Vox ac30 pentode or triode. 1: v, three-way brilliance, Ch.

Vox ac30 pentode or triode Channel 2 features the highly-prized and desirable Vox Top Boost preamp circuitry. Tone gets more alive, the amp responds more directly and musically. Both amplifiers were cathode biased. Phase Inverter: AC15 or AC30 Schematic TONE CUT: AC15 or AC30 Schematic MASTER VOLUME with BYPASS switch - 1Meg Pot with switch Half power Switch - Pentode/Triode Switch Tubes: 3 x ECC83/12AX7 2 x EL84 1 x EZ81 (rectifier) Jul 1, 2008 · Johnny, an AC30 is a "33" watt amp clean, but much more output than that dirty. Feb 19, 2021 · I'm finishing up an AC30 type build that incorporates 3 channels: 1. This is what a Vox AC30 wishes it sounded like, in it's dreams! Mint Conditions To commemorate the 50th Anniversary of VOX guitar amplifiers in 2007, Vox first introduced the AC15H1TV, and later the same year, the AC30H2. a sweet high gain tone, but the triode mode. not sure yet. Jan 9, 2008 · According to Vox, this drops the power from the full 30 (pentode) to 15 watts in triode, enabling you to squash the power amp a little more at lower volume levels. Triode / pentode (agai… Sep 13, 2012 · Pentode Triode switch Power Output 15 Watts RMS into 8 or 16 ohm loudspeaker load — selectable via rear panel switch. " The pentode mode seems to gives the amp more punch with slightly less headroom but still doesnt make it easy to get the amp to break up and its because the amp is just so damn loud. The EF86 Mode switch re-configures the EF86 valve from Pentode mode to Triode mode. 2: v, t, b, All: top cut), bass shift switch, pentode/triode EF86 mode switch, O/P pentode/triode (15W/7. Show More Sep 14, 2022 · The result was too much noise, too much distortion, too much microphony. True to its past, the AC15C2 “TWIN” relies on 3 x 12AX7 dual triode vacuum tubes in the pre-amp stage, and 2 x EL84 pentode tubes in the power While most guitar amplifier manufacturers were incorporating dual triode tubes such as the 12AX7, 12AT7 or 12AU7 into their preamp circuits, Dick Denney decided to include a pentode tube, the EF86. 3 volt heaters would give you Mar 16, 2008 · Hey guys - am very new to electric world so please bear with me. While the preamp sections of most amplifiers were powered by dual triode tubes such as the 12AX7 and 12AU7, Vox lead engineer Dick Denney took a different path. Vacuum tubes, or thermionic valves, use heated filaments to control electron flow in a vacuum, leading to a warm, linear sound prized in high-fidelity audio and guitar amplifiers. The input signal level is way too low to overdrive the stage and the tiny bit of harmonic distortion produced by the pentode gain stage is likely quite inaudible. Mar 19, 2008 · I have an original 1965 AC30 JMI TB and it is a wonderful amp but only uses the triode preamp section while the Matchless DC30 also has the pentode (EF86) section giving you more versatility. A single-tube EF86 Channel with a Triode/Pentode Switch, a "Bass Mode" Switch (taken from VOX's recent Handwired model), and a Brilliance Switch; 2. 6 OR 6. The EF86 was an integral part of the preamp (V1, Normal Channel) of the Vox AC30/4 - black panel, four inputs, TV Front and split front format, 1960-1961. Sign In. Dimensions (W x H x D) 527 x 527 x 263. Bad Cat's Black Cat is a further refinement of the basic architecture and a little less raw than the Matchless DC-30. It instantly improves sustain, thickens tone and is adding a "three-dimensional" character with decent compression and smooth harmonic distortion when driven to the limit. (I may even try a hybrid AC30/4/6 so that it has the top boost, or maybe a switch to enable top boost etc. Posts: 663 JMI 30/4 vs Vox Herritage AC30 H2 Position 1 is a new position voiced like the early AC30 “Treble” amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. As used in the DC-30 – and the Vox AC15 (and briefly, the early AC30) that inspired it – an EF86 pentode preamp tube helps to create a sound in the amp’s second channel that is really quite different from the classic Top Boost chime and shimmer most consider the “classic Vox sound. Pentode vs. Power tube screen grid is connected to either the plate in the triode mode, or the B+2 screen power supply in the pentode mode. ” Position 1 is a new position voiced like the early AC30 "Treble" amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. versions). Volume, Treble, Bass controls. Now in short supply, the EF86 Pentode tube is at the heart of this elusive tone. I'm pretty sure it doesn't have the tremolo/vibrato circuit, which takes up about half of the AC30's construction. Both channels use the "Top Cut" control. The AC30 continued to evolve with the introduction of the AC30/6 in 1960, which added a Brilliant channel to the standard complement of Normal and Vib-Trem channels, increasing the number of inputs to six. Look at the tube charts on my website, Welcome To Vacuum Tube Central® UL introduces more feedback to the output stage so it it doesn't sound as round as triode or pentode. Position 1 is a new position voiced like the early AC30 “Treble” amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. vs. Unique single halo type getter & plate coating; N709/6BQ5 equivalent Jan 8, 2017 · But I don't know how well it does in terms of sounding like a triode. Through Channel 1 in Pentode mode with the Bass shift set to 1, the Cut control set to full, and the Brilliance channel off, a 1972 Fender Stratocaster sounds tight Fender Deluxe Reverb, Vox AC30: Tabung Triode: Fender Champ 12, Vox AC4TV: Tabung Pentode: Marshall DSL40C, Mesa Boogie Mark V 25: Fitur Tambahan (Remote Control, Input/Output Beragam, Tone Control) Fender Twin Reverb, Ampeg SVT-VR No I know the AC30/4 had an EF86 Pentode in the normal channel input, that's what I'm planning on building here. Oct 15, 2013 · triode mode - connect the plates and screens together. 375 inches Jun 20, 2002 · I also like the recent Heritage AC-15, but it is loud in pentode mode, and I don't like the tone of triode mode. 69 1 available store 4. Mar 23, 2006 · In analyzing this, I thought that I should double the cathode resistor to get the stage running closer to the standard 12AX7 Vox AC30 values. Position 1 is a new position voiced like the early "AC30 Treble" amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. Nov 21, 2006 · Yeah I'm pretty clear on what he's saying not to use. That sounded significantly better than using delay before the amp (guitar>delay>jumpered AC30). 1 switch "EF86 Mode" pentode or triode selections -Channel 2 (top boost) 1 volume, 1 treble and bass with 1 interaction I possd a Vox AC30 in the 70, I regret Whatever it is, there is an undeniable magic about this period of VOX amplification. Pentode & Triode settings allow for low volume crunch Vox AC30 VR Guitar Combo Amp Combo Guitar Amplifiers $192. Save for a couple of speaker outs, that's it. Below pages from the Mullard "Audio Valves" booklet of April 1954 relating to the EF86 pentode - specifications and characteristic curves. 5 Super Premium power pentode, highest quality in current production. Triode The signficant changes to the circuit are: the introduction of an EF86 valve (of much higher gain than an ECC83) as V1; an ECF82 as V2, mounted in an anti-vibration socket with thick white rubber base, the pentode half of the valve serving the tremolo effect, the triode for the input stage of the Normal Channel; a mains transformer giving a Aug 11, 2024 · When comparing vacuum tube vs transistor technologies, it is essential to understand their fundamental differences and applications. FWIW I'm a died-in-the wool 6V6 Aug 25, 2015 · A triode has three active elements while a pentode has five. With a pentode/triode switch, the arrays are essentially eliminated from the circuit, decreasing effectiveness and cutting output power approximately in half — hence the term “half-power switch. 3A 85W Pentode mode half power measured at the start of visible clipping on a scope: Clean 21VAC 1. 3VAC 2. Jan 14, 2002 · I recently built a Clubman 35 type amp (some tweaks). 3 voicings plus a bass shape switch. The Vox AC30 was originally introduced in 1959 at Hank Marvin's request as the "big brother" of the fifteen watt (15 W) AC15 model, Vox's original flagship amplifier, because the AC15 was not loud enough with the screaming fans at Cliff Richard's concerts. Putting an EF86 in a 12AX7 slot with 6. 4 modes (the modeling part line 6) very convincing, to simple mode 1 = fender Vibrolux clean, great reverb, twin reverb, bassman mode 2 = 59; Marshall plexi, mode 3, Vox AC30, Mesa mod 4 Boogie. has a less vibrant response and sounds dull. ” Tube Combo Guitar Amp Vox AC30H2: 32 images and 1 review View and Download Vox AC15H1TV owner's manual online. "All told, a rare combination of qualities that together create an amp that is unparalleled in the studio and pure bliss to play cranked up in clubs and on small and medium stages. The EF86 Mode switch reconfigures the EF86 tube from Pentode to Triode; Triode gives lower gain and more headroom, while Pentode is the original high-gain tone with less headroom. This is why the anode output resistance of a triode is relatively low, compared to a pentode where this feedback loop is broken by the presence of the screen grid. Nov 21, 2022 · There are also oddball tubes such as the ECF82 found in original Vox AC10s, which combine a triode and a pentode in a single glass enclosure. These amps had defective power trannys, and mine was replaced. Sep 1, 2010 · The speaker is a British made H1777 cone in a Chinese bell. Jul 6, 2019 · As for settings. May 11, 2024 · I used a similar switching scheme in a 70s Twin reverb that had 4 cathode biased 6V6s (JJs for the higher voltage rating, as well as some heavy sag resistors). Forgot your password? Sign Up Jan 8, 2017 · Remember that a triode incorporates its own internal feedback. JMI-made Vox AC30s, 1960-1968. Denney included an EF86 pentode tube in the preamp circuits of the JMI Vox AC-2, AC-4, AC-6, AC-10, AC-15 and AC-30/4 amplifiers. Position 1 is a new position voiced like the early VOX AC30 “Treble” amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. Mint ConditionsTo commemorate the 50th Anniversary of VOX guitar amplifiers in 2007, Vox first introduced the AC15H1TV, and later the same year, the AC30H2. Position 1 is a new position voiced like the early AC30 Treble amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. These amps have been updated to include dual channel sound, tremolo circuitry, and footswitching capabilities. rock. Valve Complement 1 x EF86, 3 x ECC83/12AX7, 2 x EL84, 1 x EZ81 (rectifier). What is it that makes EF86 based VOX amplifiers some of the most collectible in the world? Maybe it’s the way the amp naturally overdrives, almost breathing with a life Super Premium power pentode, highest quality in current production. Please consider making a donation. This is the same speaker that comes in the current Custom series AC30C2X. AC15H1TV musical instrument amplifier pdf manual download. Below pages from the Mullard "Audio Valves" booklet of April 1954 relating to the ECC83 double triode - specifications and characteristic curves. Two channels are provided on the AC15C2: Normal and Top Boost. Apr 29, 2024 · Developed from Lee De Forest's 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode (Fleming valve), the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode. According to the AC30 schematics I have, each triode sees a 220k on the anode and the cathodes for the first two triodes are sharing a 1k5. The VOX-twang certainly is there. alter the tone to be somewhat smoother. VOX dropped the pentode front-end because it created too many problems for them. Tube Set - for Vox AC30 Includes: x3 12ax7 (AKA ECC83) preamp tubes / factory matched x4 (matched quad) of EL84 power amp tubes The Psvane ECC83 is a high quality, high gain, dual triode. com SixShooter. 1: v, three-way brilliance, Ch. I have a 1994 Matchless DC30 as well as the AC30 and I prefer the Matchless for all around playing due to its Pentode channel. Speedin’ like a space brain I put the Night Train in Pentode mode, with the Gain barely above the 9 o’clock position, tone controls at noon, and the tone switch selected to Bright. You have LOTS of options (including triode/pentode mode?) Power up and have some Vox fun! Pentodes have occasionally warmed classic preamps from Gibson and Vox, but these are the exceptions. JMI lead engineer Dick Denney chose a different path. Jun 17, 2009 · I'm researching a Vox AC15H1TV for my next build and I know this much: Ch. rogercook Member. Vox and Vox-inspired anps (like Matchless) used the EF86 Dr Z had an entire line of amps with EF86 preamps (not the same as the Vox design) Tweed Fender, Valco and Gibsons used octal 6SJ7 pentode tubes Gibson use 5879 pentodes in their preamps Dynaco used a 7199 (triode and pentode in one envelope) The EF86 Mode switch re-configures the EF86 valve from Pentode mode to Triode mode. Unique single halo type getter & plate coating; N709/6BQ5 equivalent Nov 8, 2013 · With pentode/triode switching, the grids are effectively removed from the circuit, reducing the efficiency and dropping the power output roughly in half — thus the use of “half-power switch” as a frequent synonym. I love the VOX tones of the past - British Invasion to U2 - and am looking at the AC30 vs Position 1 is a new position voiced like the early AC30 “Treble” amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. Z Stangray (EF86) and DB4 (5879) (both amps now discontinued) and of course numerous Matchless amps. Volume, bass, treble, triode/pentode switch. Note that dropping the power in half does not reduce the amp’s volume or SPL by 50%. Within a few years the bad circuit was ripped out and replaced by lower-gain circuits using triode valves (not pentodes). Bogner). Triode offers a useful variation if you want a thicker, less focused sound with a bit more of a vintage growl to it. 1/mu of the output voltage is added to the effective grid voltage. Fifty years later, the magic returns. The sound of channel two is the inimitable. He designed the Normal channel of the 1960 AC-15 to include an EF86 pentode tube. As is well known, AC30/6s used just one: V8, for the modulation of the Vib/Trem circuit. Kinda weird but helpful. Position 1 is a new position voiced like the early AC30 "Treble" amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. In sum - three channels normal (half of triode), topboost (triode + top boost unit), and brilliance (pentode, like in ac15's or ac30/4), build into replica AC30/6 chassis. The Vox AC15 is a highly revered amp, capable of delivering amazing sounds at a power level that won't crack wall plaster. The VOX AC30 combo amp has long been an icon, known as the sound that powered the 1960’s “British Invasion. - 15W, guitar head-unit, seven-tube chassis, preamp: 1 X EF86, 3 X 12AX7/ECC83, power: 2 X EL84, rectifier: 1 X EZ81, two channels (EF86/Top Boost), top black control panel, two inputs, six white chickenhead knobs (Ch. VOX out to a recent gig. With a standard strat it needs a boost pedal in front of it if you want it to start to break up, but not with something with hotter pickups. My own design, incorporating Merlin's 'triode/pentode morph control', honed with many, many iterations. 1 is EF86 based, with Vol and Brilliance pots, a Bass Shift switch, and a pentode/triode switch; Ch. I believe Fender squished the Twin part fairly early on, as they did with the Super Twin (a piggy back AC30 with a closed back cabinet and an optional swinging metal frame like a hammock!!) which Super Premium power pentode, highest quality in current production. Most small Doubling the wattage gets you 3 more db, which is about the smallest difference that humans can detect. With a spring reverb, like the AC30, no need of tremolo and vibrato, no real need of top boost, but i'd love to have a 2 mode switch on 1 jack; a EF86 mode with pentode-triode switch, and the bright levels like the AC15HTVH1, and an another mode with the classic bright channel from AC30, withe bass-tre-hig level and a kind of switch bright Experience the legendary Vox AC30 tone in a streamlined and straightforward design with the Vox AC30 Guitar Combo Amp. want to run a Pentode circuit in triode mode. Vox AC30 Silver Jubilee Vox AC15 Pentode Preamp and Power Amp "That extra half a triode made one hot rock amp. VOX Hand-wired Heritage Collection Combo Amp/ Amp Head/ Speaker Cabinet. JMI retained the generic Vibravox name, even though the circuit was tremolo only. 3A 27W Chan2 16VAC 1A 16W Chan3 17VAC 1. Half Power Switch in the BootHillAmps. They sound like something from the Black Crowes. Like Channel 1, this channel includes two inputs wired with a 6dB gain difference. It's a neat amp and has a unique sound. The AC30 Nov 7, 2008 · Hello guys, Recently ive modded a fender hot rod deluxe to that Nov 26, 2024 · Position 1 is a new position voiced like the early "AC30 Treble" amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. in comparison. Based on the Vox Brilliant Channel. Triode/pentode switches are also fitted. It has been said that the AC30/6 lacked some of the clarity of the original model, and that’s ostensibly why Vox responded with its Top Boost “brilliance” modification in 1961. For a test, I took the. May 6, 2004 · Remember me Not recommended on shared computers. But just like regular pentodes, the big issue is finding examples that are non-microphonic and will stay non-microphonic. Below pages from the Mullard "Audio Valves" booklet of April 1954 relating to the ECC82 double triode - specifications and characteristic curves. Triode mode will give a lower gain tone with higher headroom. I like these on Top Boost Channel with a les paul with P-90s : Gain 12 o'clock, Treble 2 o'clock, Bass 10 o'clock - cut control to taste - Master volume and Pentode/Triode Switch set to whatever it takes to get the right sound at an acceptable volume. 😕 I've read at least one article on biasing a JFET to have a similar distortion characteristic as a triode. Unique single halo type getter & plate coating; N709/6BQ5 equivalent "As used in the DC-30 - and the Vox AC15 (and briefly, the early AC30) that inspired it - an EF86 pentode preamp tube helps to create a sound in the amp's second channel that is really quite different from the classic Top Boost chime and shimmer most consider the 'classic Vox sound. Running a pentode in 'triode' mode definitely changes its clean and overdrive tone so it's more than just a 'half power' mode. Triode/pentode selector for EF86 valve (triode cuts the gain and volume). Exceptional clarity in the mids--sounds like an expensive boutique amp. Its warmth and sparkling 3-D sound has charmed musicians for over forty years now. Finally, the "EF86 Mode" slide switch allows the EF86 preamp circuit to operate as either a high gain pentode or a lower gain triode. This tube has a noval base and is praised for its warm and complex sound. V2: Phase inverter. Vox initially offered a 1×12" version but subsequently introduced the May 22, 2019 · AC30's are not really ideal for playing at home. It will be based on stock AC30/6 chassis, but the trem/vib channel wont be there. Channel 2: Based on the Top Boost Channel. Instead I will do the third channel pentode based. I never hear of anyone blowing Blues with those amps. Turns the applied input mains Position 1 is a new position voiced like the early AC30 "Treble" amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. I found the sound to be nice and chimey, but not too bright, even at really high volumes. Just killer EL84 tone These aren't to common, and they are still pretty expensive, but I've had Swart, Dr Z, Marshall, etc. Aug 24, 2016 · Channel 2 is not really a top-boost like channel. 3 volts depending on how they are wired. Unique single halo type getter & plate coating; N709/6BQ5 equivalent Super Premium power pentode, highest quality in current production. ("Fetzer valve"). This stripped-down, single-channel guitar combo amplifier delivers the full-fledged AC30 experience, inspired by the iconic Top Boost channel that fueled some of the most famous riffs in rock history. Jan 28, 2008 · Position 1 is a new position voiced like the early AC30 “Treble” amps, while position 2 is the original brilliance circuit, which acts as a dramatic bass cut. 12. Only 500 will be built. Add in some modern tone shaping control enhancements and the result is perhaps the finest VOX amplifier in the company’s 50 year history. It was better than pentode/triode switch in my opinion. and I have kept this VOX. " -Dave Hunter JMI-made Vox AC30s, 1960-1968. The EF86 is a single, very large preamp tube by comparison. Triode = half power = 7. I've been a bit skeptical, because, as far as I know, an actual triode doesn't have a three-halves law once you add an anode load resistor to it! VOX AC30 Top Bost JMI Product 2x12" Grey Bullet, Wooden Transf. 5 watts. The 30-watt AC30 Handwired head features two channels of JMI-made Vox AC30s, 1957-1968. Cranking one for a crunch tone is fine for Brian May My advice would be to find a more suitable amp for playing in your house. Original Vox footswitch 1965 Code AM26. 7A 118W Chan2 46VAC 2. VOX realized this very quickly. Sep 17, 2010 · Also, the OIGINAL AC30 was a single twelve amp with a TV set style front and the "AC30" we know and love today was originally called the AC30 Twin. Lately Ive been running my EF86 channel on pentode, with the amp's power section set on triode. This change also involved swapping the original EF86 pentode tube to an ECC83 (12AX7) twin triode. Oct 29, 2008 · My amp has two pentode/triode switches. Channel 2 is the "Top Boost" preamp channel. The tone of a CLASS A operated guitar amp is well known from the legendary VOX AC30. 75 x 20. want to run a Pentode circuit in triode mode. But if you have an arsenal of other amps, is this really different enough to be needed? The pentode-mode EF86 is certainly "different enough" but I don't know if triode-mode would be the same. To commemorate the 50th Anniversary of VOX guitar amplifiers in 2007, Vox first introduced the AC15H1TV, and later the same year, the AC30H2. So Pentode = full power = 15 watts (AC15 versions) or. The EL84 output pentode was introduced by Mullard in 1954. First 1966 Vox AC30 JMI Top Boost Vibrato in very nice conditions, all original, matched tube, 2x12" Silver Bullet, 4 Sovtek EL84 Matched with a rectifier tube GZ-34 Variable Voltage Selector Ready to play. Also, the Matchless has one the Matchless DC30 is a little harsher than the Vox AC30 which compresses easily and yet To commemorate the 50th Anniversary of VOX guitar amplifiers in 2007, Vox first introduced the AC15H1TV, and later the same year, the AC30H2. Denney so preferred the additional gain and rich harmonics offered by the EF86 that he designed it into the preamp circuits of the Vox AC-2, AC-4 Oct 15, 2013 · In ultralinear mode the tube produces a little less power than pentode and the transfer curves look different (the tube behaves differently). The EF86: The magical VOX tone. JMI 30/4 vs Vox Herritage AC30 H2. 2 is 2 12AX7s with Vol, Treble, and Bass pots, A common Top Cut control, and Output is 2 EL-84s with a pentode/triode switch. The main difference between This vs. It's loud enough to still have a "clean" tone although "Vox clean" is it's own thing. Used in many vintage HiFi applications. A schema of the ECF82, pentode on the left hand side, triode on the right. The amp used a EF86 preamp tube, the same valve used in Vox amps manufactured in the late 50s and early 60s. Oct 14, 2014 · Bit off topic, but in my opinion you get more pentode characteristics out of the pentode tube when its not used as the first gain stage like it commonly is. 5 watts (AC15 versions) or 15 watts (AC30. Perfect for Vox AC30, from soft overdrive and organic sustain to great harmonic crunch. This is the ultimate Vox collectible amp producing every Vox tone from the 1958 AC30/4, early 60’s top boost and then on up to the later, modern versions. An age when the most simple of circuits produced some of the most complex of tones. sound of the Top Boost Nov 18, 2009 · Triode mode will give a lower gain tone with higher headroom. I can read schematics but prefer working off layouts when soldering as I get lost when reading a schematic! However, I Oct 14, 2007 · Channel 1: EF 86 channel. Also for: Ac15h1tvl, Ac30h2, Ac15htvh, Ac30h2l, Ac30hh, V112htv, V212h. Your search for the Holy Grail of VOX tone ends here. Other valves encompassed are the GZ34, EL34, EL84, and EC82. No tremolo, no reverb. Pentode mode is the original mode and has a very sweet high gain tone with not very much headroom. Apr 8, 2016 · You get a lot of control with this amplifier – most notably a 3 band EQ and a presence control. Mar 9, 2017 · Vox AC30 hum issue. The late 90's AC-15 also sounds great, and has a master volume. This will be a fun The AC30 continued to evolve with the introduction of the AC30/6 in 1960, which added a Brilliant channel to the standard complement of Normal and Vib-Trem channels, increasing the number of inputs to six. Great medium volume tones from this, and I seem to get a little more meat from the EF86 running pentode. As the ultimate collectible AC-30, Vox issued the AC30H2 in a mahogany enclosure. The AC30/6 was certainly the amp you think of as quintessential VOX sound and it. The amp used a EF86 preamp tube, the same valve used in Vo By 1960, most guitar amplifier manufacturers were incorporating dual triode tubes such as the 12AX7, 12AT7 or 12AU7 in their preamp circuits. 1A 18w Pentode mode Half Power Full output - Master channel vol dimed: A triode has three active elements while a pentode has five. A Vox AC30 behind a replica of Paul McCartney's Höfner 500/1 bass and George Harrison's Gretsch Country Gentleman guitar. Dec 7, 2007 · The first channel's pre-amp tube is triode based like an old AC30 (12ZX7) and the second channel is pentode based (EF86) like an old Vox AC15. The AC30 The mu g1-g2 of the EF86 is ~38, which makes this tube similar to having a single-12AY7 when switched to triode mode. When your triode/pentode switch is in the EF86 position, the cathode follower grid has no ground reference - the cathode follower gets its bias voltage from the anode of the preceding triode. Like channel one, the dual input jacks are wired with a 6 db volume difference between them. Musical innovators like the Beatles, Stones, Bryan Adams, Brian May and many others loved the sound of the EL84-based Vox AC30 guitar amplifier, making it one of the most Based on the classic AC15, the AC15C2 “TWIN” is part of the VOX Custom Series line. 01mfd coupling capacitor between the EF86 anode and the switch. This guarantees you a good sound that’ll fit in any live or recorded mix. Feb 24, 2007 · Pentode to Triode channels on the Matchless. Post by Reg18 » Thu Mar 09, Well, I figure it's going to be either cutting two of tubes out or going from pentode to triode mode - those seem Dec 3, 2007 · In my recent quest to totally shake up my writing, recording and playing habits/style/groove, I pulled the trigger today on a new handwired Vox AC30 H2 with the help from my great friends George and Todd at, you guessed it AIN'T SHE PURRRRRTY? :applaude :spabout I have all of the specs Jan 14, 2005 · The difference in gain between triode and pentode modes is big enough making it difficult to do a direct a/b-comparison. Denney so preferred the additional gain and rich harmonics offered by the EF86 that he designed it into the preamp circuits of the Vox AC-2, AC-4 It's also interesting to switch amplifier classes to see what difference that makes to the sound, though there's a noticeable level jump between Class A and Class A/B and also between Triode and Pentode operation. It uses a lower gain (unbypassed) parallel triode 12AX7 driven tone stack into an EF86, followed by a Vox like PI and two cathode baised EL34s running about 100% dissipation (OEI 50 watter OT). Pentode mode is the famed original mode and has a very sweet high gain tone with not very much headroom. Anaheim, CA (January 20, 2010) -- VOX Amplification has updated its classic AC30 and AC15 guitar amplifiers to create the new Custom Series. ' New Month We are at $50 this month in Donations. But I would like to see a real guitar-amp application that accomplishes Aiken's suggested goal of emulating or improving upon EF86 pentode input stage performance using cascode triode arrangement maybe with a 6N1P or whatever dual-triode tube. When used as a pair in an ultra-linear push-pull configuration with 43% distributed loading the output could reac True to its past, the AC15C2 “TWIN” relies on 3 x 12AX7 dual triode vacuum tubes in the pre-amp stage, and 2 x EL84 pentode tubes in the power stage. Models in the new series include the AC30C2X, AC30C2 and AC15C1. I mention these amps because all feature reduced watt modes using: 1, 2, or 4 El-84's in triode or pentode mode (depending on which model). The Vox AC30 is a guitar amplifier which included the EF86 pentode in its "Normal" channel. Loudspeaker VOX/Celestion Alnico Blue 12" loudspeaker - 8 ohm. 9A 133W Chan3 2. The difference between the OT on a stock AC30 and a 36 Watt shouldn't make any significant difference. Oct 20, 2007 · I've got a Vox AC30 transformer set and have been wanting to build a single channel EF86-based AC30/4 type amp for while. Two types of Class A and Class amp A / B (this is the complete analog, thank you Mr. That Explore Comparisons. 75 x 10. The reason to get an AC30 instead of an AC15 is clean headroom, not volume. Channel 2 Channel 2 is the Top Boost Preamp channel. 5 mm / 20. Isn't the Z-Wreck a version of the Trainwreck Liverpool? (If so, the font of almost all knowledge is The Amp Garage - TAG [1] ) If I were to build an AC30, I think it should have the tremolo and vibrato circuits in, too. 5W) switch, power switch, speaker the 6Ж4 = 6AC7GT Pentode made in Russia is mostly used as upgrade for the chinese 6J4P in audio amplifiers. Rectifier is a EZ-81. As is well known, AC30/6s used four: V1: one half each for the Normal and Brilliant channel input stage. JMI-made Vox AC30s, 1959-1968. I use a 5W amp at home and use the AC30 for playing with a drummer/bassist. In the up position (Pentode), the Night Train runs at 15 watts, and the down position (Triode), the head drops the wattage down to a modest 7. To commemoratefrom 6368402 VOX AC30 - H2L - LIMITED EDITION HARDWOOD CABINET Jun 16, 2018 · Pentode mode full output - Master/channel Vol dimed: Clean 44VAC 2. To demonstrate its use and quality the Mullard applications lab produced an amplifier design - the now classic 5-10 high quality audio amplifier. VOX AC30 Top Bost JMI Product 2x12" Grey Bullet, Wooden Transf. sound of the Top Boost preamp circuit. The Matchless is based on an early version of the AC30 with the aforementioned pentode preamp. Developed in 1952-1953, the EL84 was first used at JMI by Dick Denney in his AC15 (the AC1/15) of 1957/1958 and by Derek Underdown for the "Model H" organ also of 1957/1958. 30 watts (AC30 versions). POWER SWITCH. The pentode mode does indeed put out. Most people know that a 12AX7 is a dual triode, that is, two preamp tubes in one small bottle. This is a bigger factor with Vox amps than Fender amps because Vox amps are class A and have less headroom to start with. I have a lot of previous experience building all types of pedals and even very complex guitar wiring. There are some noteworthy modern derivatives such as the Dr. It might work if you removed the . Personally, this option doesn’t. 1960-1961. ” Apr 16, 2014 · TOP BOOST Channel: Vox AC30 Schematic HOT/COOL Switch: Tone controls are lifted from ground a bit. I think they sound different despite the legacy! Cheers //Rolf. The data sheets on this page come from the third volume of a three volume valve (tube) and semi-conductor manual issued by Amperex in 1965. Mar 3, 2019 · All have mid, treble, bass, and EQ sliders (MK V series has a presence knob) making it possible to dial in a lot of tones. Nov 4, 2018 · Having the same number of pins and being pinned the same are NOT the same thing! For starters the EF86 is a pentode and the 12AX7 is a dual triode. Maybe not as pretty as a Vox AC30 but it is a fraction of the price. This tube had nearly become extinct until operating mode of the power amplifier to Triode Mode which will halve the power output and will. The EF86 also has an internal shield structure that is physically tied to pins 2 and 7. While most guitar amplifier manufacturers were incorporating dual triode tubes such as the 12AX7, 12AT7 or 12AU7 into their preamp circuits, Dick Denney decided to include a pentode tube, the EF86. Sep 1, 2018 · AC30 layout and mods for build Hi, I want to build an AC30 from scratch. Some of the sheets originally came from Philips, others from Mullard. appeal to me because I don’t see why you’d. Also, the 12AX7 heaters are 12. use this only if the b+ is 400V or below as modern tubes can't handle such voltages (rounder sounding clean and smoother breakup, also subsantially less power) Vox AC30/4 - Mullard EF86 preamp valve. A DPDT switch disconnected two of the cathodes and one of the speakers with the other pole. That may not be relevant to your case, though. Schematic OS/005 includes an enclosed dashed region indicating the contents of the optional rear add-on Vibravox. Triode mode will give a lower gain tone with higher headroom, while Pentode mode is the famed original Vox mode and has a very sweet high gain response with less headroom. Denney used cathode bias for the AC30 Twin too, the new design completed by April 1960. " 1-Dave Hunter First Stage Pentode Preamp Nov 8, 2024 · A pentode tube includes two additional elements: a screening matrix and a suppression panel, which improve efficiency and energy production. Two Blues will easily handle prolonged use with a Vox AC30 or a JTM45 (or an AC50) cranked. As for the EF86 It was in the early AC15's and number of the AC30/4 amps. Pentode and triode are both types of vacuum tubes used in electronic circuits. Twin-triode voltage boosting continues to dominate the front ends of the amp-building industry. I’ll narrate instead. The unique character of an EF86 pentode at the front end, however, is worthy of consideration for any design. A special note sounded in music history as the Vox AC30 30-watt guitar amp was introduced. jafmp vtov nsyv gyrmfug ftih gvlgtbo vcq bpnc xidq hgoiberks