Tomcat - Aiken Amplification
Contents
1. military style turret board construction no PC boards using chassis mounted tube sockets for ease of maintenance and reliability Built to last Premium tight tolerance parts are used for reliability including 2W 196 carbon film and metal film resistors 5W metal oxide power resistors 630V axial leaded polypropylene film foil capacitors and low noise sealed 2W mil style RV4 pots 12 08 11 Copyright 2003 2011 Aiken Amplification Inc Page 3 of 14 Massive custom wound high interleave transformers rated for over twice the maximum amplifier output power allowing the amplifier to be run full power into an attenuator continuously without failures Output power at onset of clipping 12W Built in power attenuator with OdB 3dB 6dB 9dB 12dB positions as well as a VAR position that enables a second continuously variable control that goes from 15dB down to bedroom levels for low volume recording or apartment bedroom volume practicing Perfect for studio or club use This is actually a true attenuator working between the output transformer and speakers functionally similar to some of the current attenuators on the market but a completely unique design that doesn t lose highs or lows as you attenuate the signal TomcatMKIIManual doc 12 08 11 Page 4 of 14 Copyright 2003 2011 Aiken Amplification Inc Front Panel Controls and Switches Input jack Plug your guitar in here and you are ready to rock2. Bright switch This switch when enabled in the up position make the amp brighter for a more shimmery treble response Gain switch This switch when enabled in the up position gives the amp approximately a 10dB gain boost which drives it into the smooth singing distortion range This switch can also be remotely activated using the rear panel footswitch jack so it can be used as a boost for solos Note that the front panel switch will override the footswitch so if the footswitch is to be used the front panel switch should be left in the up position Volume The volume control adjusts the overall level and amount of gain the amplifier has For cleaner tones set the volume lower for more drive and distortion set the volume higher When used in conjunction with the attenuator the amplifier can be set for any desired amount of clean or distortion tone Tone The tone control adjusts the ratio of high frequency to low frequency equalization At the clockwise end of rotation the tone is bright and at the other end the tone is dark Cut The cut control rolls of the highs after the phase inverter giving a darker smoother tone TomcatMKIIManual doc 12 08 11 Page 5 of 14 Copyright 2003 2011 Aiken Amplification Inc Attenuator The attenuator controls the overall output level and allows turning the amplifier up to get full volume overdrive tones at lower volumes without sacrificing tone quality This
3. Also be sure to pay attention to the orientation of the tubes when putting them back in the socket The tube pinout is keyed so it can only be placed in the socket in one direction and if the tube is forced in incorrectly it can damage the tube or the ceramic socket TomcatMKIIManual doc 12 08 11 Page 9 of 14 Copyright 2003 2011 Aiken Amplification Inc Biasing This amplifier is cathode biased no adjustments necessary and is designed to run at rather conservative voltages and currents so you should be able to just plug in a new set of tubes and play without worrying about whether the tubes are biased correctly In rare occasions a tube or pair of tubes may be so far out of the normal specified range that they will not work properly with the amplifier This should be immediately apparent when playing the amplifier as the volume and tone will be very weak or mushy Note If a tube is biased too hot the plate will glow a dull red color The plate is the large grey metal box structure seen inside the tube Don t confuse normal filament glow with plate glow Plate glow can usually be seen as a hot spot near the center of the plate sometimes accompanied by a hot smell and some ticking noises as the metal expands Continued operation with glowing plates will soon result in failure of the tubes possibly damaging screen grid resistors or other amplifier components The HT fuse should prevent any major damage to output or power trans
4. approach avoids the buzzy sound characteristic of master volume amplifiers The attenuator features 0dB 3dB 6dB 9dB and 12dB positions as well as a VAR position which enables a second continuously variable control that goes from 15dB down to bedroom levels for low volume recording or bedroom apartment practicing It is okay to switch the attenuator to different settings with the amplifier on but it is recommended to not be playing while changing positions because a rotary switch such as that used in the attenuator will have a small fractional amount of time where there is no connection at all during the switching process While we have never seen an output transformer or tube damaged by this it is remotely possible that the transient may cause a problem so it is not recommended Before changing positions just stop playing for a second change to the different attenuation level and continue playing Variable This control is only enabled when the attenuator is set to the VAR position It allows adjustment from 15dB down to very low bedroom levels to allow quiet practicing or recording Pilot lamp The pilot lamp lights when power is applied to the amplifier and the power switch is on The pilot lamp features a screw on jewel that can be removed from the front panel to replace the bulb without having to remove the chassis The bulb is a standard 47 bayonet style bulb available at most electronics supply s
5. only on certain notes can be indicative of a cabinet problem Check all rear panel screws handle screws and chassis mounting screws to insure they are tight Check to insure there are no speaker or reverb cables rattling against the baffle board Check the two screws that hold the nameplate to the front of the amplifier as the nameplate can cause a rattle or buzz if it is loose enough to vibrate against the front panel board If the nameplate buzzing cannot be stopped by tightening the screws a small piece of double stick tape affixed to the rear of the nameplate will dampen the vibration Some speakers are known to exhibit cone cry or ghost noting which is a second out of tune note that occurs only when playing certain notes on the guitar If this is suspected try another speaker to see if the problem goes away Some preamp tubes are more susceptible to filament induced hum than others The ECC83 12AX7 is a dual triode two tubes in one package and some tubes will exhibit hum in only one of the two sections or in both Try replacing the preamp tubes with different ones to see if the hum decreases The JJ Tesla ECC83S is the least microphonic and least noisy current manufacture tube we have found Hissing noise A small amount of hiss is a characteristic of higher gain tube amps and is generally unavoidable Excessive levels of hiss are usually caused by bad preamp tubes Some preamp tubes have more hiss than others Try replacing t
6. Cliff FCR6918P no LED but one can be added as shown below It is available from Musician s Friend http www musiciansfriend com or other online stores If you desire a visual indication of boost on status an LED may be added by simply connecting it across the contacts of the switch with the cathode of the LED going to the sleeve connection of the jack as shown in the schematic below A good LED to use is the CML 5100H1 Digikey part number L10001 ND available from http www digikey com Later models require a 220 ohm resistor in series with the LED as shown in the second diagram below Earlier models up to 0028 possibly 0029 0032 check with factory FOOTSWITCH J1 D1 1 V RED LED 2 SW SPST PHONE JACK Later models serial numbers 0033 and higher possibly 0029 0032 check with factory FOOTSWITCH R1 2 Xi SW SPST PHONE JACK RED LED TomcatMKIIManual doc 12 08 11 Page 8 of 14 Copyright 2003 2011 Aiken Amplification Inc Tube layout and replacement i a Ae Q EL84 6BQ5 EL84 6BQ5 ECC83 12AX7 ECC81 12AT7 PHASE INVERTER PREAMP C X 8 8 p L b CHOKE 9 T 8 B J V I N PT Ie J The Tomcat uses one ECC81 12AT7 preamp tube one ECC83 12AX7 phase inverter tube and two 6BQ5 EL84 output tubes The preamp tubes are house
7. are in call the factory or inquire with someone locally who will know the correct mains voltage HT Fuse 500mA fast acting fuse Impedance Selector The impedance selector allows selection of 4 8 or 16 ohm output impedance to match the speaker in use Be sure to set this switch to the appropriate setting for the speaker or speakers connected to the amplifier Speaker Jacks Two speaker jacks are provided to allow use of the amplifier with up to two external speaker cabinets More than two external cabinets may be safely used with the amplifier but this will require the use of Y cables for the extra two cabinet connections Be sure to use only quality speaker cable do NOT under any circumstance use guitar cable to connect the amplifier to a speaker cabinet Doing so may cause damage to the amplifier Footswitch This jack allows connection of any standard footswitch to remotely turn on the gain boost on and off A footswitch is not included with the amplifier It can be ordered from us or you can build your own using the information shown in the next section of this manual TomcatMKIIManual doc 12 08 11 Page 7 of 14 Copyright 2003 2011 Aiken Amplification Inc Footswitch Since a boost footswitch is not included with the amplifier some may prefer to make their own or use an existing footswitch rather than purchase one Any standard footswitch that shorts the tip to the sleeve of the 1 4 jack will work A good one is the
8. d in removable bayonet metal shields The shields can be removed by pushing down on them and rotating the shield to the left then pulling it upwards off the tube The tube can then be pulled out of the socket The output tubes have spring wire retainers that can be slipped off to one side allowing easy removal of the EL84 tubes The tube complement is as follows starting at the side closest to the input jack preamp ECC81 12AT7 phase inverter ECC83 12AX7 output tube 1 output tube 2 The chassis top view layout is shown in the diagram above You may freely sub any 12xxx type tube in the two preamp and phase inverter positions It won t hurt anything and you may find some different tones you like The 12AU7 is a good lower gain tube for the first position as is the 5751 Other choices are 12AY7 12AT7 or 12AZ7 In addition different manufacturer s tubes will sound different Some people prefer the tone of various Ei Sovtek or other tubes and some insist on NOS tubes for a true vintage tone Feel free to experiment Note vacuum tubes especially output tubes can get very hot in normal operation and may cause burns if removed before they have a chance to cool down Be sure to wait several minutes before replacing tubes to allow them to cool down Do not under any circumstances remove or replace the tubes with the power on as this could cause a deadly electrical shock should the glass break exposing the high voltage plate terminals
9. e more susceptible to microphonics than heads because the sound field coming from the back of the speaker can excite the tube into oscillation In rare cases the EL84 output tubes can be microphonic particularly if they are at the end of their lifespan TomcatMKIIManual doc 12 08 11 Page 13 of 14 Copyright 2003 2011 Aiken Amplification Inc Specifications Output Power Input Impedance Input sensitivity Tube complement Fuses Footswitch Dimensions Weight TomcatMKlIManual doc 12 08 11 12W at the onset of clipping into resistive load at rated impedance 1Megohm nominal 10mV for output clipping all volume tone controls fully up gain boost off One ECC81 12AT7 one ECC83 12AX7 two EL84 100V 120V Mains 2A slo blo HT 500mA fast acting 200V 240V Mains 1A slo blo HT 500mA fast acting Accepts any normally open on off footswitch to control gain boost function Head 20 W x 8 3 4 H x 9 D Combo 25 W x 18 2H x 10 2D Head 22lbs 1x12 Combo 45 lbs Page 14 of 14 Copyright 2003 2011 Aiken Amplification Inc
10. formers or other expensive components TomcatMKIIManual doc 12 08 11 Page 10 of 14 Copyright 2003 2011 Aiken Amplification Inc Speakers Changing speakers is like getting a whole new amp Every model sounds completely different some sounding quite good and some amazingly bad The Aiken A12 speaker is a custom made speaker using British cones designed to meet our exacting tonal requirements The amplifier is also particularly well suited for use with Celestion loudspeakers which give the characteristic Voxy British sound this amplifier is designed to create Celestion Greenbacks have less volume and a dip in the mids which makes them nice and smooth They are rated at 25W so they make a nice match for the Tomcat Celestion Alnico Blues are by far the loudest with a nice chimey top end but not extremely cutting highs and full bottom end but their rather pronounced midrange and very low power rating 15W may make them undesirable for some users Jensen P12B bell alnico s are far brighter than the Celestion Alnico Blue but don t have as good a low end response They can however sound very nice when paired with the Alnico Blue in a 2x12 configuration Celestion Vintage 30 s have a very pronounced midrange which may be a bit too harsh in an open back configuration which naturally enhances the midrange frequencies and can sound a bit boxy with the wrong speaker They do sound good for some blues styles and can easily handle the p
11. guitar cables Fluorescent lights and light dimmers can be a source of hum buzz as can computer monitors If the buzzing only occurs when using effects or a tuner the problem is likely a ground loop hum in particular the Korg rack mount tuner seems to be susceptible to ground loops If this is the case the hum buzz will go away if the guitar is plugged straight in to the amplifier The solution is to use a ground loop hum eliminator there are a few on the market or make a guitar cord with a telescoping shield to go from the output of the effects to the input of the amp This is a cord with the shield cut on one end The cut end should go into the amplifier input jack and the end with the shield must go into the output of the effects unit tuner In a emergency a ground lift plug three prong to two prong adapter can be used on the tuner effects box but this is not recommended due to safety concerns If you do use a ground lift adapter you should check to see if there is any AC voltage present from the chassis of the rack effect tuner to the chassis of the amplifier If so do not use the adapter TomcatMKIIManual doc 12 08 11 Page 12 of 14 Copyright 2003 2011 Aiken Amplification Inc If the buzzing only occurs when playing the guitar try replacing the speaker or plugging the amplifier into an extension speaker cabinet A buzzing noise from the speaker can indicate a blown speaker or one with a warped frame Buzzing noises that occur
12. he preamp tubes with different ones to see if the hiss decreases Ticking noise Some tubes tend to exhibit a low level ticking noise right after the amplifier is taken off standby The noise stops after a second or two when the tube has had a chance to stabilize and is not indicative of a problem Ringing noise or feedback that occurs with no guitar plugged in If the amplifier exhibits a ringing noise especially when tapping on the chassis or if it makes a howling or whistling feedback noise when the volume is turned up but no guitar is plugged in there is probably a microphonic tube in the amplifier likely in the first position the small tube closest to the input jacks or in the reverb recovery position Remove the shield and lightly tap on the tube with the volume turned up A small amount of noise is normal but a loud ringing noise indicates a microphonic tube which should be replaced In a emergency you can swap the preamp tubes around until you find the least microphonic one to put in the first position Typically the phase inverter tube is the least susceptible to microphonics so the most microphonic tube should be used in this position The least microphonic tube should be used in the first position When purchasing tubes be sure to purchase tubes that have been tested for microphonics Many vendors do not test for microphonics and you could end up wasting your money on tubes that are unsuitable for use Combo amps ar
13. in harmonic complexity lt is specifically designed to be very reactive to the speaker cabinet it is connected to giving wide variations in tone with different speakers The amplifier was designed specifically to capture the typical class A cathode biased non negative feedback tone at lower volumes with the addition of an over the top footswitchable gain boost for soloing TomcatMKIIManual doc All tube signal path The preamp tube is an ECC81 12AT7 the phase inverter is ECC83 12AX7 Output tubes are EL84 The rectifier uses massive 3 amp 1000V ultra fast recovery diodes UFREDs for the utmost reliability and a tight fat low end Front panel controls connections Input jack Volume Tone Cut Attenuator and Variable There is also a bright switch and a gain switch which is footswitch controllable Rear panel controls connections AC mains input international voltage selector allowing operation at 100V 120V 200V 220V 230V 240V 50 60Hz impedance selector switch for 4 8 or 16 ohm operation two 1 4 speaker jacks and a gain footswitch jack Solid finger jointed birch ply cabinet The head is 20 wide 8 3 4 tall and 9 deep the combo is 25 wide 18 77 tall and 10 4 deep Solid 16 gauge steel chassis zinc plated yellow chromate conversion coated for durability corrosion resistance and appearance Front and rear faceplates are gold anodized aluminum for durability and a classic appearance All hand wired
14. not lit Is the amplifier plugged into a functional outlet of the appropriate voltage Is the mains fuse blown If so replace with the appropriately rated fuse If the fuse again blows the amplifier may have a shorted output tube or rectifier tube Replace the tubes and fuse and power the amplifier up again If the fuse still blows the amplifier will need to be serviced Pilot lamp lit but no sound Is the HT fuse blown If so replace with the appropriately rated fuse If the fuse again blows the amplifier may have a shorted preamp tube output tube or rectifier tube Replace the tubes and fuse and power the amplifier up again If the fuse still blows the amplifier will need to be serviced Is the speaker functional and plugged in correctly Insure the amplifier s output impedance selector is correctly set to match the speaker in use Is the guitar cord functional Bypass any pedals and plug straight in with a known good cable to test No reverb The amp is not designed to have reverb so if you don t hear any you don t need to worry about it Humming or buzzing noise Unplug the guitar cord from the input and unplug any cable used for jumpering the two inputs If the buzzing stops try replacing the cord Be sure to use only guitar cables not unshielded speaker cables If in doubt unscrew the connector and look to see if there is a shield around the center connector Some smaller speaker cables are easily mistaken for
15. omc at User s Manual Aiken Amplification Inc 1225 Montague Avenue Greenwood SC 29649 Tel 864 993 8383 http www aikenamps com Contents COItents oi Aen e eet oe 2 Getting Slanted 2s ci iex ein aia hie ies 3 Front Panel Controls and Switches lt lt lt lt lt lt rrrrrxxzze 5 Rear Panel Controls and SwifC S 5 re rrrrree 7 geo dire pct EL ai des eA ia 8 Tube layout and repDlaC ITI TI lilii iiia iniit nn 9 BIASING 10 SP CAK CIS ish eii ate Reti date Eier SUE EE 11 Houbloshooting ua nba ate to datu onde ac c fcire esu ens 12 SDOCITICAUIOINS Amstaue MC 14 TomcatMKIIManual doc 12 08 11 Page 2 of 14 Copyright 2003 2011 Aiken Amplification Inc Getting Started Congratulatons on purchasing your new Aiken Tomcat amplifier The Tomcat is a push pull cathode biased no negative feedback amplifier featuring two EL84 tubes in the output stage The deceptively simple yet highly effective controls include Volume Tone an AC 30 style Cut control and our very transparent built in attenuator which features a Variable control that is enabled at the last setting to take the volume down to bedroom levels Features include The design features a single channel no frills signal path for the utmost
16. ower of the Tomcat Celestion G12H30 s are like a cross between the Greenback and the Vintage 30 with more low end than the Vintage 30 and not quite as pronounced a midrange so they tend to sound subjectively better in an open back cabinet Closed back cabinets have better and tighter bass without the pronounced midrange hump of the open backs but they don t disperse on stage as well and tend to be beamy sounding very loud out front but if you stand above and to the front or back you can t hear yourself as well Still there is nothing quite like the tone of a cranked up 4x12 cabinet loaded with Greenbacks Fora more portable closed back a 2x12 loaded with either of those Celestions will do the trick nicely Putting a 2x12 on each side of the stage fills up the tone very well and provides an almost stereo like sound field because of the cancellations that occur when standing in different places on stage The Greenbacks or Alnico Blues are the recommended speaker for 2x12 and 4x12 cabinets for the classic vintage tone When changing speakers always insure that the output impedance selector is set to match the impedance of the speakers connected to the output jacks The Tomcat has two paralleled output jacks and can easily drive two 4x12 cabinets to extremely loud volume levels despite the 12W power rating TomcatMKIIManual doc 12 08 11 Page 11 of 14 Copyright 2003 2011 Aiken Amplification Inc Troubleshooting Pilot lamp
17. tores Power switch The Power switch turns the amplifier on in the up position and off in the down position Glory switch What good is power without the glory The Glory switch allows muting of the amplifier output when not in use When the switch is in the up position the amplifier is on and when it is in the down position the amplifier is on standby The tube filaments remain on and warmed up so the amplifier is ready to play as soon as it is taken off standby The correct powerup sequence is to turn the amplifier on with the power switch and then after it has had time to warm up the Glory switch is turned on When turning the amplifier off the Glory switch should first be turned off then the power is turned off after a few seconds TomcatMKIIManual doc 12 08 11 Page 6 of 14 Copyright 2003 2011 Aiken Amplification Inc Rear Panel Controls and Switches AC Mains Plug the supplied IEC mains cord into this outlet to provide power to the amplifier Mains Fuse 2A slo blo for 100V 120V operation 1A slo blo for 200V 240V operation AC Mains voltage selector Set this switch to the appropriate position to match the mains voltage in the country in which you are using the amplifier WARNING Do not adjust this control with the AC mains cord plugged in and the power on Damage to the amplifier will result if the switch is set to the wrong position If you have any doubts as to which is the correct voltage for the country you
Download Pdf Manuals
Related Search