Glassware Unbalancer as I/V stage

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Luca72c

Member
Joined 2013
Hello to everyone,
i would like to build an Unbalancer from Glassware Audio Design to use as I/V stage for a Buffalo III DAC, but I'm really stuck as i'm a newbie in tubes circuits and i can't understand Glassware's site infos about that product (i.e. components included in the kit, what else i need to build it, what PS and transformers should i use, etc...). Unfortunately i can't get any answer from Glassware Audio Design: their email address seems dead...
I see there was a thread on this subject in this forum, but it has been removed, i don't know exactly why.
Could someone please provide me the infos i need to carry on this project (even on PM)? Has someone built an Unbalancer for Buffalo III yet that could help me?
Many thanks in advance!
 
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B

Bud Barnez

Member
Joined 2005
Luca72c said:
Hello to everyone,
i would like to build an Unbalancer from Glassware Audio Design to use as I/V stage for a Buffalo III DAC, but I'm really stuck as i'm a newbie in tubes circuits and i can't understand Glassware's site infos about that product (i.e. components included in the kit, what else i need to build it, what PS and transformers should i use, etc...). Unfortunately i can't get any answer from Glassware Audio Design: their email address seems dead...
I see there was a thread on this subject in this forum, but it has been removed, i don't know exactly why.
Could someone please provide me the infos i need to carry on this project (even on PM)? Has someone built an Unbalancer for Buffalo III yet that could help me?
Many thanks in advance!
Click to expand...

Blitz started this thread which should be relevant:

http://www.diyaudio.com/forums/digi...alancer-vs-ee-minimax-plus-my-experience.html

There is a manual for this circuit which you should read thoroughly. I've tried to attached it in case you haven't seen it, but it's just slightly over the size limit to attach.

So check here: http://tubecad.com/2011/11/25/Unbal...89F=0&bcsi_scan_filename=Unbalancer 9-pin.pdf

You will need DC power supply of around 240V.

You need to choose your I/V resistor values and there is a choice of tubes you can use. The manual provides the component values to use depending on the tubes you select. Select a combination of I/V resistor and tube type according to the gain you need for your required output for your amplification/speakers.

There is another document where Broskie shows this application for I/V converter use. See here: The Unbalancer
 
L

Luca72c

Member
Joined 2013
Bud Barnez said:
Blitz started this thread which should be relevant:

http://www.diyaudio.com/forums/digi...alancer-vs-ee-minimax-plus-my-experience.html

There is a manual for this circuit which you should read thoroughly. I've tried to attached it in case you haven't seen it, but it's just slightly over the size limit to attach.

So check here: http://tubecad.com/2011/11/25/Unbal...89F=0&bcsi_scan_filename=Unbalancer 9-pin.pdf

You will need DC power supply of around 240V.

You need to choose your I/V resistor values and there is a choice of tubes you can use. The manual provides the component values to use depending on the tubes you select. Select a combination of I/V resistor and tube type according to the gain you need for your required output for your amplification/speakers.

There is another document where Broskie shows this application for I/V converter use. See here: The Unbalancer
Click to expand...

Thank you very much! In facts i didn't see that manual... I've problems with Glassware's site, i can't find much... :confused:
Anyway, it seems to me that manual refers to older versions of Unbalancer, that had PSs on board, instead newer version needs external PSs. Am i wrong?
What glassware PSUs can i use for newer versions of Unbalancer? And what R12 resistor (or what else) should i use in accord to that PSU specifications?
 
B

Bud Barnez

Member
Joined 2005
Luca72c said:
Thank you very much! In facts i didn't see that manual... I've problems with Glassware's site, i can't find much... :confused:
Anyway, it seems to me that manual refers to older versions of Unbalancer, that had PSs on board, instead newer version needs external PSs. Am i wrong?
What glassware PSUs can i use for newer versions of Unbalancer? And what R12 resistor (or what else) should i use in accord to that PSU specifications?
Click to expand...

There a few options for the power supply. This looks like it would work for you: PS-15 High-Voltage Power Supply & Two Low-Voltage Regulated Power Supplies

You will need power for B+ (high voltage, 240V in this case) and a low voltage for your heaters (6.3V or 12.6V depending on tubes you use).

The PCB linked above provides both the high voltage and low voltage on one PCB, so it's quite convenient. You could use separate PCBs, one for B+ and another different supply for heaters. It's up to you and how you wish to implement and where it will ultimately fit - often determined by chassis size. You also need to think if there's anything else you want to power inside the case.

Glassware's power supplies:

PS-1 - Both B+ and heaters
PS-5 - Only B+ (tube based)
PS-7 - Only B+
PS-15 - Both B+ and heaters (x2)
PS-14 - Both B+ and heater (x1) cheaper than PS-15
Janus shunt regulator - both B+ and heaters

I used a tube regulated power supply PCB and made the unballancer point to point without a PCB. It will be easier to use PCBs for both.

If you want a Glassware power supply, to me the PS-1 or PS-15 look to be best for your needs. The Janus shunt could work well too. But I'm no expert and never built any of them either. If I had to recommend one then still the PS-15 as it's in stock. Someone else may advise you better than me.

...you then just need a suitable transformer or two.

Select R12 once you know how much current each HV channel will consume and when you know the power supply voltage you will achieve. R12 is used to achieve the correct voltage for B+. So your raw B+ supply can be higher than your ultimate aim for 240V. You use the R12 to bring voltage down to 240V from whatever your power supply gives raw. You can build your power supply first, then select R12 to provide ultimate desired voltage.

[see page 15 on manual].
 
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L

Luca72c

Member
Joined 2013
Bud Barnez said:
There a few options for the power supply. This looks like it would work for you: PS-15 High-Voltage Power Supply & Two Low-Voltage Regulated Power Supplies

You will need power for B+ (high voltage, 240V in this case) and a low voltage for your heaters (6.3V or 12.6V depending on tubes you use).

The PCB linked above provides both the high voltage and low voltage on one PCB, so it's quite convenient. You could use separate PCBs, one for B+ and another different supply for heaters. It's up to you and how you wish to implement and where it will ultimately fit - often determined by chassis size. You also need to think if there's anything else you want to power inside the case.

Glassware's power supplies:

PS-1 - Both B+ and heaters
PS-5 - Only B+ (tube based)
PS-7 - Only B+
PS-15 - Both B+ and heaters (x2)
PS-14 - Both B+ and heater (x1) cheaper than PS-15
Janus shunt regulator - both B+ and heaters

I used a tube regulated power supply PCB and made the unballancer point to point without a PCB. It will be easier to use PCBs for both.

If you want a Glassware power supply, to me the PS-1 or PS-15 look to be best for your needs. The Janus shunt could work well too. But I'm no expert and never built any of them either. If I had to recommend one then still the PS-15 as it's in stock. Someone else may advise you better than me.

...you then just need a suitable transformer or two.

Select R12 once you know how much current each HV channel will consume and when you know the power supply voltage you will achieve. R12 is used to achieve the correct voltage for B+. So your raw B+ supply can be higher than your ultimate aim for 240V. You use the R12 to bring voltage down to 240V from whatever your power supply gives raw. You can build your power supply first, then select R12 to provide ultimate desired voltage.

[see page 15 on manual].
Click to expand...

Thank you very much again, your informations are very useful!
 
L

Luca72c

Member
Joined 2013
Bud Barnez said:
If you want a Glassware power supply, to me the PS-1 or PS-15 look to be best for your needs. The Janus shunt could work well too. But I'm no expert and never built any of them either. If I had to recommend one then still the PS-15 as it's in stock. Someone else may advise you better than me.

...you then just need a suitable transformer or two.

Select R12 once you know how much current each HV channel will consume and when you know the power supply voltage you will achieve. R12 is used to achieve the correct voltage for B+. So your raw B+ supply can be higher than your ultimate aim for 240V. You use the R12 to bring voltage down to 240V from whatever your power supply gives raw. You can build your power supply first, then select R12 to provide ultimate desired voltage.

[see page 15 on manual].
Click to expand...

Well, please rectify my understandings.
I choose ECC802 as input and 6cg7 as output tubes. Assuming i will use a PS-15 PSU, i will need:
1) on PS-15 B+ set to 240V. Can it be set? Or the oputput is fixed to 350V (i will use 400V caps)?
2) on PS-15 Low voltage set to 1x6.3V and 1x12.6V?
3) 1 Transformer with 1 sec. 240VAC and 1 sec. 12VAC? Or i need 1x 240VAC and 2x low voltage secs (2x 12VAC or 12VAC + 6VAC)?
On Unbalancer board i will find 2 power inputs to power heaters (then use 12.6V AND 6.3V sources)? Or there is one single input, so i should connect a 12.6VDC single low voltage source to power both 12.6V and 6.3V tubes?
More: when i try to calculate R12 value, i find that the voltage drop is relative to current flow. But how can i know how much current flows? What it depends from?
Sorry, i know i'm a bit sturd about that, but as i said i'm a total newbie in tubes circuits... but i try to understand better :eek:
 
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J

jama

Member
Joined 2004
Hello again, I could do two photos. One with PSU and the other with B3 and unbalancer. PSU has two transformers, one with 170VAC 100mA and the other with 15VAC and 2A. I am using four hexfred diodes, one 220UF/350V, inductor of 15H and output to other box with electronics. The other transformer to low turn-on 12.6 V into filaments of four tubes (see unbalancer doc)
 

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jama

Member
Joined 2004
Caps: I have used caps from failed projects. Four very expensive, 1uf and 0.1 teflon VCAP. But I know that Obbligato Film works very well too. And to high voltage I use one 4-pole of jensen. From others failed projects I use Vishay, Riken and Neohm resistors
 
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Eldam

Banned
Joined 2012
Yes Luca, I know it... but at home I always found the limitations was not the pre but always the speakers or the DAC : firstly this last : all the mods I do are listenable with the pre.

Because unfornatully I need several sources : DVD, CD player and streamer... In my own environment : a pre is good enough to make impedance adaptation and analog volume control !

But the day I only have a streamer... sure I go for a direct connection as my amp is 100K OHMS input ! I'm not so far... don't need really a dvd... we are on the main system with a DNLA NAS & TV... very usefull... we stream from the NAS or our PCs....
 
L

Luca72c

Member
Joined 2013
Just one more question, hoping that someone can give me some suggestion.
Assuming my Buffalo IIIse/Unbalancer combo will act as a preamp in my system, i would like to use a remote control ALPS volume potentiometer to control its output, because my power amplifier doesn't have any.
Where could i connect it to obtain minimum audio quality loss: to Buffalo IIIse volume control socket (digital action) or just after Unbalancer output, before power amplifier connection (analogue action)?
I fear connecting it to Buffalo IIIse i will loose full bitperfect reproduction, while connecting it after Unbalancer output i could badly affect impedance and audio signal.
What do you think? Anyone made some experimentation about that?
 
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