sorenb

Can you elaborate a bit on the reason why you believe that the circuit design is flawed? does it include both PSU and AMP board from the Carbon Group Buy?

So you are talking about noise you've discovered using your custom boards rather than the GB boards? Can you elaborate a bit on the reason why you believe that the noise your are measuring is caused by leaking resistors?

Glad to hear, although it took a very loooong time to arrive.

Will there be new V5 and GR HV boards with ground plane? I guess, if people mount the components raised and stick to boards of good quality it shouldn't be a problem?

Meaning that any Carbon build will be "severely compromised" just by using the boards from the Group Buy?

That looks like your own personal edition of the "kgsshvpssicfetsmall3" having 330uF pre-reg, and 220uF post-reg - but as you like mini, you've replaced those 220uF for 100uF and shrinked it a bit to go from small to mini. The only schematic the other persons did publish has 680uF pre- / post- reg, so how are people to know that 680uF caps is NOT what the PSU is designed for?

Meaning that the GND from the PSU are connected two times at each AMP, and uses the signal GND for ref for the HE90 voltage divider?

Thanks. How does the Carbon compare to your BHSE?

Appriciate your description, thanks. In terms of change in sound, have you noticed any difference during the time you've had it?

I'm sure it does ... a pretty fine amp that is ;o) Have you notice any change in how the Carbon presents the deep end during the time you've had it?

Nice build you've got there Purk :o) Un-twisting the output wires, isolating the AC wiring and some hot snot to further secure the caps would be an easy fix.

Fiat lux ... Fiat musica

If someone wants to power up the Circlotron using a variac it might cause a bit of trouble. When powering up the driver it has B+ at the output until the driver output stage begins to conduct current, then it drops to some ~0V (if proper adjusted that is) Having B+ at the input of the Circlotron output board will turn on the SiCs at full throttle going for 7,5Amps (900V/120ohm) ...however limited by the HV900 current limiter. Better to power up the driver at full mains, and afterwards dialing in the output boards + HV900's using a variac. That approach seems to work out pretty ok. Only applies to the HV900: For anyone building this Kevin recommends to increasing the current sensing resistor from 5,1ohm -> 12ohm to further protecting the output if something should go wrong. /Edit: as per Kevins comment below.

I'd rather change the values off the zener-string a bit an tap the NB from there. Then you only need to add three resistors and a couple of caps. Like Kevin has done here: As you may notice, there are two NB BIAS connections corresponding to the two pins on the jack. /S

for the amp @20mA they seem to be a bit on the small'ish side

You have been added to the sheet here

probably the BIAS ... the HV has balast resistors that will burn the energy

it comes and goes ... I often loose it when changing into the DIY section ...a refresh however solves the problem in my case

everyday is a Black fried day

As it says in the headline it's B for both SOIC-8(5USD) and TO-71(7,5USD). (based on a quote on >100)

As Luvdunhill has a limit of 100 total for his mini-GB, and the the count was well above 100 not counting myself and luvdunhill, I've got a quote from Trendsetter at 5USD/ea, at minimum of 100, I've decided to organize a GB for those who still wants the LSK389B at 5USD/each, state your interest here At this point in time there are almost 100. Please be aware that the GB started as for SOIC-8 package alone. I have added the TO-71 to the spreadsheet. 20160120: GROUP BUY CLOSED

Thanks, found it here: from the SDS it seems to contain AMINOETHANOL and ALKYLBENZENE ... the latter is known to be carcinogenic ... I guess for amateur use the >99% isoprophanol + rinsing in deionized water is a better way of cleaning the pcbs in comparison to the Electrolube stuff

As Luvdunhill has a limit of 100 total for his mini-GB, and the the count was well above 100 not counting myself and luvdunhill, I've got a quote from Trendsetter at 5USD/ea, at minimum of 100, I've decided to organize a GB for those who still wants the LSK389B at 5USD/each, state your interest here

Circlotron Driver board from the Group Buy is working. As I'd like to test as much as possible before connecting everything, I'd decided to hook the driver up as an amp. The Carbon V5 and Circlotron driver board are very similar although there are a number of differences that require a bit of tweaking to make it work. The biggest difference is in the servo part of the driver board and since the driver board is missing the A06 - controlling the current in the tail of the output stage directly from the opto - it is probably not possible to run the output stage at 20mA as it will exceed the opto current capabilities. The pic shows (I believe) everything needed to 'convert' the driver into an amp - I haven't tried to get the servo to work though. The important alterations is: (not including servo - amp only) NOT populating the 10k/10uF besides the opto terminal (until it is actually gonna be used that is) parallel the 500ohm in the tail of the output stage with 150ohm or thereabouts (I just solder one on top - easy to remove again) adding 2x (100k + 100k) for feedback. adding 2x 5k1 ballast resistors to the output This is as I hook'ed it up, and dialed it in for 20mA operation - has ran for some days 24x7 without any problems. For the servo to work a few changes in addition to the picture above is needed: the opto has leg2 tied to GND - this trace needs to be cut. Remove: the 47uF between the opto leg1 and leg2, and 5k resistor between OpAmp leg6 and opto log1 Add: 1uF between OpAmp leg6 and leg2, 200ohm between OpAmp leg6 and opto leg 2, and GND to opto leg1