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amp as in ZTX214
Help Support GroupDIY Audio Forum:
ruffrecords
Well-known member
[quote author="uk03878"]amp as in ZTX214[/quote]
Oh, I see, you mean the transistor itself. Do you have any left?
Ian
Oh, I see, you mean the transistor itself. Do you have any left?
Ian
ask
Well-known member
bump :roll:
Just wondering, and hoping for a successfull DIY "Helium"
Just wondering, and hoping for a successfull DIY "Helium"
ask
Well-known member
Am I right in tkinking that the line in goes straight to the amp, bypassing the tranny?
ruffrecords
Well-known member
[quote author="ask"]Am I right in tkinking that the line in goes straight to the amp, bypassing the tranny?[/quote]
Generally yes, and certainly in the 69. I think as a rule Helios consoles just had transformers at the mic input and the main outputs. Inserts were generally unbalanced.
Ian
Generally yes, and certainly in the 69. I think as a rule Helios consoles just had transformers at the mic input and the main outputs. Inserts were generally unbalanced.
Ian
Wonderlandaudio
Well-known member
In those days,Line input actually meant MIX mode, so those line ins were actually tape returns. Xformers were in groups of 8 inside the console.
Anyway, talking about vintage Helios consoles means no rule applies. Not 2 consoles are the same, not even close.
Anyway, talking about vintage Helios consoles means no rule applies. Not 2 consoles are the same, not even close.
enthalpystudios
Well-known member
had the wonderful experience of tracking some guitar thorugh a space eho, silvertone tube combo, rca ribbon, into a helio micpre/eq module the other day.
sounded phenomenal. i think we'll have to use that helios module again, and again, and again, and then use something else so it doesnt all sound like helios.
or maybe not.
sounded phenomenal. i think we'll have to use that helios module again, and again, and again, and then use something else so it doesnt all sound like helios.
or maybe not.
ruffrecords
Well-known member
[quote author="Wonderlandaudio"]In those days,Line input actually meant MIX mode, so those line ins were actually tape returns. Xformers were in groups of 8 inside the console.[/quote]
Interesting snippet. Do I take this to mean they did use transformers on line inputs but they were simply remote from the module? What transformer did they use?
Ian
Interesting snippet. Do I take this to mean they did use transformers on line inputs but they were simply remote from the module? What transformer did they use?
Ian
G
Guest
Guest
here's what I saw inside two Helios modules
http://www.groupdiy.com/index.php?topic=193030&highlight=interstage#193030
"A module from the FIRST Helios desk ever made
I spotted - Colvin Pots - the turret board with BIG mustard caps
Then - Veroboard/Stripboard
Lustraphone transformers and the inductor
Then he pulls out the module from the SECOND ever Helios desk
Now this one is quite different inside - two little RadioSpares (RS Components) Interstage transformer right behind the panel
"
http://www.groupdiy.com/index.php?topic=193030&highlight=interstage#193030
"A module from the FIRST Helios desk ever made
I spotted - Colvin Pots - the turret board with BIG mustard caps
Then - Veroboard/Stripboard
Lustraphone transformers and the inductor
Then he pulls out the module from the SECOND ever Helios desk
Now this one is quite different inside - two little RadioSpares (RS Components) Interstage transformer right behind the panel
"
enthalpystudios
Well-known member
quote from psw:
perhaps these are still available... anyone know? sowter 7490 also looks good, not sure which would be more.... lustraphoney
or if his transformers are the mic in with 1:1 tap, or if they are for eq's, line out or something.
it would be awesome to see this materialize however!
perhaps these are still available... anyone know? sowter 7490 also looks good, not sure which would be more.... lustraphoney
or if his transformers are the mic in with 1:1 tap, or if they are for eq's, line out or something.
it would be awesome to see this materialize however!
G
Guest
Guest
Lustraphones just happened to be what was on the shelf at the time these were built
They werent chosen specially
They werent chosen specially
Wonderlandaudio
Well-known member
[quote author="uk03878"]Lustraphones just happened to be what was on the shelf at the time these were built
They werent chosen specially[/quote]
MarinAir was chosen because the factory was close to Neve´s. Painton quadrant faders in EMI TG consoles were leftovers from the REDD consoles... the 2nd inductor in the 1073 midrange eq was a leftover used in lopass filters... I´ve noticed that all the things, or at least most of the things we love from old gear are either design errors, technical limitations of the time or mostly casualties...
They werent chosen specially[/quote]
MarinAir was chosen because the factory was close to Neve´s. Painton quadrant faders in EMI TG consoles were leftovers from the REDD consoles... the 2nd inductor in the 1073 midrange eq was a leftover used in lopass filters... I´ve noticed that all the things, or at least most of the things we love from old gear are either design errors, technical limitations of the time or mostly casualties...
enthalpystudios
Well-known member
yeah, so it needs to be exactly the same thing right? ;]
j/k... but seriously, i'd imagine that the sowter 7490 is a good solid transformer with the correct taps.
and thats about all you'd want out of a transformer i guess, in any case, is a well built transformer with the correct taps.
man, re reading this thread, a lot has been done! i wonder how much those elmas are. also wonder if there are any others that will fit. although i'm all up for going quality, even the elmas cost my right nut
j/k... but seriously, i'd imagine that the sowter 7490 is a good solid transformer with the correct taps.
and thats about all you'd want out of a transformer i guess, in any case, is a well built transformer with the correct taps.
man, re reading this thread, a lot has been done! i wonder how much those elmas are. also wonder if there are any others that will fit. although i'm all up for going quality, even the elmas cost my right nut
ruffrecords
Well-known member
[quote author="enthalpystudios"] i wonder how much those elmas are. also wonder if there are any others that will fit. although i'm all up for going quality, even the elmas cost my right nut[/quote]
I am currently investigating alternatives form Lorlin that are significantly cheaper. The only real downside seems to be they are rated for only 10,000 operations instead of 25,000 that the Elmas do. For DIY projects 10K should be more than sufficient and the prices are roughly in the same ratio too.
Ian
I am currently investigating alternatives form Lorlin that are significantly cheaper. The only real downside seems to be they are rated for only 10,000 operations instead of 25,000 that the Elmas do. For DIY projects 10K should be more than sufficient and the prices are roughly in the same ratio too.
Ian
enthalpystudios
Well-known member
cool man!
are they the size of the lorlins i'm used to? or smaller lorlins hopefully.....
are they the size of the lorlins i'm used to? or smaller lorlins hopefully.....
Wonderlandaudio
Well-known member
The difficult parts to clone the Helios would be basically both inductors, which I don´t know who made them or who makes the substitutes now. Definitely neither Sowter nor Carnhill. At the end of the day a rotary switch is a rotary switch, mechanically diying at 10000 op´s or 25000 will be dusty and scratchy earlier almost for sure.
And would be of help a correct schematic. Some of them out there aren´t. as some people have noticed yet.
And would be of help a correct schematic. Some of them out there aren´t. as some people have noticed yet.
ruffrecords
Well-known member
[quote author="enthalpystudios"]cool man!
are they the size of the lorlins i'm used to? or smaller lorlins hopefully.....[/quote]
Depends what you are used to. They have a PCB mounting model type PT. The most expensive switch to make is the 2 pole 10 way for the bass EQ control in the Hellios 69. Using the PT series you need a base 1 pole 12way switch, a 1pole 12 way wafer and a pair of spacers from the PT series, which totals about 7GBP before tax (from RadioSpares). These switches are about 32mm high
Lorlin also do an RA series, which according to their website 'A precision range of wafer switches for high quality instrumentation, the dual wiping contacts for each terminal ensure reliable low resistance contact. RA wafers can be stacked to provide numerous switching configuration'. These are a more conventional hard wired type of wafer switch and I expected them to be a lot more expensive. However, I have a preliminary quote from them for a two pole 10 way of 6.68GBP ex works but there is a minimum order quantity of 100 - way to much for me alone but a possibility for a group buy.
For the single pole switches, for the gain, treble and mid controls, Lorlin do a very small (TO5 sized) MT series which is less than 10mm in dia. RadioSpares are due to stock a limited range of these starting some time this month so I don't yet have prices.. The only downside of these parts so far is that their rated life is only 5000.
Lastly, for prototyping purposes I am messing around with some switch kits from RadioSpares (Part no 352-187) which are made by NSF in the UK. These have a really long rear shaft so I am going to try spacing wafers by the length of the capacitors on the bass control and wiring the caps between them. That way I can build a switch bass switch assembly which has just three flying leads. Building the bass switch this way does cost nearly 18GBP though. I'm thinking of a similar construction techniques for the single pole switches in the prototype which would then cost about 11GBP.
Ian
are they the size of the lorlins i'm used to? or smaller lorlins hopefully.....[/quote]
Depends what you are used to. They have a PCB mounting model type PT. The most expensive switch to make is the 2 pole 10 way for the bass EQ control in the Hellios 69. Using the PT series you need a base 1 pole 12way switch, a 1pole 12 way wafer and a pair of spacers from the PT series, which totals about 7GBP before tax (from RadioSpares). These switches are about 32mm high
Lorlin also do an RA series, which according to their website 'A precision range of wafer switches for high quality instrumentation, the dual wiping contacts for each terminal ensure reliable low resistance contact. RA wafers can be stacked to provide numerous switching configuration'. These are a more conventional hard wired type of wafer switch and I expected them to be a lot more expensive. However, I have a preliminary quote from them for a two pole 10 way of 6.68GBP ex works but there is a minimum order quantity of 100 - way to much for me alone but a possibility for a group buy.
For the single pole switches, for the gain, treble and mid controls, Lorlin do a very small (TO5 sized) MT series which is less than 10mm in dia. RadioSpares are due to stock a limited range of these starting some time this month so I don't yet have prices.. The only downside of these parts so far is that their rated life is only 5000.
Lastly, for prototyping purposes I am messing around with some switch kits from RadioSpares (Part no 352-187) which are made by NSF in the UK. These have a really long rear shaft so I am going to try spacing wafers by the length of the capacitors on the bass control and wiring the caps between them. That way I can build a switch bass switch assembly which has just three flying leads. Building the bass switch this way does cost nearly 18GBP though. I'm thinking of a similar construction techniques for the single pole switches in the prototype which would then cost about 11GBP.
Ian
ruffrecords
Well-known member
[quote author="Wonderlandaudio"]The difficult parts to clone the Helios would be basically both inductors, which I don´t know who made them or who makes the substitutes now. Definitely neither Sowter nor Carnhill.[/quote]
Sowter make any inductor you specify for the one off price of their standard ones (about 40GBP) but that is a little expensive IMHO. I have purchased some core and former kits from RadioSpares and plan to wind my own for a prototype. The bigger of the two (10H or 12H depending on who you believe) is going to be hardest to make - might be best to find someone who can make a batch for a reasonable price.
Ian
Sowter make any inductor you specify for the one off price of their standard ones (about 40GBP) but that is a little expensive IMHO. I have purchased some core and former kits from RadioSpares and plan to wind my own for a prototype. The bigger of the two (10H or 12H depending on who you believe) is going to be hardest to make - might be best to find someone who can make a batch for a reasonable price.
The main difference seems to be in contact material. The 10,000 life ones use silver whilst the 25000 ones use gold over silver. You also need to be careful how you define life. Most manufacturers define it as when the contact resistance reaches 10 times its initial value but even then it is only about 100 milliohms which is not going to affect circuit operation. The other thing to remember is that life is very dependent on the contact current and published life expectancy figures generaly assume currents of the order of tens of milliamps. Again, the currents in the Helios pre will be much lower so switch life should increase significantly.
Ian
Wonderlandaudio
Well-known member
IMHO 40 quid for an inductor is far more than a little expensive...
enthalpystudios
Well-known member
especially for one of those little tiny inductors.
buyt regarding the switches, those are the lorlins i'm used to... but i'm kind of going for small here, to fit a more or less standard sized module, so it may be elmas or grayhills for me, unless i can find a reasonable alternative.. i do have a bunch of small, 1/8" shaft, grayhill 2x12's that could work there however.
i plan on getting some frontpanel layout work done soon here, and will probably have them engraved locally, i'll post my findings if anything turns out.
buyt regarding the switches, those are the lorlins i'm used to... but i'm kind of going for small here, to fit a more or less standard sized module, so it may be elmas or grayhills for me, unless i can find a reasonable alternative.. i do have a bunch of small, 1/8" shaft, grayhill 2x12's that could work there however.
i plan on getting some frontpanel layout work done soon here, and will probably have them engraved locally, i'll post my findings if anything turns out.
