insanity

May I ask where you bought it? Was it from a commercial seller?

OMG now I really want a 007 to complement my 009... Please keep us posted on what you think. Did you get yours form PJ?

To all who own a KGST and a KGSSHV. Which one do you like better with the 009? I have a clear preference for the KGST that persists even after rebuilding the on board KGSSHV with c4686 instead of 1n100d. I would have expected them to become almost equal, but to my ears the difference is not small. Can anyone else share their impression on this? I am even thinking about selling the KGSSHV and building a second KGST or just get a BHSE?

I had ceramic sockets from ebay that were impossible to get a tube into. I used a 1.1mm drill and a lot for muscle to open up the sockets. I suggest to use some lubricant when you do this. Something like electrocontact spray. Otherwise you will have a really hard time. I thought I only had the problem, because I bought relatively cheap sockets. But if the problem also occurs with teflon sockets, this really sucks. Could you please post a link to the sockets you bought?

I will give it a try. Thanks for the picture.

Birgir, could you provide a picture of the when mounted to the headphones? Somehow I have a hard time understanding exactly what you did. I would greatly appreciate it.

Sorry I am out. Can't justify buying a backup set of boards at 90$. sorry.

Same for me. If the cost is reasonable, I'm still in for a set.

667-ECQ-E2105KF

I'm in for 1 set too.

Its this one: http://www.mouser.ch/ProductDetail/Schaffner/FN9290-4-06/?qs=%2Fha2pyFadugBZovmQ3il67V%2F2HEIfMEF%2FTt44J7gppo%2FoQvTfCvEHg%3D%3D Total overkill probably.

The star ground of the bread board is connected to the chassis through the wires leading to the IEC. The IEC has a ground to chassis connection through its mounting screws. Furthermore the XLRs and also directly connected to the chassis through their mounting screws. The toroid, the IEC, the PSU board and the amp boards have direct connections to the bread board.

Yes, that breadboard is starground as well as a connector for the transformer and the switch.

Here are some more pics of the internals I have some additional venting holes drilled under the tubes, but I guess with a 3U case, this would not have been necessary. Furthermore I didn't have the US screws for the small heatsinks. I had to use m3 with a washer all the way on the rear of the sinks (looks crappy, but... whatever). The voltage reg near the washer has some shrinking tube over it, just to be safe. Pot is an alpha from Birgir with the corresponding pcb. The brown pcb on the left is for star ground and mains. Because I wanted that pcb mounted inside as is, I had to use the side panels of the case the "wrong" way around. This is why there are some additional holes on the mounting brackets of the front panel.

@headincoulds. I have not done an extensive comparison, since I have changed the output transistors of my kgsshv to 4686 (which was a very big improvement over the ixys mosfets). My current impression is still that the KGST fits the 009 a bit better for my taste. @earspeakers. The KGST is a slimline case from modushop with 10mm front, the KGSSHV is a pesante case from modushop with a 10mm front. Both frontpanels were sent to schaeffer in germany (FPE in the US) for machining. After working with both types of cases, I think the slimline is superior in every way.

Two brothers ;-)

Depending on the cost I might be in for an additional backup set.

I guess it should be 100mA, This is the fuse you need, if you build the 500V version. As you are building the 450V version, you don't need to populate this part.

Joamat, do you have any comparison with a conventional kgsshv, a kgst oder a bhse? New star sounds like better than BHSE?

Really looking forward to hearing your impressions spritzer, especially in comparison with the KGST and KGSSHV.

very nice indeed. can we see some more pics of the inside?

Ok I just measured my tubes with the following parameters Vplate = 338V, Vgrid -18.4 (arbitrary, just set the first tube to around 10mA). With around 20 tubes, I got values ranging from 5mA to 12mA. Since I do not have much experience with matching tubes, I wanted to ask what you would call well matched for the KGST. How close should a pair of tubes be? 5%? 10% 20%? Would you only pair tubes of the same brand/manufacturer (see below)? If I put together pairs for the KGST, should I make pairs with 4 tubes as close to eachother as possible or is it fine to make 2 pairs such as 5mA 5.4mA and then maybe 10mA and 10.5mA? Furthermore I noticed I have some black tubes, some darkgrey ones and also some light grey ones. I thought only GE and RCA (if I remember correctly from reading) manufactured 6s4a tubes. Does anyone know if this is true? Thank you so much for your assistance.

I have a question concerning the matching of 6s4a tubes for the KGST. In the datasheet 250V is stated as the max average plate voltage, where as 550V is the maximum dc plate voltage. The KGST runs at +-350V (=700). So what is the plate voltage in the KGST? 350? 700? I would like to measure my tubes as close to real operating conditions as possible. To what plate and grid voltage should i set my tester?

When you use the insulating washers on the front side (which is how it should be done), you will probably have to enlarge the mounting hole of the transistor tab with a corresponding drill. It is easy, just make sure that you clean of the metal debris thoroughly. As mentioned you have to use the right washers that are long enough to go all the way from the transistor tab into the ceramic insulator. This way, the whole metal screw will be insulated and does not add extra capacitance (which is good too). With this mounting method I have successfully build the KGSSHV and KGST and never had any arcing problems. If you do it right, there is IMHO no need for PEEK screws.

Cool build. Have you managed to get it silent in the this version? Does the 2sc4686 still count as an in production part?