Tube with Power IC Output Stage - JLTi

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Elkaid

Elkaid

Member
Joined 2003
Hello guys,

I have a good 70VA 2X30volts toroid transformer left somewhere. Is there any drawback in using it instead of a 2X25Volts transformer to feed the 6922 ? Thanks !

(Sorry I know that this is the kind of question I should asked weeks ago when this thread started)

:wave2:
 
fdegrove

fdegrove

diyAudio Senior Member
Joined 2002
CE QUI PEUT LE PLUS, PEUT LE MOINS...

Hi,

I have a good 70VA 2X30volts toroid transformer left somewhere. Is there any drawback in using it instead of a 2X25Volts transformer to feed the 6922 ? Thanks !
Click to expand...

If you want to maintain original circuit values, you will have to burn off some volts....
Other than that, no problema.

Just promise this "petit Belge" to send Daniel Lannois over to Belgium at least twice a year, okidoki?

Bon boose,;)
 
Variac

Variac

diyAudio Editor
Joined 2001
BurningAmp.org
Paid Member
Re the Black Beast:
Pretty clever using the cones as pivots/ solid supports.
I considered something similar for my speakers, but decided that I actually wanted the head unit a little decoupled from the bass box. I guess the back bracket has the third point (probably adjustable) I think you have answered a question I had but maybe you can confirm: Is the crack between the bass box and open baffle inconsequential considering the wavelengths involved?

Thanks
 
Joe Rasmussen

Joe Rasmussen

Member
Joined 2003
customanalogue.com
Variac said:
Re the Black Beast:
Pretty clever using the cones as pivots/ solid supports.
I considered something similar for my speakers, but decided that I actually wanted the head unit a little decoupled from the bass box. I guess the back bracket has the third point (probably adjustable) I think you have answered a question I had but maybe you can confirm: Is the crack between the bass box and open baffle inconsequential considering the wavelengths involved?

Thanks
Click to expand...

Cones, or 'Tip Toes' are used as you guessed, with the third point at the end of the rear slanted bracket. The crack, or gap, needs to be reasonably small, say 25mm, which is what you see.

There are heaps of interesting tweaks, such as the Vifa XT-25 Tweeter that is recessed to match up with the acoustic offset of the mids. The Tweeter is actually glued into place on sorbothane pads, which acts as a suspension, isolating mechanical energy of the open baffle. The increased sense of focus is quite a nice gain. The crossovers are low order minimum phase 'transient perfect' - 6dB/Oct and 9dB/Oct - also arranged in such a way that at the crossover frequencies you have complimentary phase, this results in very even off axis power response, very little inter-driver phase disturbances, creating a good blending of the drivers. There is one really good thing about this approach, the driver integration is oh so good and the usual driver discontinuities melt away. The critical transition between mids and the XT-25 is just about as perfect as you can get from multi-drivers.

I have several local loudspeaker manufacturers applying the theories and they get good reviews in the local press. The BBs are a labour of love, not profit, so I never charged a cent in passing on my ideas.

The BB IVs are now in their fourth rebuild/incarnation. The original MK I was now a horrible 17 years ago... yikes! I'm growing old!

Does anyone recognise the mids I'm using? If you wanna do open baffle 3-ways, you oughta know because this one is an absolute honey. A clue: It's Danish.

Joe R.
 
Joe Rasmussen

Joe Rasmussen

Member
Joined 2003
customanalogue.com
tbla said:
hey joe......:eguitar:

i just want you to know that your contribution to this forum is top notch.......say - are you from denmark....?

btw....everybody is top notch (did i forget some...?)
Click to expand...

What can I say? :cannotbe:

Yep, Danish, but Aussie resident. Wife is Sicilian, so that makes our three boys Bavarian? That's the half-way point, isn't it? :rolleyes:

Still have a Danish passport. Came out in my early teens with my parents. My Dad was a big-wig at DR (that's the Danish BBC, for those that don't know), being the boss of 'Dubbing' (Sound Department). He had long service leave, and wanted to taste what life was like Down Under.

Hey Nuuk, this oughta impress you:

I was born in the inner city Copenhagen suburb of Frederiksberg, no more than 2 kilometres away from the one and only original Carlsberg Brewery! :drink:

Joe R.
 
P

PeteM

Member
Joined 2003
Hi
Protos

The GC's are pretty fresh out of the box :))

I built a none buffered version trying to leave room for a valve stage.

The GC's in standard form are great, although they can be a little ruthless with some music in the high frequency.

Having built Joe's buffered version this has smoothed dramatically,but remains very fine in detail..

The mid and treble are very valve like,perhaps a little more extended in HF.Where they out perform the 2A3 is in both bass extension and control.I have just fitted a 50K DACT to the controller so the sound is changing all of the time.

They are built around basic parts using panasonic FC caps for power supply,and polyprops elswhere..Resistors at the momment are all metal film,I rather get to know the sound this way and maybe tweak in the future..

I am also trying various LPF caps, currently using 680pf the sound is great.

Pics are here http://www.petemoore.pwp.blueyonder.co.uk/music/

Regards
Peter
 
N

nowater

Member
Joined 2002
a few general questions

What sort of DC can the LM3886 withstand on its inputs? What is the symbol used in the datasheet for this parameter?

And does it amplify any input DC across its outputs?

And when an opamp's datasheet shows Vin+ and Vin- terminals, does that imply it will take a balanced input direct to those terminals?

Thanks for any help,
Grant
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
Re: a few general questions

nowater said:
What sort of DC can the LM3886 withstand on its inputs? What is the symbol used in the datasheet for this parameter?

And does it amplify any input DC across its outputs?

And when an opamp's datasheet shows Vin+ and Vin- terminals, does that imply it will take a balanced input direct to those terminals?

Thanks for any help,
Grant
Click to expand...

If I remember corectly-I downloaded OP cookbook from TI site.
there you have plenty of info .
if TI site is not correct target for ya,try little googlin' for "OP cookbook"
cheers!
 
analog_sa

analog_sa

Member
Joined 2002
What sort of DC can the LM3886 withstand on its inputs? What is the symbol used in the datasheet for this parameter?
Click to expand...

From the datasheet: common mode input voltage < 80v, differential < 60v. Of course it amplifies dc across the inputs. It will take a balanced input but not directly. And it will need to have a negative feedback if used as amplifier. Maybe you should read a book on opamps. These questions hint at the possibility of smoke around your opamp projects :)
 
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