Help with custom electronic project...

  • Thread starter Thread starter peritus
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peritus

peritus

The not fountain head
I am an avid thrift shopper / garage saler... Anywho...

Might have posted about this here before... Either way, some things have changed...

I'm now in possesion of two nearly identical 1963ish consumer reel to reels, both with lots of tubes...

The first one I got was a Voice of Music ($15) and the other a Philco (FREE).... I'll try to get some pics up, but trust me, the Philco is just a repackaged VM (see their website for details)...

What I want to do is rackmount the microphone preamp stages... I know this is butchering vintage equipment. So here are my reasons....

Ever try to lug one of these things around? Ugh!

No XLR, currently... Only 1/4" TS plugs...

I have two.. One whose transport is not functional (vm) and one that works pretty well (philco)... If it works on the broken one and sounds good, I might go for two channels of preamp (in separate boxes, of course)... Not that I expect them to sound identical...

Motor noise... Yeah... I seriously think this is a factor....

Heat... Again.. A factor... The current cooling/venting is totally uncool...

Controls/etc..... I would like to use better pots and such on the rack model....

Power cord... It would be cool to use a IEC power cord (sheilding, durability).. Although I'm not too sure about the grounding situation, at this point...

Tube accessibility..... Ever try dismantling one of these deals?... Very annoying to do over and over...

Cool factor... Yup.. I'm a sucker for having a one off piece of gear...

Learning... I wanna learn about this stuff!!! I see cool tube stufff more often than I am in a position to purchase... It would be nice to get closer to being able to diagnose such pieces without worrying if I'll end up with a pile of rubbish, by chance... Not to mention the desire to someday construct my own design...

I have so many old consumer reel to reels that I want to start doing something cool with 'em... Can't imagine that the result will be glamorous.. Bet it'd be cool though!

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So anyway... I have the schematics for the "broken" one at home... I'll scan them and post them up here later today or tomorrow, sometime...

Just let me know if you have any idea of how I could bring the plan to fruition... :)


P.S. Any forseeable problems with adding a switch for impedance matching? Hi/Lo
 
Perhaps the learned folks at homerec will be able to help you out, I know there are a few electronics guys who hang out here.

If not try asking at this forum:

Group DIY forums

Lots of very cool and knowledgable people who are into doing exactly what it is you're wanting to do.

I'm getting parts together for a 2 channel tube pre at the moment:

http://www.gyraf.dk/gy_pd/g9/g9pd.htm
 
Kevin DeSchwazi said:
Perhaps the learned folks at homerec will be able to help you out, I know there are a few electronics guys who hang out here.

If not try asking at this forum:

Group DIY forums

Lots of very cool and knowledgable people who are into doing exactly what it is you're wanting to do.

I'm getting parts together for a 2 channel tube pre at the moment:

http://www.gyraf.dk/gy_pd/g9/g9pd.htm
Click to expand...

Sounds good... Thanks and good luck.... :)
 
Not sure why I ventured into this forum (maybe the 'most recent post' name intrigued me!), but for circuit advice and other info about restoring these (safely) go to http://www.vintage-radio.com (for component/safety info) and http://www.vintage-radio.net (discussion forums).

They're pretty much into restoring stuff as opposed to modifying it, but some of the guys over there are making their own valve/tube based stuff.

The other option is to go to the analogue forum here and check our Dr Zee's Ampex and other projects, he could probably give you some pointers.
 
arjoll said:
Not sure why I ventured into this forum (maybe the 'most recent post' name intrigued me!), but for circuit advice and other info about restoring these (safely) go to http://www.vintage-radio.com (for component/safety info) and http://www.vintage-radio.net (discussion forums).

They're pretty much into restoring stuff as opposed to modifying it, but some of the guys over there are making their own valve/tube based stuff.

The other option is to go to the analogue forum here and check our Dr Zee's Ampex and other projects, he could probably give you some pointers.
Click to expand...

Will definately look into it... Thanks
 
peritus said:
Nevermind.. Answered my own question...

http://www.prodigy-pro.com/forum/viewtopic.php?t=14734

Very tempting project... I wonder how it would compare to an Avalon or something (I'm high end shy.. ;) )....
Click to expand...
I'll answer anyway.

My BOM is valued at around £280 (a bit over $500) but I'm using all high quality components. The in/out trannies are OEP, the poly caps are WIMA and Phillips, Neutrik connectors, Lorlin switches etc. I've budgeted £40 for the 4 tubes. I'm on the look out for Mullards but I'll probably end up buying quite a few different ones and seeing which ones I like best.

So it's not exactly cheap but to buy the same box ready built by Jakob would cost over £1,000 (just shy of $2,000).

People speak VERY highly of how the pre sounds, Jakob reckons an engineer sold his Fearn when he heard the G9 but I take stuff like that with a LARGE grain of salt. :D I'm confident the pre will sound great though.

I'm building a 2 channel transformerless, tubeless pre as well; an IC opamp design based on the pres in the Amek Mozart console but I'm having some problems getting that going. The G9 is a much easier build though.

You learn a lot by sourcing your own parts but there are a couple of good kits available if you want to ease yourself in a bit more. Hamptone does a tube and a JFET pre kit which have a great rep and JLM in Australia sell some good kits as well.

The guys that run both of those companies hang out at group DIY as well so they're always on hand to troubleshoot and answer questions.

Yeah it's good fun for sure and you can end up with some cool sounding gear which is a bonus!
 
Kevin DeSchwazi said:
I'll answer anyway.
Click to expand...

Cool....

I wonder if I could find the parts locally.... We have two MAJOR electronics players, here: Mendelson's (lots of new old stock) and PartsExpress (mail order).... I'm almost positive that Mendelsons would have most everything I'd need.. Problem is that the store is of the "surplus" variety and I don't know that I'm experienced enough to source the parts by hand....

Are you etching your own boards?... I'm very reluctant to go down that road.... Seems like something I shouldn't just jump into head first... Not mention probably being expensive for start-up costs....

I guess I could go kit, but I'm the type of person to only be able to afford a little at a time :(....

Maybe I can go hang out at Mendelson's and ask some questions... First thing I'd look for, I think, would be the transformers.... Hmmm.. :o
 
None of the parts are hard to source for the G9. There's a good US BOM here:

http://members.cox.net/skylargray/G9partsMar-04-2006.xls

I'd like to get into etching my own boards but for existing projects you can get them ready made from a couple of the guys at Group Diy. They're pretty cheap and very well made too (silver tabs which make soldering really easy, ready drilled, silk screen etc.), much better than what i could make. I paid €25 ($30) for a G9 board.

Check this thread:

http://www.prodigy-pro.com/forum/viewtopic.php?t=10776

"I guess I could go kit, but I'm the type of person to only be able to afford a little at a time :(...."

That's the great thing about DIY, it's pretty ulikely I'd be able to blow £300 on a preamp in one go but I've just been getting a few bits at a time over the last few months.

I think I have roughly 2/3 of what I need, I got the board and that's pretty much stuffed with all the poly caps, resistors, diodes etc. Got a 2U case, switches, knobs etc.

I just need the trannies, tubes and toroids for the power supply plus a few other bits like the electrolyitc caps and some big 2 watt resistors. And the front panel. So I should have all the parts within the next month or so.
 
Right on.. I got the list printed and am going over it... I'll probably be placing an order with Gustav in the next few days (WOW THATS CHEAP)... Is that the guy you went with?

Thanks....
 
peritus said:
Right on.. I got the list printed and am going over it... I'll probably be placing an order with Gustav in the next few days (WOW THATS CHEAP)... Is that the guy you went with?

Thanks....
Click to expand...
Yup, Gustav is top notch. I think he works in a PCB factory and uses the equipment in his own time to make the boards, so the results are very professional.

I don't think he makes much money from doing it either, if any at all.
 
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