DIY Audio Projects Forum

Hi

Still not finish but i'm close. Pictures below of my hybrid nr. 2 ( the Rogers Gomez construction ). It's made out of an old serial switchbox-case. It'll be a gift to a friend, because i allready have an akkuversion of it.

The last thing i have to do, is to wire it up.



More pictures here: http://johnkramme.dk/hifi/gomezamp/

Regards from John Kramme

That's a cool tube socket mount you made there. Very tidy though I suppose that will change a bit when wired huh?

John,
No worries no one will ever think less of you. For others not familier with Tina, it will change the notation of values from 1000 uF to 1m. If you work on power amps you will see that they are rated in 1000uF or 10,000uF and so forth, not 1m and 10m. Just a little quirk Tina does.

Like the look of that amp so far

Rogers

That amplifier is going to be really compact, I'm guessing the power tranny will be outside the chassis though?

When I construct my amplifier I have a small Hammond enclosure that will hopefully be big enough to fit the whole power supply into.

_________________
My Mini 12AU7 Tube Preamp, Pioneer SX-D7000, JVC XL-V221BK, JBL L80T, DCM TF700

• Project Page - Mini 12AU7 Tube Preamplifier
• Support/Questions - Mini 12AU7 Tube Preamp thread

Thanks for the help + quick reply you guys are great!

Thanks Gio and Rogers

Regards from John Kramme

ok for my version of this I'm using IRF610's since digikey refused to sell me anything else.. and all I had on hand were 510's.

Roggom, (or anyone) 2 questions.. (maybe 3) ..;

- first, you mentioned "As far as output caps 440uF will put you where you want to be, you can bypass it with a poly film 1uF (red drop or orange drop) for better frequency response. Basically solder it in parallel to the electrolytic." whouldn't that just give me a 441uf cap.. but wait, the electrolytic is polarized and the other isn't so that'd give me.... a headache ... (can you explain how/why this works? or what i should read to figure it out for myself?)

- Second, hmm.. TINA, I've tried to get useful information from that.. most of the time i give up halfway into trying to build my circuit (I have a heck of a time trying to get TINA to use component values anywhere near what i actually have, guess i need more practice) do you still have the Tina model you made? if so, can you post or send me the file?

- third, where do you kids get your cute little orange caps? I've never seen 'em at the electronics shops I go to.. (tho I'm gonna drive up to Frye's this weekend and that may answer my question)

KrammeAcoustics, great idea to use a switch box case! I have a ton of those I stored away when they where surplussed by my workplace.. they just seemed like perfect project boxes to me too (basically just saying it was nice to see something i could relate to on this forum) besides, those parallel switches have gotta be useful for something I'm planning on using an apple cd300 case for this project because it already has 12V power-supply Stereo input jacks and a ground terminal, but.. I'll definitely be posting projects built in switchbox cases here in the near future too!

PS if anyone gets sick of hearing from me please just tell me, this forum's great, and i don't want to make it unpleasant for the regulars to visit

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- See what doomed project I'm working on now at http://oak1780.livejournal.com/

Hi oak

Great, diyaudioprojects.com has a lot of ...good ideas, i like this place a lot.

I look forward to see your version of switchbox cases, with your ideas inside.

Sick of you (?) ...not at all.

Oak,
The IRF610 will work fine as will the 510 (if you are using low voltage). I use IRF612 because I got a bag of 100 from Ebay for $5 bucks or so. It has a nice curve as a Mosfet Source follower. The 610 will have a better response to higher frequency than the 510.

Bypass caps, orange drops (available at AES http://www.tubesandmore.com/) are popular for power supply and coupling caps. There are those who will argue that if you use high quality caps you do not need them. In short they will improve the high frequency response that the electrolytic may not handle. In tube circuits you will find poly film, Mylar, and various others as a 600 electrolytic will be humongous.You can go with the electrolytic only and be OK.

Here is the Tina sim for the amp, I named it Yeker for yaha/szekeres, but in other builds changed it to NP-100. Name is not important, but try to play with Tina, you can substitute the irf 510 inplace of the irf612 and run Analysis, AC analysis, then AC transfer characteristics and see the output curve. Then change it back and do the output curve again and tab between to see the difference.

Try calling some old school tv repair shops to see if there is a local electronics store around. They are usually mom and pop and have resistors, transistors etc. There has to be some around your area.
Always here to help.

Rogers

Salvage some junk TV's or computer monitors, pleanty of IRF610's, 630's and 640's from the ones I've salvaged.

Some computer power supplies will also have compatible tranies in them.

_________________
My Mini 12AU7 Tube Preamp, Pioneer SX-D7000, JVC XL-V221BK, JBL L80T, DCM TF700

• Project Page - Mini 12AU7 Tube Preamplifier
• Support/Questions - Mini 12AU7 Tube Preamp thread