B1 with Korg Triode

My B1K does not do this at all.

Maybe a silly suggestion, but maybe you should plug only a single channel into your switcher to make sure you did not swap channels in either the switcher or the preamp builds.

Alan

Ok, so I did some listening tests where I used a passive switcher (Schiit SYS) to switch the B1K in and out of the signal path to my ACA in real time. I noticed a number of sonic differences (all positive with the B1K in the path) but one of the most striking was some mid-hi instrument notes moving from one speaker predominance to the other. I'm inclined to believe this is due to the phase inversion of the B1K. Has anyone else noticed sound phenomenon with the B1K that they specifically ascribe to phase inversion?



I have no good way to do a switched-phase experiment in real time as I don't have the gear to invert speaker phase without power-off of the ACA. I'd be worried about blowing amp or speakers doing that live.
 
I bought everything at diyaudio except the "miscellaneous completion" package which they did not have. I can say that this method is working for me. When I bought, the "miscellaneous" package was the one item that was keeping the kit from being available.

I caused myself headaches because I did not make a complete list of absolutely everything I needed right off the bat, and have now had to order four times from Digikey (partly to support the later addition of an IR volume control from Academy Audio).

Make a list of those miscellaneous parts (note that the 2 100 ohm resistors in the BOM in the PDF should actually be 4), then make a list of all the other parts like 2xDPDT switches, sockets, rubber standoffs etc, and order them from Digikey or Mouser or wherever. Only part I ordered from China was the volume knob and that's probably available locally but I didn't know where to look. Plus, I don't need the knob right away 'cause I plan to use IR for volume.

Would you please post what parts you needed to buy to add the Academy Audio volume control? Thanks.
 
Would you please post what parts you needed to buy to add the Academy Audio volume control? Thanks.

It doesn't require a lot. The only thing that you must add is something to deliver +/-9~15vdc to the volume control, at low current. Apparently the board and IR receiver together draw < 20mA per each side of the +/-, I plan to add a dc-dc converter to the existing 24vdc supply to provide +/- 12vdc. You might want to add some smoothing components to that. Down the road I may run a +/-15vdc converter with +/-12vdc analog regulation downstream of that.

You will need to decide how to deal with connections to the board. The existing right-angle pins will not fit in the Korg chassis, they must be removed and if you replace with straight pins you will need those.

Other than that, I can't think of anything else that is essential.

I have a question in to Academy Audio regarding the power supply -- the dual-polarity "clean analog power" requirement sure sounds like active circuitry to me. Also, they specify maximum input signal voltage at a specified power supply voltage which also suggests active circuitry. I may need to upgrade my power supply if there is active circuitry. I'm waiting to hear.
 
6L6 built the last batch, so that is up to him but in general it is non-deterministic and up to the availability of the kit builders. I can tell you now having built 2 kits that it is a serious labor of love and takes a TON of time to get in the professional and easy to use format you have seen delivered by the store kits to-date, so please be patient I am sure they will be replenished eventually... :)

--Tom

Appreciate the reply. I'm more than willing to wait. It certainly nice to have guys dedicated to helping rookie DIY guys like me put together gear that delivers quality. I was just curious if it was like the ACA which seems to repopulate on a regular basis. Didn't know if the B1 followed a similar pattern.
 
I bought everything at diyaudio except the "miscellaneous completion" package which they did not have. I can say that this method is working for me. When I bought, the "miscellaneous" package was the one item that was keeping the kit from being available.

I caused myself headaches because I did not make a complete list of absolutely everything I needed right off the bat, and have now had to order four times from Digikey (partly to support the later addition of an IR volume control from Academy Audio).

Make a list of those miscellaneous parts (note that the 2 100 ohm resistors in the BOM in the PDF should actually be 4), then make a list of all the other parts like 2xDPDT switches, sockets, rubber standoffs etc, and order them from Digikey or Mouser or wherever. Only part I ordered from China was the volume knob and that's probably available locally but I didn't know where to look. Plus, I don't need the knob right away 'cause I plan to use IR for volume.

The completion kit is the only thing that pops up 'sold out'....so I may look at the BOM and see what it will take to get it all ordered up. Knowing me I'll just wait it out for the complete kit. I've got enough going on to keep me busy. Thanks for the reply.
 
It doesn't require a lot. The only thing that you must add is something to deliver +/-9~15vdc to the volume control, at low current. Apparently the board and IR receiver together draw < 20mA per each side of the +/-, I plan to add a dc-dc converter to the existing 24vdc supply to provide +/- 12vdc. You might want to add some smoothing components to that. Down the road I may run a +/-15vdc converter with +/-12vdc analog regulation downstream of that.

You will need to decide how to deal with connections to the board. The existing right-angle pins will not fit in the Korg chassis, they must be removed and if you replace with straight pins you will need those.

Other than that, I can't think of anything else that is essential.

I have a question in to Academy Audio regarding the power supply -- the dual-polarity "clean analog power" requirement sure sounds like active circuitry to me. Also, they specify maximum input signal voltage at a specified power supply voltage which also suggests active circuitry. I may need to upgrade my power supply if there is active circuitry. I'm waiting to hear.

I bought one of these Blocked just waiting for it to be delivered. I ordered through TRC they had a back-order on it so I won’t have it until around the 24th. I received my Academy Audio volume control today though. Hope that link worked it is showing blocked but still works for me.
 
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Lenny Novikov of Academy Audio replied to my query and I have attached our exchange as a PDF, edited for clarity and brevity, see below.

So, is there a way to get a very clean +/- 12vdc from the 24vdc in a relatively small, inexpensive package?

I know -- small, clean, cheap -- which two of those do I really want?

Is there a +/- version of a really effective but compact smps filter out there somewhere?
 
I'm thinking about the Academy Audio volume control (AA VCU) as it applies to the Korg.

1. The AA VCU has no capacitor protection at its input or output. However, DC at its input is harmful, therefore a capacitor at its input is desirable.

2. The AA VCU produces no DC, therefore the Korg does not need capacitor protection from the AA VCU.

Ergo, the 10uF capacitor at the input of the Korg could be removed and placed in front of the AA VCU to protect both the VCU and the Korg thus avoiding an additional capacitor in the signal path.

Can someone see a problem with this reasoning?
 
I'm thinking about the Academy Audio volume control (AA VCU) as it applies to the Korg.

1. The AA VCU has no capacitor protection at its input or output. However, DC at its input is harmful, therefore a capacitor at its input is desirable.

2. The AA VCU produces no DC, therefore the Korg does not need capacitor protection from the AA VCU.

Ergo, the 10uF capacitor at the input of the Korg could be removed and placed in front of the AA VCU to protect both the VCU and the Korg thus avoiding an additional capacitor in the signal path.

Can someone see a problem with this reasoning?

Yes. Korg needs input cap to bias 1st stage jfets.

The muses VCU does not need a cap in front of it unless your source has DC present. Simple as that. No DC, no cap needed.
 
So, is there a way to get a very clean +/- 12vdc from the 24vdc in a relatively small, inexpensive package?

I know -- small, clean, cheap -- which two of those do I really want?

Look at Texas Instruments, TLE2426, Rail Splitter

8-pin DIP package, is that small enough?

8-pin DIP adds a noise reduction cap that lowers output noise to 30 uV (TO-92 is 120 uV).

It'll even handle the current you need, might want a little heat sink on it though.

Cinco

Edit: Oh wait... I should have read those notes muse sent you first. To be able to tie the ground of +12/gnd/-12V 'rail splitter' supply to B1K +24V supply ground, you' d need a 2nd 24V Supply. Be sure to isolate well.

Maybe this one not so easy.... cheap and small and cleanish though..... did you say you wanted easy?
 
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Look at Texas Instruments, TLE2426, Rail Splitter

8-pin DIP package, is that small enough?

8-pin DIP adds a noise reduction cap that lowers output noise to 30 uV (TO-92 is 120 uV).

It'll even handle the current you need, might want a little heat sink on it though.

Cinco

Edit: Oh wait... I should have read those notes muse sent you first. To be able to tie the ground of +12/gnd/-12V 'rail splitter' supply to B1K +24V supply ground, you' d need a 2nd 24V Supply. Be sure to isolate well.

Maybe this one not so easy.... cheap and small and cleanish though..... did you say you wanted easy?

Well, my thinking is to use an isolated output module to generate +/- 15vdc, and filter that with an ultra low noise module to +/- 12vdc.

First module is
Blocked

And I was looking at this to make it low noise:
LT3045 LT3094 Linear Voltage Regulator Low Noise RF Linear Power Supply Module | eBay

But if I could use the TI chip in lieu of the second module that would save time and money. Will it work easily with the isolated splitter module in front of it?

Frankly, I'm not finding much in the way of small, low power, low noise dual voltage regulator pcbs.
 
Well, my thinking is to use an isolated output module to generate +/- 15vdc, and filter that with an ultra low noise module to +/- 12vdc.

First module is
Blocked

FWIW, I used a couple of Traco modules like that Mean Well piece in my first power supplies and found it essential to add the filtering described in the datasheet before and after the module to avoid EMI. Mean Well offers a packaged converter (NSD line) that already has the filters.
 
FWIW, I used a couple of Traco modules like that Mean Well piece in my first power supplies and found it essential to add the filtering described in the datasheet before and after the module to avoid EMI. Mean Well offers a packaged converter (NSD line) that already has the filters.

I have been looking at this unit ever since you mentioned it a little while ago, and I'm intrigued, but the output is not particularly quiet, is it? Is it "good enough" to use without further smoothing?

Since it's rated at 10 watts - 420mA per side - and the requirement is only 20mA per side, I wonder about removing the heat sink to reduce the volume in the Korg. Any thoughts on doing that?
 
Smooth enough is a good q. I need +/-12 and +/-5, so was going to put a regulator after it anyway.

I bought 3 since I was ordering, if you have the ability to measure before and after filtering I'm happy to send one to you - PM me your address.

Regretfully, I do not have the ability to measure at the moment, but Digikey is but a click away, and have ordered the 15v version and will add a 12v low-noise regulator later if noise is a problem. Glad to know about the included EMI filter, that's a big deal, and package is 1" x 2" x .5" with heatsink.
 
Turn on/off thump

Would like to know more about this on/off thump --

How soon (in seconds) after power on does it occur, and how soon after power off?

What causes it?

Any solutions other than a delay relay at the output?

The Academy Audio VCU has a pin that could drive an output relay, but delay is only 1 second. Not sure if that's of any benefit or not.