[KN4YRM]

Hello,

A few questions about the kit:

1. Does it ship to US? Roughly how long to arrive? Is there a US distributor?
2. Comes with tubes?
3. Comes with power supply wall wart? If so, for what voltage/country? If not, what supply (ac or dc, and voltage & amps) needed?

Danke,
Randy

[Roger@kainkalabs]

Dear Randy,

1.) yes, we (normally) do ship to the US and you can order directly from our old-style shop where in the final step German VAT is subtracted for customers outside of the EU:
http://www.ak-modul-bus.de/stat/experime...rt100.html

BUT...
ATM our normal (affordable) shipping method as registered mail for commercial goods is suspended by Deutsche Post due to the low air traffic from and to the US. This can change every day but I expect this situation to continue still for at least the rest of 2020.
The only shipping method possible ATM is via DHL which take an extra surcharge. For orders above 200 Euros net shipping costs are zero for the customer and we pay all shipping costs. For orders below 200 Euros net  I can prepare a quote for you. You can place an order (without prematurely paying of course) and I will return a quote to you with the adjusted shipping costs depending on weight and volume of your order. You then can decide if you really want to plae the order or cancel it.

2.) Yes, if you mean the "RT100KIT". Not only the 4 tubes but also all passive and active components, cables etc. are supplied which are needed for the experiments in the PDF manual. You can download the manual in English and German beforehand from the above mentioned site in our online-store
Nevertheless you can also buy the bare experimental board "RT100" without the tubes and without the components and cables.

3.) No. You need a 12V/1A power-supply with a standard 5.5/2.1mm cylindrical power plug. The special thing about our RT100 is that all experiments work with a single 12V supply. That is by always connecting the 6V heater-filaments of 2 equal tubes in series and by using tubes that already work with inly 12V anode-voltange (or plate-voltage as you might call this in the US :-)
You can order such a supply with a US power-plug also in our shop but it will probably be easier and cheaper to get this in the US if you not already have one at hand.
http://www.ak-modul-bus.de/stat/steckern...ntern.html

We have developed special tube-supplies for experiments with higher anode-voltages for advanced hobbyists.
There are 3 types available 12...60V (recommended for beginners), 60...120V and 120...240V. 
They are all linearly regulated (noise-free for radio-reception etc.), but sadly only for 230V AC mains voltage. If you are interested I can look if I find an identical transformer for 110/120V AC that fits into the existing PCBs.
The links to these are also present in the product page for the RT100KIT in our online-shop.
In that case you use the 12V power-supply only for the heaters and the dedicated tube-supply for the anode-voltage.

Best regards
Roger

[KN4YRM]

Dear Randy,

1.) yes, we (normally) do ship to the US and you can order directly from our old-style shop where in the final step German VAT is subtracted for customers outside of the EU:
http://www.ak-modul-bus.de/stat/experime...rt100.html

BUT...
ATM our normal (affordable) shipping method as registered mail for commercial goods is suspended by Deutsche Post due to the low air traffic from and to the US. This can change every day but I expect this situation to continue still for at least the rest of 2020.
The only shipping method possible ATM is via DHL which take an extra surcharge. For orders above 200 Euros net shipping costs are zero for the customer and we pay all shipping costs. For orders below 200 Euros net  I can prepare a quote for you. You can place an order (without prematurely paying of course) and I will return a quote to you with the adjusted shipping costs depending on weight and volume of your order. You then can decide if you really want to plae the order or cancel it.

2.) Yes, if you mean the "RT100KIT". Not only the 4 tubes but also all passive and active components, cables etc. are supplied which are needed for the experiments in the PDF manual. You can download the manual in English and German beforehand from the above mentioned site in our online-store
Nevertheless you can also buy the bare experimental board "RT100" without the tubes and without the components and cables.

3.) No. You need a 12V/1A power-supply with a standard 5.5/2.1mm cylindrical power plug. The special thing about our RT100 is that all experiments work with a single 12V supply. That is by always connecting the 6V heater-filaments of 2 equal tubes in series and by using tubes that already work with inly 12V anode-voltange (or plate-voltage as you might call this in the US :-)
You can order such a supply with a US power-plug also in our shop but it will probably be easier and cheaper to get this in the US if you not already have one at hand.
http://www.ak-modul-bus.de/stat/steckern...ntern.html

We have developed special tube-supplies for experiments with higher anode-voltages for advanced hobbyists.
There are 3 types available 12...60V (recommended for beginners), 60...120V and 120...240V. 
They are all linearly regulated (noise-free for radio-reception etc.), but sadly only for 230V AC mains voltage. If you are interested I can look if I find an identical transformer for 110/120V AC that fits into the existing PCBs.
The links to these are also present in the product page for the RT100KIT in our online-shop.
In that case you use the 12V power-supply only for the heaters and the dedicated tube-supply for the anode-voltage.

Best regards
Roger

Roger-

Let me tell you a little about my goals and maybe you can make some suggestions to get me up to the 200Euro point.

What I like about the RT100 is a convenient platform to do some tube learning and experimenting. I have a signal generator, oscilloscope and many multi-meters so the idea is to play around, take some measurements, do some of the labs in the pdf and try to understand tubes the way I understand solid state stuff.

Part is just intellectual curiosity but also to have a good understanding for my hobbies of amateur radio and guitar. Ultimately the plan is to build some audio amps for listening to music, and also a guitar amp. Radio is maybe a longer term goal, but right now it seems more complex than audio signals.

In the very short term, the idea would be to gain enough knowledge to try and design and build a simple headphone amplifier (not just unity buffer). From what I think I know, this involves a preamp tube and power tube. It seems to me the RT100 will help me learn a lot about the preamp (low voltage) stage, not sure about the power stage. 

As for power, to clarify, I have several 120vac->12vac  and also 120vac->12vdc wall warts, and of course my 0-30v adjustable bench DC power supply. It was not clear to me if the kit expects DC or uses tubes to rectify, etc.

So long story short, maybe you can suggest tubes, sockets or whatever you have that would facilitate building or at least bread-boarding a simple headphone amp, to get up over the 200Euro threshold. Of course it doesn't need to be super quality headphone amp, just proof-of-concept for learning.  I have drawers filled with passives, but really never done anything with tubes. Feel free to correct me on any bad assumptions I have above.

[Roger@kainkalabs]

So the RT100 is quite perfect for you as a beginner in the tube-hobby :-)
You already have the power-supply you need for the RT100 (DC).
The only thing you additionally need for a headphone-amplifier is a little step-down transformer (like our TR110) if you want to use it with "modern" headphones that have an impedance near 8 ohms.
The reason is that tubes can deliver a lot of voltage but not a lot of current. That´s why up to the 1970s the typical impedance of headphones was 2000 ohms. These could be directly atached to the output of a tube-amplifier. When transistor amplifiers replaced tube amplifiers the characteristic impedance of headphones first sank to the 600 ohms studio-norm. These still could be connected directly to tube-amplifierts without the need of a step-down transformer. But then came the Walkman and because you only had 3VDC as a  supply voltage from 2 AA/AAA cells, the headphones impedance had to go down to 8...64 ohms to get sufficient power into the coils for having an adequate loudness. Same is true with todays smartphones that are operated from 3.7V lithium batteries.
And of course connecting loudspeakers with an impedance between 4...16 ohms to tube-amplifiers is only possible with a step-down transformers. That´s the reason why you typically see 3 transformers in a tube audio-amplifiert (no matter if it´s a power-amplifier or a headphones-amplifiert): 1 is the transformer for the heaters and supply-voltages and the other 2 are the stepdown transformers for the left and right channel. These are very big for power-amplifiers, but can be quite small for headphones.
So to make a long story short. For "modern" headphones with low impedance you only need 2 step-down transformers  like our TR110 to build a stereo headphones-amplifier with our RT100KIT.
If you have "old" headphones with 600 or better 2000 ohms impedance you can connect them directly to the tube-outputs.
So there is basically nothing else for starting your experiments because you already have the necessary power-supply. Tubes need DC, the heater can be operated with AC ord DC, but DC is better because then there is no mains-hum that can couple into sensitive amplifier circuits.
So instead of talking you into some additional parts that you don´t need in the end, I would recommend the RT100KIT plus two stepdown transformes TR110 and pay the higher shipping costs instead of blowing up your order to 200 Euros.
The only things that could be useful as an addition would be one or more of our tube-experimental kits.
But except for the 2SH27L-KIT I haven´t yet translated the manuals. So that also doesn´t meke much sense.

Best regards
Roger

[KN4YRM]

The only things that could be useful as an addition would be one or more of our tube-experimental kits.
But except for the 2SH27L-KIT I haven´t yet translated the manuals. So that also doesn´t meke much sense.

Best regards
Roger

Ich verstehe ein bischen Deutsch (obwohl jetzt vielleicht kann ich nicht schreiben und sprechen so gut wie wann ich student war). Welchem kit empfehlen Sie?

[Roger@kainkalabs]

Dear Randy,

net-prices & recommendations are as follows:

KITRT100:   94,40 €
2xTR110  :    9,32 € (1:10 step-down transformers)
KIT2SH27L: 15,43 €
SHIPPING:   30,00 €

These are the kits I would recommend for you. The KIT2SH27L comes with 2 Russian so called "battery-tubes" that work with 1,5V heater voltage and 9...12V anode voltage. Our author Burkhard Kainka (who made all the tube experimental kits) devised some very interesting circuits with these tubes.
As I already said I wouldn´t try to blow up the order with parts/kits just to get over the 200 Euros limit.
But perhaps you find some interesting tools in our "Every maker should have one..." section (where most tools have a separate YouTube video that describe them):
http://www.ak-modul-bus.de/stat/laborzubehoer.html

Best regards
Roger