Hello,
I just finised my tube entry project
the AN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
its quite nice and really affordable, for the sound it self I subjetively must say it sound very clear I was missing nothing, therefore im satisfied with the kit.
see the image of the amp here http://hex.dan.sweb.cz/minitubeamp/DSC_0837.JPG
does anyone here made it as well?
For the begining I builded it as it came, but I would lilke to make a few changes so I would like to get the experience from someone else as well.
Cheers,
Imagios
I just finised my tube entry project
the AN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
its quite nice and really affordable, for the sound it self I subjetively must say it sound very clear I was missing nothing, therefore im satisfied with the kit.
see the image of the amp here http://hex.dan.sweb.cz/minitubeamp/DSC_0837.JPG
does anyone here made it as well?
For the begining I builded it as it came, but I would lilke to make a few changes so I would like to get the experience from someone else as well.
Cheers,
Imagios
This looks like it:
Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
This looks like it:
Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
Yep was just about to say this.
I came across this the other week. Interesting miniaturized pentodes.
I wonder how they sound compared to the common size tubes that we use.
hello,
I bought it on australian Ebay: K272 - STEREO TUBE PREAMPLIFIER - HEADPHONE DRIVER KIT - eBay Tube, Valve Amplifiers, Amplifiers, Audio, Electronics. (end time 18-Dec-09 15:46:10 AEDST)
as Oatley Elec. do not ship to Czech Republic.
Its easy to build, sound for a amateur nice. But I never lisened to a tube amp therefore please take this with some distance. newer the less I have a headphone amp self made from a kit based on the TDA7053 chip and personaly I like these tubes more than the chip. (but this must say nothing)
Im not much knowledgeable in electronics, so I build only kits. But I would for sure change some parts on the board. a potentiometer would be fine...
I would be interested to know the THD at the amp... but have no equipment to measure it.
But as a introduction to tubes I think its great 1-easy to build, few parts that you can hardly mix up, 2- low voltage (Im not skilled egnouth to play with deadly voltages) 3- good sound (subjetively on common headphones) I will as well conect this as a preamp to mi tripath amp from 41Hz to see what difference it will make.
Never the less I was not sorry to instal golden cinch to the amp and a quite expensive jack connector as you might see here http://hex.dan.sweb.cz/minitubeamp/DSC_0836.JPG
as well for thouse who might be interrested the "shine" of the petodes:
(ISO 200; 30 seconds exposition)
http://hex.dan.sweb.cz/minitubeamp/DSC_0845.JPG
the biggest problem with the amp is the ring sound comming from vibrations they suggest to use rubber grommets, that I dont have and that are not a par of the delivery(thats a pity) but I dont know how much bether it will become. I can not imagine to use this as a travel amp in a bus,car, train as I think it would ring... but to have it on stable place makes it a quite nice travel amp, desk at work, library, waiting room, what ever ...
One common 9V battery can power the amp for good 10 hours without loose of "power"
but I think to buy a Li-ion batery and make it a travel amp with rechargable embeded batery. Quite easyer than to exhange bateries.
I bought it on australian Ebay: K272 - STEREO TUBE PREAMPLIFIER - HEADPHONE DRIVER KIT - eBay Tube, Valve Amplifiers, Amplifiers, Audio, Electronics. (end time 18-Dec-09 15:46:10 AEDST)
as Oatley Elec. do not ship to Czech Republic.
Its easy to build, sound for a amateur nice. But I never lisened to a tube amp therefore please take this with some distance. newer the less I have a headphone amp self made from a kit based on the TDA7053 chip and personaly I like these tubes more than the chip. (but this must say nothing)
Im not much knowledgeable in electronics, so I build only kits. But I would for sure change some parts on the board. a potentiometer would be fine...
I would be interested to know the THD at the amp... but have no equipment to measure it.
But as a introduction to tubes I think its great 1-easy to build, few parts that you can hardly mix up, 2- low voltage (Im not skilled egnouth to play with deadly voltages) 3- good sound (subjetively on common headphones) I will as well conect this as a preamp to mi tripath amp from 41Hz to see what difference it will make.
Never the less I was not sorry to instal golden cinch to the amp and a quite expensive jack connector as you might see here http://hex.dan.sweb.cz/minitubeamp/DSC_0836.JPG
as well for thouse who might be interrested the "shine" of the petodes:
(ISO 200; 30 seconds exposition)
http://hex.dan.sweb.cz/minitubeamp/DSC_0845.JPG
the biggest problem with the amp is the ring sound comming from vibrations they suggest to use rubber grommets, that I dont have and that are not a par of the delivery(thats a pity) but I dont know how much bether it will become. I can not imagine to use this as a travel amp in a bus,car, train as I think it would ring... but to have it on stable place makes it a quite nice travel amp, desk at work, library, waiting room, what ever ...
One common 9V battery can power the amp for good 10 hours without loose of "power"
but I think to buy a Li-ion batery and make it a travel amp with rechargable embeded batery. Quite easyer than to exhange bateries.
Anyone know about Oakley's K261 preamp Kit.
It seems to use a smal smps to supply the 30v HT.
Oatley Electronics
It seems to use a smal smps to supply the 30v HT.
Oatley Electronics
Attachments
I have one too and decided to upgrade some of the mediocre quality parts since I want to use it as a preamp with my mini Aleph in the living room.
Here's my BOM
Resistors: all resistors 1% metalfim types
Caps: C1,C2,C4,C5 MKP1837 0.1uF C7,C8 Elna Silmic ARS 220uF 25v
Trimpots: Piher 1M
Opamp: OPA2134PA
I replaced the opamp socket with a better one and connected a decoupling cap (a "104") to the supply pins on the reverse side of the PCB.
For the tubes I came up with a diy socket. I butchered a large IC socket to make two 5-in-line sockets for the tubes. Tube (re)placement now is quick & easy.
The Elna's are 12.5mm diameter and they just barely fit. I plan on using MKP1837 0.01uF bypass caps on the Elna's once I have them.
As for tube dampers I use a short piece (~32mm) of clear silicon tubing with the side cut open.
Here's my BOM
Resistors: all resistors 1% metalfim types
Caps: C1,C2,C4,C5 MKP1837 0.1uF C7,C8 Elna Silmic ARS 220uF 25v
Trimpots: Piher 1M
Opamp: OPA2134PA
I replaced the opamp socket with a better one and connected a decoupling cap (a "104") to the supply pins on the reverse side of the PCB.
For the tubes I came up with a diy socket. I butchered a large IC socket to make two 5-in-line sockets for the tubes. Tube (re)placement now is quick & easy.
The Elna's are 12.5mm diameter and they just barely fit. I plan on using MKP1837 0.01uF bypass caps on the Elna's once I have them.
As for tube dampers I use a short piece (~32mm) of clear silicon tubing with the side cut open.
Attachments
Last edited:
All -- Good info here --
Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
There also are several great threads on the forum for this site.
Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit
There also are several great threads on the forum for this site.
Anyone know about Oakley's K261 preamp Kit.
It seems to use a smal smps to supply the 30v HT.
Jameco Electronics sells the power IC for $.40 each. Had to look around to find it.
Click the red (and hard to read) button on the Oatley page for this board for complete info (PDF) including a schematic.
Looks cool but shipping is nuts to North America IMHO.
Best online info about SMPS for tubes is here:
http://groups.yahoo.com/group/NEONIXIE-L/
http://groups.yahoo.com/group/NEONIXIE-L/files/Power Supply Designs/
Last edited:
For the tubes I came up with a diy socket. I butchered a large IC socket to make two 5-in-line sockets for the tubes. Tube (re)placement now is quick & easy.
Kewl -- Cut up SIP 'header' strips (see: 5x 40-pin Female Headers 0.1" spacing *fcbusa 5 x pcs - eBay (item 360131819147 end time Feb-09-10 12:04:59 PST)) work good too.
As for tube dampers I use a short piece (~32mm) of clear silicon tubing with the side cut open.
Wow -- great idea -- is it just garden variety fish tank tube? Doesn't the tube get too hot?? thx.
Kewl -- Cut up SIP 'header' strips ...
Check the fit of the tube leads in those 'header' strips first. I'm not sure if they will make and keep good contact.
Wow -- great idea -- is it just garden variety fish tank tube? Doesn't the tube get too hot?? thx.
Yup, it's just a piece ordinary silicon tubing, the open side allows for easy removal. Don't know if those tubes get hot in normal use, I have only tested mine with very cheap headphones for a short while.
From the manual:
The warmth in this preamplifier can certainly not be attributed to the heat given off by the filament: The 1.2V filament draws just 10mA! You can barely see it glow in a very dark room.
I built one of these, albeit I dont have a tube amplifier (yet) to compair it against, I though it sounded dead smooth and tight.
cheaper to buy from their website directly, but shipping takes best part of 3/4 weeks to the UK
I have a spare kit (I bought 3 lol) if anyone from the UK wants one that wont take 3 weeks to arrive.
drop us a PM. (I do have feedback elsewhere i.e. avforums, ebay etc)
cheaper to buy from their website directly, but shipping takes best part of 3/4 weeks to the UK
I have a spare kit (I bought 3 lol) if anyone from the UK wants one that wont take 3 weeks to arrive.
drop us a PM. (I do have feedback elsewhere i.e. avforums, ebay etc)
Mine's playing too. I'm impressed with how it sounds using my Sennheisser PX-100. Really nice lows. Plenty loud too. I feel no need to increase the opamp gain.
I have a pair of the PX-100 as well, nice to hear that it plays nicely with them. I am sorely tempted for portable use with my iPod Classic.
VR2 connection to V2 heater
Surely that's a mistakeon the schematic?
Neat. The filament/VR2 setup on V2 is kind of odd though.
Surely that's a mistakeon the schematic?
Surely that's a mistakeon the schematic?
Surely it has to go there otherwise there would be a voltage due to the filament of V1???? Maybe the cap. C3 needs moving to give an AC path to ground?
Andy
.
Surely that's a mistakeon the schematic?
No, not necessarily - the effective bias for both tubes should be the same, note however that the effective plate voltage isn't because that filament is floating 1.2V above ground. I think there might be a bit of an issue with the first tube's bias as well, but apparently it works well enough in practice.
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