6sn7 cascode. Power tubes should dissipate about 8W each, it is about 0.

6sn7 cascode The kit originally started out as a 6H8C/6P6P (Russian 6SN7, Chinese 6L6) with an off-equivalent of a 5AR4 rectifier. I have the normal shoe box full of 12AX7's but I would like to make something with an octal tube to stay with my linestage 6SN7 common cathode pre. Joined 2004. You'd better try both and see what you Post subject: New Amp - GU-50 Triode w 6N1P Cascode - Seeking advice. I used E810F for this (7788 tube in the US). I have been playing with various cascoded input Driver stage for my 777 Amp and so far, the ultra linear cascode has performed the best in this Amp. Re: Limitations of 6SN7 cascade driver for 300B, aka "flesh and blood" 198. It means that its pins are arranged for easy making cascode schemes and the tube is with low microphonic construction. The 6SN7 has a low intrinsic distortion which the mu follower degrades very little. com. Yea I suppose your right. tomchr. Cascode amplifiers were quite common in RF and Radar circuits. I see so many 300B designs that only swing 60-70V, which isn't even half what they need. The octals have a less fizzy top end than the 12AX7s, and they tend to be a bit fatter sounding. neurochrome. I measured at the top of the first anode, using a 1 uF capacitor into a 10M probe. 60. With the cascode, you should get a dV/dI on the order of a Telemachus is a SET 300B amp. I'm not well versed in design, still learning and was just curious about this. CCS(6sn7)->CF->TS->GS->CF->SE PA I plan to use a mosfet for the first CF before the TS and then a tube CF as the last one using a lower R to get some current draw and 2nd order compression. Also, 1. The performance of shunt cascode transistor Q1 is important, please try to use the ZTX558 here. The output is then a traditional series feed output with high quality output transformers. First off, thanks to Alessandro Galavottis very straightforward design for 1/2 of a single 6SN7 for a driver, going to a 2A3. It uses a 6SN7 cascode input stage followed by a MOSFET source follower, or “grid driver”, that drives the 300B grid. 2008-09-07 4:19 pm #2 2008-09-07 4:19 pm #2 Like a Pentode's screen, a cascode stops V1's control grid from seeing intrinsic negative feedback from the other plate that drives the actual load. As mentioned earlier the 6sl7 shouldn’t stress the power transformer at least. The 6SN7 is a good example of a tube that works well there. The RF Cascode circuits are used for very small signals, very low bandwidth circuits the resistive plate load gave the gain, linearity, and voltage swing that is needed. 2015-11-15 7:16 pm #12 The cascode voltage gain stage uses an ECC88 as input tube, for its low noise and high transconductance, and a 6SN7GTA/GTB to bear the high voltage 6sn7 filaments Whereas a standard 6SN7-based cathode follower would offer an output impedance of 400 ohms, the extra-resistor modified cathode follower can easily present twice that If stage 1 is a cascode, Zout is fairly high but it's resistive and highly constant when valve Gm changes. I have one used one to play with I think so it But it is no big difference between 6SN7 and 12BH7. IV 3. I am about to change the 68k anode resistor in my SE Chinese amp's 6SN7 cascode input stage for an Ixys 10M45. Most people say they do not sound any different. At the same time, the circuit regulates the current source M5, and the cascode voltage via Q1. There had also been some variants with grid caps like the 6C8 and 6F8. Joined 2003. The problem is long interconnects are required to connect from the system to to the powered speakers either side of a massive screen for movies. The current can be adjusted from about 2. Tubes so far are 6CG7 and 6DJ8. This feeds a 6SN7 cascode driver stage which in turn feeds the 300B output tube. You should get the gain you need from a differential cascode made of 7N7 sections, as the triode in that type is reasonably high gm. The open loop gain when using a 6SN7 is pretty low. I don't expect good results with 6SN7, sad to say. For guitar amps it can be imagined to be a simulation of a MJ shows an uncredited design, of a cascode feeding a 6SN7 cathode follower with feedback from the top tube to the CF to provide a low output impedance for driving whatever. It was officially registered in 1941 by RCA and Sylvania as the glass-cased 6SN7GT, originally listed on page 235 of RCA's 1940 RC-14 Receiving Tube Manual, in the Recently Added section, as: 6SN7-GT. 35mA/V) compared to the 6DJ8 (10 mA/V), in order to get to the larger Response was that it was harder to drive than the trioded cascode input. While I was working on this, I looked at a bunch of KT88 circuits and didn't see any using a 6SN7 driver. You have the added option of a pentode stage or a cascode, both of which have fans. Posted by SteveBrown on January 16, 2002 at 11:43:41 . 1 v LOUT GND R-OUT 125_1V 3. 27. With all these factors in mind, and noting that the output this is our very best preamp, using larger 6SN7 octal tubes, in a larger 5" tall chassis. — Since 1999 — Welcome to over 600 posts and to over 50 articles on amplifiers, tube-based preamps, crossovers, headphone amplifiers, single-ended amplifiers, Re: Limitations of 6SN7 cascade driver for 300B, aka "flesh and blood" Posted by Thorsten (M) on January 16, 2002 at 16:16:15 . But I’m thinking of using a 6j5 single triode in the driver stage on each. Alashikata. Ite. I think I paid about $8 a Limitations of 6SN7 cascade driver for 300B, aka "flesh and blood" Posted by RJM (A) on January 16, 2002 at 11:12:29 . 2007-10-01 4:00 pm Looking at the original schematic I would swear it was made for 6SL7, not 6SN7. 37. 6A3sUMMER. 2023-10-09 7:19 am #595 2023-10-09 7:19 am #595 If you use the 6SN7 like a cascode, you will change the pentode very well. How does a Cascode sound next to a Shunt regulated Push Pull or a (fill in the blank). 9 420 0. JPG. The power tranformer is a Hammond 278X (800V CT @ 230mA + 5V CT @ 3A + 6. The following stage is a 6SF5 anode follower. Joined 2016. The TL431 3-pin chip regulates the screen voltage of the output valve, and uses this 210V for a supply voltage. For Stuart Yaniger wrote a great article for audioXpress in February 2009, The ImPasse Preamplifier, describing a tube preamp to drive a pair of Nelson Pass’ First Watt F4’s (or I want to build a CCS as a plate load for a 6SN7 so that I can get a 250 v pp swing with low distortion. For the gain stage, you could use a 6SN7 with the same plate load and by reducing the cathode bias resistor to Cascode circuitry has also found its way into preamplifier circuitry as manufactured by Dayton-Wright Paragon, DB Systems, and Audio Directions among others. I have not built like that, and prefer an all-tube active load on a single 6SN7 stage. The power supply, OK that's more complicated. Pretty simple: A PC86 high transconductance triode with a FZT560 PNP VAS feeding a cascode CCS at the bottom end gives insane loop gain. But if you use the rarer 6SN7s for better sonic attributes, it's hard to Congrats Glory! I have the Zu Definitions and use M60's. You might instead try the cascode 6SN7 front end I used with my 300B amp (which is what that second one you posted is doing), and replace the 300B in my amp with a KT88 and use some plate to plate feedback like they DN-IXTP cascode CCS samples . I rewired it more like that "Time Bandit" example, with a cascode using a voltage divider for the upper section grid and it sounds WAY better with 3X the output. Her design apparently performs well, and involves totally rewiring the 6SN7 circuitry, and many new parts, although they are not expensive. She ended up with a cascode front end and replaced the rectifier tube with a 5AR4. Though you can get away with running them cool if cathode driven by a pretty good gm tube in cascode. It requires only one external resistor and that’s it. Input 2 is Marshall-y with a couple 6SL7 stages. Fixed bias is used and DC is used for all of the filaments, with dual regulated DC supplies for the output tubes. B. This solution is relatedly easy to implement, however it requires more components. 33uf coupling cap, which solved the weak bass and even running the 300B at 80% into a 5K OT it's putting out 6W of clean power. The tube needs to meet the requirements of the circuit or vice versa. The results through the triode mode seem good, bringing a low THD and an output pwr(rms) of 4. Low distortion - the tube CCS helps bucket loads, the driver then helps provide a low impedance low distortion too. A train stops at a train Yes, the circuit is certainly feasible. It won't be that high in reality and you don't have to max it out I use LM317 as CCS for the 6SN7 long tail pair phase splitter. 6 Anode characteristic curves for these two types were In any case, it looks like the 6sn7 is set up as a cascode effectively turning it into a single triode. 6SN7 cascode amplifier (T397E) Details Written by: Newton C. 6SN7s date from 1940 so fit in well the overall sonics. In-> Input 6sn7 -> cascote 6sn7 -> mosfet driver. Is it as straight forward as it looks or am I missing something? Also, would it be OK if all the triodes where 6SN7's or should the cascode be a 6922? I need a low distortion driver with low output impedance to drive a high capacitance. The appeal of the cascode is the "pentode I like the cascode circuits. The 6SN7 was originally released in 1939. I also feel using an LED for the bias helped a lot in making this work well. Again why not just build the thing as designed, test it, and then listen to it? You can change it later if so inclined Joined 2009. 2. This fixes the plate voltage of the 6SN7 and allowed the tube to find its plate current based on the bias. I am doing a similar comparison using cascode Ixcp10m45s mu follower vs n channel source follower. Posted: 05 Dec 2022 5:02 pm . Joined 2002. Wishing everyone a Happy New Year and many repairs in the coming Months. I just made it a 12BH7A instead of 6SN7. Two vintage NOS Triplett milliamp meters will monitor bias current. gif. The EL34 is pentode connected and, along with six MJL3281 200W NPN transistors, drives the 8-ohm loudspeaker. A AT7 does the job well. After some thought and trying a few different things, I got this 6SN7 cascode working well. Joined 2009. HEDGE, Ph. You need to lower the plate and cathode resistors because the 6SN7's plate resistance is about 8,000 and the 6SL7's is 44,000 ohms. The plate resistor is quite high, and a 6SL7 would make more sense using gNF. AB763 From what I gather a 6SN7 or an ECC88 are supposedly the optimum tubes for a cascode (in terms of maximising the space between the grid curves) FWIW. I can easily see someone who didn't find the solution I did might feel a 6SN7 CASCODE won't work well. First functioning Cascode! First waveform 1KHz sine wave. 1v 221k 470K R-IN 470K ransformer SPEC: 200-0 x 1 T30 Transformer IS recommanded loc-f 2-44V 12mA 200K 47K 6. Fully 95% I am about to change the 68k anode resistor in my SE Chinese amp's 6SN7 cascode input stage for an Ixys 10M45. Can anyone recommend newer versions,that sound really well,and have low noise? New Amp - GU-50 Triode w 6N1P Cascode driver - Seeking advice . Not gonna argue with them because I've listened to this amp, as well as many other people who have built it and I know how good it sounds The measurements start around the 8 minute mark. With 3Vpp in I am getting just shy of 140Vpp at the grid of the 300B with no clipping and it sounds fantastic. This amp will also have a 6sn7 cascode input gain stage. Search titles only 6SN7 Cascode Driver for 300B. However, substituting a 12AX7 or 5751 for the upper cascode tube will have negligible effect. What do these calculators do? These calculators compute. Swapped out to all JJ 5AR4/6SN7/6L6GC. hey-Hey!!!, I have a similar reaction to 801. In fact you just might have too much in the mids with that tube. Response was that it was harder to drive than the trioded cascode input. It looks like 5 or 6 ma would be about right The cascode with 317 and the MOSFET has inferior performance as Jung It looks like it might be outstanding in LTP or Cascode service. 34. I was going to use an LR8 but I think the 10m45 will be more robust. Steve. A negative For your reference, the tube pinout diagrams for the the 6SN7 twin triode, 300B directly heated triode and 5U4GB twin diode tubes are shown in Figures 3, 4 and 5. The second is a cascaded 6SN7 driver with unbypassed cathodes. Nothing wrong about using the 6SN7, however when you cascade 2 stages the sound is muddled at low levels. B 6SL7 7F7 70 44 kn 1. Just like a little EL84 sounds just like a 6L6 you now. 2007-07-24 6:28 pm #31 2007-07-24 6:28 pm 6SN7 / 300B Single-Ended Triode (SET) Tube Amplifier - Rear View. 2Mn 1. Looking for a jumping off point here. 12BH7 has a margin of 45-50 dB from 2nd downto 3rd harmonie in my circuit at 1 Watt RMS out. Most of 240 kHz amplifier using the LF356 (CB3994E) Precision Current Monitor (CB3995E) Long Interval Timer LF355 (CB3996E) 250 kHz Adder Amplifier LM108 (CB3997E) I have already tried some tube rolling with different makes of 6v6 and 6sn7’s which didn’t make any difference really. And yeah, that 6SN7 cascode doesn't have a ton of gain, it really like a pre-amp or at least a fairly hot source. Nov 27, 2011 #1 Four resistors and one coupling cap in the circuit. tubelab. Likely with a 6SN7 you will get away with it. Lerch98 • The 6CG7 is a direct 12ax7 Cascode Schematic The schematic of that power supply will be in the article. Unfortunately, With a cathode-to-plate voltage of Soviet version 6Н8С. Joined 2005. 3 KB · Views: 111 I. It seems this design somehow it sims like it should work well, but in practice it doesn't. 3V CT @ 6A). Just remember it is YOU who helps this site be what it is. 3. I think it's a 6SN7 in cascode, with a mosfet source follower and then a 12ax7 gain stage with another cathode follower going into an EL34. I like the unique sound of 6SN7/6H8C esp zero feedback, I'm not sure The 6SN7 got very popular among tube amp builders during the 1990ies. zip. L. Neurochrome. I Search. These are not new production I am speaking of and have no experience with new production. Input 1 uses a 6SN7 cascode input followed by a defeat-able single knob tone control and volume with a pull-boost feature. I've also used them with success as DC-coupled cathode followers in 5f6a/marshall type circuits, where the reduced gain doesn't matter much and can easily be compensated for. The power tranformer is a Each channel consists of a 6SN7 cascode driving a 6L6GC tetrode. Looking for 6SL7 + 6SN7 MM phono preamp schematic - Mike C 09:48:07 11/05/08 (0) 6SN7 is the last tube I would want to see in power output stage. Why mess with it. This gives the 2nd stage full voltage headroom, something the direct-coupled Many designs out there use 2 stages of 6SN7 for example. This EF86 driver has a gain of 60 so no gain stage is required. Join me exploring this exciting hobby! This channel focuses on designing, building and testing various kinds of DIY audio equipment. Although the 6S-series tubes are often metal-cased, there was never a metal-envelope 6SN7 (there being no I haven't put in the component values but I'm debating a cascode or just using the two triode halves as two gain stages before the CF. The mu-follower is a high gain, low output impedance inverting stage with excellent PSRR and very low non-linear distortion; making it enormously popular for hifi. 2015-02-26 6:12 pm #9 2015-02-26 I tried both 6SL7 and 6SN7, and I like the 6SL7 better--seems clearer and punchier in this amp, not just gainier. A Shunt Cascode is identified by having a current-source to force-feed the cascode node, with the cascode device (usually PNP) directing the 'overflow current' to the output. Very simple. Mainly because the 6SN7 is cap coupled to the 2nd stage. Cheers! SY. New Amp - GU-50 Triode w 6N1P Cascode driver G-807 and its pal the 6P7S, many 6N1P, 6N2P, If you put back C7 across R10, the 6SN7 cascode will then have more gain, which should result in more gNFB applied around the amp, which should lower distortion. A much larger PCB, with NO room to add a phono section inside. Attachments. 8 KB · Views: 871 A. D. Tubelab_com. The cascode is just two 6SN7 sections stacked. Although the 6SN7 cascade stage presented by Herb Reichart seems simple, foolproof, and sufficient, I've noticed that most 300B SE circuits do not choose to follow that circuit topology. Unless you have very sensitive speakers, you will want a valve with a mu of at least 30. A. THE "cascode" amplifier-a series connection of two 6SN7 7N7 20 7 kn 2. Logged A bus stops at a bus station. With B+ = 480v at the OP transformer CT, available power is 54w with input signal of 900mV amplitude (630mV RMS) @ 1kHz. 2ma I have built 6SN7 version of this driver but the gain is only about 6, so I add a front end gain stage of 6SN7 cascode. Like a Pentode, you can run a cascode in any number of You can view a cascode as a "synthetic" pentode. Member. huggygood. SYclotron. Shunt Cascode stages work best with high-quality, small triodes (or triode-connected pentodes) with a minimum 20 to 30mA/V. Here the circuit I thank for yours commentaries and suggestions, thanks . 6SN7 variants The 6SN7A and 6SN7W were both short-lived designations for 6SN7GTs made to military specifications. We feel the 6SN7 (CV181) has a more relaxed presentation than their miniature cousins, these larger driver valves are the best in their class for their musical sound and longer life. Readings as follows – both channels are identical. You're unlikely to find a good sounding sub for the 6SN7 IMO, take a look at my previous post as it hopefully (SRPP, WCF, cascode, etc. It too has a very high O/P impedance. TIA. I have some 6SL7's and 6SN7's tubes. 6 KB · Views: 374 6SN7 SE Driver for 300B. The 6SN7 is not a particularly good CF valve, because it has low transconductance. For guitar Hi gm triodes provide the most gain, and the ECC82 Post subject: Re: 6V6-6SN7 Humless "Lacewood" Amp. I try to New Item Arrival di Beyond The Music! List Item: - Ultrasonic Telemachus The very first Ultrasonic Telemachus di Indonesia! Ultrasonic adalah brand butik dari Swedia, yang specialist membuat Tub 6CG7's sound great! I wish they were still made in good quality like the good old days. I have tried a bunch of SET designs for 300B and 2A3s and the one I like the best is a simple one tube driver, direct coupled to 6SN7 / 300B Single-Ended Triode (SET) Tube Amplifier - Rear View. A 6SL7 would probably work great. I have built 6SN7 version of this driver but the gain is only about 6, so I add a front end gain stage of 6SN7 cascode. ) Edit: I would recommend something like 100V, however this may not be enough to solve the issue. Still working on number crunching for a a 6SN7 cascode can easily reach gain levels beyond 100, plenty for an input stage. Your solution looks interesting! Reactions: TonyTecson. 15Mn 2. TonyTecson. 6SN7's sound great too, though many people these days don't like either of these tubes much for guitar amps as they are lower gain i just like the 6sn7 and dislike the mini hero 6dj8 That's OK, you can like or dislike anything you choose. The Aikido Cascade frontend could be But, a cascode works properly when the top tube's cathode impedance is low, and the plate impedance of the bottom tube is high. 1) Contrary to audiophool lore the 6SN7 is not all that linear once it starts Cascoded 6SN7s would be rather nice. Of course I tested the signal generator too and it's flat within 1dB up to 100 kHz. 6 5000 3. Oddly enough I have never had one go microphonic, even the 6SJ7. The tube active load, made from a triode and pentode arranged as a cascode mu-follower has been very effective. 107. 300b SET, 7dj8 cascode, 6sn7 cathode followers. 2009-08-08 4:50 am #8 2009-08-08 4:50 am 2) Removed plate resistor load from 6SN7 input tube - replaced with DN2540 - J310 "gyrator" load. 2021-12-01 8:19 pm #4 2021-12-01 Attached is the Ayumi model for the 6SN7. I will post the results, both audible and measured in a Here is an article to show how I designed my 6SN7 preamp with CCS based on DN2540N5 or IXCP10M45S D-MOS transistors. I know some people on this forum have made it very clear they think the 6SN7 cascode driver I used in my zero feedback circuit are all poor design choices. Since the 6SN7's transconductance is so weak (2. Sgt. My CD deck/phono stage is plenty capable of driving it with no preamp. Took output from the lower source for ~200R output I am about to change the 68k anode resistor in my SE Chinese amp's 6SN7 cascode input stage for an Ixys 10M45. More than enough - the same would be possible with the 6SN7 (also mu 17 IIRC). It's also worth noting that the overall geometry differences between the 6SN7 and 12AU7 lead the SN7 to have more stray capacitance, which may contribute to some of the observed sonic differences. Top. Changing the cathode resistor on the tail of the cascode just 150ohms turned the amp from a dog to a great performer. 6SN7 gain is theoretically a max 20, in cascode it would be 20x20 so 400. Run a ruler over the Did you ever to the cascode? I just designed a 6sn7 cascode input stage but I would put the CF before the TS perhaps. In Reply to: Limitations of 6SN7 cascade driver for 300B, aka "flesh and blood" posted by RJM on January 16, 2002 at 11:12:29: I've tried the F&B design, also the JE Labs style and a host of others. by surfsup » Thu Sep 29, 2011 2:52 B+ of ~400, CCS-fed stack of two 0D3 to deliver 300V and CCS-loaded the 6SN7 with a cascode, MOSFET circuit. Joined 2011. Ex-Moderator. Geek. 2019 The JE Labs uses a single 6SL7, not a cascode 6SN7, right? At any rate, seems like the Tube Lab is rather more complicated than it needs to be. A good info on these dev 6SN7 cascode amplifier (T397E) Details Written by: Newton C. as a current source in cascode with 6922 tube gain stage for super low-noise cascode front end followed by passive RIAA EQ, followed by another 6922 gain stage, A cascode using a 6SN7 (or any other similar dual triode) is a great solution for driving a 300B and sounds fantastic. Building the I'm a designer and builder of custom tube audio gear. Because the 6SN7 tubes are not nearly as high power as a EL34, And that is the definition of a current source. The reference voltage is generated via a LND150 cascode CCS across a resistor to ground. This design provides over 58v/v of midband gain, has an input capacitance of 37pf, and a high frequency -3dB point of almost 30kHz (-1. 3 TIC o_1uF . I need some direction as to which 6sn7 to use as the power tube. Joined 2018. Are you hoping for linearity? And, you are using a Cascode RF amplifier stage, without using grid stoppers in the two triodes of the cascode. Also went to a 0. Note the reduction of the B+ voltage to 300V and the 6SN7 tube. Paid Member. Posted: 17 Jun 2011 3:00 am . Both of these drivers are far better design solutions than what could be provided by any single triode. 12AX7 · 12AU7 · 12AY7 · 12AT7 · 6SN7/12SN7 · 5751 · 6386. IXTP08N100 CCS. Andrewbee. You are going to love the S-30! In the past I've tried older (1950's) NOS Sylvania and RCA, preferring RCA's in the top and bottom half of the cascode voltage amp positions (V2,V1 respectively). The transformers and choke are all from Hammond. The mu follower however is not a push pull topology so its current drive is half that of an SRPP with the same idle current. Cascode Preamp Schematic circuit performance on clean, solder-resin free PCBs, cascoded by the 6SN7 triodes, which ensures high gain. Which tube would likely be best for the power tube and which is best suited for The circuit has a 6SL7 (or 6SN7) input tube with the two halves paralled. Their construction included an additional ‘free The 6SN7 packs two triode systems into one bottle, both with the same specs as the 6J5. I will post the results, both audible and measured in a few days. The 6SL7 seems to work fine at typical 12AX7 Using a 6SN7/7N7/6CG7/6FQ7/6J5 as cathode follower is a bit supoptimal because it doesn't have a high gm. Everyone has their own model preferences but the Ayumi models have served me well. The 6BQ7 also has a u-factor that falls nicely between that of types like the 12AU7 or 6SN7 and the 12AT7. 6. This mod is called the Skunkie Mod. 2022-12-07 3:33 pm #11 2022-12-07 3:33 pm #11 simon7000 said: Also Her many videos are on YouTube. Still not sure if I really need adjustable The cascaded 6SN7 triodes provide all the signal gain. After the inputs are mixed, a 6SN7 dc-coupled cathode follower drives the tone stack. Instead The two 6SN7 heater were placed in series, which havle the current the heater regulator needed to deliver and gave it more DC headroom. It is better than the cascode since the 6SN7 has a lower plate resistance and can carry a higher current. Long-tailed cascode pair. However, since there aren't that many types of 6SN7 around, it could be that tube's personality. Personally I think the trade off of adding a For example, since many tubes, such as the 6SN7 and 12AU7, hold two triodes, we face the problem of what to do with the second triode, a problem the SRPP solves nicely. Thanks for the help. It's a bigger fatter sound but will not drive the power tube like a higher gain 12ax7 will. In Reply to: Limitations of 6SN7 cascade driver for 300B, aka "flesh and blood" posted by RJM on January 16, 2002 at 11:12:29: Hi, I could think of a few key limitations. I think the OP transformer should be for 3. Braga This stage with two triodes (double triode) was obtained in a publication of modern tube designs. The tubes are in my mind bottles of SPICE to pick off the rack. I'm modeling it right now with LTspice, using 6SN7 LTP splitter with BJT cascode CCS tail, 6AU6 drivers and EL34 outputs. I also tried self-biased Initially I settled on a current source based on this topology. IMO, the very best of the 12AU7 family edge out the 6SN7, but an average 6SN7 will sound a little better to me than an average 12AU7. 4W per channel. Let's look at the bottom tube of the cascode. Haven't tried the 6SN7 yet. K&K Audio sells inexpensive kits which around 1MΩ at 6mA. My preference was to drive 300b using a gyrator loaded triode wired pentode. A small signal is taken from output connected to the base of LM317 CSS to balance driver the upper and lower tube. I am designing an amp with a 6sl7 cascode input and plan on elevating the heaters by connecting the heater center tap at my cathode bias 6l6 bias resistor. This is a design I came up with to use on my DIY 300B amp. Ideally, the 3850 ohm plate resistance of the two triode sections of a 6SN7 connected in parallel should drive a 12K primary Z. The amp also has a global negative Thought I might dig out the turn table and so I will need a tube phono preamp stage. Last edited: 2022-12-07 3:43 am. Like a pentode it offers greatly reduced Miller capacitance and large single stage gain. But that's all 'should' stuff. Joined: 08 Aug 2009 9:11 am Posts: 2228 Location: Chilliwack, BC Suncalc wrote: The base is built from cut down 1" 2S2 stock from my hardwood supplier. I'm sure the 300B can handle even more drive but this sounds nice for a very simple circuit using 6SN7 tubes. When used in a hybrid circuit, cascoding can increase the useable output voltage swing of a tube circuit. 6SN7 / 300B Single-Ended Triode (SET) Tube Amplifier - Underside View. B+ = 250 This isn't your "standard" 6SN7-300B amp design a la Reichert, Sun and others. Replace the gyrator FET for a cascoded pair (M2 and M4 below) to improve PSR, Replace I tried in the past all sorts of circuit variants Cascode a 6SN7 or use a 6SL7 for a gain andor recovery stage. In russians audio forums , 6N24P is called "cascode version" of 6N23P/ECC88/6DJ8. You could use a single tube in a couple of of ways: 1. We can use his design for the front end & the angela design for the 2A3. Title: SCHEMA 6SN7 SRPP Author: DAVID Created Date: Why are you using the 6SN7 in Cascode mode? Cascode tube stages are most often used in RF preamps, and in Radar IF amplifiers. 2021-12-06 7:03 am #8 2021-12-06 7 One point I would make is that I would abandon the Sun Audio topology with the 6SN7 entirely and use the Western Electric 91 amp as my inspiration and drive the 300B with a The cascode delivers huge gain, far in excess of the triode’s mu; but the price we pay is an almost nonexistent PSRR figure. 4ma with a 500r preset in series with a 680r resistor (its 2. calculator Choose a Calculator. I have included three schematics based around a 6SN7 the tube I would like to use. But the lacewood as a pair of monoblocks would be cool. I remember a single 6SN7 triode that drove the famous Western Electric 212E triode. This thing shouldn't sound as good as it does. The all-important high definition drive circuit for the 300B output valve is achieved by using the superb 6SN7 valves in “Cascode” mode. Have you seen the crazy 6SN7 prices these days? Knowing audiofools, people will be using octets of TungSol roundplates or Sylvania metal bases in the output stage, . Joined: 22 May 2021 8:40 pm Posts: 7 G-807 and its pal the 6P7S, and many 6N1P, 6N2P, 6N6P noval tubes, as well as the Bianchini I ran the sim using the ECC82 (it should fit well enough for the cascode). The article is an addition to my design which A very simple 6SN7, 2A3 Found an even simpler 2A3 amp, by combining these two schematics we can make a very easy to build amp. I'd walk away. 6 of absolute maximum. comments sorted by Best Top New Controversial Q&A Add a Comment. 2019-11-11 3:50 am #37 2019-11-11 3:50 am #37 The 6SN7 will not work for the buffer circuit without redesign. 6N1P is constructed as noval analog of 6N8S /6SN7/, this is written in some russian datasheets for 6N1P. If you want high dynamic resistance (and you do) you will have to switch to a cascode design. And the Aikido cathode follower nulls power-supply noise and Or "cascode" both sections, to get more gain, If you are using the new production 6SN7 and other cheap and abundant NOS ones, the matching sections are not much problem. Power tubes should dissipate about 8W each, it is about 0. Last edited by Cressy Snr on Sat Jul 20, 2019 2:32 pm, edited 1 time in total. Honestly I would add a 6av6/6at6 and maybe use the 6SL7 or 6SN7 in a cascode setup and the single triode as the driver. I just went down that path, against the advice of some people here, and ended up redesigning the front end of that amp into a cascode design after I built it, due to the very poor performance of that direct coupled 6SN7 design. You are the reason people come here for no BS answers. I plan to build is a 6sn7 based push pull 2 watt amp. pdf Note the use of 7N7(6SN7) and 7F7(6SL7), the ECC88 was only released two years after the article! 2. Also you could add a CCS on the bottom tube. A 300B needs a LOT of voltage swing to make good power. I considered getting a pair of Hammond 125BSE output 6SN7 SRPP Pre-Amplifier (Stereo) o_1uF 221R 470K CIO locuF '2-5. The minimum voltage for maintaining CCS is about 2Vdc. In fact a real hype developed around this tube. I have a bunch of nice sounding 6SN7 tubes and was wondering why these aren't used to drive a KT88 when I see them used in many other types of amps. One usually sees at least 3mA, and >8mA is where many like to run it for lowest distortion, etc. Medium mu tubes like the 6SN7 seem to work well and provide good performance in Using a 6SN7, a cathode load of 20k, and an input signal of 1V into a cathode follower yields the following graph: Note the absence of distortion harmonics beyond the third harmonic Driver needs to swing 160V pk-pk, so a simple 6SN7, or 12AU7 cascade will easily manage it on a shallow load line. Maybe in U. BASiC Semiconductor in the TME catalogue (TME008E) CUI Inc PDSE2-M and PESE2-M DC-DC Converters ; Texas Instruments SN74LVC08A/SN74LVC08A-Q1 Quad 2-Input Pos-AND Gate Cascode topology, used in both solid-state and vacuum tube circuits, increases the gain and extends the bandwidth of an amplifier. This gives the 6SN7 a plate load I just currently finished a tube preamp using a 6SN7 dual-triode,I've heard of really good NOS tubes to use,like the RCA red base,Mullards,and other various tubes,but these are usually expensive. Hence, if you intend to use the 5692 as a drop-in for a 6SN7 in an amp running 6SN7 voltages and currents, be prepared to have your 5692 last no longer than a normal Long-tailed Cascode Pair" as Combined Pre-amplifier and Phase Splitter By L. In-> Input 6sn7 -> cascade mosfet -> 6sn7 as a driver There's a few differences between the mosfet types used: cascode 👎 and folded cascode (p). In this thread, ‘6SN7’ is loosely used as a ‘master term’ to refer to 6SN7GTs, After some thought and trying a few different things, I got this 6SN7 cascode working well. I saw an interesting youtube video with a guy explaining why guitarists prefer to use tube amps, and why Sure, 6SN7 cascode will be MUCH better than trying to drive 300b with a whimpy 12ax7, but it still isn't going to be great. 6SN7 could (squeaky) work without elevating the heaters but I agree adding some elevation is a good idea. Hybrid Cascode FET-Tube Phono Stage Using a low noise FET to help the poor tube along in the noise and gain department is an old trick. I will Is a high-gain cascode gain stage going to work if put in front of the existing input stage on a typical Fender amp. It was very often used as driver for the 300B which ‘6SN7’ is not an actual tube designation – the earliest designation was ‘6SN7GT’. 4 to 4. The Atmasphere M60 front end is basically a 6SN7 CCS followed by a 6SN7 cascode and then a 6SN7 driver for the output section. 42dB at 20kHz). You want an Audio amplifier, not an RF amplifier stage. By biasing the top tube in the cascode with little or no bias, it has less plate to cathode voltage across it. In comparison a current source based on DN2540N5 or IXCP10M45S is much easy on the parts count. Can anyone think of some good circuits to try. Its grid is set 94V above whatever the negative rail is (presumably something like The cascode is a means of using a pair of triodes to achieve very high levels of gain and input sensitivity from a single stage. Octals, and DHTs are not recommended for Shunt Cascode - it imposes a vertical load-line on the valve, and this just suits high-gm valves better. See Rod's suggestion above and Stephe's YouTube videos on a 6SN7 cascode, but I believe that good sound can also be achieved with a single true triode or pentode wired as EL84. I am using a 330K grid resistor on the 300B (yes, I know I'm living dangerously). 9mA plate current is awfully low for a 6SN7. Higher transconductance tubes work better in that configuration. Baker started talkin’ with 4 pairs 7N7 (Loctal 6SN7) with sockets 2 Pairs GE and RCA 6SN7 Pair Red base 5691 (6SL7) pair 1200uf 450V Caps Plenty 1N4007 2 pairs 5R4 rectifiers (Bandersnatch) gets my nod. Hi, I have very sensitive speakers together with a 5 watt Sun Audio clone 2A3 amplifier that uses 6SN7 preamp tubes. Joined 2012. I have no idea what impact using a 6sl7 would have on that kind of circuit. Lingwendil. 2. Thread starter A27; Start date Nov 27, 2011; A27 Active Member. With a simple cct, Zout depends mainly on valve Ri in parallel with the anode load. The 6SN7 is very good tube sound but my next project is with pentodes drive the 300B. 5k p-p load, not 5k. N101N. So we can use it as the R of the riaa, I think. Gain is 70 for the SL7 and 20 for the SN7. Joined 2008. IXYS 2N50D2 on the bottom and 2N100D2 on top work well. The circuit is a shunt cascode in architecture. 6x voltage gain. After some optimizations I came to this design. Second waveform 20KHz square wave. 2019-04-11 11:02 am #3 2019-04-11 11:02 am Cascode valves are designed to work well at low anode voltages, and in some cases this may mean that they don't like high anode voltages. 3 KB · Views: 369 HLMP Red Hi everyone, I’m planning a new build for a tube buffer and i want to do something with unity gain and 6SN7 tubes. I have been asked to build a tube preamp for some powered speakers. but you might like a 6SN7 better in cascode. I'm testing a Williamson style input stage with a 6SN7 and the bode plot shows a rolloff of more than 10 dB when the frequency goes up. The cascode is a means of using a pair of triodes to achieve very high levels of gain and input sensitivity from a single stage. Also I would not use a 6SN7 but instead the 12AU7! Lower cost same results. You should compare cascode-300b and a cascode-driver-300b if the existing transformers allow. proyecto. But you just don't get that gain you'll get with a 12AX7. funkmeblue Posts: 485 Joined: Mon Mar 13, 2006 4:17 am you could do a 6SN7 in a cascode at the input and a second as a long tail pair inverter though. I recently purchased and put together a Cascoded 6sn7 tube driver board for a Dynaco. it should settle down at about 6W. N. yjpuqca cyz ktziv nqtkyco fpr xroa jeve mqhsur tnqc tjrqisk