HE-569 pre/eq 500 series

[Rocinante]

I am friends with and have several acquaintances with people that attended that party. The general consensus was the originals sounded better but the remakes were really well done. Everyone but Tony and someone else (whom I will not say their name as it is their prerogative) was very open to help me in building Helios stuff. That includes David from Cinemag who was very helpful. All agreed the Cinemag output transformerd was the way to go for individual Mic preamps/eq's. Tony built a buffer to increase headroom.

 

[Squeaky]

And then there is the Beyer vs Lustraphone vs Sowter argument and the fact that apparently Tony's modules weren't racked properly by <some company> for that shootout. Regardless of the reputation of those involved (no real idea who any of them are), I felt that confirmation bias and cronyism (my opinion based on the web comments I have read) could have crept in unnoticed. However, I freely admit that I do not know any of the parties. I guess we should be thankful that a lot of the discussion is recorded on the web so we can all judge for ourselves (if we so wish to). In any event, I don't pay a lot of attention to this or any other shootout (at least anymore) for that matter. Perhaps I'm just jealous because I don't have golden ears and can't hear much over 10k anymore.

As an aside, I have read a lot of Tony Arnold's posts over various fora and he always came across as a bit prickly. Seemed to me like he would be a hard character to like (if you didn't know him personally and only had a web presence to judge). I really believe he tried his best to be true to Swettenham's initial silicon based designs.

There will be many who argue that if you clone the Lustraphone transformer perfectly you will get "the sound". Others will say that the little three transistor preamp is "the sound". Others will whisper of germanium designs (never seen a schematic) as the only ones worth their weight. And still yet others will say that the designs themselves are nothing special and it is the extraordinary talent that was recorded through the desks that is "the sound". I believe a lot more in the latter than the former. That being said, on a different thread GroupDIY member Tubetec, quite validly, pointed that you can almost hear the evolution of the Helios desks across the music that was recorded through them, so I suppose there is a sound. Distortion ("sizzle") from discrete components I guess is what it is. The edge of headroom being pushed.

From my perspective, I personally like the fact that the Helios amps sound good (at least to my ears), are discrete and are simple to build.

PS. All the Cinemag and Sowter transformers I have used have been excellent. I frankly cannot say that a Sowter 7490 (or the like) is "better" than a Cinemag CMMI-10C (see above quote about not hearing much above 10k). The Sowter has a -20dB tap which is true to the Lustraphone (I also note that "apparently" the Tony Arnold Sowter input transformer was not quite the same as the 7490). Both the Cinemag and Sowter work well in the Helios type circuits that I have employed them in. I have never used a Beyer transformer.  Cyril Jones also wound a transformer that was highly rated. I have used a Jensen 1:10 quite happily.
PPPS. If you wanted to dive in, you could always argue about how much better Led Zeppelin would have sounded (or not) if they had been recorded by Alan Parsons at Abbey Road?

 

[Winston OBoogie]

  All the Cinemag and Sowter transformers I have used have been excellent. I frankly cannot say that a Sowter 7490 (or the like) is "better" than a Cinemag CMMI-10C 

The Cinemag CMMI-10C is an excellent transformer for Helios mic amps.  At least, that's my personal opinion after comparing directly against the original Lustraphone.  Someone should convince Cinemag to also include that  winding and tap for line input and then it would be a fantastic choice. 

When I had a chance to look over a few of the modules involved in that listening test above, I didn't see how anything conclusive could have been gleaned tbh.  Some modules had been racked up with correct power supply rails and output buffers, some hadn't.
 




 

 

[Whoops]

If you wanted to dive in, you could always argue about how much better Led Zeppelin would have sounded (or not) if they had been recorded by Alan Parsons at Abbey Road?

I got horrified thinking about that, almost gave me an headache that possibility.
I would go for the "or not",

"You could always argue about how much worse Led Zeppelin would have sounded if they had been recorded by Alan Parsons at Abbey Road , instead of being recorded through Helios consoles with Glyn Johns, Eddie Kramer and Andy Johns?"

 

[Winston OBoogie]

All agreed the Cinemag output transformerd was the way to go for individual Mic preamps/eq's. Tony built a buffer to increase headroom.

Yep, those Cinemag outputs are nice 
I posted a schematic of a simple high current buffer that was used on some modules that came from Lenny Kravitz's stash of Helios (I think it's posted in the main Helios thread on here).  Use that, or something like it, to drive a Cinemag strapped 150:600 and you're golden. 

 

[Whoops]

Yep, those Cinemag outputs are nice 
I posted a schematic of a simple high current buffer that was used on some modules that came from Lenny Kravitz's stash of Helios (I think it's in the main Helios thread on here).  Use that, or sometime like it, to drive a Cinemag strapped 150:600 and you're golden.

The circuit you posted is quite nice and a really good solution to have a balanced transformer output.
I have some boards for the amps, and the 2x lustraphone clone transformers from Cyril I want to build this for a long a time, but been busy as hell in the last 2 years.
I would like to try the circuit you posted with the Cinemag output on future my build.

Thank you so much for sharing that circuit and for all the valuable info you share

 

[Whoops]

pahstah,
I found in my Helios docs, some EQ curves drawing , maybe it can be of some help in finding the proper Q

 

[Winston OBoogie]

The circuit you posted is quite nice and a really good solution to have a balanced transformer output.
I have some boards for the amps, and the 2x lustraphone clone transformers from Cyril I want to build this for a long a time, but been busy as hell in the last 2 years.
I would like to try the circuit you posted with the Cinemag output on future my build.

Thank you so much for sharing that circuit and for all the valuable info you share

Nice.  You have most of the stuff already in place then for when you have time 

Thanks for posting the curves,  very useful

 

[Rocinante]

As an aside, I have read a lot of Tony Arnold's posts over various fora and he always came across as a bit prickly. Seemed to me like he would be a hard character to like (if you didn't know him personally and only had a web presence to judge). I really believe he tried his best to be true to Swettenham's initial silicon based designs.

I can say that my discussions with Tony via email weren't very productive once he realised I wasn't going to purchase anything.

 

[TwentyTrees]

Just to confirm my continued interest in this project.  ;D

 

[pahstah]

I've sent the version 4  gerbers  to the pcbs shop last week, they should be here by the end of the week

 

[iprovlek]

Great Pahstah!!!

thumb....

Hardly wait....

 

[TwentyTrees]

Thanks very much for the update!

 

[rachansky]

Getting exciting now 

 

[pahstah]

this version uses vtb9042 inductor for mid band frequencies. in the former version i used vtb9047 but it lacked a 100mH tap, so i tried a version with a 100mH inductor added to the vtb9047 but it added a weird noise when switched in, so i decided to go with the right inductor. this involved redesign the board to make space to the new inductor wich is bigger than the former, and redesign the 2128 amp making it smaller. so i hope this next version is the final one.

 

[Winston OBoogie]

this version uses vtb9042 inductor for mid band frequencies...
... i hope this next version is the final one.

Great stuff Paulo, you're on the home stretch.
Off topic:  IS that one of the newer API 1608 desks that you have?   

 

[pahstah]

Off topic:  IS that one of the newer API 1608 desks that you have? 

if you mean the one you see in the picture, that is a legacy one. but I guess that the new one has little changes from the former

 

[Winston OBoogie]

if you mean the one you see in the picture, that is a legacy one. but I guess that the new one has little changes from the former

Yes, I meant the desk shown on the first page.  Nice one. 
A row of Helios in that "penthouse" section would be fantastic 

 

[pahstah]

Yes, I meant the desk shown on the first page.  Nice one. 
A row of Helios in that "penthouse" section would be fantastic 

that's for sure!
but my secret dream is to build an helios mixer... maybe someday

 

[TwentyTrees]

that's for sure!
but my secret dream is to build an helios mixer... maybe someday

Yeah, I hear you! Eight Type 69s in a Cranborne 500R8 would make a pretty great studio centrepiece and portable tracking rig...