Hello,
I want to build an amplifier using 300B. I have chosen the Shishido shcematic:
https://i.pinimg.com/originals/7a/49/f7/7a49f7f4ea46cbe232b242f674720c46.gif
I have a question about v2.
Can i replace this tube, 6F6 with E80L? I can buy 6F6, but i think that E80L has a better sound. If some of you guys have some experience with E80L wold help me.
Thanks,
Remus
I want to build an amplifier using 300B. I have chosen the Shishido shcematic:
https://i.pinimg.com/originals/7a/49/f7/7a49f7f4ea46cbe232b242f674720c46.gif
I have a question about v2.
Can i replace this tube, 6F6 with E80L? I can buy 6F6, but i think that E80L has a better sound. If some of you guys have some experience with E80L wold help me.
Thanks,
Remus
The two tubes are quite different, not to mention that the E80L is far more expensive. Since the tube is used as a voltage amplifier, the distortion will be fairly low, thus the two are likely to "sound" about the same. But if you insist on using the E80L, then the circuit has to be re-designed.
I already have 5 pcs of E80L. I saw on the specs that E80L is something special and i thought that can sound better.
The special is that E80L is a long life power pentode with similar characteristics than "ordinary" video output pentode EL83.
Certainly, but the amplifier stage with E80L needs to be completely redesigned.
So the sound would be similar and the effort would be useless. Now i want to know how to design a stage like that? Do you have any formulas or online books?
Thanks,
Remus
Thanks,
Remus
Morgan Jones is always a good place to start.
IMO, for the price of a pair of NC-20 transformers, you could build a better 300B amp.
Before you try to re-design the amplifier, you should read Shishido's article in Glass Audio, the driver tube (6F6) was not just picked randomly, since he relied on interstage distortion cancellation. So "better sound" of the E80L may not be what's best for the amplifier as a whole.
Yes, you are right. This was my conclusion. I found this tubes, 6f6 and i hope that the schematic will work. I will post pictures with the project.
I think nobody can say anything definite about the "sound" of E80L compared to 6F6.
At least the amount and spectrum of harmonic distortion depends a lot on how the stage is biased and what the load impedance is.
Do you mean, to design for good sound ? If so, then I can say that such formulas or straightforward design methods do not exist. Those who look for "best sound" do a lot of experimental design.
Of course, the sound of every different tube is different.
E80L in triode mode could be worth the effort of redesign. But what sound of an amp you, in the end, will prefer, thats a mystery to any of us. Because its like changing a recipe from a cookbook. Will the new recipe smell and taste better in the end? You dont know the sonic characteristics of any of those tubes, but you think you should change the ingredients of this recipe. You are like a chief cook with not any experience in cooking at all, but you will change one great recipe from the famous Paul Bocouse. Forget about changing ANY of the components, until you have at least build the amp in original state once. THAN, after finishing, you can change one gain stage by redesigning. Not before you have ever tried.
Here is a listening experience with E80L, but that doesnt mean, that this tubes sound is comfortable in this Shishido Circuit. It all depends on the working operation points of a given tube. You are a novice, so dont change with the wisdom of tube sound, that you could not have at this stage.
Comparing Eight Tubes For Low Power Amplifiers Article Submitted By Mike Zivkovic Of Teresonic
You are right! I will stay with the recipe. I found 6F6, but i don't understand on some sites 6F6 is in a metal case in other is in a glass tube. I think that inside is the same. After the amp will be finished i will try to modify the schematic. I liked your comparison.
To me, the quality of gears are determined by three major factors: choosen components (as the are the ingredients of the recipe), circuit design (the recipe) and build quality.
The Shishido circuit is not a common concept, its design is rather unusual but interesting anyway.
The Shishido circuit is not a common concept, its design is rather unusual but interesting anyway.
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Type 6F6 indicates the original version, which was a metal-cased tube.
Type 6F6G was made with a curved glass envelope.
Type 6F6GT was made with a straight-sided glass envelope.
All of the above use 6.3V heater with octal (8-pin) base.
You can substitute type 2A5 (with a 2.5V heater and a 6-pin base) or type 42 (6.3V heater with a 6-pin base). These are electrically identical to type 6F6 except for heater voltage and/or base pinout.
All this information can be seen in the datasheet:
http://www.r-type.org/pdfs/6f6-1.pdf
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Thanks!
I have found the last type with glass envelope. I hope it will do the job. No i have to find some transformers. I have in mind to buy from Toroidy. Transfer Multisort Elektronik - Electronic components - Error 404. For interstange i am waiting for a pair from Hammond they were the only guys that had interstage transformers.
I have found the last type with glass envelope. I hope it will do the job. No i have to find some transformers. I have in mind to buy from Toroidy. Transfer Multisort Elektronik - Electronic components - Error 404. For interstange i am waiting for a pair from Hammond they were the only guys that had interstage transformers.
I dont recommend toroid output trannies. All great designs are non toroid. And thats for a good reason. Im not talking about WE 111C, thats not an output trans for SE Design.
Use conventional designs, the quality of the OPT is relevant to the sound.
Use conventional designs, the quality of the OPT is relevant to the sound.
Yeah, I knew we would get here sooner or later, which is why I brought this up in post number 7.
You will not get great results by taking a design that called for a very specific set of high end transformers, then just sticking in whatever Hammond has in their catalog.
You will not get great results by taking a design that called for a very specific set of high end transformers, then just sticking in whatever Hammond has in their catalog.
both driver stages, gain combined ~ 85x
you can achieve same number with unbypassed ecc83 under fet gyrator... crisp sound driver with low Zout
also you save $ on unused driver TX.
endstage you can copy-paste; no problems
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