over at Gearslutz.
Agreed. What many don´t know is that this is how Schaller started out,and not without merit. The only real drawback,or whatever you wanna call it,is that the Schaller stuff WAS and IS expensive.
A KV-50 or KV-40 like ours was no childs play as you were to fork up what was asked.

I´m aware of the whole drum setup scenario. That,as far as i´m concerned,is the easy part. We checked the 5 Bogen heads on a meter for inductance and they came up OL. In turn we measured for capacitance,and that ended up at approx 100pF=open circuit. What we measure is the capacitance of the wire per se that the inductance is made up of.

Trying to locate Bogen UK-100 heads has become a real issue. A nuisance of sorts,as basically every other tapehead known to man can be dug up one way or another and the mere proposition that Bogen UK-100 can not simply fail me.
I have a very hard time taking that to heart.

However,keeping the unit stock isn´t my main agenda. My agenda is putting together a usable half highwattage combo that´ll stand roaring away at various venues. IOW,i WILL get this working one way or another.
In searching for info on the system i ended up checking a Philips unit out that was obviously real expensive at the time and aimed for use by various radiostations and what have you not.
Very little has been arrived on as far as inductance,flux asf though. More to the point,nothing has been arrived on as far as that goes. That a Schaller drum echo works i guess is beyond reason,but what to do when spares are obsolete-from what it seems?

On the other hand..the amp works and works well. It roars along in a rather contemporary manner (vs stock that is) and as far as that goes i´m about as happy as can be.
The lack of stock reverb tho...i´m not one of those that say die easy. Stubborn..yeah,might be,but OTOH it normally pays off. Not thus far this time though :evil:
In my book someone across the globe HAS to possess a number of Bogen heads. Simple as that...

Bogen Germany in turn,as much as i´ve read,is the same company as the US counterpart. Have written Bogen in Germany and still await some sort of reply.

If i only knew the inductance of the heads i guess some sort of equivalents could be mustered somewhere?
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Re: Schaller KV-50

Postby Muziekschuur on Tue Aug 12, 2014 7:28 pm

hit me up at fvandenberg at zeelandnet dot nl and guide me through the measuringpart and I can get you some numbers. The Echo sound should still work. And I do have an extra disc for it.
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Re: Schaller KV-50

Postby Racing on Wed Aug 13, 2014 11:57 am

Thanx a million.
On my cellphone right now but i´ll shoot you an e-mail as i get home.

DC resistance can be measured with a regular DMM however measuring for inductance takes a rather specific instrument.
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Re: Schaller KV-50

Postby Muziekschuur on Wed Aug 13, 2014 8:47 pm

I own a Mitsubishi scope, multimeter (all chinese) and a full tube Ediswan signal generator. A tube tester is present too... (tho I am not really technical).
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Re: Schaller KV-50

Postby Racing on Wed Aug 13, 2014 11:44 pm

You´ve got mail Sir... :mrgreen:

That said the old neverendingstory Schaller of mine has been on the backburner a bit,no wonder i guess. Anyways. Got to toss a few fresh speakers at it today and daaaaayyyyyyyum! :shock:

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Just some generic Eminence LadyLuck´s...but DAAAYYYYYYYYUUUUUUUUUUM! Them made the combo into a true performer. Let me tell ya. These speakers for some reason have caught a LOT of flack down the road and TBH i truly fail to see why.?

In short? Friggin happy as pie! Now...for that (/¤&%(¤)/&%)(~~~~~&¤% reverb..
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Re: Schaller KV-50

Postby Muziekschuur on Wed Aug 20, 2014 8:32 pm

Why not cut the wire to it.... Make another box put a B$^((&%$$er reverb pedal in tha box and some rca to jack connectors between and use that as tha secret verb for a while....

I'm still working on my Carlsbro.... Sorry.... ANd some rooms to paint and a new door to fit ..... etc etc.... Well... yur married with kids or not i'd say... :mrgreen: :sleepy:
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Re: Schaller KV-50

Postby Racing on Sun Aug 24, 2014 3:20 pm

Nah.
I got no real issues from a practical POW turning it into a tapeecho instead. As my screen name implies i do own a lathe,TIG welder,bridgeport asf so the parts needed for the transformation...not the end of the world to me. All good even.

It´s just that i would consider it sort of a defeat to stray away from the stock setup. Silly maybe but it would be nice to keep that Schaller echo...simple as that.

A regular reverb though would make away with the delay for instance...so that´s out. If i need to...tapeecho is the route i´ll take.
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Re: Schaller KV-50

Postby moritz on Mon Aug 25, 2014 3:14 pm

Nice work you've done on that amp there, well done.

Regarding the reverb unit, a crazy suggestion maybe, but what if you simply wrap a short length of reel-to-reel tape around the echo drum (attached via double sided tape, glue, etc.) so that the oxide side of the tape (the side that the tape heads normally come in contact with) is facing outwards?
The idea being that it'd allow you to just use any old 'regular' tape heads. Something like half-inch tape looks like it'd fit nicely. It'd probably need to be replaced periodically due to the short length, but should still get some decent miles out of it. And if you ever track down a set of those Bogen heads down the road, just rip the tape off and revert to stock.

That is unless I'm reading this all wrong... I'm assuming the issue lies simply with your current heads not agreeing with the particular type of oxide coating on the drum?
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Re: Schaller KV-50

Postby grazioso58 on Sun Mar 15, 2015 8:28 pm

Sorry to resurrect this thread, having similar issues with rather rustic and handyman attacked tube schaller kv50 albeit mostly working . i would really appreciate any good schematics, so far i have been able to locate only the one from http://schaller.forbi.net/Schaller_div.html for kv40... it seems bit different from kv50 and echo part seems real sketchy.....it is mentioned here that someone reverse engineered is it available for download?
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Re: Schaller KV-50

Postby grazioso58 on Tue Mar 17, 2015 7:13 pm

Well never mind Detlef Rieck to the rescue :)
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Re: Schaller KV-50

Postby Racing on Tue Mar 17, 2015 9:45 pm

Yep.
Detlef knows...true enough. Sorry to be a bit late to the party.. :)
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Re: Schaller KV-50

Postby Racing on Fri Oct 09, 2015 11:34 am

As i´ve written the echo of this KV-50 was down and out.
Main issue being the shot tapeheads. The Bogen made tapeheads. Well. Since i´ve searched high n low for a parts donor and..it finally paid off.
According to the seller one of the heads is out on this unit too,but that at least leaves me with SOME working heads,and hence hopefully an echo that´ll work again..

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Yep. This one´s seen some service alright. All of the tubes are missing. The drivebelts are shattered and in turn some idiot has taken the ferrous lining of the spinning aluminium drum off. In short...this is a no-worky ...

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Basically all i need from the unit are the tapeheads. However,my current line of thinking is to check the e-lytes and so forth out and clean the unit out with rubbing alcohol and so forth and then install fresh drivebelts and a set of tubes to see if i can get the thing working as a complete unit at first.
Point being that this way it´ll be easier to "move" the needed pts when done and what´s more do so with the knowledge that they indeed work.

What´s a drag all said n done is that these units are half expensive when up for sale. That i ran into this molested one was pure chance really and i sincerly hope the seller was on the money as ar as the heads being ok.
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Re: Schaller KV-50

Postby Racing on Sat Oct 10, 2015 10:11 am

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As it turned out the unit wasn´t THAT shot after all. That there pot tho,that doubles as on/off switch,was. To the point where i took it apart basically just to conclude it was beyond salvation.
So. Set the breaker for "on" and replaced the pot with a fresh one.

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The working end then. Nothing much to say.. Top left the oscillator,below it the underside of the motor and from the middle out to the right the various entry and recovery stages.

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Indeed. One of the all in all 5 heads was shot.

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Unit works off of this drum. In stock form it´s got a layer of sprayed on ferrous metal and from what i´ve understood many mistake this layer for rust..and sand it off of there...rendering a unit that is useless.
As this drum IS sanded down i´m going to try and dress it with regular tape and see if that would do it..got nothing to lose so..

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..not the end of the world though as i´ve got a working drum intact from the amps original unit. The white head being the erase one and the other next to it the recording one. The recording one being the same head as the playback ones.

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The oscillator signal as well as instrument signal heads for that there soldersupport. In short that´s where you measure for function of recording and erase both.

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This in turn is the opposite side. Where the playback signals are all headed before entering various recovery stages et al.

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Yep. VICTORY!!!! Over a year worth of wait is to an end! The unit works,after a thorough checkout..sans the one playback head then....but it works...

Seing that first on the agenda here,before taking it down to install what´s needed in the other KV unit,is to measure inductance of the heads. That and physical dimensions as well as core gap. That way i hope to be able to find some sort of replacement head,and thus..one of the real pitfalls of these units will come to an end too....
In turn i´m going to try and raise the heads approx 5mm to make them "see" formerly unused territory on the drum. That...and try the destroyed drum with regular tape as stated,cause if that works that´d be the elimination of another pitfall that seems common with these units.
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