Do you have any you would want to sell?
I also have a small bag (10 - 20) of loose nuvistors and 2 or 3 new ones. Again they are in the warehouse. I will look for them this weekend. I gave up on nuvistors since they are not cheap and sockets are hard to find. Check out old Tektronix plug ins. My experiments revealed some serious microphonics, but this was several years ago (like 20).
I have a bunch of sub mini tubes like the ones used in these tiny amps. You can stuff them into the old 8 pin IC sockets made for the op amps in the round metal can. I fried one before it would put out a watt. No glow, it just died. I am experimenting with them for hybrid amp use. They are also just the ticket for a top secret guitar preamp that is mounted IN the guitar. OOPS, I didn't say that.
tubelab.com said:
........They are also just the ticket for a top secret guitar preamp that is mounted IN the guitar. OOPS, I didn't say that.
Not that 'top secret guitar preamp project'?
I read about it last week on the net !!
Andy
poynton said:Cheating ? Yes !
Must include the psu as well.
Andy
hi, you are living in a free country, you can simply build a smaller Amp at any time...
Gerd
Smallest valve amp
they made tube hearing-aids from the early 1950's ( if that counts )
http://cgi.ebay.com/Vintage-1950-75...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247
These're also *very* expensive....
From the description:
"in the case it measures 3-1/8''x6-1/2''x9-1/2'' and it weighs 5 pounds"
I'd say you'd need 2 x of these for Stereo
El Gippo
they made tube hearing-aids from the early 1950's ( if that counts )
http://cgi.ebay.com/Vintage-1950-75...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247
These're also *very* expensive....
From the description:
"in the case it measures 3-1/8''x6-1/2''x9-1/2'' and it weighs 5 pounds"
I'd say you'd need 2 x of these for Stereo
El Gippo
kuroguy said:Saw this one a while back. It too has a separate power supply.
http://www.jogis-roehrenbude.de/Leserbriefe/Hermann-Mini-Amp/Hermann-Mini.htm
this was my inspiration to build the Kolibri.
Herrmans amp was some smaller than a CD sleeve, and I made it some smaller than a MC sleeve
The OPT´s are the smallest possible types for the desired quality. If I would use smaller cores I can´t get the -3dB at 25Hz.
Now we can wait for the next version from nhuwar, smaller than a minidisk ???
Gerd
Among the smallest, undoubtedly the coolest!!!
http://www.impamp.com/
Can't believe no-one else posted this yet... Click on the pic for more images and videos.
http://www.impamp.com/
Can't believe no-one else posted this yet... Click on the pic for more images and videos.
poynton said:Cheating ? Yes !
Must include the psu as well.
Andy
I agree.
To qualify, the amp. must drive speakers and have an internal power supply.
semiconductors/ics only allowed in the power supply and as biasing/ccs , in my opinion.
so the earmax pro is out (although very nice)
The Yaha is also out as it is a hybrid.
Andy
semiconductors/ics only allowed in the power supply and as biasing/ccs , in my opinion.
so the earmax pro is out (although very nice)
The Yaha is also out as it is a hybrid.
I think we can disregard this. Didn't they invent cr@ppy audio plugs for Philips etc.hifi (DIN45500) means 10W mono and 2 x 6W stereo
Andy
Actually Poynton as the originator of this thread I have stated that external ps is ok, just extra points for internal, but I do agree that it must be able to drive typical speaker loads and no hybrids. Is anyone winding there own trannies, also does anyone know the supplier of the Kolibri output trannies.
cheers fergs
cheers fergs
Steerpike said:The Kolibri is WAY prettier & sexier than the impamp.
Thank you!
poynton said:To qualify, the amp. must drive speakers and have an internal power supply.
IMO is an external PS the better solution for such small designs. You get better noise margin, less humming (stray effect from the mains transformer) and you can use the PSU also for other things.
Gerd
poynton said:The impamp also has an external psu.
It is also lacking a useable volume control.
andy
My thoughts on impamp:
I think it is a hybrid. In one of the videos you see the output stage in push-pull. It is not possible to drive this in Stereo with common ground without a phase splitter.
The 6021 has a µ of ~30, to less to get 1 W from a line-input.
And I think, 1 W out is hard to get, from 2 triodes with Qamax 1,1W per system..... it must be hard class B with excess of maximum cathode current 22mA, at max. rated plate voltage of 165 Volts...
For max power the grid must controlled with grid current, but this can not come from a line signal.
Gerd
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Tubes / Valves
- Worlds smallest HiFi valve amp