Slow Blow pre?

[Bluzzi]

Fotis: On your power supply schematic you have 470uf/400v and I have a BOM listing 4700uf/400v.

I am assuming 470uf is correct? If so, then that saves a lot of $$$$ compared to the BOM I have. I'm compiling a BOM for the PS right now.

Jim

 

[Bluzzi]

michal_k : As you see there are many BOMs and schematics floating around for this project.

I am starting to look at Fotis' Power Supply and I am compiling a BOM for it. If anyone wants it let me know.

Jim

 

[Bluzzi]

Dax:

That is really interesting! I agree with you on caps at input and output. Solen is in Montreal actually and I can try and see if we can get some sort of deal (if any values come up theirs).

I have the Fotis schematic for the Power Supply. That is the one I am basing my project on. I asked Fotis for permission to post but I believe that he has it posted earlier on this thread anyway so if I don't hear from him I'll have it available on an FTP site specifically for this project. I can make it available to everyone here.

I think if we can all settle on a PS design things will seem more stable. For me it i still a bit confusing as I am not an engineer. I just use what experience and little knowledge I have as well as common sense and my ears.

I also like the idea to have a shield cage. Myself I just want a dual channel unit so the 48v and 12v heater current is adequate.

Jim

 

[michal_k]

I'd love to have a final version of schematics, please send me them via email: mkali [at] student [dot] agh [dot] edu [dot] pl

cheers,
m.

edit: tommorow i'll see if I can get a good deal on chokes. it's 4am in here, time to go to bed.

 

[Bluzzi]

michal, if its no problem I will post on an FTP site. I'll post the link here for all.

By the way the caps on the schematic are 470uf not 4700uf! The BOM I had had that typo.

Jim

 

[Bluzzi]

Sorry to be posting so much guys. I'm excited what can I say.

FTP is up. few things in there for now. I'll add as we progress.

http://www.circlesound.ca/diy

user & password are slowblow

The psu files you will note are slightly different. which one is THE one?

Jim

 

[michal_k]

got the reply from trafo company, they want 30eu for "audio" version of that transformer. -3% for 10pcs, -12% for 50+
I should know something more about choke this evening.

Thanks for the schematics 

 

[pyjaman]

Hi,
cool to see this project coming back!

i built a total of 5 units.
2 classic slowblows using ll1538xl, 2 of another version using 12sx7 and 6n6p, input tx is oep. they are in a 3U case with external psu. at the moment they are still in a provisory case but the frontplates are near completion. see attached pic.

the last one has 2 6sn7 SE stages (i can switch off one of the stages for less gain) into one 6n6p srrp.

i love all of them.

peace

christian

Hello Christian, Since I have been collecting part myself for months to build a 6N8S (6sn7) and 6N6P version of the slowblow, could you tell me what B+ and resistors values did you use for the 6n6p SRPP stage? how does it sound compared to the "classic" version ? and what about the double 6sn7 SE stage ?
thanks.

Laurent.

 

[mikeyB]

Hey Guys - ask FotisGR if he can supply the iron for the psu - I think he has relative (bro-in-lo or sumthink) that manufactures - seem to recall power transformer for €45 and chokes for €25 each - yep - just check back on page 3 of this topic - prices I would expect to be slightly more if he can still get them done for us!!

 

[sismofyt]

I'm open to all suggestions but I think we should listen to the guys that have built some of these already.

i've build a few ;D

 

[skipwave]

I'm open to all suggestions but I think we should listen to the guys that have built some of these already.

i've build a few ;D

You crack me up, dude.  ;D

Is your website still up? I remember cool photographs.

 

[Bluzzi]

Stop rubbing it in!  ;D
You started all this! Shame on you!

I see that you have been busy with some organic type of DIY. I have a few of those builds too. Watch out they get out of hand as they age!

Jim

I'm open to all suggestions but I think we should listen to the guys that have built some of these already.

i've build a few ;D

 

[peterc]

The legend is lurking...... 8)

 

[penquista]

hello,

i will soon take some pics of the wiring and have a look at the resistor values i used. if i remember well b+ is 310V
i hope the drawing of the dual se stage i use is readable. with the switch i bypass one of the stages.

christian

 

[pyjaman]

hello,

i will soon take some pics of the wiring and have a look at the resistor values i used. if i remember well b+ is 310V
i hope the drawing of the dual se stage i use is readable. with the switch i bypass one of the stages.

christian

Yes, thank you Christian, I'd really appreciate, as for the sound off the 6n6p relative to 5687. Your drawing shows the switches that disconnect the first stage, but not how you then connect second stage to input. (not a problem for me as I already have my idea on this). Note that the two gain settings (with and without first stage) are phase reversed...

Laurent.

 

[Bluzzi]

Shouldn't we be trying to establish 1 power supply design that will work for all the variations first before going into the amp stage discussions?

My intention is to establish a set of schematics and BOMs for everyone. I don't know about the rest of you but I have so many different versions I wouldn't know where to begin. That's why I posted the power supply schematics on the ftp site (url etc. previously posted). There's 2 that I found and slightly different.

Anyone check them out? Your thoughts?


Jim

 

[michal_k]

I'm gonna try to simulate'em in PSPICE next week, but I believe that all of them will be fine. I'll also try to desing(copy ) a regulated PS, just for comparision and more flexibility. Now I'm busy with my university stuff so no time for slow-blow pre.
I'm still waiting for the choke price, anyone knows if FotisGR still provides them? If so I don't need to look for iron supply anymore.
Any of you thinks that 200mA for a b+ is a bit overkill? It significantly raises a price of choke and, come on, it's just tubes. I'll also try to calculate biases for them to verify if we need so much current.
If one of you can do any of this erlier than next week then you're welcome  ;D

 

[Bluzzi]

Do you mean by "all of them" the power supplies I posted?

I'm also having a hard time finding the chokes at less than ($70CDN Hammond).

Jim

I'm gonna try to simulate'em in PSPICE next week, but I believe that all of them will be fine. I'll also try to desing(copy ) a regulated PS, just for comparision and more flexibility. Now I'm busy with my university stuff so no time for slow-blow pre.
I'm still waiting for the choke price, anyone knows if FotisGR still provides them? If so I don't need to look for iron supply anymore.
Any of you thinks that 200mA for a b+ is a bit overkill? It significantly raises a price of choke and, come on, it's just tubes. I'll also try to calculate biases for them to verify if we need so much current.
If one of you can do any of this erlier than next week then you're welcome  ;D

 

[sismofyt]

i don't have time to comment / upload schematics until the end of this week. patience, ok?

cheers,

ole

 

[michal_k]

well, I don't see any difference in your PSU schematics. I didn't look careful though. Here's a simpler PSU I found that I believe will do just fine.

i also think it's worth waiting for sismofyt's verified schematics. I'm interested in 6sn7 version cause I like this tubes.

one more thing: are we doing this PTP or someone designs PCB?