Synths used on Enola Gay - OMD

 

See also the OMD Documentary:

Update to Pleiades 3 DC90 RIAA electron tube battery powered moving magnet cartridge preamplifier for vinyl records

 At your risk.

Va is 1.3V, Vb is 48V.

One channel has been built so far with Wago connectors.

It works and sounds very nice. 

Signal path:

Africa - Toto - Sony CD Walkman line out - Lipshitz inverse RIAA network - Pleiades 3 DC90 - Sennheiser HD580

It consists for an input transformer, 1 DC90 with grid at space potential (only a capacitor is connected to control grid), 1 DC90 with 10MOhm grid leak bias, 1 DC90 with 1MOhm grid leak bias, and the output transformer. Signal transformers are Sowter ones on octal bases.

As there is no chassis it picks up RF and FM radio can be heard!.

So there is some hiss which should almost be gone when it is built on a Hammond diecast aluminum enclosure.

A rough preliminary frequency response test with anti RIAA (inverse RIAA Lipshitz) network gave -5dB at 20Hz and 20KHz.

Al Schmitt on recording techniques

 

How Frank Sinatra managed to record in 30th street church studio

 Sound engineer Frank Laico narates his discussion with producer Don Costa:

There should be OR not AND on the All Rights Reserved notice of sound carriers

For example, below the second sentence is possible correct as the logic operator OR covers all cases. Is the 3rd version the correct? 

For example in a room are musicians and somebody asks: "Please come forward those who play flute and piano" 2 musicians only come. If the proposal is: "Please  come forward those who play piano or flute", 7 musicians come. Those 2 who play both, those who play the piano only, those who play the flute only. 

I was very lucky to learn this by my teacher of Mathematics Babis Pantazatos. He would thoroughly explain the Aristotelian Symbolic Logic, logic, operators, truthy tables, set theory. On few books such as the book of BBC producer Alec Nisbet on microphones the OR operator is used.

All rights of the producer and of the owner of the work reproduced reserved. Unauthorised copying, hiring, lending, public performance and broadcasting of this recording prohibited.

All rights of the producer and of the owner of the work reproduced reserved. Unauthorised copying, hiring, lending, public performance or broadcasting of this recording prohibited.

All rights of the producer or of the owner of the work reproduced reserved. Unauthorised copying, hiring, lending, public performance and broadcasting of this recording prohibited.

Updates on the Pleiades 3 DC90 battery powered electron tube RIAA MM or MC vinyl disc reading cartridge preamplifier

At your risk. Take all safety precautions. There may be smoke or fire in case of short circuit until a suitable fuse is used in series with a battery.

Va is 1.3V. A 100mA safety fuse is now used.

Vb is 48V.

1st stage operates with grid at space potential, ie with just a coupling capacitor connected to control grid. 2nd and 3rd stages would not turn on in this way due to the initial transient voltage at turn on from the previous stages. S0 a 10Mohm resistor was connected between grid and ground.

It works and the preamplifier sounds very nice. It is directly feeding the Sennheiser HD580 headphones through the output transformer at a low volume.

It makes sense to use an input transformer even for MM cartridges and and additional input transformer for MC cartridges. So thing to having one transformer inside a ribbon microphone, and then the input transformer of the preamplifier.

Promising results.

There is hiss from the second stage, due possibly from bad electron tube contacts or RF pickup.

NOWHERE, NoWhere or NowHere?

 At your risk.

Someone was wearing a NOWHERE T-shirt on the bus.

Could it be the sound leakage to the other instrument mics that can make a piano sound recording so good?

 

If more than one microphone is used even in mono, this can help the listener's brain recognize which is the direct signal and which is the reverberant signal.

If just one microphone is used, the mic has no brain, it picks up the sum of 2 signals. Direct and reverberant. So the information of what is the direct signal is lost forever.

But there are 2 microphones at different distance from the source,  hidden in the 2 sums are 2 almost exactly the same direct signals with the only difference a time delay. The extra time direct sound takes to travel to the more distant microphone.

Is it possible that the brain uses this information to recreate the original direct signal from the musical instrument? So thereby making the distinction between sound of instrument and sound or the room? 

Could it be that solo piano recordings with just 2 microphones will have an inferior piano sound to a piano concerto where mics are used for the orchestra section. And these microphones pick up the piano too with a meaningful delay? 

Apart from the soft playing is this one reason why Largo from concerto in F minor - Bach, pianist: Glen Gould sound so nice and atmospheric but with definition?

Information for this thought was provided by Al Schmitt on Vocal and Instrumental Recording Techniques book explaining the importance of leakage of good acoustics to very good quality microphones to the end sonic soundscape. 

For example the guitar microphones picks up also the singer, or the singer's microphone picks up also the guitar>

On he above example the orchestra microphones pick up also the piano which is also captured with the closser to it piano microphones.

Recording the upright piano with 2 microphones one behind the other

 At your risk

This happened almost by chance trying in almost in vain to record a nice sound. 

So by instinct this unorthodox way came by.

Stand at the right of the piano by its side.

First mic a Unidyne B Mexico pointing at a angle to the cetre of the piano at 24in distance. Then on the same stand another Shure Unidyne B USA behind the other mic by 24in again. Both at the same line pointing towards the center of the piano. The 1st mic feeding the right channel, the 2nd mic feeding the left channel of Sony TC-D5M.

Interesting and promising result. Maybe the best recording i have done so far of a piano in a small living room.

So far my best piano recording may be one at Napier College church in Edinburg. A large church helps so much doing away the early reflections. 

A similar one mic behind the other setup in a bedroom with mics pointing at right angle sounded amazing with a Pleiades oscillator and glockenspiel recording, see previous post. Instruments were on top of of bed with Tempur matresse.

Pleiades BD139 Oscillator Schematic

At your risk. Take all safety precautions. A suitable fuse must be in series with any battery.

Another variable resistor can be added in the feedback path instead of the wire link.

This schematic naturally derived from the Pleiades 2N3053 single transistor audio power amplifier operating in class A (electrons flowing all the time). 

Most of this plus the original schematic (above) is derived from the electronic construction  game with springs Polycyclomatic 1002. Here is how it looks like:

https://www.radioerasitexnisam.gr/articles/15-%CF%80%CE%BF%CE%BB%CF%85%CE%BA%CF%85%CE%BA%CE%BB%CF%89%CE%BC%CE%B1%CF%84%CE%B9%CF%83%CF%84%CE%AE%CF%82-%CF%84%CE%BF-%CF%80%CE%B1%CE%B9%CF%87%CE%BD%CE%AF%CE%B4%CE%B9-%CF%84%CF%89%CE%BD-70s

Thank to a discussion on the beach with John and his Xenophon, both studying engineering there was encouragement to just convert one of the Pleiades single transistor prototypes. In just a few seconds a nice oscillator came up. Wago connectors made the modification possible so quickly. The 12V battery powered oscillator was feeding a Philips 8 in woofer. By adjusting the 2 variable resistors a bass sound repeated in tempo was created. The tempo can be changed by touching the cone of the speaker for current unknown reason. So there is much more flexibility as the pitch can also be affected.

2 Shure Unidyne B microphones, one behind the other at 24in were used to record in stereo the oscillator together with a glockenspiel. The result has some kind of magic from the natural reverberation of the glockenspiel together with the antithesis of the electron generated bass with harmonics sound. It was recorded on SONY TC-D5M.

The amazing Largo from F minor concerto by Bach

 

Here it's Glen Gould recording it in the famous orthodox church of 30th street used as a recording studio by CBS (Columbia Broadcasting System) engineers:

A Forest Recording?

 Malte Marten

A major 7th chord is nicely used. Key is F sharp minor. So D major 7th is beautifully used.

Wicked Game (cover) - London Grammar Using Shure SM7 Moving Coil Inside Magnetic Field Microphone

 

Notes originally written to my friend Markos:

When we talk about dynamic microphones we really mean a moving coil inside a magnetic field microphone. 

A similar mic to the SM57 (God Only Knows - Brian Wilson vocal, possibly uses the Shure Unidyne III which is really the same to SM57) is the SM7. SM stands for Studio Microphone.

Here is London Grammar on a cover using the SM7. Listen for what we were discussing on how humans sing the first few milliseconds of the note flat, and then good singers immediately raise pitch so that it sounds correct to listener's brain.

The singer is very close so the mic will receive spherical waves instead of plane wave fronts so there will be proximity effect, boost of bass and mid. They probably correct bass using a external electrical filter or they might use the filter inside the mic activated by a switch on the side.