Hello,
With a friend of mine we planed to build Thorsen RIAA. We will use two valve : Amprex 7025 and Phillips miniwatt ecc88. We were brainstorming on High Voltage PSU, when i ask an another friend of maine about a schematic, i configure and simulated this under one :
The +250V output voltage present a 107db 100hz PSSR. What did you think about this regulation and do we need other capa (what amount) after regulation?
Marc
With a friend of mine we planed to build Thorsen RIAA. We will use two valve : Amprex 7025 and Phillips miniwatt ecc88. We were brainstorming on High Voltage PSU, when i ask an another friend of maine about a schematic, i configure and simulated this under one :
An externally hosted image should be here but it was not working when we last tested it.
The +250V output voltage present a 107db 100hz PSSR. What did you think about this regulation and do we need other capa (what amount) after regulation?
Marc
Konnichiwa,
I am not sure if the transistors have sufficient voltage ratings. Also, circuits like this one tend to be instable without load capacitance. Past that I suspect a "boosted LM317" circuit would probably provide superior objective performance, but by all means build as you like. Be aware that most new designs do not quite work the way simulations predict and need debugging.
Sayonara
Idefixes said:
I am not sure if the transistors have sufficient voltage ratings. Also, circuits like this one tend to be instable without load capacitance. Past that I suspect a "boosted LM317" circuit would probably provide superior objective performance, but by all means build as you like. Be aware that most new designs do not quite work the way simulations predict and need debugging.
Sayonara
Kuei Yang Wang said:
Hello thorsen, my friend is not a HT afficionados. I was unable to find a schem relative to your bossted LM317 that why i ask him about un regulated PSU. He said me : "it runs under simulation but i don't know in reality what it will give". Have you a schem from your one?
Thanks. Marc
Konnichiwa,
See post 28 in thishere thread:
http://www.diyaudio.com/forums/showthread.php?postid=338903#post338903
Sayonara
Idefixes said:
See post 28 in thishere thread:
http://www.diyaudio.com/forums/showthread.php?postid=338903#post338903
Sayonara
Here's Thorsens Schema under eagle:
As you advise i separate the GND in 2 stars connected through through external Cu wiring
And the Pcb interpretation
What do you think about it?
Marc
An externally hosted image should be here but it was not working when we last tested it.
As you advise i separate the GND in 2 stars connected through through external Cu wiring
And the Pcb interpretation
An externally hosted image should be here but it was not working when we last tested it.
What do you think about it?
Marc
more gain
I built this circuit a few months ago. I used S&BTx103's before it and S&B TX102's after it then into my power amp.
I've now decided that I want to try the Behringer dcx2496 digital crossover but, as this is a pro audio piece of kit, I believe I'll need more signal to drive it properly.
I've no intention of giving up this phono pre it's a superb sounding amp, but I would like some complementary gain stage that I can build into the chassis after the TVC, possibly using the B+ and heater supplies.
Will anyone (Thorsten?) recommend a suitable circuit
Thanks
Kev
I built this circuit a few months ago. I used S&BTx103's before it and S&B TX102's after it then into my power amp.
I've now decided that I want to try the Behringer dcx2496 digital crossover but, as this is a pro audio piece of kit, I believe I'll need more signal to drive it properly.
I've no intention of giving up this phono pre it's a superb sounding amp, but I would like some complementary gain stage that I can build into the chassis after the TVC, possibly using the B+ and heater supplies.
Will anyone (Thorsten?) recommend a suitable circuit
Thanks
Kev
Re: more gain
Konnichiwa,
First, the easiest methode may actually be to modify the input circuit of the DCX2496 to have a more apropriate "full scale" level (one resistor per channel changed), from +22dbu to +12dbu, a switch that is present on the DEQ2496 and works fine and makes the DEQ quite compatible with consumer gear.
That failing, I would suggest to place the Amplification stage BEFORE, not after the TX102 and drive the DCX directly from the TX102. The Active stage should be applied to both digital sources and to the phonostage output.
A good idea might be a 2A3, choke loaded, which will give a little over 10db gain, very linear and will provide around 1KOhm drive impedance to the TX-102.
Otherwise, using a 6S45 and a 4:1 stepdown transformer (if using parallel feed S&B do have a suitable anode load choke and the TX101 Line transformer - with battery bias and a TX-102 that would be in effect the final version of the Euridice covered on Brian Cherry's AA board) will give around 20db gain after the TX-102, this circuit has been build previously largely like that and sounds excellent as linestage....
I am sure other options exist, if you do not get frightened by using NFB, elsewhere a simple 6SN7 (5687 also usable) linestage with a feedback loop is presented, which could be used before or after the TX-102.
Sayonara
Konnichiwa,
KevinTams said:I've now decided that I want to try the Behringer dcx2496 digital crossover but, as this is a pro audio piece of kit, I believe I'll need more signal to drive it properly.
I've no intention of giving up this phono pre it's a superb sounding amp, but I would like some complementary gain stage that I can build into the chassis after the TVC, possibly using the B+ and heater supplies.
Will anyone (Thorsten?) recommend a suitable circuit
First, the easiest methode may actually be to modify the input circuit of the DCX2496 to have a more apropriate "full scale" level (one resistor per channel changed), from +22dbu to +12dbu, a switch that is present on the DEQ2496 and works fine and makes the DEQ quite compatible with consumer gear.
That failing, I would suggest to place the Amplification stage BEFORE, not after the TX102 and drive the DCX directly from the TX102. The Active stage should be applied to both digital sources and to the phonostage output.
A good idea might be a 2A3, choke loaded, which will give a little over 10db gain, very linear and will provide around 1KOhm drive impedance to the TX-102.
Otherwise, using a 6S45 and a 4:1 stepdown transformer (if using parallel feed S&B do have a suitable anode load choke and the TX101 Line transformer - with battery bias and a TX-102 that would be in effect the final version of the Euridice covered on Brian Cherry's AA board) will give around 20db gain after the TX-102, this circuit has been build previously largely like that and sounds excellent as linestage....
I am sure other options exist, if you do not get frightened by using NFB, elsewhere a simple 6SN7 (5687 also usable) linestage with a feedback loop is presented, which could be used before or after the TX-102.
Sayonara
Re: Re: more gain
I wouldn't want to modify this yet as it's brand new and still under warranty and if it doesn't perform as I hope then I'll sell it on.
OK no problems here.
This will need a separate B+ supply from the phono stage and I guess to fit it onto the chassis I'll have to move the psu's onto a separate chassis, but looks interesting.
This looks very expensive.
NFB doesn't bother me, sound quality and not too expensive are the main factors.
Would you go for the 2A3 in preference to a 6SN7, 5687?
thanks
Kev
Kuei Yang Wang said:
I wouldn't want to modify this yet as it's brand new and still under warranty and if it doesn't perform as I hope then I'll sell it on.
OK no problems here.
This will need a separate B+ supply from the phono stage and I guess to fit it onto the chassis I'll have to move the psu's onto a separate chassis, but looks interesting.
This looks very expensive.
NFB doesn't bother me, sound quality and not too expensive are the main factors.
Would you go for the 2A3 in preference to a 6SN7, 5687?
thanks
Kev
Re: Re: Re: more gain
Konnichiwa,
Your call,considering the cost I'd not bat an eyelid....
Or you could build a seperate linestage... ;-)
Not THAT BAD, but yes.
If cheap & servicable is the key the 6SN7 (but for my taste fitted with 5687's) Linestage from here would be good:
http://www.diyaudio.com/forums/showthread.php?postid=353015#post353015
I'd stick the 102 behind it, manipulate the feedback resistor value for the right amount of gain (not too much though), BTW ignore the whole nay saying in the thread by some technocrates, it works fine, actually the design is based on one by Jim Fosgate, I din't feel like namedropping at the time.
Sayonara
Konnichiwa,
KevinTams said:
Your call,considering the cost I'd not bat an eyelid....
KevinTams said:
Or you could build a seperate linestage... ;-)
KevinTams said:
Not THAT BAD, but yes.
KevinTams said:
If cheap & servicable is the key the 6SN7 (but for my taste fitted with 5687's) Linestage from here would be good:
http://www.diyaudio.com/forums/showthread.php?postid=353015#post353015
I'd stick the 102 behind it, manipulate the feedback resistor value for the right amount of gain (not too much though), BTW ignore the whole nay saying in the thread by some technocrates, it works fine, actually the design is based on one by Jim Fosgate, I din't feel like namedropping at the time.
Sayonara
Building can begin, we (a friend and me) recieved valves
Wa have some more parts to purchase so we will have time to fixe power supply.
Marc
An externally hosted image should be here but it was not working when we last tested it.
Wa have some more parts to purchase so we will have time to fixe power supply.
Marc