Is it some 12ax7's or something splitting the gain away from the 6n1p into separate tubes without changing the wiring at all (apart from an additional tube to heat)??? Seems to me that thats it, but there could be some tube voodoo that I don't know:\
Ray is right, we just use one half of the tube. Why ? I thought it could make my life simpler to have independent channels. (Cabling tweking, etc.)
i can see no advantance in using to tubes half , u are drawing more heather energy from your transformer and there is no need because the 2 halfs of the 6n1p are seperated bij a schield internaly wich is grounded to earth
grtz ko
There is advantage, depends on what you desire. I myself wanted a more symmetrical layout that having 2 separate tubes afforded. I also believe it is easier to match sections rather than finding a perfectly internally matched tube. Although the 6N1P is a bit of a current hog (600mA) most windings are easily up to the task, at least mine at 3A is.
There is almost nothing written about the effectiveness of internal electrostatic shields in multisection tubes. There are data sheets that specify the capacitances between these shields (usually in the order of 1-3 picofarads) giving rise to the thought there still might be some, albeit small, inter-tube crosstalk.
Maybe that helps a little.
Jeff
I am not aware of any schematics that show the use of 2 tubes rather than one. Simply use the same schematic and use 2 tubes, pick a single side of each tube (usually the opposite side so you can swap the 2 tubes between each other and use the opposite side of the internal section with a single swap) and wire that side according to any available pinout schematic.
I personally used 1,2, and 3 on the right channel and 6,7, and 8 for the left channel. Any combination will suffice. You could use 1,2,3 on each tube on both sides, or 6,7,8 for both sides, or 6,7,8 for the right and 1,2,3 for the left....you get the idea.
If your 6.3v secondary is rated at less than 3A (1.5) you will get a hotter transformer by using 2 tubes as another author suggested. This 6N1P draws 600mA which is a bit high by miniature tube standards (close to the super hog 5687). If you are using the 6DJ8 you should have no problem at all, it draws half the current as the 6N1P.
There is no 12AX7 in this circuit, at least in it's original form. I am uncertain as to what you are referring to here. This is a 2 stage circuit with a driver tube (6N1P) and the output tube (KT88 or other 7AC pinout tube of choice).
Maybe I am lost here, you might want to clarify.
Jeff
In regards to the use of two dual section 6 position rotary switches to switch the power section cathode resistor values....one needs to be careful not to switch to a very low resistance on certain tubes (in fact all of them at 120R I would think).
Thanks for drawing that out....it seems very simple now that I see it. At first I couldn't visualize it in my head but now I am kicking myself it is so simple.
Jeff
Jeff
Thanks for drawing that out....it seems very simple now that I see it. At first I couldn't visualize it in my head but now I am kicking myself it is so simple.
Jeff
Jeff
Presume this is an impedence select (high current) - Check weber speakers site -- they are cheapest.
Very good quality switch! Thanks for the referral to the Weber site. Here is the selector I will buy: https://taweber.powweb.com/store/rot2-3.jpg
Thanks!
Jeff
Thanks!
Jeff
Hey I've read the whole thing twice now. I notice nobody seems to have used Toroids here atall.
For my iron I'm thinking:
http://www.antekinc.com/pdf/AN-4T360.pdf (power)
http://www.antekinc.com/pdf/AT-020L.pdf (OPTS)
And then the Hammond in the Diagram.
The Antek is cheap as dirt and delivers 360V/550mA so it's absolutely up the task right? And toroids are less wont to interfere with things EM wise right? The OPT's are the wrong impedance but I gather that's not all-consumingly important.
Just worried there's some huge thing I'm missing here...
For my iron I'm thinking:
http://www.antekinc.com/pdf/AN-4T360.pdf (power)
http://www.antekinc.com/pdf/AT-020L.pdf (OPTS)
And then the Hammond in the Diagram.
The Antek is cheap as dirt and delivers 360V/550mA so it's absolutely up the task right? And toroids are less wont to interfere with things EM wise right? The OPT's are the wrong impedance but I gather that's not all-consumingly important.
Just worried there's some huge thing I'm missing here...
The mA and voltage ratings are fine on this transformer except you do not have a 5V secondary.
Proper input impedance is very important, with your proposed primary impedance you will suffer losses in power to some degree.
How much is S/H for these toroids? I have seen many times where tube gear parts are less expensive from certain vendors but you end up making it up in S/H in the end.
Jeff
Opt
Raypalmer,
I did miss that too.....yes it is a Push Pull OPT. It could be used but you will suffer bandwidth losses as the core saturates. If you are looking to do this on a budget there are much better products out there. I for one would try the $26 mid-line of Edcor SE output transformers. They are rated for 40-17khz which is generally sufficient considering most peoples hearing abilities and room size constraints (most people after the age of 30 or so cannot hear anything above about 17-18khz anyways) and on the other end....your room size will dictate the lowest sound that can effectivly reproduced b/c the length of one cycle becomes longer than the longest axis of the room. Count on about 40hz for the average sized listening room. So having said that it is a reasonable approach, esp on a budget to use an output transformer with a bandwidth in this range. I have used them and was satisfied with the results. You can get all the iron for about $150 with Edcor OPTs and power transformer and Hammond or Triad chokes. Edcor also supplies a great power transformer that works in this application for about $80, the XPWR134. I had to use a dropping resistor of about 22R (I think, I will have to look under the amp to see what I ended up using) b/c the XPWR134 has a slightly higher rated mains voltage. I think you will have better results with a dedicated SE OPT.
If you are hellbent on using a toroid then I would not scrimp and spend the cash on Plitron's products.....they will set you back easily over $1000 for iron alone in a project like this though. I myself have not used them but there is plenty written about the excellence of these products.
In the end, I fear if you decide to use these toroids you found you will be totally dissatisfied with the results.
I don't think you ever mention how much they cost, how inexpensive are these?
Jeff
Raypalmer,
I did miss that too.....yes it is a Push Pull OPT. It could be used but you will suffer bandwidth losses as the core saturates. If you are looking to do this on a budget there are much better products out there. I for one would try the $26 mid-line of Edcor SE output transformers. They are rated for 40-17khz which is generally sufficient considering most peoples hearing abilities and room size constraints (most people after the age of 30 or so cannot hear anything above about 17-18khz anyways) and on the other end....your room size will dictate the lowest sound that can effectivly reproduced b/c the length of one cycle becomes longer than the longest axis of the room. Count on about 40hz for the average sized listening room. So having said that it is a reasonable approach, esp on a budget to use an output transformer with a bandwidth in this range. I have used them and was satisfied with the results. You can get all the iron for about $150 with Edcor OPTs and power transformer and Hammond or Triad chokes. Edcor also supplies a great power transformer that works in this application for about $80, the XPWR134. I had to use a dropping resistor of about 22R (I think, I will have to look under the amp to see what I ended up using) b/c the XPWR134 has a slightly higher rated mains voltage. I think you will have better results with a dedicated SE OPT.
If you are hellbent on using a toroid then I would not scrimp and spend the cash on Plitron's products.....they will set you back easily over $1000 for iron alone in a project like this though. I myself have not used them but there is plenty written about the excellence of these products.
In the end, I fear if you decide to use these toroids you found you will be totally dissatisfied with the results.
I don't think you ever mention how much they cost, how inexpensive are these?
Jeff
Ah nuts I didn't See that they were pp....
I guess It has to be the edcors! The power tranny is only 50 bucks though so depending on shipping I may still get that ( no 5v tap but the 6.3's are 5a so I can run all four tubes off of one of those and drop the other 6.3 down to 5v for the rectifier)
I guess It has to be the edcors! The power tranny is only 50 bucks though so depending on shipping I may still get that ( no 5v tap but the 6.3's are 5a so I can run all four tubes off of one of those and drop the other 6.3 down to 5v for the rectifier)
Okay so as I mentioned before I may still get the Antek Toroid if shipping is reasonable.
But the Edcor OPT's are basically a no-brainer, that price is unstoppable. And the 10H Hammond choke I'll be able to get from Partsconnexion up here in Canada which can save me a little money in duties.
Question: What output impedance do you guys like for OPT's (I religiously build all my speakers to 4 Ohms)??
Further question: What type of pots did you use for the 10K trimmers? I was thinking of just going cheap (can you tell that I'm on a budget:/) and using something like these.
But the Edcor OPT's are basically a no-brainer, that price is unstoppable. And the 10H Hammond choke I'll be able to get from Partsconnexion up here in Canada which can save me a little money in duties.
Question: What output impedance do you guys like for OPT's (I religiously build all my speakers to 4 Ohms)??
Further question: What type of pots did you use for the 10K trimmers? I was thinking of just going cheap (can you tell that I'm on a budget:/) and using something like these.
I myself build all my speakers to 8ohms so of course that is what my secondaries are. I don't think there is any question here though....if your speakers are all 4ohm then you should go with 4ohm taps. Unless you plan to build some 8ohm speakers then you could go with a 6ohm secondary in between the two and use it for either. Jack Eilano at Electra-print is a big advocate of this and writes about it some on his website: Electra-Print.com High-Fidelity Audio Tranformers . I have never tried this before but it sounds reasonable.
Maybe I am loosing my mind but I do not remember anything about a 10K trimmer pot in this circuit. Are you referring to the 100K pot for the input volume control? If this is what you are referring to a nice pot (not 95c) is the Alps Blue Velvet. If you want to go cheapo but still have an excellent result try a shunt mod with a cheap pot ands a single high quality 91K resistor for the voltage divider. I use the shunt mod with the Alps above.....great way to do it. This is of course if this is what you are talking about. Again, am I loosing my mind....did the circuit ever have a 10k trim pot for anything....I think I have seen about every version of this schematic on the web and I don't recall this anywhere.
I think I wrote and provided a schematic on this thread earlier on the shunt mod. If not PM me and I will provide it to you.
Jeff
Raypalmer,
I almost forgot....I recently paid the design fee to have Edcor build a near replica of the Angela Universal power transformer. It has all of the voltages you need complete all in one trafo. It lists for $61 but it is not on thier website yet. The code for it is XPWR144, send an email to Phyllis at Edcor and tell het you want the one I had her design for me, or just ask for the XPWR144. You could use the 380v taps with a dropping resistor or probably use an 5AR4 rectifier with the 320 taps (I just modeled it on PSUD2 with the 320 taps and a 5AR4 rectifier and increasing the first cap value to 50uf brings the B+ to 398v which is perfectly acceptable) This way you could get everything from one place and have some symetry of design (all blue iron) and save shipping costs (everything shipped from one place will be cheaper I think).
Let me know if you need help with changing a few things around on your power supply to get what you need.
Jeff
I almost forgot....I recently paid the design fee to have Edcor build a near replica of the Angela Universal power transformer. It has all of the voltages you need complete all in one trafo. It lists for $61 but it is not on thier website yet. The code for it is XPWR144, send an email to Phyllis at Edcor and tell het you want the one I had her design for me, or just ask for the XPWR144. You could use the 380v taps with a dropping resistor or probably use an 5AR4 rectifier with the 320 taps (I just modeled it on PSUD2 with the 320 taps and a 5AR4 rectifier and increasing the first cap value to 50uf brings the B+ to 398v which is perfectly acceptable) This way you could get everything from one place and have some symetry of design (all blue iron) and save shipping costs (everything shipped from one place will be cheaper I think).
Let me know if you need help with changing a few things around on your power supply to get what you need.
Jeff
At least I know now I am not loosing my mind......I think he is referring to the 100K input pot for volume control in which case I would not try using the 95c job at AES.
Jeff
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