It was about a Mosfet Maida. It went down for good apparently. I will look to find something to replace it.
K thanks Salas. Once built I might give it a go. If the results are good I'll report back.
Nick
Nick
Salas,
I've built a resistor loaded version of your 6V6 preamp with my B+ of only 300V, so I used 7.5K anode resistor as recommended by you with very good result.
I have a pair of Magnequest plate chokes, BCP-15 which is 50H/40ma/575ohm. I'd like to know if theirs inductance is enough for adequate bass response and in the case they can be used then how is the new B+ should be.
I've built a resistor loaded version of your 6V6 preamp with my B+ of only 300V, so I used 7.5K anode resistor as recommended by you with very good result.
I have a pair of Magnequest plate chokes, BCP-15 which is 50H/40ma/575ohm. I'd like to know if theirs inductance is enough for adequate bass response and in the case they can be used then how is the new B+ should be.
Congratulations for your build. Let us know more about the system you added it in. Build photos are welcome. About the plate chokes, yes they are a bit on the low Henry side...
It will roughly show -3dB at 10 Hz and 40deg phase shift there theoretically as a combination. Not great for zero LF phase shift, but it will play bass. Up to you deciding a test if its handy so to see how you like them. It will play couple of dB louder also, so normalize that when comparing. You will be needing 180V B+ for them.
It will roughly show -3dB at 10 Hz and 40deg phase shift there theoretically as a combination. Not great for zero LF phase shift, but it will play bass. Up to you deciding a test if its handy so to see how you like them. It will play couple of dB louder also, so normalize that when comparing. You will be needing 180V B+ for them.
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Salas,
Thanks for your response, The system I'm using now consist of:
Source-Mac mini =>DAC-TEAC UD501 => 6V6 preamp => Fetzilla Power amp =>ProAC 2.5 clone
With 6V6 preamp, the system has become very dynamic and the frequency response is good from bass to treble, very good for classical music which I listen most of the time. I'm sorry no picture at the moment.
I'll try choke load and compare with resistor load later.
Thanks for your response, The system I'm using now consist of:
Source-Mac mini =>DAC-TEAC UD501 => 6V6 preamp => Fetzilla Power amp =>ProAC 2.5 clone
With 6V6 preamp, the system has become very dynamic and the frequency response is good from bass to treble, very good for classical music which I listen most of the time. I'm sorry no picture at the moment.
I'll try choke load and compare with resistor load later.
Hi Salas,
I just wanted to verify if you are now using a 2.2uf output capacitors. If. Im not mistaken you have mentioned in one of your posts but cannot remember where. Im ordering parts for the build, and want to get the right one.
Thanks
I just wanted to verify if you are now using a 2.2uf output capacitors. If. Im not mistaken you have mentioned in one of your posts but cannot remember where. Im ordering parts for the build, and want to get the right one.
Thanks
Hi Salas,
One more question, sorry for the inconvenience. I also have an ldr based volume control which i will be usinginstead of the 100k pot. Do i still need to wire a 100k resistor from the grid to the ground of the 6v6? Also is it very important to retain the 1k resistor at the grid of the 6v6? In my last build i took it out as it sounded a little better without it.
Thanks
One more question, sorry for the inconvenience. I also have an ldr based volume control which i will be usinginstead of the 100k pot. Do i still need to wire a 100k resistor from the grid to the ground of the 6v6? Also is it very important to retain the 1k resistor at the grid of the 6v6? In my last build i took it out as it sounded a little better without it.
Thanks
not Salas, but it is a good practice to install a 1meg grid bias resistor(not absolutely required) and a 1 ik carbon com resistor closest to the grid, pin 5...
the choice of output capacitor size is dictated by the input impedance of the amp that your preamp will drive...
the choice of output capacitor size is dictated by the input impedance of the amp that your preamp will drive...
Hello Ajt,
Thanks for the response. Very much appreciated. My 45 amp has I
Believe a 1 MEG input impedance. What do you think is the appropriate value for the output caps?
Out of topic, i hope one day to go back home. Hope all is good over there.
All the best.
Thanks for the response. Very much appreciated. My 45 amp has I
Believe a 1 MEG input impedance. What do you think is the appropriate value for the output caps?
Out of topic, i hope one day to go back home. Hope all is good over there.
All the best.
With 1 M input you can have 0,1 uF or smaller even on 6V6 output. Good, can go for quality over quantity. Set 10 M for output resistor to ground.
Like those maybe http://www.ebay.com/itm/0-1uF-5-600...016?pt=LH_DefaultDomain_0&hash=item3ccb51bb78
Like those maybe http://www.ebay.com/itm/0-1uF-5-600...016?pt=LH_DefaultDomain_0&hash=item3ccb51bb78
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yes, you need not put in more than what is needed...
the reason people put big caps is so that they can also use the preamp on ss amps which have lower input impedance...
Tubo, you are better off where you are......ours is a land of sorrows, both man made and natural calamities abound, you must have heard the news....
the reason people put big caps is so that they can also use the preamp on ss amps which have lower input impedance...
Tubo, you are better off where you are......ours is a land of sorrows, both man made and natural calamities abound, you must have heard the news....
Based on 575 Ohm DCR spec that was given, so the voltage drop will be small also.
Winter came, got cold outside - finally - so found some time to rearrange my 6V6 pre as CT and finish the wiring.
If you can live without the gain it has one of the best sound for a preamplifier. Also much easier to get it quiet and not microphonic. I really love it like this.
Sound wise, more bass more resolution and more natural than a #26 or an AVC from Intact audio I was using.
When I find some time and persuade myself to get it out of my system for a few days, I have a more solid aluminum subchassis to put everything on, and maybe arrange thing a little better, especially on the underside!
If you can live without the gain it has one of the best sound for a preamplifier. Also much easier to get it quiet and not microphonic. I really love it like this.
Sound wise, more bass more resolution and more natural than a #26 or an AVC from Intact audio I was using.
When I find some time and persuade myself to get it out of my system for a few days, I have a more solid aluminum subchassis to put everything on, and maybe arrange thing a little better, especially on the underside!
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