Projects for next hollidays (the world smallest VBITNGC??) - Page 2

Upupa Epops · 21st December 2004, 08:43 AM

Franz, this tubes, run over by car, probably lose good sound

. Try some another, which are still round

.

Franz G · 21st December 2004, 03:34 PM

You may not believe it: I decided, to use a conventional double triode, eg. E88CC.

Why?

Because the 1AD4 are direct heated valves. This makes it more complicated, more parts needed, to realize a cathode follower.

It should fit in the minicase, most resistors and connections must be soldered direct under the board.

Franz

steenoe · 21st December 2004, 03:41 PM

Franz, that looks good

Cant beleive you are able to fit all that into that small case

Please keep us posted on how it eventually sounds

Steen.

phase_accurate · 21st December 2004, 03:44 PM

Hi Franz

Your case looks as if you went shopping in Bethlehem, maybe this is a good omen for an amp built over Christmas ?!

Regards

Charles

Franz G · 21st December 2004, 03:48 PM

Quote:

Your case looks as if you went shopping in Bethlehem, maybe this is a good omen for an amp built over Christmas ?!

Smile

No, they are not from Jaeger at Bern Bethlehem, they are from Dreyer in Thun.

Do you know the shop in Bern? Do you live nearby?

But, today I bought this heathsinks in Bethlehem

I am preparing a pcb and of course: fitting in all parts will be a challenge, as I did not find any SMD tube sockets

.

Franz

phase_accurate · 21st December 2004, 04:26 PM

Hi Franz

No I don't live nearby (thoug in a rural area this side of Berne). But they were within convenient walking distance to my workplace when they still had their shop in the city. There is no decent electronics shop left in the city nowadays unfortunately. So one has to travel far or do mail-order.

Regards

Charles

troystg · 21st December 2004, 07:55 PM

Hi Franz-

I am familiar with tube theory and have worked with tubes(Klystrons and TWT's) but not in the audio spectrum.

I am very curious about those tubes(1AD4).

You mentioned to Upupa you knew they would not be good for your project.

Do you know what were they intended for and if they can be used for audio buffers or moderate gain?

I'm looking at the technical data and am I reading this right? 45VDC as the screen and plate voltage! Man that is low... Last tube I played with had 8K on it...

Edit:

By the way, it looks as though you changed chips to the TF version correct? Also, why squeeze in 4 largish caps? Why not build an external regulated supply and feed both channels with smaller local supply caps? Same cable to pwr supply, just frees up more space.

Franz G · 21st December 2004, 08:16 PM

Hi Rabstg

There are many of this subminiature tubes existing:

DF64
6SH5B
1SH18B
1P24B

Imho, the first of them where invented for the controlling electronics of the V-missiles in WWII.

And after, used for hearing aids

Here, a foto from a phono pre, using submini valves:

And here a link to a small amp with subminis (german only, sorry):

http://www.jogis-roehrenbude.de/Wett...-Amp/index.htm

Yes, I use those TF-version, as I found them in my hobby box (samples).

And: I will use a regulated external supply, but I am still used, to apply 1000uF nearby the chip. The 500uF Panasonics are thinner but longer, dont fit in.

Franz

Upupa Epops · 21st December 2004, 08:20 PM

Franz, in this small chassis are " directly heated " LM chips

. Use higher anode voltage than at last time, you will get lower distortion

.

PMA · 21st December 2004, 08:21 PM

Franz,

how about AZ11 tube?

21st December 2004, 07:55 PM	#17
troystg diyAudio Member Join Date: Apr 2004 Location: Lousy Anna	Hi Franz- I am familiar with tube theory and have worked with tubes(Klystrons and TWT's) but not in the audio spectrum. I am very curious about those tubes(1AD4). You mentioned to Upupa you knew they would not be good for your project. Do you know what were they intended for and if they can be used for audio buffers or moderate gain? I'm looking at the technical data and am I reading this right? 45VDC as the screen and plate voltage! Man that is low... Last tube I played with had 8K on it... Edit: By the way, it looks as though you changed chips to the TF version correct? Also, why squeeze in 4 largish caps? Why not build an external regulated supply and feed both channels with smaller local supply caps? Same cable to pwr supply, just frees up more space. __________________ Troy Thinking positive doesn't make things better, it makes you a better person.

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21st December 2004, 08:43 AM	#11
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Franz, this tubes, run over by car, probably lose good sound . Try some another, which are still round .

21st December 2004, 03:34 PM	#12
Franz G diyAudio Member Join Date: Jun 2004 Location: Bern / Switzerland	You may not believe it: I decided, to use a conventional double triode, eg. E88CC. Why? Because the 1AD4 are direct heated valves. This makes it more complicated, more parts needed, to realize a cathode follower. It should fit in the minicase, most resistors and connections must be soldered direct under the board. Franz

21st December 2004, 03:41 PM	#13
steenoe diyAudio Member Join Date: Mar 2004	Franz, that looks good Cant beleive you are able to fit all that into that small case Please keep us posted on how it eventually sounds Steen.

21st December 2004, 03:44 PM	#14
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	Hi Franz Your case looks as if you went shopping in Bethlehem, maybe this is a good omen for an amp built over Christmas ?! Regards Charles

21st December 2004, 04:26 PM	#16
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	Hi Franz No I don't live nearby (thoug in a rural area this side of Berne). But they were within convenient walking distance to my workplace when they still had their shop in the city. There is no decent electronics shop left in the city nowadays unfortunately. So one has to travel far or do mail-order. Regards Charles

21st December 2004, 08:16 PM	#18
Franz G diyAudio Member Join Date: Jun 2004 Location: Bern / Switzerland	Hi Rabstg There are many of this subminiature tubes existing: DF64 6SH5B 1SH18B 1P24B Imho, the first of them where invented for the controlling electronics of the V-missiles in WWII. And after, used for hearing aids Here, a foto from a phono pre, using submini valves: And here a link to a small amp with subminis (german only, sorry): http://www.jogis-roehrenbude.de/Wett...-Amp/index.htm Yes, I use those TF-version, as I found them in my hobby box (samples). And: I will use a regulated external supply, but I am still used, to apply 1000uF nearby the chip. The 500uF Panasonics are thinner but longer, dont fit in. Franz

21st December 2004, 08:20 PM	#19
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Franz, in this small chassis are " directly heated " LM chips . Use higher anode voltage than at last time, you will get lower distortion .

21st December 2004, 08:21 PM	#20
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	Franz, how about AZ11 tube?

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