Tram 2 OTL DHT Linestage

Transcription

1 Tram OTL DHT Linestage 1

2 O.T.L. (output transformerless) DHT (direct ht triode) Linestage Builders Guide 1.34 Specification Signal/Noise ratio: >10.dBA Output Impedance: 500 Ohm Response: better than ±0.5dB 0Hz - 0KHz Distortion: THD & N: < 0.1% All msurements referenced to +18dBu (6V), +10dBu (.45V) and +dbu (1V) for the respective outputs All msurements taken with EML45 and vary with tubes employed Input Connections: RCA 5 pr switchable by remote or front panel knob with front panel LED indicators (remote not included) REC/MON Connections: RCA 1 pair Output Connections: 3 pairs of output connectors (RCA), +6db, -3db, -1db Volume Control: 17 step with LED front panel level indicators remote controlled or knob controlled (remote not included) Power Consumption: VAC or 0-40VAC 50/60hz 10W Dimensions: 30 (L) x 300(W)x170 (H)mm Tubes: 1 pc 6AS7 equivalent, 1 pc 5U4 equivalent, pcs A3 or 45 Weight: 10 kg (packed) remote control not included

3 DIY HiFi Supply This manual is the property of DIY Hifi supply Ltd and may not be reproduced or distributed by any mns in whole or in part. Right to use the manual for the construction of the Tram kit is granted to the purchaser of the kit. WARNING: The high voltages present in this kit can kill and the high operating temperatures can burn. Observe all precautions and never connect the kit to an electrical supply until it has been fully assembled, checked and rdy for testing. You assume total responsibility and liability for the use and operation of this kit both for yourself and people around you. Confirm that large capacitors are discharged before working on the amplifier Requirements The kit builder needs to have basic soldering skills and be able to rd and understand the wiring diagrams presented. Refer to the diagrams at ch step throughout the manual and ensure you double check all wiring at ch stage. It is also advantageous to refer to the circuit diagrams at the back of the manual throughout the build. Warrantee The kit cannot be returned for a refund. Defective parts will be replaced provided they are returned within 30 days of purchase and are confirmed defective and not misused. No further Warrantee is expressed or implied. This is to protect you the buyer to be assured of receiving a brand new kit and not one that has been returned by someone else which may have been misused. 3

4 Chapter 1 Introduction The Tram has unique ftures only found in linestages costing 6 x as much: 1) Valve Rectification with 5U4 and All Film Cap Big L small c power supply. ) 6AS7 Super Mu and CCS act together as active impedance multiplier to provide an anode load even better and more stable than a high inductance choke. (no voltage sag on transients, extended downward dynamic resolution) 3) The Audio Circuit : Undistorted Output Voltage 10V RMS, output impedance around 500 Ohm. SET, DHT, Class A, no nfb. 4) Volume Control is Ultimate Volume Control module with 17 steps and 5 position selector (remote Control supplied by user. 5) Fixed bias with Auto bias System eliminates detail slurring capacitor on the cathode. 6) Ultra Low noise Filament supply for low level dynamic range The net result is a very dynamic, involving linestage which can drive most any load and that sounds tonally correct. 7) Obbligato caps, silver wire, All are chosen for their total sound in combination with ch other. To give you an id of our priorities: We eschew clinical, cold, soul-less hifi. We like BIG, bold, dynamics and rich tonal colours. We seek to evoke emotional response to the music above intellectual response. Hifi that only satisfies the mind will be soon discarded for something else. We believe the Tram will stay as the hrt and soul of a musical system. The Tram starts with good layout. We wanted a single chassis solution together with power transformer. So transformer at the front, triodes at the back close to input/output connections. Tube rectifier and 6AS7 closest to the transformer. B+ is supplied from the ultra low noise film cap power supply module and the cathode supply comes from our filament supply module with added capacitance. The Tram mounts the triodes on the 3mm tube subplate which is in turn mounted to the chassis with compliant isomount standoffs. Knuckle rap on the chassis doesn't transfer so we've done well. We have provisioned 3 outputs: +6db, -3db and -1db. The user needs to select in system but in general: amplifiers with input sensitivity of to 6v would match +6db outputs; 0.7v - v amps: -3db outputs; below 0.7v amps: -1db outputs. The Tram can comfortably handle amplifier loads down to k ohms. Why DHT OTL linestage? DHT sound better. On the test bench we get very low noise and very low distortion. What little distortion is there, is of the single ended type which many feel to be consonant with the sound of music. The Tram as presented can use either 45 or a3 types, just plug and play. What you get is very low distortion, linr output with all the tonality offered by direct hted triodes as close to the source as possible. 4

5 Projekt box 40 x 360 Projekt box 40 x 360 top plate ISO mount feet Silver knob Direct Hted Power Transformer (pc) Power supply module Ultimate Volume Control System Controller Board only Ultimate Volume Control - Audio Board only Filament supply (pair) ABS (pc) CCS Octal Teflon socket 8 pin Silver RCA jack (pair) Tinfoil.uF Obbligato uf/35v SCR 0.047uF/1000v Obbligato Premium Cap 10uF Obbligato 10uf/50v Nichicon 000uf equivalent Carbon Comp 1k Takman REY.5w 470k Kiwame w 1r Kiwame w 470r Kiwame w k4 Takman REY.5w 80r Takman REY.5w 560r Generic film 0.1uf Diode bridge Kiwame w 6k8 Kiwame w 4r Capacitor 150uF/450V Resistor 33 Ohm/W Kiwame Miniature Choke Cable Ties long 1 pr pair Extra Parts for Powersupply 1 1 Kiwame 100r w 4

6 Chapter Installation Notes Recommended Solder It is recommended that silver solder be used. Solder Technique Solder mns to apply the iron tip to the point that needs to be soldered to ht it and at the same time apply the solder. The iron and solder come together at the same time when soldering any joint or tinning a wire and the solder should start to flow evenly around the joint. Allow the solder to cool naturally and do not blow on it. The finished joint should appr shiny and not dull. Many problems are due to poor solder technique. Cln the iron tip regularly on a wet sponge between ch soldering step. Connections Dress a wire by stripping off enough insulation and then attaching it to the designated point or component. It is a good id to tin all wires before attaching them. Always wrap the wire around the connection point to make a good mechanical connection. When connecting a wire to a valve base pin it is recommended that enough insulation be removed so the wire can be wrapped around the pin to form a good mechanical joint before soldering. When attaching wires to any of the PCB s or switches you should strip off a small amount of insulation and then apply solder to the exposed wire to tin it before fixing it to the PCB. Tips for Successful Kit Building Follow the sequence of diagrams: These instructions were designed to make assembly as simple as possible and minimize interference between assembly steps. Identify and msure parts: Be sure of the identity/value of ch part before you install it. Many kit builders actually msure the value of resistors with a multimeter before installing them. Note: the parts in your kit may not look exactly like the ones pictured here as suppliers of parts are sometimes different. Follow the schematic: It is a good id to have the schematic diagram of the unit nrby and to compare the instructions with the schematic. After installation, check the diagrams again: Once a part is installed, double-check the installation Check off ch assembly step when completed: Use a pencil to place a check mark next to ch connection when it is completed. 6

7 Chapter 3 Hardware 1) The chassis hardware comes mounted and pre-assembled. Just follow the wiring diagrams. ) AC Filament wires should be twisted about 3 turns per inch (>1 turn/cm) to enhance hum suppression. 3) HT wires should also be twisted but keep the AC and DC and ground wires in separate bundles. Do not tie them together. We recommend you use the included soft silver/teflon wire as hookup wire; it does not sound bright but is very fast and smooth. If the system is too bright, look elsewhere for the problem. Avoid pcv coated hookup wire like the plague. 4) Best to cover the transformer covers and make sure the unit is protected against scratches when turned upside down. 7

8 Step 1 silver wire except brown wires from bridge 8

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11 Step 11

12 Step connect according to your mains voltage: 110v 10v use 115v configuration 0 40v use 30 v configuration 1

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18 Step 3 all use copper wire 18

19 Step 3 Optional: Install extra LR decoupled Power Supply Capacitor Under some conditions the Tram II can exhibit pulsing hum. This happens if the mains voltage fluctuates too quickly for FCUPS to catch up. In this case install an additional capacitor as shown. Parts: 1 Capacitor 150uF/450V 1 Resistor 33 Ohm 1 Miniature Choke Cable Ties Assemble as shown. 19

20 Step 4 all silver wire 0

21 Step 5 (see next page for CCS detail) Silver wire 1

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24 Post buildup Testing & Adjustment 1) Before you attempt to power the Tram up, plse double check your work against the diagrams shows in this manual, check that wires are connected correctly and check that components on the various PCB's are straight, not bend out of position and that no components touch. ) Check the correct fuse is installed (inside the IEC connector pull out drawer where power cable connects). This should be 1A slow blow for 30V and 3A slow blow for 115V. Check there is continuity from mains rth pin of the IEC socket to the chassis. 3) Do not insert any tubes yet. Attach the mains cable and switch Tram on.you should see two LED's on the front panel light up, one ch at the input selection and volume control. 4) Under the chassis you should see one LED on the FCUPS Module light up. 5) Use a multimeter to test the hter voltage as shown for one channel. 6) Adjust the multiturn potentiometer (highlighted to the right in cyan) to the lowest voltage adjustable, this is normally around.7v. Once the Tube loads the Filament supply the voltage will drop to the correct level. Rept 5) & 6) for the second channel. 7) Switch the Tram off and back on. Test immediately after switch-on between ground (marked black to the right) and the grid of the left channel tube (marked red to the right). 8) You should msure around -65V (+/- 10V) Rept for second channel. 9) Switch Tram off. 4

25 10) Insert 5U4 Rectifier Tube and 6AS7 Super Mu-Follower Tube. 11) Switch Tram on. The two previously unlit LED's on the FCUPS should light up, one rching full brightness almost instantly, the second slowly turning on. 1) After a few minutes test the +B Supply voltage at the output connector of the FCUPS at the points indicated in red and black (respectively), you should msure around 50V. 13) Switch Tram off. Allow several minutes for the tubes to cool down and for the high voltage to drain off. 14) Insert the DHT Amplification tubes, observe pinning the larger diameter pins belong into the larger diameter socket holes. 15) Switch Tram on. Wait for around 5 minutes to let the circuit stabilise. 16) Using a normal multimeter test the voltage between ground and DHT Anode (marked black and respectively in the picture to the right). It should msure 10V +/-5V. Be careful to make sure your probes do not accidentally touch any other part, connection or wire. Normally the voltages are not correct, so you need to adjust the multiturn potentiometer on the CCS PCB for the correct voltage. This adjustment is somewhat interactive with the active bias system, so do not attempt to set the voltage straight in one go. Instd adjust to cover around 1/ of the difference between the actual voltage and 10V, then wait for several minutes, rept the adjustment as above, wait again and this way work towards the required 10V.Normally three to four rounds of adjustments get close enough. This adjustment is only required once, it does not need to be re-adjusted for different DHT's. 5

26 17) Having completed adjustment. Insert the Tram into a system. Use the -1dB output initially to connect to your amplifier(s) and connect a source to input 1. 18) Switch Tram on. It will take around 3 minutes to rch optimum operation conditions, small noises and a small amount of hum that disapprs as Tram rches operating conditions are normal. 19) Play some music and slowly turn up the volume. You should have a low output, unless your amplifier is very sensitive. 0) We recommend using the lowest output connection that provides the highest desired output levels with the volume control set to around the 3 O'clock. This minimises microphonics and tube noise. If you find that even on the lowest output connector you still have excessive gain and cannot rch the 3 O'clock position you can reduce the value of the resistor between the -10dB Output and ground (560R in the schematic below). 1) If you find at any step during testing and adjustment you encounter unexpected results, plse first check all wiring and connections. If you cannot find anything wrong, plse contact us with as detailed a description as of the problem as you can and if at all possible photos of the section showing problems. 6

27 Operation As with a Formula class racing car, A DHT OTL linestage trades certain niceties for ultimate performance: 1. Placement: best is away from other equipment with transformers. The grid of the DHT is very sensitive to picking up environmental noise. The Tram self noise is very low so if you are having noise pickup issues try rrranging equipment.. Either A3 or 45 can be used in this amp. Switch off power before changing tubes. Generally tubes with less microphonics or ringing when pinged with a fingernail, will sound better. Some current production triodes use coiled springs (traditional is to use straight wire tensioners) and we have found these to ring like a bell. 3. Amplifier and spker sensitivity will also determine noise and microphonics. You will need to experiment which of the 3 outputs to use. We have provisioned 3 outputs: +6db, -3db and -1db. The user needs to select in-system but in general: amplifiers with input sensitivity of to 6v would match +6db outputs; 0.7v - v amps: -3db outputs; below 0.7v amps: -1db outputs 4. The Tram can comfortably handle amplifier loads down to k ohms 5. When powering up the Tram a couple of minutes are needed for bias and B+ circuits to stabilize. This sequence actually protects the tubes against current in rush. During this settling time some hum will be hrd through the spkers. 6. The chassis will run about 0C above ambient temperature. This is normal as the chassis acts as a ht sink. 7. All parts are premium and since there are no electrolytic caps in the signal path it will take about 50 hours of playing to settle in. It is normal for some brightness during that time. 8. Tubes: 6AS7/6N13 and 6080 can be used for the Super Mu position. 5U4/5Z3P can be used for the rectifier 45/A3 can be used for the triode position 9. Tubes positioned as per labels 7

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29 Using Universal Remote Controls The UVC can be remote controlled from any remote control that implements the RC-5 remote control protocol (see Appendix 1) and supports audio components (Amplifier/Prmplifier). Examples of relatively inexpensive remote controls that are known to work are the Altronics stock number A1009 Universal 6 in 1 Remote Control and the Altronics stock number A In 1 Jumbo Pre-programmed Remote Control. Similar or identical remote controls are available from a range of electronic retailers. Many also offer considerably more sophisticated universal remote control solutions (Logitech, Sunwave etc.) at higher cost which tend to all allow the programming for the use with the UVC. There are also many universal remote that it intend to only control TV/DVD/VCD/VCRs, but no audio equipment. This type of remote control will not work with the VC. Plse make sure the remote control supports audio amplifier devices before purchase as indicated by programmability for audio devices such as tuner prmplifier amplifier etc. Most universal remote controls work by entering a three or four digit brand code. This code is in no way standardised, but specific to the individual remote. It is usually printed in small print on a page included with the remote, listing brand codes and equipment. An example of such an instruction/code page is found here: Note that these codes ONLY apply to the Altronics A In 1 Jumbo Pre-programmed Remote Control and not to any others. Select a brand code for an audio amplifier, receiver or audio prmplifier by Marantz, Philips or Rotel. This should produce a working control. Often several codes are listed and it may be necessary to try several ones and possibly several brands. A Brand Code for an audio device must be used, in other words, a brand code for Philips amplifier will work, but a brand code for Philips TV will not. 9

30 The RC-5 Remote Control Protocol The DIYHFS s UVC uses industrial standard Philips RC-5 code The RC-5 protocol was developed by Philips in the late 1980s as a semi-proprietary consumer IR (infrared) remote control communication protocol for consumer electronics. However, it was also adopted by most Europn manufacturers, as well as many US manufacturers of specialty audio and video equipment. The advantage of the RC-5 protocol is that (when properly followed) any CD handset (for example) may be used to control any brand of CD player using the RC-5 protocol. # The RC5 code is made up of parts: (1) Device Address (to identify the correct device; e.g. TV, VCR, Pre-amp etc.) () Command (e.g. Volume +) The UVC s software is set to respond to RC-5 IR Commands as follows: Device (Address) ¾ ¾ ¾ Pre-amp01 (0x10) Pre-amp-0 (0x13) Tuner (0x11) Note: any one of the above device will work. Commands (address): ¾ ¾ ¾ ¾ # 30 Volume + (0x10) Volume (0x11) Channel + (0x0) Channel (0x1)