Germanium Olympic (Helios) Amp Cards

[Strat96]

A few weeks ago someone had reached out to me and we were talking about Helios and even more specifically the Olympic Modules.

Jim Dowler is making an excellent 65 Olympic and his website shows some excellent details about what he is doing and Olympic itself.

There are two schematics, one with two Germanium PNP another with only one Germanium NPN with two silicone. The first is a design I have never seen before and the other looks just like the MMC/15C1/2128 circuits.

The only other information I have came across is a hazy photo of an Olympic module with one Germanium and two Silicone on a wired solderboard.

My impression over the years was all stages of the amp card were Germanium, but based on the photo and the new 65 Modules it is appearing to be only one stage of the Olympic amp cards are Germanium.

Does anybody have any photos or information on these older modules?

 

[crosstalk]

The circuits on the web site are pre Helios design's , the two transistor circuit with Germanium transistors is the post EQ makeup gain amplifier,
this circuit was never use in Helios desks as they only used Silicon transistors. the circuit with the three transistors referred to as the MMC 1
card is used in both desks but the Helios desks cards had Silicon transistors 2N3707 , 2N4058.

Regards

Crosstalk

 

[crosstalk]

Theses are original boards from the pre Helios desk, all of the electronics were built on veroboard

Regards

Crosstalk

 

[Strat96]

Thank you Crosstalk. Over the years I have read many posts and you have always been such a great help to the community. I really appreciate it. The photo helps to fill in the gaps between about the history.

I have always thought that the Olympic Design followed into Island and other early models with the only difference being the use of Silicone since the schematics for these consoles show a negative supply voltage, reversed NPN and PNP positions as well as capacitors.

Since asking about these older cards, I have done a little reading and I can only guess that the reasoning behind using the negative supply voltage was to minimize the use of NPN Germanium Transistors, and maybe in the very beginning that design went on to the first run of the Helios Consoles? The exception being that the post-EQ card is no longer the two transistor circuit.

Here is the Hyde Street schematic from the technical documents section with -24:
Helios Schematic - Technical Documents

 

[InterstellarObscure]

Theses are original boards from the pre Helios desk, all of the electronics were built on veroboard

Wow, super-cool to see these large clear Olympic card photos. The only other photo I've seen of the 2-transistor card was barely visible from Kieth Grant SOS interview. I guess some of the silver console cards were incorporated into the Raindirk that replaced it.

But if I understand right, the entire silver Olympic Studio 1 console consisted of just these 2 cards.

I sure would love to see some more Olympic module photos if anyone has any : )

 

[JShaffer]

This is too wild of a coincidence, as I had reached out to a friend in the UK about just the same thing just a few weeks ago... I wonder if he is who reached out to you.

I'm hoping to build some cards to drop in as alternatives to the 2128 for testing and to see if I prefer these for eq make up in certain situations (or always?)

Wow this forum is the best!

Crosstalk, do you happen to have photos of the underside of those boards?

Many many thanks all around

 

[kags]

I have a two channel rack made from Olympic modules. Someone used a Dymo labeled and called one channel Mick and one Keith. Supposedly these modules came from The Rolling Stones mobile system. I can take some photos on Friday. I did some repairs a while ago and I think I got my schematics from Orphan Audio. Photos on Friday….

 

[JShaffer]

Outstanding

 

[Cyril Jones]

Hi 2020 is some time ago.

The photo of the small module is residing on the Raindirk Series 3 wrap around console that was fitted to the Olympic Renix room and used on echo returns. 8 were fitted after assembly to new panels to fit into the console meter panel.

The large black can is an inductor by UTC and if my memory is correct a 2 transistor germanium type amplifier

The module were specifically requested by Keith Grant as were other small but useful modifications to aid his mixing style.

Keith so loved the Raindirks Olympic had purchased that he relocated the console to Twickenham Film studios when he moved there.

Cyril

 

[kags]

I have a two channel rack made from Olympic modules. Someone used a Dymo labeled and called one channel Mick and one Keith. Supposedly these modules came from The Rolling Stones mobile system. I can take some photos on Friday. I did some repairs a while ago and I think I got my schematics from Orphan Audio. Photos on Friday….

These modules were racked years probably 20 years ago by Mercenary Audio. We recently replaced the power supply and rebuilt the output driver card. Each channel has two of the same cards.

 

[kags]

I found a lot of information here. Helios
Some other info:

 

[Whoops]

photos of what are "supposedly" early Olympic Pre-Helios modules,
got these over the years from many different sources

 

[Cyril Jones]

Re Whoops Good set of old helios modules. Photos 2 and 3 show the UTC inductor used within the mid section. I can verify as I cut one open extremely carefully to settle and prove my argument - not steel cored but ferrite!
Photo 3 and 5 the original germanium circuit MMC1 type amplifier.
Of course you all may be aware of the various types Cyril

 

[JShaffer]

More great contributions

Thanks Whoops, and thanks for weighing in Cyril! Your Lustraphones are sounding incredible in my console!

Does anyone have a schematic for the "hybrid" MMC1? Is the germanium transistor a 2G308? I'm supposing the germanium is VT3 with VT1 and VT2 being NPN silicon transistors?

 

[Whoops]

The ones that used Germanium the transistor was the 2G308.

I guess the schematic is the same as this one posted in the Technical documents section,
with -24V supply and with 2x 2G308 instead of the 2x 2N4058 (VT2, VT3).
But it's better if someone like Cyril, Jim Dowler or Dave Amels confirms this as I'm not sure.
Please report to us what you find out

 

[JShaffer]

Awesome, Whoops... that fills in some gaps. The only aspect that confuses that theory is that in the photos of the "hybrid" MMC1 cards, it looks like there's just one germanium transistor and it's closest to the filter caps and output caps... though I can't see the underside of the veroboard, that leads me to believe it's VT3 but does that mean VT1 is an NPN, VT2 is a silicon PNP, and VT3 is the 2G308? Could be... but seems kinda strange to me. Hmmm

 

[Whoops]

Awesome, Whoops... that fills in some gaps. The only aspect that confuses that theory is that in the photos of the "hybrid" MMC1 cards, it looks like there's just one germanium transistor and it's closest to the filter caps and output caps... though I can't see the underside of the veroboard, that leads me to believe it's VT3 but does that mean VT1 is an NPN, VT2 is a silicon PNP, and VT3 is the 2G308? Could be... but seems kinda strange to me. Hmmm

From what I was told some cards only had 1 germanium transistor installed, in that case the output transistor. But others had 2 germanium transistors.
But please verify all this info with the very knowledgeable people on Helios I told you above as I was born after Helios closed down.
So what I know is info I've been collecting from different random places and sometimes the sources can be dubious.

 

[kags]

Lots of Helio (and other) info can be found here: Helios

 

[InterstellarObscure]

From what I was told some cards only had 1 germanium transistor installed, in that case the output transistor. But other had 2 germanium transistors.

Just following the components on the vero-board Olympic card photos posted above by Crosstalk, the pre-amp card looks to me like it follows the MMC1 Hyde St schematic pretty close, except there's a germanium PNP in the place of VT3.

There's a lot of great info, including schems of the germ pre-amp and 2-transistor make-up circuit on Jim Dowler's website. He sells 500-series modules based on the Olympic console circuit.

photos of what are "supposedly" early Olympic Pre-Helios modules,
got these over the years from many different sources

maybe worth adding here also that there were at least two silver consoles built by Swettenham for Olympic.

There was the "germanium/hybrid" Studio 1 console with large silver skirted knobs:


and then there was also a silicon-transistor console with black Elma knobs built for one of the auxiliary studios (was it Studio 2 or 3?):


Both consoles used -24 power. The 2nd console ended up at Hyde St Studio for a time, where that -24v schematic came from.

A lot of people describe the silicon Swettenham console as the first official Helios desk.

 

[InterstellarObscure]

incidentally, here's a neat short film of a Soft Machine recording session in one of the Olympic rooms where the silicon Swettenham desk was installed. There's a few brief shots of the control room area showing the console, but the whole film is pretty interesting. I made a YouTube playlist with this video and several more related called Olympic Sound Studios London