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Tube-I-zator Professional PCB

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DQ828

DQ828

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Joined 2010
DVD

Crom just made me aware of the Rohpoint GG102A resistors that you are recommending

Do you have any idea what value would be suitable for BIII as the I/V resistors?

Also in the attached photo's it shows little brass stand offs, do you know what they are called I'm having trouble finding them?
 

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C

Crom

Member
Joined 2012
DQ828, Phew, glad you saw that tb1- tb2 connection that was needed -that's what I was trying to point out to you a while back. Make sure it happens on the tube side as per picture.

Re the I/V resistor, I'm using stock 56R and it sounds lovely. Russ / Brian from Twisted pear seem to recommend experimenting from 20R-32R so I've bought a few options which I'll be trying over the next week or so. I'll report back. I think the difference that you should notice is that it distorts (or you lose separation between the instruments) when you play it loud. I think it has something to do with the ability to deal with voltage swings. However, if someone can explain the logic behind the values I'm all ears ;-)
 
pinnocchio

pinnocchio

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Joined 2010
quebecdiy.forumactif.com/
I was using 30R and it sounded better than 56R in my tests.

BTW, if anyone wants a Tube-I-Zator, I'm selling mine. I changed my entire DAC so it is available.

Don't get me wrong, it is an absolute amazing I/V but I decided to leave tubes for a while. In all I have built 4 of the Tube-I-Zator!

I had a balanced setup but one is already sold. I'm using ClarityCAP MR on coupling and TX-2575 for R I/V (x2) and Rk (x4). Salas SSHV2 for high tension and the Tubes are TJ Full Music 12AX7. All parts are very good quality.

See here : http://www.diyaudio.com/forums/swap-meet/222479-fs-tube-i-zator-dac-iv.html

See here for my first two boards using DVBProjekt / Salas SSHV1 post #543
http://www.diyaudio.com/forums/group-buys/156149-tube-i-zator-professional-pcb-55.html

Thanks
Do
 
DQ828

DQ828

Member
Joined 2010
Well with the yellow wire in place it makes no difference to the voltage, The SSHV Vin is reading 161V & the Vout is reading 151V DC this is after about 20min with the tubes in place.

I still have one very hot heat sink & one luck warn, if fact it may be picking it's heat up from the heat sink beside it, as you don't need to put you finger on it to know it's hot ouch.
 
dvb projekt

dvb projekt

Member
Joined 2009
Paid Member
DQ828 said:
Well with the yellow wire in place it makes no difference to the voltage, The SSHV Vin is reading 161V & the Vout is reading 151V DC this is after about 20min with the tubes in place.

I still have one very hot heat sink & one luck warn, if fact it may be picking it's heat up from the heat sink beside it, as you don't need to put you finger on it to know it's hot ouch.
Click to expand...

The different temperatures on the heatsinks are normal. In our configuration we have a power dissipation of ~5.8W for IRF840 and ~1.2W for IRF9610.

258093d1325539253-simplistic-mosfet-hv-shunt-regs-sshv1.gif


With the usage of R1=56R (current adj.) we get a constant current of ~40mA.
If everything is ok, the SSHV input voltage should be ~180VDC.

I remember that one member had a problem with his transformer, witch wasn´t able to get a stable voltage for 40mA current...:rolleyes:

Anyway, how changes your input voltage, when you turn the output voltage slowly down?
Perhaps we must lower the resistor value in the C-R-C filter a bit, to get more input voltage to the SSHV.

DQ828 said:
And lastly is it normal for the heater elements to glow brightly for about a second when you first turn it on?
Click to expand...

The heater flash on startup is normal for a wide family of tubes. Nothing to worry about. ;)
 
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DQ828

DQ828

Member
Joined 2010
dvb-projekt said:
I remember that one member had a problem with his transformer, witch wasn´t able to get a stable voltage for 40mA current...:rolleyes:
Click to expand...

Don't say that I spent a fortune at a local manufacturer on the transformer, could has easily upped the amperage at the time:eek:

Anyway, when I turn the unit on the voltages are 131out 156in

I then turned it down a bit I got 120out 156in

I do have a 5v 3A secondary on the transformer that is not going to be used can it come into play somehow?
 
DQ828

DQ828

Member
Joined 2010
Ive been wondering how I could test the transformer to see if can really supply the 150v 0.1A. If I supplied a resistance of 1540 Ohms & checked the voltage across the resistor, and if it was still 150V then it would be suppling the 0.1A @150V therfore theoretically it wouldn't be the transformer causing the problem. Does that make sense?

How could I safely create 1540 ohms of resistance?
 
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DQ828

DQ828

Member
Joined 2010
dvd

"Perhaps we must lower the resistor value in the C-R-C filter a bit, to get more input voltage to the SSHV."

Which resistor should I change & can you recommend what ohm's it should be?

Can it be a 1/4W Metal film?

I assume by not having the correct voltage at the input I have less shunt mA.

What would be the effect to the music signal of lowering the voltage to the tubes to say 140v?
 
dvb projekt

dvb projekt

Member
Joined 2009
Paid Member
DQ828 said:
Which resistor should I change & can you recommend what ohm's it should be?

Can it be a 1/4W Metal film?

I assume by not having the correct voltage at the input I have less shunt mA.
Click to expand...

You could change the 1K0/2W resistor in the C-R-C to 820R/2W to get more input voltage to the SSHV. The drawn current stays at ~40mA (56R at SSHV).


Best regards,
Oliver
 
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