Author: simon

2 – Output Connector Wiring 

 

The Universal Tube Output Stage can be connected either for stereo single ended

connections or with two modules for stereo balanced connections.

 

2.1 – Stereo Single Ended Connection

 

Shown below are the connections that need to be made from the RCA sockets to the Universal Tube Output Stage for a stereo single ended arrangement.

Depending on the RCA connectors used you may have to solder the wires to the RCA Sockets.

 

It is important that the RCA sockets are mounted such the sockets metal shell does not make contact with the Chassis.

 

2.2 – Stereo Balanced Connection

 

Shown below are the connections that need to be made from the XLR and (optionally) RCA sockets to the Universal Tube Output Stage for a stereo balanced arrangement.

Depending on the XLR & RCA connectors used you may have to solder the wires to the XLR and RCA sockets.

 

It is important that the RCA sockets are mounted such the sockets metal shell does not make contact with the Chassis.

 

The metal shell of XLR connectors is designed to contact the chassis for shielding and hence it can and should make contact with the chassis.

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1 – Power Supply Wiring 

 

If your local power supply is in the range of 100V to 120V AC wire up the mains transformer

as shown below.

If your local power supply is in the range of 220V to 240V AC wire up the mains transformer

as shown below.

 

Muting

 

The Universal Tube Output Stage is fitted with a relay based muting circuit (shunt type so it is completely disconnected when unmated) which also performs a turn-on delay.

 

For CD-Players that produce unwanted noises etc. between tracks it may be desirable to use this circuit to mute the signal the same way the original analogue stage did.

 

As this requires you to find the actual logic signal that controls the muting in the original equipment this is quite advanced and no simple guidance is possible. You will most likely require a copy of the service manual and the ability to read the schematics within. The Universal Tube Output Stage can accept mute signal that either mute when a “High” signal is present (use the connection labeled Mute) or that can mute when a “Low” Signal is present (use the connection labeled /Mute).

 

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Specifications

Appendix B – Silk LCR EQ Connections and Performance

Silk Transformers of Thailand have been manufacturing a wide range of conventional and uncommon magnetic components for many years.

The trend to use vacuum tube phono stage circuits has been back to the high-end scene for several years. Most designs based high impedance, high loss R/C networks in either feedback loop or passive, to provide RIAA compensation.

Even though this scheme has been implemented to most of available phono stage circuits, due to ease of design, implementation and low cost, for many audiophiles, those phono stages still do not provide enough sense of reality.

Recently the trend of alternative design called LCR RIAA phono stage circuit is now on rising and gain popularity among discerned audiophiles. This is only natural, as the pre-emhasis RIAA networks in many Cutting Lathes for cutting LP’s also used LCR Circuits to shape the original equalization.

The LCR RIAA comprises of inductors, resistors and capacitors to form a low impedance constant impedance T-network that functions to compensate for RIAA playback standard. This low impedance characteristic yields exceptional signal transfer that usually lost from high impedance R/C RIAA network.

The Silk LCR RIAA is built based on the best Superpermalloy core inductor and performs within +/- 0.5dB from RIAA standard (from 20Hz-20KHz) and on average less than +0.15dB from the RIAA standard. The SILK LCR RIAA requires either 600 ohm source impedance or 600 Ohm load impedance.

B.1 LCR RIAA connection diagram 

B.2 LCR RIAA Response

Appendix A – Cinemag MC Stepup Connections and Performance

CineMag was founded in 1979 in North Hollywood, California. Its mission is to manufacture the very best audio magnetic components in the world. However, its history goes back to 1953 when its founder, Tom Reichenbach, was a youngster and was already making transformers with his father, Ed. Edward Reichenbach’s experience in the audio transformer business goes back to Altec Lansing during World War II.

In order to obtain the very best results in an audio design, it is imperative that each and every detail of manufacturing be closely watched. The smallest deviation from ideal manufacturing processes will result in product which does not meet our criteria. For this reason, CineMag carries out all manufacturing at their own facility at Canoga Park, California.

The CineMag CMQEE-3440A’s design derives from the classic “Quad 8” Range designed originally for Electrodyne Mixing Desks. It can be connected with impedance ratios of 37.5/150 and 600 ohm to 50KOhm, translating into step-up ratios of 1:36, 1:18 and 1:9.

A.1 Transformer connection diagram 

A.2 Transformer Test Results 

A.3 Transformer grounding & Secondary Hookup 

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1 – Introduction and Overview

The Vinyl Song is a State of the Art Phono Preamplifier/Equalizer with 38dB (MM) and 62dB/68dB (MC selectable) of gain. By using the Silk 600 Ohm LCR RIAA EQ Modules not only a very precise equalization is attained, but also noise is kept very low. The (optional for the MC version) Cinemag step up transformers provide the extra gain for MC pickups without adding noise or colorations.

For ease of application all connections on the Universal Tube Output Stage are provided as screw terminals and all configurations are handled by gold-plated jumpers, so no or only minimal soldering is required on the actual Universal Tube Output Stage Module.

In fact we have found mechanical connections to sound better than soldered. The kit is also supplied with premium RIAA parts – polystyrene capacitors and teflon shielded mini coax. Although contained in one box the transformers have their own iron shielding cage with a net result of state-of-the-art quiet and incredible dynamic range.

5 – Testing and first power-up

The modules making up your Vinyl Song Kit are individually tested before shipping. So no extensive testing is required. However, we recommend a set of basic checks before first switch-on.

5.1 Basic testing and checks 

Please re-check all the wiring and connections against the drawings and Photos. Check that no components on the PCB have been shifted or pushed from their correct position and that no components make any contact with others.

You should especially check Q2 and Q102, located near the tube socket. You can find their exact location by checking the component designators on the PCB Overlay.

Check that for 115V Mains a 1A slow blow fuse is fitted to the IEC Sockets fuse holder. For 230V the Fuse should be 0.5A.

5.2 Testing the Mains Transformer Wiring

Using a multimeter set to resistance measurement check the following conditions are present on the IEC Connector:

1) There is no continuity or resistance from either the L(ive) or N(eutral) pin to the E(arth) Pin.

2) There is a zero ohm or very close to zero ohm (<<1Ohm) resistance between the E(arth) pin and the Vinyl Song Chassis.

3) If your Vinyl Song Kit is wired for 115V you should measure around 15 to 20 Ohm between L(ive) and N(eutral).

4) If your Vinyl Song Kit is wired for 230V you should measure around 60 to 80 Ohm between L(ive) and N(eutral).

5.3 First Switch-on

We recommend you carry out the first switch-on without the E88CC Tubes fitted, with the case open and the cover from the shielding case for the transformers removed.

Upon connecting the mains cable and turning the power switch to “On” the power LED should light up, followed by one each Blue LED on the UTS Boards.

There should be no smoke or burning smell. If you notice any such, please immediately switch off and disconnect the mains cable. Then check your work and rectify any faults.

If all appears okay leave the Vinyl Song on for another minute or two. Then switch off, disconnect the mains-cable and check the temperature of the mains transformers.

If they are at room temperature all is okay. If they have a very elevated temperature you may have a short somewhere in your wiring or a damaged transformer.

If everything is okay, you can fit the transformer shield cover, the tubes and complete the assembly of the Vinyl Song.

For a final check connect the mains cable and switch on. After around 1 minute measure with your multimeter the DC voltage on each RCA Output. This should be no more than a few millivolt.

If all is as expected, you can move your Vinyl Song into your system for a first listen.

4 – Wiring the chassis and Modules

Please check your Kit content against the list to the right.

Take care to first review the steps outlined below, assemble the necessary tools, parts etc.

Many of the required connections can be made without using a soldering iron. However the connections for the RCA Jacks and from the MC Stepup Transformers as well as the LCR Modules require soldering. For the RCA Jack ring connections and the ground binding post we recommend a soldering iron of at least 50-60Watt power. All other solder connections should use a smaller soldering iron with 25Watt power or (better) be of the electronically regulated type.

When making connections to the IEC sockets and the mains transformers take great care to make solid connections and to isolate the bare connections using the included heat shrink sleeving. Please avoid pulling the wires exiting from the Transformer, as too much tension may cause internal shorts or disconnect the wire, rendering the transformer unusable.

The iron cover of the transformer shielding cage is set into place on the blue mastic provided. This provides a non-vibrating fit and makes removal easy.

4.1 Parts included in the kit:

4.2 Wire up the mains connections 

4.3 Wire up the Power connections, outputs, Led & Switches

4.4 Wire up the LCR EQ Modules 

4.5 Wire up the MC Stepup Transformers and MM Inputs

4.6 Photo of completely wired input section

4.11 Photo of completely wired Vinyl Song, transformer shielding closed

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3 – UTS Settings and wiring
This application will produce a moving magnet and high output moving coil cartridge compatible Phono stage. It use two Universal Tube Output Stages together with a LCR 600 ohm module to form the RIAA Equalisation network as Phonostage. One UTS Module will be used for each channel, so Tubes used should be identical in manufacturing and preferably matched.

The resulting Phono Stage will offer 47kOhm input impedance and around 38db Gain in MM mode. Gain with the Cinemag MC stepup transformers will be 62/68db with a load of 140/36ohms.

Our implementation produces the most accurate RIAA EQ we have ever seen from an LCR type phono stage:

We include military specification polystyrene caps with the kit to meet these specs. Such adherence to RIAA standard results in very quiet playback that minimizes grove noise and diminishes the presence of tics and pops.

3.1 Jumper Settings

Please note that Capacitor C109 is (intentionally) not fitted. It is not used and should be left off the PCB. The connection pad on the PCB near the upper end of the PCB (as above) is used to take off the signal feeding the LCR RIAA.

3.2 Input/Output Wiring Diagram MM Only

Please note that the Mute and Mono Switches may be safely omitted. If the mono Switch is omitted the four 33 Ohm Resistors also can be removed.

In most Phono Stages using LCR RIAA Equalization the LCR RIAA Module is coupled using either capacitors or transformers. In our circuit no such coupling device is needed.

The LCR RIAA Module is coupled directly to the output of the input gain stage using only a single Tantalum resistor to present the correct impedance to the LCR RIAA module.

In order to allow this direct coupled circuit, the wire feeding the LCR EQ Module via the 680 Ohm resistor is soldered on the PCB to the connection for the omitted C109, nearest to the edge of the PCB that contains the audio connections.

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2 – UTS module Specifications: