The Mono Phono Preamplifier for Historic Records

 Hi!

Just finished a new variable EQ phono stage and took some photos before it got shipped to its new owner.

Like previous builds of  mono phono preamplifiers, this unit has separate controls for the bass turn over frequency and the roll off at 10kHz.

This allows for a variety of settings to cover a wide range of EQ curves from early 78rpm records to 33rpm vinyl mono LPs.

The actual phono stage and power supply have separate chassis similar to the stereo LCR RIAA phono stage.

The EQ networks are done in LCR topology as in the stereo phono stages. The inductors are mounted directly behind the face plate besides the EQ setting switches.

Some photos from the construction steps. Here the top plate with vibration damped mounting of the tube sockets.

Some parts mounted:

Output and interstage transformers as well as the B+ smoothing chokes are mounted on the top side under transformer covers:

There is a second support plate for B+ smoothing capacitors, a choke for the heater supply and the remaining parts of the EQ networks.

About one third of the EQ networks mounted :

The power supply top plate:

Chokes go on a separate plate...

.... which is mounted to the underside of the top plate:

Finished preamplifier:

Bass turn over selector:

Treble roll off selector:

Vibration damped mounting of the D3a tubes:

Side view of phono stage:

Back side:

Some sound clips with a similar phono can be found in the post about a 78rpm demo at the Munich High End show.

Best regards

Thomas

Live from Munich : High End 2017 - Part 8, 78rpm sessions

Hi!

Today we held some sessions with historic recordings in room F231c.

Frank Wogatzki presented various 78rpm records from his collection:

Like this one:

The variable EQ phono preamp specifically made for this event:

Another shellac played by Frank:

And one more.

Here Frank tells the story how he convinced me to build variable EQ phonos:

Tomorrow and on Sunday we will repeat such sessions. Come to room F231c and join us on a journey through the history of Jazz

Best regards

Thomas

Live from Denmark : ETF 2016 - Part 20, 78rpm fun

Hi!

As in previous years Frank brought some of his 78rpm shellac records.

Here we see him with one of his latest finds to add to his vast collection of tonearms and turntables specifically for 78rpm records.

Peter mounted a suitable cartridge on his PTP...

... under Franks watchful eyes:

So we could have some fun with 78rpm records, some might get blocked in some countries due to copyright:

Best regards

Thomas

Gramophone Company Ltd. "His Masters Voice" 78 RPM record player

Hi!

Today I'd like to show something completely different. My good friend Frank with whom I did a 78 rpm Shellac demo at last years ETF visited and brought a marvellous piece of equipment to play with.

An 78 RPM record player for Shellacs, made by The Gramophone Company Ltd. in 1935. The player was named "His Masters Voice" and has the Nipper Dog logo prominently displayed on the side.

View from the top:

Tonearm with Nipper logo embossed:

The screw at the front of the arm fastens the needle which needs frequent replacement. There is a small trough underneath the arm to catch the needle when the screw is unfastened:

The inside with the motor:

The mechanics beneath the platter:

Frank also brought some shellacs from his collection to listen too. We started with a record from Rex Stewart on the label Amiga from 1947:

There was a concert planned 1947 in West Berlin. Due to a power outage they needed to find a new location and wound up in a Club which was located in the eastern part of the city. There several recordings were made among these the 'Linden Blues':

Next we played a record with Peggy Lee and Benny Goodman from 1942:

And this is how it sounds:

And finally a record from my collection. The Beggars Blues on Vocalion. A very old label, probably recorded in the 1920ies or 30ies!

And a video which shows it playing on the HMV:

I hope you enjoyed this post about historic 78 RPM records. Thanks a lot to Frank for the fun session!


Best regards

Thomas

ETF.14 Berlin November 20 - 23

Hi!

This years ETF is coming up. As last year I will post reports and keep you updated about the highlights of the event. I will also show some stuff myself,a new version of the ShellacSavor preamp with variable EQ settings for 78rpm records.

This preamp will be part of a joint set up with my friend Frank, who introduced me to 78rpm records after last years ETF. Frank prepared a presentation and will talk about the history of Shellac records and we will demo with a broad selection of Jazz music.


Different to the first implementation, the new preamp comes with a separate power supply to minimise PSU interference.

Besides this I will also bring a D3a LCR phono stage, the 'phase 1' cost down version. It will be combined with a matching line stage, the 6AH4 preamplifier. These units will be part of the system of the Munich gang.

Tune in November 20th through 23rd for 'almost live' updates from the ETF!

Best regards

Thomas