Helios thread

[ruffrecords]

[quote author="Wonderlandaudio"]IMHO 40 quid for an inductor is far more than a little expensive...[/quote]
Depends. You pay that much for an input transformer and the materials cost is much the same. The big inductor in the Helios is 10H which is one hell of a lot of wire. However, I do agree it should be possible to obtain good quality inductors more cheaply.

Ian

 

[ruffrecords]

[quote author="enthalpystudios"]especially for one of those little tiny inductors.[/quote]
I wouldn't call them tiny. 10H is large by anyone's standards and it might well be a good idea to find a group buy source for this. The other inductor is a few hundred milliHenries so it should be practical to wind them ourselves.

Ian

 

[lotus]

BUMP

 

[enthalpystudios]

well, if i can be of any help, i have a lustraphone version mic/eq module here that i'm racking up for a buddy of mine... a very lucky buddy of mine ;]

its got the back to back turretboards right behind the switches, and the lustraphone next to it. behind those there are two 8way (i believe, not sure off hand) edge connectors on top one another, and two plug in cards, one is a 'line amp' and one is something else......

anyway, if this is something close to the modules that we're talking about working with, and if anyone is into the idea of original circuit layouts, one thing i could certainly do to help is run them on the scanner, or certainly doublecheck anything. most parts look original, but an iron has definitely been in here and melted a little blue plastic off an elma.

 

[Guest]

[quote author="enthalpystudios"]well, if i can be of any help, i have a lustraphone version mic/eq module here that i'm racking up for a buddy of mine... a very lucky buddy of mine ;]

its got the back to back turretboards right behind the switches, and the lustraphone next to it. behind those there are two 8way (i believe, not sure off hand) edge connectors on top one another, and two plug in cards, one is a 'line amp' and one is something else......

anyway, if this is something close to the modules that we're talking about working with, and if anyone is into the idea of original circuit layouts, one thing i could certainly do to help is run them on the scanner, or certainly doublecheck anything. most parts look original, but an iron has definitely been in here and melted a little blue plastic off an elma.[/quote]
I know exactly what you are talking about because I have seen that module (see this post http://www.groupdiy.com/index.php?topic=193030&highlight=interstage#193030)
Call Cyril and ask him.. (nicely)

 

[enthalpystudios]

well i guess what i'm trying to say is that with the sowter (close enough for me) transformers, it would be a lot of fun to think up a clever way to make these diy-able...

i have only a couple hand drawn schematics, and i have to double check, but i'm not exactly sure which model this one is, or if its anything like the one people here are interested in building, but i'd certainly be happy to double check things to help with component identification and schematic interpretation and what not. anyway, i feel like it could be a fun little project.... i was also thinking about boards, and think that the layout of this module and others like it is quite a neat layout... from my measurements, and again, i'm not sure if something like this is possible or just better left to offboard elmas, but i wonder if a doublesided board could use pc mount grayhills alternating on either side of the board. makes it easier to do the LF freq switch as well.

i really need to start with a simple pcb layout and just start trying to do it rather than talk up ideas that i'm not actually working on....

anyway, i'm not sure what the best way to proceed would be. Also, I suppose that with offboard switches, those who might want to just make a rackmount unit could do so rather than going with little modules.

also, i don't see an output transformer on this one, unless i'm totally mistaken, i just have a small iron core inductor, a large, black encased inductor, and the large lustraphone.

did these have output transformers, or was that left up to different places down the signal chain?

 

[ruffrecords]

[quote author="enthalpystudios"]i have only a couple hand drawn schematics, and i have to double check, but i'm not exactly sure which model this one is, or if its anything like the one people here are interested in building, but i'd certainly be happy to double check things to help with component identification and schematic interpretation and what not. [/quote]
That would be cool. I would really like to see some close up pics of this.

did these have output transformers, or was that left up to different places down the signal chain?

No they didn't, as you correctly surmise, they were further down the chain - basically at the final output - Helios inserts were unbalanced.

Ian

 

[enthalpystudios]

excellent... good to know about the output transformers. i also like, in general, the idea that not everything has to be balanced. these days its always balanced this, balanced that, but for most peoples setups, who cares. i have all kinds of unbalanced stuff that has no real troubles.

anyway, do let me know whatever you need, and my roommate has an excellent camera that i can use when hes around, so no problems.

 

[Lindell]

Found some pix:

 

[Wonderlandaudio]

The Clapton´s console original ( click to enlarge )

 

[CJ]

the coil is in thaty silver can, middle bottom?

 

[Sonic Screwdriver]

[quote author="CJ"]the coil is in thaty silver can, middle bottom?[/quote]

That is the input transformer I would guess? The EQ coils being located vertically and to the right

Thanks for posting the pics BTW

regards

David

 

[mrcalrec]

Do not buy anything from Wonderlandaudio - Pedro Rodriguez. I think he is a scam artist. I bought a Neve 2254A from him through Ebay and paid through paypal on May 23rd - $2000 US. I have not heard a peep since. He was very responsive prior to the sale. One he received my money - nothing. I have sent at least 50 emails - no response. I know other who have been ripped off as well.

 

[rotheu]

Hi everybody,

Just built helios 69 prototype, but having some problems. It has strange frequency responce.The famous 100Hz bump is not bell shaped. It's a low shelf which starts at about 110-120Hz and at the end of the spectrum I get 6dB of boost (20Hz). It's happening in the amp, not the filter. Right now i have only the filter and gain make up amp. I can imagine another amp on the input will give double boost. Also the headroom is low. I get some crazy distortion(sounds great though :twisted: ). I reversed transistors and caps polarity and used +24 PSU. Any ideas? Thanks.

 

[khstudio]

[quote author="mrcalrec"]Do not buy anything from Wonderlandaudio - Pedro Rodriguez. I think he is a scam artist. I bought a Neve 2254A from him through Ebay and paid through paypal on May 23rd - $2000 US. I have not heard a peep since. He was very responsive prior to the sale. One he received my money - nothing. I have sent at least 50 emails - no response. I know other who have been ripped off as well.[/quote]

That sucks

I don't want to get involved here but I've heard bad things about that guy for a LONG time.

The MODERATOR of this forum should be notified to keep an eye on things. :wink:
This is a forum of trust.

 

[rotheu]

Is there any way to make the through cut of the mid section in the filter wider. More of a regular dip instead of notch? I tried adding resistance but it doesn't make it wider, just cuts less. The Q stays almost the same. Thanks.

 

[rotheu]

BTW , fixed the problem I was having before with the amp.

 

[lotus]

so how does it sound? what input transformer did you use? have you implemented a output transformer?

 

[rotheu]

[so how does it sound? what input transformer did you use? have you implemented a output transformer?]

The micpre sounds really good. Didn't do real life tests yet, just some speach and run few prerecorded tracks through it. Sounds very open, natural and punchy. I've used Jensen 10KB-D 10K/600 step-down line input xformer reversed, 1/4, which gives about 12dB of gain (instead of 20dB with the original 1/10). I also added direct coupled two transistor output driver and Edcor WSM 600/600 xformer. Still messing with EQ. Tried using small audio transformers from mouser suggested by NewYorkDave as inductors. Inductance values are good, but the problem is self-resonance. When used in low boost circuit, along with boosting the lows it is boosting high shelf by the same amount and I endup having a wide Q dip at around 1K. Same with highs. Edcor WSM 10K/10K works great for low boost though, unfortunatly it's 5 times more expensive ( I'm planning on building 16 channel mixer with this modules).[/quote]

 

[rotheu]

so how does it sound? what input transformer did you use? have you implemented a output transformer?

The micpre sounds really good. Didn't do real life tests yet, just some speach and run few prerecorded tracks through it. Sounds very open, natural and punchy. I've used Jensen 10KB-D 10K/600 step-down line input xformer reversed, 1/4, which gives about 12dB of gain (instead of 20dB with the original 1/10). I also added direct coupled two transistor output driver and Edcor WSM 600/600 xformer. Still messing with EQ. Tried using small audio transformers from mouser suggested by NewYorkDave as inductors. Inductance values are good, but the problem is self-resonance. When used in low boost circuit, along with boosting the lows it is boosting high shelf by the same amount and I endup having a wide Q dip at around 1K. Same with highs. Edcor WSM 10K/10K works great for low boost though, unfortunatly it's 5 times more expensive ( I'm planning on building 16 channel mixer with this modules).[/quote]