Slow Blow pre?

[peterc]

geez, just what we need. another arrogant 'designer' and a small group of flunkies hanging on his every word. i think ive seen this before. lol

Nassstyyyy!!! :razz:

Peter

 

[Bluzzi]

I want to built a 2 chanel unit. Then I will have multiple orgasms! :grin:

jim

 

[Flatpicker]

[quote author="Bluzzi"]I want to built a 2 chanel unit...[/quote]Me too!

We need to nail down a transformer configuration using available components. I?m guessing it could be similar to the one used in the G9? Or, would it be more feasible to get a group buy together for a custom toroidal with all the correct voltages?

Next we need to nail down some type of standard BOM with each part sourced for those of us on both sides of the pond. The more consistent we are, the easier it will be to address and troubleshoot problems.

 

[Bluzzi]

Flatpicker, maybe it would be easier to use 2 or 3 transformers instead of trying to locate one with 3 voltages.

Also selecting input transformers will be interesting.

I have 2 other double projects unfinished so I am not in a hurry for this one. Which is good as I'd like to see us all put together a well documented project (BOM, Layout etc).


jim

 

[sismofyt]

[quote author="FotisGR"]Just tell me your experience with 12sn7 tubes. I have only some RCA tubes . Did you tried some of these babies? [/quote]

hey fotis, i prefer old stock tubes, RCA, Sylvania etc. they are lots of them out there, cheap too. don't like Sovtek, re-branded Groove Tubes and the likes. they're overpriced and / or unreliable

 

[sismofyt]

[quote author="FotisGR"]Yesterday i change my favorite mullard with a TFK ecc82. It's unbeleivable :shock:
Some friends found them on a ham festival in Germany for 7Euros each absolutely nos. [/quote]

unbelievably expensive, but you got lucky i guess. i have no love for those tubes

 

[sismofyt]

[quote author="DaxLiniere"]I take it you are saying you like those tubes.
Hmmm.... discrepancies amongst members - that's a first! :grin:[/quote]

there are no rules, just preferences and personal taste

 

[sismofyt]

[quote author="solder_city"]geez, just what we need. another arrogant 'designer' and a small group of flunkies hanging on his every word. i think ive seen this before. lol[/quote]

arrogance is my middle name and i feed of groupies. come join my cult

lol. indeed

kiss & hugs,

grandmaster slowblow

 

[sismofyt]

[quote author="Flatpicker"]We need to nail down a transformer configuration using available components. I?m guessing it could be similar to the one used in the G9? Or, would it be more feasible to get a group buy together for a custom toroidal with all the correct voltages?

Next we need to nail down some type of standard BOM with each part sourced for those of us on both sides of the pond. The more consistent we are, the easier it will be to address and troubleshoot problems.[/quote]

it's not that expensive to get a custom trannie done. i don't pay more than off the shelf types. it would surely be more expensive to use multiple trannies. fotis offer is good and cheap, i'd recommend that

i won't make a BOM as such, because you cannot get all the parts in one place. also i haven't seen to pres using the same parts, people have a tendency to use whatever they have / can get

but anyway, it's so bloody simple that i think a BOM is not neccesary

and there shouldn't be any problems to troubleshoot :wink:

 

[sismofyt]

[quote author="Bluzzi"]Flatpicker, maybe it would be easier to use 2 or 3 transformers instead of trying to locate one with 3 voltages.

Also selecting input transformers will be interesting.

I have 2 other double projects unfinished so I am not in a hurry for this one. Which is good as I'd like to see us all put together a well documented project (BOM, Layout etc). [/quote]

use one powertrannie. yes, the selection of the mic trannie is indeed interesting. the pre will take anything really. jazzy put in two different ones, switchable too. neat

layout? i do not recommend making a pcb. it seem to be all the rage here, so go ahead. i have a lot of pictures of various slowblos and i think they say more than owrds. i'll put them up in short while at sismofyt dot net along with all the documentation i got

good enough?

 

[DaxLiniere]

Good enough? I think it's great! thanks again!!


Your loyal sycophant,
Dax.

 

[sismofyt]

[quote author="Flundran"]It would be neat to find a transformer with all three voltages needed in the PSU. I read from an old thread someone suggested the TRA200 from this company:
http://die-wuestens.de/

sec 230V 0,12A ; 20V 0.12A; 6,3V 4A.

And then use a voltage doubler for 48V and running the heaters on 6V. Is there any disadvantages with running heaters on 6V instead?

Another option is to have a transformer custom-made, but it?s pretty expensive I guess..[/quote]

i think using 6V heaters is the very best option. however, the current demands doubles (almost 2,5A) which means that the heater Vreg needs to be re-designed. the reason i like 6V instead is that there are SO MANY really nice octal tubes, like the 6J5G and the 2C22 which are killer. and they're cheap. often cheaper than the 12SN7

the 2C22 is my favourite baby

group, say hi to 2C22 ....

that power trannie would do ok. just voltage double the 20V. still think fotis' offer is better though

 

[sismofyt]

[quote author="DaxLiniere"]I think it's great! thanks again!!


Your loyal sycophant,
Dax.[/quote]

no problem. membership is up this month. i need three virgins and a book of manley schematics this time

 

[Bluzzi]

sysmofit - thanks for all the help you are giving us.

Isn't fotis's PT for 220vac primary only? If not then yes that would be the best solution for us 110 volters.

The layout would be great for some like me that don't know enough to alter a design or substitute parts (I can do that to a certain extent).
Same for the layout. Its just a security blanket for me!

Deciding on a PT for 110v would be a start. If its fotis's all the better.

jim

 

[sismofyt]

it's sismofyt, please

yeah, i do believe it's a 230VAC trannie, but maybe a dual 115VAC version could be made instead?

i will make enough notes, suggestions etc so part swapping will be a bliss. i hope i'll find some time next week to wrap it up

 

[Bluzzi]

err.....I meant sismofyt sorry.

See that's why I need the layout!

jim

 

[rafafredd]

It´s great to see sismofyt posting again. :thumb:

 

[FotisGR]

Hi rafafredd i am happy to meet you again.
I just received an email form sismofyt about the main transformers.
So, the transformer that i use for 2 channel slwblow was 150VA. I think that reducing it will be less heavy for shipping cost, more cheap and enough for more people.

My cousin (the producer) can made main trafos for slowblow or everything you need with 230V or 110V primary.
The price for 80VA toroid multivaltage (230VAC , 48VAC and 12VAC) will be 35Euros and the shipping cost for europe is about 10-15 euros.
The chokes are 10H/150mA - 65Ohm toroid and the price is 25 Euros each.
These are what i use on the pictures of my project except the power trannie that is 150VA version (45Euros). http://www.qsl.net/sv3eao/Micpre/123_2371.jpg


I think that are good news :thumb:

Cheers
fotis

 

[Kingston]

If I may suggest,

Welter makes cheap but very high quality transformers for us europeans at least.

Have a look at this site. I'm sure there are others as well.

http://rpm.fi/

 

[FotisGR]

Welter makes cheap but very high quality transformers for us europeans at least

They look like good but the prices are high. 46E for a small chock(dr3) and main trafo from 54E without VAT is not a cheep one :grin: