so design one. 6N6P has low plate resistance, which you need in a 300b driver. And it is a double triode, so you can do a lot with it.
I don't have any though. I have quite a few nice pentodes that work well triode strapped though...
I was trying to "design" my own driver stage for 300B using tubes such, 6N23P-EV, 6N6P and 5687 but no luck so far. Previous setup I had with 6SN7 and was good, but I want something different in terms of 'better' sounding.
I use 6Nx series tubes in different preamps and they perform very good, therefore I wanted to have same driver for 300B tube as well.
I use 6Nx series tubes in different preamps and they perform very good, therefore I wanted to have same driver for 300B tube as well.
Questions from a builder
Hi,
I know this is a bit absurd to post a reply to a thread started 15 years ago, but I have a few questions about the schematic on post #1.
I have started constructing a pair of these, and want to know a bit more.
It looks like James D. is still active on the forum, so here goes:
According to later posts by the OP, the 6n6p B+ is fed from a 20h choke with no cap decoupling it.
1-Does this make Plate 1 of the 6n6p choke loaded?
2-If so, would it be advantageous to make a separate RC filter (connected to the B+ rail before the last 20H choke) for the EF86?
3-There appears to be a voltage divider formed by two 100k resistors going to Plate 2 (lower triode) of the 6n6p. What is the function here? Is the upper 100k functioning as the plate load resistor?
I'm not at all questioning the choice, just trying to understand the circuit.
Thanks in advance for your help!
Regards,
John
Hi,
I know this is a bit absurd to post a reply to a thread started 15 years ago, but I have a few questions about the schematic on post #1.
I have started constructing a pair of these, and want to know a bit more.
It looks like James D. is still active on the forum, so here goes:
According to later posts by the OP, the 6n6p B+ is fed from a 20h choke with no cap decoupling it.
1-Does this make Plate 1 of the 6n6p choke loaded?
2-If so, would it be advantageous to make a separate RC filter (connected to the B+ rail before the last 20H choke) for the EF86?
3-There appears to be a voltage divider formed by two 100k resistors going to Plate 2 (lower triode) of the 6n6p. What is the function here? Is the upper 100k functioning as the plate load resistor?
I'm not at all questioning the choice, just trying to understand the circuit.
Thanks in advance for your help!
Regards,
John
In the spirit of keeping this ancient thread alive, just wanted to report that I recently had an amp based on this circuit built by a friend of mine. The project started with a clone of Audio Note Shinri that I got on a very favorable trade. The amp was a very high quality build full of high-grade components: Tango iron all around, AN tantalums, Cerafines, etc. The circuit was 12AY7 in SRPP going into a 5687 in some sort of anode follower configuration. It had crazy amounts of gain, even when used with a passive preamp; it was noisy, and in general not great-sounding -- aggressive but not well-defined or extended. But it had great iron, fancy hardware, and an amazing chassis with a 4mm solid copper top plate, which was my intention to put to use to begin with. So I looked for some interesting circuit to try that would utilize the layout and hardware, and that's how I came upon this thread.
We had a brief PM exchange with James D. discussing the potential circuit changes, which unfortunately stopped abruptly for unknown reasons, so my amp was built pretty much according to the schematic in the first post, with some changes as mentioned by Dave Dove in a later post -- 690 ohm cathode resistors for 6H6П specifically. The high voltage power supply is a 5AR4, shared cLC section and then split into another LC per each channel. We have both 2.5V AC filaments to run JJ 2A3-40, as well as 5V DC filaments using Pete Millett's boards to run 300B -- this is switchable with a single switch per channel. Opt primary is switchable from 2.5 to 5K, and the feedback is switchable as well. Also, my amp is built with 6BR7 instead of the EF86, since that had been reported by Dave Dove to be sounding better.
The circuit was definitely worth building! Clear, great bandwith, and very engaging. I particularly enjoy it with 2A3-40 @ 2.5K primary loading (the idea was to utilize the XE20s at max bandwidth), with no feedback -- this is feeding either Altec 604 or custom A7-ish 2-way. 300B also sounds great here -- not like an average stereotype 300B circuit with weak bass and soft highs at all. My reference for good 300B implementation still remains Thorsten's Legacy circuit, which I have built as monoblocks using Tribute iron. This circuit definitely is on that level, and probably a bit better in some regards. We have still some tweaks to try and some changes to make but this is a good one!!
here's what the innards of my amp ended up looking like:
In the spirit of keeping this ancient thread alive, just wanted to report that I had an amp based on this circuit built by a friend of mine. The project started with a [supposed] clone of Audio Note Shinri that I got on a very favorable trade. The amp was a very high quality build full of high-grade components, Tango iron all around, AN tantalums, Cerafines, etc. The circuit was 12AY7 in SRPP going into a 5687 in some sort of anode follower. It had crazy amount of gain, even when used with not active preamp, was noisy, and in general not great-sounding. But it had great iron, fancy hardware, and an amazing chassis with a 4mm solid copper top plate. So I looked for some interesting circuit to try that would utilize the hardware I had and this came upon this thread.
We had a brief PM exchange with James D., which unfortunately died out, so my amp was built pretty much according to the schematic in the first post, with some changes as mentioned by Dave Dove in a later post -- 690 ohm cathode resistors for 6H6П specifically. The high voltage power supply is a 5AR4, shared cLC section and then split into another LC per each channel. We have both 2.5V AC filaments to run JJ 2A3-40, as well as 5V DC filaments using Pete Millett's boards to run 300B -- this is switchable with a single switch per channel. Opt primary is switchable from 2.5 to 5K, and the feedback is switchable as well.
This circuit was definitely worth building! Clear, great bandwith and control, and very engaging. I particularly enjoy it with 2A3-40 @ 2.5K primary loading (the idea was to utilize the XE20s at max bandwidth, which happens to be 2.5K setting, and is an ideal load for a 2A3-40, which, in turn, fits the bill with higher B+ than a 2A3), with no feedback -- this is feeding either Altec 604 or custom A7-ish 2-way. 300B also sounds great here -- not like an average stereotype 300B circuit with weak bass and soft highs at all. My reference for good 300B implementation still remains Thorsten's Legacy circuit, which I have built as monoblocks using Tribute iron. This circuit definitely is on that level, and probably a bit better in some regards. We have still some tweaks to try and some changes to make but this is a good one!!
here's what the innards of my amp ended up looking like (almost complete -- Miflex coupling caps not installed yet):
[IMG]https://lh3.googleusercontent.com/pw/ACtC-3eji_16cwiIsGmtdD8qfYc-X4J7TceMD1JROb5cYJDXuv0QC4QXp3KHSzYlrmUcMWvfl7cjFqpbVBOV7dmndq5bv6Un4rvXFAagZ2T4zk9MFNhxLDlzK4zGvxlN1OEXAyletOFooBg59BSKDrLFz9nq8w=w1024-h768-no?authuser=0
We had a brief PM exchange with James D. discussing the potential circuit changes, which unfortunately stopped abruptly for unknown reasons, so my amp was built pretty much according to the schematic in the first post, with some changes as mentioned by Dave Dove in a later post -- 690 ohm cathode resistors for 6H6П specifically. The high voltage power supply is a 5AR4, shared cLC section and then split into another LC per each channel. We have both 2.5V AC filaments to run JJ 2A3-40, as well as 5V DC filaments using Pete Millett's boards to run 300B -- this is switchable with a single switch per channel. Opt primary is switchable from 2.5 to 5K, and the feedback is switchable as well. Also, my amp is built with 6BR7 instead of the EF86, since that had been reported by Dave Dove to be sounding better.
The circuit was definitely worth building! Clear, great bandwith, and very engaging. I particularly enjoy it with 2A3-40 @ 2.5K primary loading (the idea was to utilize the XE20s at max bandwidth), with no feedback -- this is feeding either Altec 604 or custom A7-ish 2-way. 300B also sounds great here -- not like an average stereotype 300B circuit with weak bass and soft highs at all. My reference for good 300B implementation still remains Thorsten's Legacy circuit, which I have built as monoblocks using Tribute iron. This circuit definitely is on that level, and probably a bit better in some regards. We have still some tweaks to try and some changes to make but this is a good one!!
here's what the innards of my amp ended up looking like:
In the spirit of keeping this ancient thread alive, just wanted to report that I had an amp based on this circuit built by a friend of mine. The project started with a [supposed] clone of Audio Note Shinri that I got on a very favorable trade. The amp was a very high quality build full of high-grade components, Tango iron all around, AN tantalums, Cerafines, etc. The circuit was 12AY7 in SRPP going into a 5687 in some sort of anode follower. It had crazy amount of gain, even when used with not active preamp, was noisy, and in general not great-sounding. But it had great iron, fancy hardware, and an amazing chassis with a 4mm solid copper top plate. So I looked for some interesting circuit to try that would utilize the hardware I had and this came upon this thread.
We had a brief PM exchange with James D., which unfortunately died out, so my amp was built pretty much according to the schematic in the first post, with some changes as mentioned by Dave Dove in a later post -- 690 ohm cathode resistors for 6H6П specifically. The high voltage power supply is a 5AR4, shared cLC section and then split into another LC per each channel. We have both 2.5V AC filaments to run JJ 2A3-40, as well as 5V DC filaments using Pete Millett's boards to run 300B -- this is switchable with a single switch per channel. Opt primary is switchable from 2.5 to 5K, and the feedback is switchable as well.
This circuit was definitely worth building! Clear, great bandwith and control, and very engaging. I particularly enjoy it with 2A3-40 @ 2.5K primary loading (the idea was to utilize the XE20s at max bandwidth, which happens to be 2.5K setting, and is an ideal load for a 2A3-40, which, in turn, fits the bill with higher B+ than a 2A3), with no feedback -- this is feeding either Altec 604 or custom A7-ish 2-way. 300B also sounds great here -- not like an average stereotype 300B circuit with weak bass and soft highs at all. My reference for good 300B implementation still remains Thorsten's Legacy circuit, which I have built as monoblocks using Tribute iron. This circuit definitely is on that level, and probably a bit better in some regards. We have still some tweaks to try and some changes to make but this is a good one!!
here's what the innards of my amp ended up looking like (almost complete -- Miflex coupling caps not installed yet):
[IMG]https://lh3.googleusercontent.com/pw/ACtC-3eji_16cwiIsGmtdD8qfYc-X4J7TceMD1JROb5cYJDXuv0QC4QXp3KHSzYlrmUcMWvfl7cjFqpbVBOV7dmndq5bv6Un4rvXFAagZ2T4zk9MFNhxLDlzK4zGvxlN1OEXAyletOFooBg59BSKDrLFz9nq8w=w1024-h768-no?authuser=0
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