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new automatic bias circuit for different power tubes SE and PP
new automatic bias circuit for different power tubes SE and PP
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Old 15th July 2011, 06:30 PM   #1
milma is offline milma  Germany
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Join Date: Jun 2011
Location: Kassel Germany
Default new automatic bias circuit for different power tubes SE and PP

I offer modules as 1) PLUG and PLAY 8 pin socket or 2) PCB an circuitry for automatic setup your tube bias current from 25 - 60 mA.


Doesn’t it hurt you, having to spend your hardly earned money on expensive, selected final tubes? Having to adjust the BIAS of your power amplifier every second day and still not being able to avoid the aging of the tubes – which are already on the next day no selected tubes anymore? There’s an end of it now! There are friendlier, more up to date and much better technical solutions for your tube problem. Our offer is called “ABR”, automatic bias regulator - a typical highly innovative development of our house which you certainly have been missing in the scene up to now. The controller can be used for all tube power amplifiers - for HiFi as well as for musician equipment, as for example guitar amplifiers. Whenever you get the impression to drag behind technically with your power amplifier we should start a talk – maybe the solution of your problem is also just called "ABR".Whoever has already dealt with tube amplifiers, or maybe even has some of them in his own stereo system, knows the problem of the closed-circuit-current adjustment at the final tubes. Most tube amplifiers on the market – new and older models included – are not able to handle the time-caused change of the closed-circuit current on the final stages. For them, this means manual adjustment of the bias closed-circuit current or even replacement of the tubes. Usually there is no machinery that recognizes those changes or even adjusts them. Often the closed-circuit current gets adjusted with trimmers – frequently more than you probably would want to – only for repeating the procedure on the next day again. Especially the modern tubes can unfortunately not be compared with those of the 50s and 60. Therefore the usage of operating capable power amplifiers longs almost for an automatic control element that observes and adjusts the changes in the closed-circuit current permanently. On the market you will hardly find solutions for this problem - ours is called ABR.
After a long time of development work we were able to produce such a circuit which gets implanted in the cathode line. And the best about it: the ABR can of course also be installed in all tube amplifiers afterwards. Like this you are completely released from the tiresome and costly procurement of selective tubes for all time. Just forget this topic and start enjoying the boundless freedom and assurance of ABR. The ABR quarries the maximum of musical quality from your final tubes – during the whole lifetime of the tubes. No traditional manual or so-called semi-automatic regulators, no selected tubes – really putting things right can only the ABR. He even avoids the vaporizing of your power amplifier in case of a shunt fault or thermal collapse. The installation is very simple. One removes the cathode resistance or unpicks the cathode line of the contemplable final tubes and solders the ABR about merely the same both pipelines, pays attention to the polarity, that the negative pole is led in mass and the positive pole to the tube, also pays attention that the switching circuit stays cooled and then takes pleasure in the possibilities of this new and unique kind of closed-circuit current stabilization. From this day on you may use Chinese KT88s or even older and second-hand tubes again. As long as your tubes are capable, the ABR takes care that they work in the defined range of the closed-circuit current. If they should once, nevertheless, don’t do it any more, a red LED registers that the exchange of the final tube is recommended. Even in louder and more dynamic sections, the ABR stabilizes the cathode tension and avoids the closing of the final tubes, how it is the case when using cathode resistors (also called automatic grid preliminary tension producer). As you can see: A very elegant and intelligent answer to those problems of which you should think at latest when you are planning to change your final tubes – maybe there’s a better solution than using selected goods?
All of our customers can confirm the excellent effectiveness of the ABR, no matter whether it concerns old tube power amps or other brands. The operating duration, the operational safety and not at least the musical qualities increase exorbitant. With the ABR you are technological absolutely on the advance.
The module ABR-P should be installed isolated at the inside of the unit – installation according to the photo. An 8-pole octal compatible variation which is put in the tube base instead of the tube, which is put on it then, is also available (ABR-S)
technical Features:
no additional supply voltage necessary
Stabilization of the closed-circuit current on any values factory-provided, e.g. on 50 mA - ABR 50.
Usable for all imaginable machines from other manufacturers.
Ready mounted, checked with heat sink.
Separate additional positive output over reversible fuse (PTC).
For all current final tubes as for example KT88, EL 34, EL 84, KT 66, 8417, KT 90, KT 100, and many more.
Latching of the cathode tension also in dynamic case.
Red / green scale for permissible or impermissible area - for you as an indication when the tube has to be exchanged / runs out of the permissible tolerance of the control circumference (under +5 volt, over +50 volt).
maximum load 15 watt
Adjustment range of the cathode tension +5 till + 50 Volt.
ABR – internal resistance 1000 Ohm.
send email when you have more questions ....
ABR-P for chassis mounting - 29,-€ / pcs. ABR-S, Plug & Play version 8 pin socket, 39,-€ / pcs.
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