Hi all, I am building an amp from scratch thT will have 4x EL156 New Telefunken power tubes in pp ultralinear. I want to use as much onhamd pieces as o can. I have the following tubes onhand; 12bh7 ( Dumont), 5963 Sylvania, E80cc phillips and 12au7 sylvania , and Russian 6h30. Which of those will drive the El156 to 60 watts per channel without overworking the tubes ? I prefer to use what I have. Power supply will be 2 x274b mesh plates , run in parallel to supply enough current, and 500 V of B+ to the anodes. Can anyone help me? I don't want to
Max out the el156 @ 800v. So they will last longer. Amy ideas? My st70 clone replayed and destroyed my el34 and 5v4 tubes , so I don't want to repeat that .
Max out the el156 @ 800v. So they will last longer. Amy ideas? My st70 clone replayed and destroyed my el34 and 5v4 tubes , so I don't want to repeat that .
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The 5963 is a 'U7. !2AU7 = not linear. Do you have 4X 12BH7s? If so, you can use Williamson topology.
6H30 as a driver by far the best of the crop if works as it should. It has more grunt than needed. At 175V/16mA can swing 200V peak-to-peak into 12-15K with low distortion (mostly 2nd harmonic).
If you use the 6H30 then the 12BH7 is redundant and you might keep for another project.
Input phase inverter: I would use 1) 12AU7 or 5963 if common cathode + concertina; 2) E80CC if LTP with CCS tail.
E80CC is not more linear than 12AU7. The ECC40, that is E80CC predecessor, is a LOT better in that respect! High plate load value is desirable for both of them for less distortion, unless one wants to cancel some 2nd harmonic with another stage. I did in a 2A3 SE amp and worked well.
If you use the 6H30 then the 12BH7 is redundant and you might keep for another project.
Input phase inverter: I would use 1) 12AU7 or 5963 if common cathode + concertina; 2) E80CC if LTP with CCS tail.
E80CC is not more linear than 12AU7. The ECC40, that is E80CC predecessor, is a LOT better in that respect! High plate load value is desirable for both of them for less distortion, unless one wants to cancel some 2nd harmonic with another stage. I did in a 2A3 SE amp and worked well.
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Thanks! Looks like the 6h30 will be the driver. With the e8ccc as phase splitter . I need a source for a power transformer; any ideas. I tried edcor, they can't make one that powerful.
I suggest the e88cc in srpp as gain stage then a long tail with 6h30 to drive the grid of power tubes
Good swing and low thd
I sent a thread with a project on monos
Walter
Good swing and low thd
I sent a thread with a project on monos
Walter
There's always something custom from Heyboer, for the power trafo. However, 1st check AnTek's 400 VA AS-4Tnnn toroids out. You might be able to save $.
The problem with the 6H30П (6n30p) is lowish μ. 🙁 The type makes a superior LTP, in a Mullard circuit, given its high gm. A Mullard circuit employing a 12BH7, with the sections in cascode, as voltage amplifier and 6H30П as LTP should be tuneable to yield a satisfactory small signal gain structure.
So you suggest the 6h30 as phase inverter, and using 12bh7 to drive the EL 156?
I'm probably going to run 600v on the plates; 800 gives to many psu problems, I may need to to go to 3 parallel 274b to get enough current at 500/600v B+.
I'm probably going to run 600v on the plates; 800 gives to many psu problems, I may need to to go to 3 parallel 274b to get enough current at 500/600v B+.
Power supply
274b , and have almost 500 v But the El156 will need more current, Is it feasible to parallel 3 274b?? Could I add an RGN-1064 ? That would meet current needs. And cost less than a 3rd 274b. I have 2 Eml mesh plate rectifiers now, opinion?
. Hi, speaking of power supply, I willl need 500-600 volts B+ z. Currently I have parallel
274b , and have almost 500 v But the El156 will need more current, Is it feasible to parallel 3 274b?? Could I add an RGN-1064 ? That would meet current needs. And cost less than a 3rd 274b. I have 2 Eml mesh plate rectifiers now, opinion?
I have 3 12bh7, 3 12au7, 2 6h30, 3 E80cc
Ad to power , I phase 2x 274b mesh plates on parallel, they can yield about 340mA I need over 400. Could I parallel
In A rgn1064 , but will that work with the 274bs? It's cheaper than another 274b and readily available , and are Telefunken mesh plates.
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You need lots of B+ current. Why fuss with vacuum rectifiers, when high PIV Schottky diodes are as noise free and can handle (sic) amperes of continuous current? Another good thing about the Schottkys is you can use bridge rectification and not deal with a "tall" end to end secondary that's center tapped. SS bridge rectification brings another useful tidbit into play. If a single AnTek toroid lacks the VA "sock" your project needs, a well selected pair of toroids will. AnTek toroids are remarkably inexpensive. 🙂 A pair will cost you less than something custom.
In my opinion is much better to use a ss rectification; you need a good reservoir of current if you are in AB1.
I think that with fast recovery diode and around 1.000 uF on Vdc you will get a good dynamic perfromances.
Regarding the splitter the use of ecc88 and 6H30 is fine
In attach the schemas; they are working very good also on lab test.
Walter
I think that with fast recovery diode and around 1.000 uF on Vdc you will get a good dynamic perfromances.
Regarding the splitter the use of ecc88 and 6H30 is fine
In attach the schemas; they are working very good also on lab test.
Walter
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