mwhouston Posted January 29, 2015 Posted January 29, 2015 Just found a Oatley K282 sub-mini tube\jFet phono preamp for MM with RIAA equalisation. I forgot I had the kit and have needed another phono preamp. This uses the JAN6418 tubes and 2SK170 BL jFets. I have everything a need to finish it even a 30V DC external PS.
awty Posted January 29, 2015 Posted January 29, 2015 Finally I put my FC-100 in a nice case. Almost done. Just need to tidy up internal wiring a bit... Looks very impressive, whats the details on this amp?....without me having to try and read 100 odd pages on DIYaudio.
awty Posted January 29, 2015 Posted January 29, 2015 Just found a Oatley K282 sub-mini tube\jFet phono preamp for MM with RIAA equalisation. I forgot I had the kit and have needed another phono preamp. This uses the JAN6418 tubes and 2SK170 BL jFets. I have everything a need to finish it even a 30V DC external PS. Need photos, why does it need 30v dc?
WINEDS Posted January 29, 2015 Posted January 29, 2015 (edited) Looks very impressive, whats the details on this amp?....without me having to try and read 100 odd pages on DIYaudio. Thanks Awty! If found this design on Diyaudio a few years ago. Designed by Mihai Roender it seemed to survive scrutiny by the gurus and indeed many were full of praise including Hugh Dean. Rudi Ratlos did my iteration of boards. : Basic specs are : Class A power: 2W rms into 8ohm with Iq=0.6A (maximum Iq for optimal B class bias) Class B power: 90W rms into 8ohm OLG: 94dB CLG: 1:40 (32dB) SR: +/-75V/us Phase margin > 67grd Frequency response: DC to 210KHz (-1dB) Later Mihai stated : At +/-34V we have plenty of SOA margin and: 65W rms into 8ohm 87W rms into 6ohm 130W rms into 4ohm 260W rms into 2ohm (at the SOA limit) For speakers with SPL over 90db it is more than enough. But my backend rails are ~35.3 so maybe output power is closer to first spec. A shunt power supply is used for the front end. Output offset is about 2mv each channel. There is provision for an input DC blocking cap but it is shorted in my case as I know my sources have no significant DC output. Most of the devices are hand matched for Hfe at least. One of the most impressive things is there is absolutely no turn on thump. So I am following Mihai's madness and not using any speaker protection. Output devices are (triples of) OnSemi NJL0281/NJL0302D with integrated thermal track diodes. I do not profess to have golden ears but I find it very impressive to listen to with incredible bass control and never ever the least bit fatiguing. I can joyfully listen all day. Edited January 29, 2015 by WINEDS 1
Nada Posted January 29, 2015 Posted January 29, 2015 (edited) But my backend rails are ~35.3 so maybe output power is closer to first spec..... I wonder how many watts the amp draws from the mains at idle and at full tilt? Do you have a watt meter? Edited January 29, 2015 by Nada
mwhouston Posted January 29, 2015 Posted January 29, 2015 Need photos, why does it need 30v dc? It runs on 30V. Either provide a direct 30V or build the on-board SMPS which generates it from 5V
The Fez Posted January 29, 2015 Posted January 29, 2015 Thanks Awty! If found this design on Diyaudio a few years ago. Designed by Mihai Roender it seemed to survive scrutiny by the gurus and indeed many were full of praise including Hugh Dean. Rudi Ratlos did my iteration of boards. : Basic specs are : Class A power: 2W rms into 8ohm with Iq=0.6A (maximum Iq for optimal B class bias) Class B power: 90W rms into 8ohm OLG: 94dB CLG: 1:40 (32dB) SR: +/-75V/us Phase margin > 67grd Frequency response: DC to 210KHz (-1dB) Later Mihai stated : At +/-34V we have plenty of SOA margin and: 65W rms into 8ohm 87W rms into 6ohm 130W rms into 4ohm 260W rms into 2ohm (at the SOA limit) For speakers with SPL over 90db it is more than enough. But my backend rails are ~35.3 so maybe output power is closer to first spec. A shunt power supply is used for the front end. Output offset is about 2mv each channel. There is provision for an input DC blocking cap but it is shorted in my case as I know my sources have no significant DC output. Most of the devices are hand matched for Hfe at least. One of the most impressive things is there is absolutely no turn on thump. So I am following Mihai's madness and not using any speaker protection. Output devices are (triples of) OnSemi NJL0281/NJL0302D with integrated thermal track diodes. I do not profess to have golden ears but I find it very impressive to listen to with incredible bass control and never ever the least bit fatiguing. I can joyfully listen all day. - That does look, and I bet, sound -- great! - 1
WINEDS Posted January 30, 2015 Posted January 30, 2015 - That does look, and I bet, sound -- great! - Thanks The Fez!
WINEDS Posted January 30, 2015 Posted January 30, 2015 I wonder how many watts the amp draws from the mains at idle and at full tilt? Do you have a watt meter? Sorry I don't have a watt meter Nada. I think it was mentioned somewhere in one of the Diyaudio FC-100 threads that the amp uses 38w whilst idling but not 100% sure. 1
Stedes Posted February 23, 2015 Posted February 23, 2015 Hey guys I'm in the early stages of building one of these: http://bottlehead.com/?product=stereomour-stereo-single-ended-2a345-integrated-amplifier-kit Currently doing the wiring for the OT for each channel and power supply. It's my second ever kit (No electronics DIY experience before), my first one being a preamp from the same company. You can see my build thread here: http://bottlehead.com/smf/index.php?topic=6720.0 4
betocool Posted February 23, 2015 Posted February 23, 2015 Hey guys I'm in the early stages of building one of these: http://bottlehead.com/?product=stereomour-stereo-single-ended-2a345-integrated-amplifier-kit stereomourproto.jpg Currently doing the wiring for the OT for each channel and power supply. It's my second ever kit (No electronics DIY experience before), my first one being a preamp from the same company. You can see my build thread here: http://bottlehead.com/smf/index.php?topic=6720.0 A bit more information perhaps? Where did you get it from and what does it do exactly? Links? Looks good! Alberto
Ihearmusic Posted February 23, 2015 Posted February 23, 2015 Just about finished this one. I am in the process of making an acrylic cover for the fiddly bits. Lateral MOSFET based on Rod Elliot's P101. Still got a few issues to sort out though. I need to get my rails down to +/-30Vdc. It seems +/-50Vdc is not popular with the single MOSFETS.......they complained. 9
betocool Posted February 23, 2015 Posted February 23, 2015 Beautiful mate! Especially the square design on the soldered components, that's art! Doesn't it get too hot for the wood? 1
Stedes Posted February 23, 2015 Posted February 23, 2015 A bit more information perhaps? Where did you get it from and what does it do exactly? Links? Looks good! Alberto Hi Alberto It's an integrated amp. The link I posted in the original post takes you to the website of the company that sells them and you can order from them. The second link I posted is of a build of a preamp from the same company. It's called the Smash and you can also order that from their website too.
RoHo Posted February 23, 2015 Posted February 23, 2015 Just about finished this one. I am in the process of making an acrylic cover for the fiddly bits. Lateral MOSFET based on Rod Elliot's P101. Still got a few issues to sort out though. I need to get my rails down to +/-30Vdc. It seems +/-50Vdc is not popular with the single MOSFETS.......they complained. I love the point-to-point layout. Don't think I've ever seen it just like that with semiconductors, very cool. I assume the MOSFETs expressed their complaints by suffering a sudden, quiet death? Valves have much more strength of personality. They can complain all they like but you just ignore them and, mainly, they keep on working 2
Owen Y Posted February 23, 2015 Posted February 23, 2015 Just about finished this one. I am in the process of making an acrylic cover for the fiddly bits. Lateral MOSFET based on Rod Elliot's P101. Still got a few issues to sort out though. I need to get my rails down to +/-30Vdc. It seems +/-50Vdc is not popular with the single MOSFETS.......they complained. IMG_0216.JPG IMG_0213.JPG IMG_0123.JPG That's what you might call Solid State Architecture :-) Cheers, Owen Dark Lantern blog - http://darklanternforowen.wordpress.com/ 1
Ihearmusic Posted February 24, 2015 Posted February 24, 2015 Doesn't it get too hot for the wood? Measured 56C on the heatsinks when it was going, so not to bad. I expect it to go down a bit once I replaced the trany to reduce the rail voltage (and replace the transistor that spat the dummy).
LogicprObe Posted February 24, 2015 Posted February 24, 2015 I just pulled out the above ground pool (above, because we live on a rock cliff)................and layed turf down! Looks terrific!
SteveLuck Posted February 25, 2015 Posted February 25, 2015 Hey guys I'm in the early stages of building one of these: http://bottlehead.com/?product=stereomour-stereo-single-ended-2a345-integrated-amplifier-kit stereomourproto.jpg Currently doing the wiring for the OT for each channel and power supply. It's my second ever kit (No electronics DIY experience before), my first one being a preamp from the same company. You can see my build thread here: http://bottlehead.com/smf/index.php?topic=6720.0 Keep us in the loop on this one - I want to go down the SET route but the trouble is the push pull amp (triode wired pentodes) I own is integrated with lots of inputs and tape loops and a nice phono stage. I've been looking over the specs for bottle head and Audio Note kits but it's not a cheap proposition to jump to Pre Power and Phono amps.
Owen Y Posted February 25, 2015 Posted February 25, 2015 Keep us in the loop on this one - I want to go down the SET route but the trouble is the push pull amp (triode wired pentodes) I own is integrated with lots of inputs and tape loops and a nice phono stage. I've been looking over the specs for bottle head and Audio Note kits but it's not a cheap proposition to jump to Pre Power and Phono amps. Chaps - I've built some kits (incl the ANote Kit One 300B) & some DIY tube amps.... Aside from power output, one of the first things you want to look at is the Sensitivity of the amp (power amp) - ie. how many Volts input is required to drive the amp to achieve full output. Many suppliers are short on these key specifs. You want to know if you need to add a preamp. The Bottlehead SE 2A3/45 is specified at 0.4V sensitivity - which should work with 'Line' level sources but of course you'll need a phonostage for TT source. The AN Kit One is short on manuf specifs but it is also quite sensitive & both are provided with vol controls. Probably best anyway, if budget allows, to have an outboard phono stage - which can be upgraded over time. If required, if you are building yourself, it is not too difficult to add extra input sockets & an input selector switch. Cheers, Owen Dark Lantern blog - http://darklanternforowen.wordpress.com/ 2
mwhouston Posted February 25, 2015 Posted February 25, 2015 Most of the time a system will sound better with a preamp than without even of the power amp has an attenutaor. A truly integrated amp has a built in preamp. A power amp with atenuator is not an integrated amp. I'd go for a simple preamp. A Pass BOZ is a good start. Cheap to build and will drive into low impedances.
davewantsmoore Posted February 26, 2015 Posted February 26, 2015 Most of the time a system will sound better with a preamp This is a potentially confusing statement for some people. A different perspective is that EVERY system has a preamp already .... it's either in the source output .... in the amplifier input .... (or it's in a separate box). If you're putting a preamp in between a source and an amplifier, to improve the sound quality.... then what is wrong with the existing source output and/or amplifier input ?! If you don't have enough gain in your system.... yes, you need a preamp. If you want a preamp for it's input switching, phono, balance, or volume control functions.... then sure. ..... but if you already have enough gain (almost everyone does in modern times) ..... and you are considering adding more gain (a preamp) just solely in the quest for better sound ...... the consider what cracks you are papering over. 1
Green Wagon Posted February 26, 2015 Posted February 26, 2015 Switching unit. Attenuator. Passive pre. Active buffer. Active pre. Lets make sure were talking about the right device and not just lumping light trucks into the passenger vehicle class. Soooo, Which one are we talking about now ? All have their pros and cons. 1
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