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GB for DC coupled B1 buffer with shunt PSUs

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#581
korben69 said:
Sorry for the mistakes, here's V3.
Let me know if it's Ok or not.
Click to expand...

This V.3 BOM looks good. BC546 can be BC547/548/549/550 also, no problem, give the whole series as alternatives, or just the BC550 since there is one in the positive reg too. We take advantage of the NPN emitter/base breakdown voltage effect used as a 6-9V Zener, and we charge slowly the 47uF up to that point, then it opens the NPN under the relay coil to saturation so it pulls it. Thus any pin compatible NPNs will do.
Also don't call the circuit a symmetric B1, its easy to be mistaken for a balanced circuit (XLR). Its a single ended DC coupled B1 with symmetric shunt regulators.

Thanks for compiling the BOM. I like that this one is becoming more and more of a community effort. I like the spirit.
 
#582
woodturner-fran said:
OK,

BC550 is no problem.

Yes, they do have IRFP9140/140 in stock - pin spacing is for TO-247, right?.

Yes, the have the nichicon caps - in a range of types, ufw, upw and so on. What are the characteristics that are needed.... is it low impedance or low esr etc etc?


Lastly, if we are the use the 6V relays i take it we need a resistor somewhere close to 600R to get the right voltage?


Fran
Click to expand...

Yes, 9140/140 are 100V T0-247s, same pin order as the originals, totally compatible.

Nichicon http://it.mouser.com/ProductDetail/...EpiMZZMukHu%2bjC5l7YeDvmDiEepL4ip7S1%2bPHmRQ=

Low impedance Chemicon is a not bad cap also. http://it.mouser.com/ProductDetail/...=sGAEpiMZZMsCnlYck6hSqJDW/qaMCZY/e8WQN9SvOwg=

Yes, you wanna get close to roughly 150R when in parallel for the 6 input one and near 300R for the basic one. I.e. 660R or 330R will work.
 
#583
fingerx said:
How about if I want to use Lightspeed volume as a pot? Shall we need to change some resistor values on the preamp part?

I decided to get two Hypnotize board, can somebody tell me how can I make the payment(PAYPAL?), since I am new here:spin:
Click to expand...

What is the impedance of the Lightspeed? If it can be made for 22k and has an input, an output and a ground, use whatever you fancy.
 
#584
AFAIK, the impedance of the lightpseed varies a bit: It depends on the characteristics of the LDRs used in it.

Is there some special reason why exactly 22K is needed Salas? Its just that you can often find nice stepped pots etc in 25K or even 20K. Could we not use one of those?


Those united chemicon caps are out of stock there. I seem to saying that a lot🙄

Anyway, if its low impedance there is a good few choices. i'll do a list and come back later with some options.


Fran
 
#585
20-25k is acceptable. 22k is the centre value.

I showed those caps as good choices for guidance. Maybe they can be found elsewhere or find analogous. A Panasonic FC or FM is a typical choice. But don't worry much, those shunts tend to be less sensitive than usual for what feeds them.
 
#591
For anyone who is interested, I'm also trying to get some option on a 20 or 25k stepped attenuator for this project. It would be another option besides the lightspeed (good) and alps pots (poor IMHO).

I've used some from a seller on ebay in the past and found his to be good quality. Cost is about 20-25USD incl shipping. I've emailed him and asked would he do them in 20 or 25k.

Would people here be interested in such an option?

Fran
 
#592
Input Selector Switch for Mezmerize Deluxe BOM

It might be a good idea to also include a suitable input selector switch in the Deluxe BOM - some kind of mechanical rotary switch that will do the job properly.

I assume that we will see quite a few Mezmerize incarnations with motorized pots [there appears to be room for the motor] and remote controlled input switching, but it would still be nice to have the basic rotary switch in the BOM.
 
#594
Oh yeah, the selector switch:

mouser #105-SR2611F-26-38RN

http://www.taiwanalpha.com/english/p_e_145.htm

The reason I would go for the 2 pole is that if you do, you can use the other pole to selectively power one of 6 LEDs to show which position is selected. I've done this one time before and it was really neat. Run 5V to the centre pole of the switch and wire each leg of the LEDs to the outer poles (ie each of the 6 positions). Other leg of LED to gnd add a current limited resistor on the feed. Its simple enough but adds a lovely touch to the finished project. See here:

An externally hosted image should be here but it was not working when we last tested it.
 
#596
Salas said:
What is the impedance of the Lightspeed? If it can be made for 22k and has an input, an output and a ground, use whatever you fancy.
Click to expand...

Lightspeed volume use 100K opticoupler in series and 100K shunt to GND, somebody said that almost equal to 10K pot. Any changes if I prefer to use Lightspeed?

I saw there are 12V*2 & 15V*2 50VA power transformer can be use, in fact, which one is more suitable?
 
#597
Here's modified V3.1 BOM according to your suggestions/wishes :
a) BC550 and 560 alternatives added.
b) BOM Name : DC Coupled B1 Shunt PSU
c) Recommended Caps list : Nichicon added
d) 1N4001 Qty for Mezmerize : 7 units for Mezmerize
e) Rotary Switch for Mezmerize + Pin header for wiring

Nice to read from you 😉
 

Attachments

#598
Thanks Salas,

Yeah.. that went on to be a 24V aikido line stage. Has performed very well and only actually removed it from teh system the other night to try the B1 (regular) that I just built. TT was an ariston RD80. Things have moved on since then, I have a Teres now.

******************************
Nice job on the BMO Korben. I'll be putting my mouser project together later tonight!


*********************************
Lightspeed: the actual figure depends on the LDR characteristics - so it varies. To be honest I see it recommended a lot for the B1 so it must be a good option. I had intended to do one on the B1 I just built but haven't ironed out all the bugs in that system yet. Maybe I'll have it sorted in time for the deluxe!! The lightspeed thread or member udailey is who you need to talk to.

Fran
 
#599
woodturner-fran said:
Thanks Salas,

*********************************
Lightspeed: the actual figure depends on the LDR characteristics - so it varies. To be honest I see it recommended a lot for the B1 so it must be a good option. I had intended to do one on the B1 I just built but haven't ironed out all the bugs in that system yet. Maybe I'll have it sorted in time for the deluxe!! The lightspeed thread or member udailey is who you need to talk to.

Fran
Click to expand...
I am one of those using a Lightspeed as the volume control on a B1 - as soon as these new boards become available I will repeat this setup. One small problem might be that the new matched LDRs are setup for a 500K pot - perhaps Udailey can comment.
 
#600
Alan,

would you give us some more details or even photos of how you set it up?

My set of LDRs need a 500k pot, but thats not anywhere in the signal chain, it just controls the current going to either the series or shunt LDRs (as I understand it). Some LDRs are more sensitive and so need much less current for a given resistance, hence some batches need a 100k pot and others a 500k pot with say a 5V supply.

Fran
 
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