ruffrecords

Re: Helios 69 Module dimensions
« Reply #20 on: April 02, 2018, 07:05:45 PM »
Yes, it looks like we are in danger of going round the same loop.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


Re: Helios 69 Module dimensions
« Reply #21 on: April 02, 2018, 09:08:33 PM »
Oh well ,its new info to me at any rate ,I guess I'll take what I can from it ,and hopefully build a bit further on it ,fingers crossed anyway ::)

ruffrecords

Re: Helios 69 Module dimensions
« Reply #22 on: April 03, 2018, 03:00:39 AM »
Oh well ,its new info to me at any rate ,I guess I'll take what I can from it ,and hopefully build a bit further on it ,fingers crossed anyway ::)

Sorry, it was not meant to discourage you - there is plenty of good stuff out there about Helios. If you cannot find the answers there then by all means ask here.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Helios 69 Module dimensions
« Reply #23 on: April 03, 2018, 04:57:09 AM »
No worries Ian, and sorry I didnt mean to divert back down a road already travelled,
For some reason the internal Group diy search function didnt reveal any of the old posts on the topic ,
an external browser search however did .

Something like the neve Ba183 ouput stage is familiar and easy enough for me to understand , Im not really  visualising whats going on with the complimentary pair type setup as used in the Helios yet though , there seems to be a few different drawings of the same basic circuit also which kinda throws me a bit too.

ruffrecords

Re: Helios 69 Module dimensions
« Reply #24 on: April 03, 2018, 07:37:56 AM »
Im not really  visualising whats going on with the complimentary pair type setup as used in the Helios yet though , there seems to be a few different drawings of the same basic circuit also which kinda throws me a bit too.

I am no semiconductor expert but the 2113 circuit is not too hard to understand if you break ir down. Referring to the schematic you posted in reply No.18:

TR1 and TR2 are just the same as in the three transistor mic pre. All that has changed is the first transistor is an NPN and the emitter follower is a PNP. TR5 is the output transistor of the original design but it is a PNP. The other transistors help turn it into a line driver. TR3 and TR4 form a current mirror. The current is set by R8, R9 and R12. The idea is to provide a constant current load for TR5. TR6 and TR7 are a complimentary emitter follower connected to the output of TR5. The constant current through R11 sets the bias for these two and their standing current is set by R13 and R14.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Helios 69 Module dimensions
« Reply #25 on: April 03, 2018, 08:31:51 AM »
Thank you kindly Ian,
That will make perfect food for thaught along with my afternoon coffee.

Strat96

Re: Helios 69 Module dimensions
« Reply #26 on: April 29, 2018, 05:59:15 PM »
After I retired and got back into audio electronics, the Helios pre designs were among the first I looked at and simulated... The result is one half of the waveform distorts more than the other. The result is pleasing even harmonic distortion. I noticed that if you swapped the two resistors that set the bias,  the output sits almost exactly at half the supply voltage. So whether the pleasing distortion characteristics of the Helios pre is deliberate or the result of accidentally swapping the bias resistors we will never know.

Cheers

Ian

I have noticed this also! Glad to see more Helios conversations.
I don't care how many tapes I must bake, Analog is still the best!

My YouTube Channel (Analog Noise :: Studio Gear, Music, and Life)
https://www.youtube.com/channel/UCu4ZqdUdgNd6IOnymsdULlQ

Re: Helios 69 Module dimensions
« Reply #27 on: May 19, 2018, 09:33:13 AM »
I got a few clues about Pete's Helios through my friend Jack ,who contacted John Wolff the who's roadie ,now retired.

From John Wolff ("Wiggy") :
"It's a way back and I think the first mistake is that we bought the Helios from another studio, not Pete Townshend's. Although that has no bearing on where it went afterwards. We sold the Helios to someone who was building his own studio for about £10,000, but I can't remember who it was, maybe Bob Adcock rings a bell. Then it went to America, I think, rather than the replacement Neve as some historians maintain. But it's a bit way back as my memory search engine didn't get back to you straight away as a person of your stature is entitled because I was researching the request more thoroughly for you and David, as it is of some interest to me as well. I will let you know more when the fog of entombed memory of enlightenment clears."

Nothing concrete just yet but it is interesting to hear Johns recollections , if it did go to Robert Adcock it seems to have brought him good luck in his career ,he still makes great sounding records.

Whoops

Re: Helios 69 Module dimensions
« Reply #28 on: April 13, 2020, 03:43:18 PM »
Hi,
yesterday I scanned the full tech docs I have for the Helios Musicland console.

I'm posting the individual docs in the Tech Docs section.

Hope it can be helpful for you and future projects

Best Regards

Strat96

Re: Helios 69 Module dimensions
« Reply #29 on: September 28, 2020, 06:40:29 PM »
There various version, like this one for example:



and the Clapton one:



but they were all variations an a them so I suspect they were all in an identical panel size.

So, thank you very much for that info. 7 inches high is 4U which is what I had guessed. The width I had no idea but now I know it was 1.8 inches, an odd choice but who knows what drove the decision.

Once again, m,any thanks for the info.

Cheers

Ian

The routing modules on my console fit the 7"x1.8". However, I bought some EQ face plates from one of the consoles, powder-coated, and they are a hair shy of the 1.8". It kind of bugs me a little and I might just get new ones made. If you look at some photos of some of the consoles you can see a slight gap that exists on the EQs, probably due to the tolerances.
I don't care how many tapes I must bake, Analog is still the best!

My YouTube Channel (Analog Noise :: Studio Gear, Music, and Life)
https://www.youtube.com/channel/UCu4ZqdUdgNd6IOnymsdULlQ