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AdamR

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AdamR last won the day on December 13

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About AdamR

  • Birthday 01/08/1971

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    Porirua
  • Country
    New Zealand

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  1. AdamR

    Hello all

    Watch the high voltages with tube gear! Great to see the interest in tube tech being picked up by someone born in the 21st century. Plenty of bargains out there for old stuff to cannibalize - good luck!
  2. AdamR

    Joined Up

    Another DIY-er on board! Welcome Always been keen on Plinius gear, ever since I bought a 2.4 / 3100 pre/power combo in my early 20s... back when they were still in Palmerston North I believe.
  3. I'm in my Happy Place with amplifiers (designed and built my own tube amps) but I don't guarantee anything else ... speakers, DACs, cartridges... cables... Daily Driver... Only 15 wpc but how sweet it sounds! My first ever build. Maybe I'll put it on a better looking chassis one day, but I will not change the electronics... this thing is simultaneously a jackhammer and a scalpel One piece of gear that I'd trade in a heartbeat though is my nearly 50 year old ears. Where can I get new ones??
  4. AdamR

    IMAGE 416 - Rimu

    I've ordered a Topping D50 now, which will be added to my Chromecast Audio. I'll be interested to hear the difference it makes. I am tempted to make up my own linear 5V supply for it since I am old-school and don't like the idea of switching supplies anywhere near audio. Something involving a transformer, rectifier, lots of capacitance, linear regulator with heatsink, and a shielded twisted-pair power cable to take the clean DC to the DAC.
  5. AdamR

    Long overdue ...

    Welcome to the board - a growing community To your point about collecting CDs - the similarity with vinyl and CD is they're both physical media. Time was, not so long ago, when you met someone and got invited to their house for the first time, you could check out their CD shelf and their bookshelf to size up what they read and listen to. These days not so easy! Other thing about physical media is I feel it is far better at acquainting the listener with the artist, since you are more likely to listen to a whole album, rather than creating a playlist with one from each artist. (To this point, my teenage kids sometimes wonder why I listen to 5 or 6 songs from one artist in a row!) Anyways welcome aboard.
  6. On my blog I've got a suppliers page which lists my sources. I've used Hammond mains transformers the last couple of builds I've done, for the simple reason of aesthetics. The ones wound by the local supplier are industrial and have no end covers and are simply too ugly. I'd love to use locally made units but they don't pass my acceptance criteria. Also one of them has a mechanical hum / buzz in use, which might be fine in a control box in a noisy industrial environment, but not for audio. The Hammond transformers, while they look nice, aren't all brilliant though. For a start they're more expensive than the locally wound ones, and they run uncomfortably hot. After ~2 hours operation the transformer in my EL84 amp is too hot to touch for more than about 2 seconds. This despite the transformer being used well below its maximums. This tends to suggest a 50% de-rating (at least) is appropriate with Hammond mains transformers. Which has prompted me to look at the Polish Toroidal transformers from Toroidy, although I haven't used any of them yet (waiting for someone else to ask me to build them an amp!) their prices are a little lower than Hammond. I've been very impressed with the Hammond output transformers though. The little 1650s I use for the EL84 amp are clean down to 6Hz. A word of warning - there are lots of cheap electrolytic capacitors around on auction sites and the like... be very careful. A lot of them are fakes and/or knock-offs, which in some cases will actually explode if used close to their rating. I will only ever use capacitors from my top-tier online suppliers, RS and Element14. Good luck with your build. Hit me if you want to bounce any ideas around.
  7. Matter of fact I picked up another pair of speakers and it's also visited another audio enthusiast's place ... I was very pleased with the results Designing and building valve gear is fun. Shame good quality transformers are so expensive else I'd build more and experiment with different designs.
  8. AdamR

    IMAGE 416 - Rimu

    That's a really nice rescue you did on those cabinets. I did something similar to a pair of old KEFs but they didn't come up as good as yours. Regarding your source: For a while, I was using a PC as my main digital source and I thought it sounded OK on FLAC or hi-bitrate MP3. Then I found one of the ancient 1990-era Musical Fidelity "Digilog" D/A converters which I bought for the grand sum of $40 and I ran the optical output from the PC into that. I wasn't prepared for the massive difference in sound quality. Every single aspect of the sound was markedly better. Dynamics, Clarity, Imaging, and the darkness behind the sound. That old clunky black box stayed with me for several years.
  9. AdamR

    Welcome

    Some of us 2-channel nuts are still listening to vinyl, even!
  10. AdamR

    Kia Ora

    Welcome along. If you've got any questions about vacuum tube stuff in particular, feel free to fling them my way... and yeah some of the old-school gear from the 70s and 80s has a certain unmistakable aesthetic. Seems there's a few of us around the Wellington area.
  11. Are those measurements right? The picture looks like a bit more than 40mm height
  12. AdamR

    Coloured Vinyl

    My experience some of the coloured vinyls from the 70s and early 80s had more surface noise, but current pressings don't seem to suffer from that problem.
  13. In an earlier thread I posted about the new valve amp I made. (You can read more on it here if so inclined). I've only one pair of decent speakers, my old KEF C95s which it does a great job with. But, I'm quite keen to hear it playing through a few different pairs of speakers and in some different size rooms, etc... so if anyone is curious as to how a 15w valve amp sounds then ping me a PM and let's hook up a listening session. Amp weighs 10kg so reasonably portable, and has line and RIAA inputs (for MM only, not MC) I know... weird request, right? I should just go out and buy more speakers. But I would like to hear what this amp sounds like on a variety of different speaker types. I don't know anyone in the audio fraternity, hence this post. Anyone interested?
  14. Thanks yeah I have a continuous improvement goal with my amps; this is the fourth one I designed and built, each an improvement on the previous. There are a few things I want to improve about this one, specifically: 1) I want to go to independent power supply rails for left and right channels, to minimise crosstalk 2) I want to change the topology to the phase inverter. The DC coupling requires the first gain stage to run at a lower voltage than ideal for the linearity of the tube (I've already re-designed the board for this so I can check this one off... next build will incorporate it) 3) More DC decoupling for the RIAA stage (also, already designed onto the board layout, waiting for the next build) Other than that, the changes I want to make are cosmetic. I'd love to silkscreen the top side of the boards, but I don't have the equipment or knowledge to do that, plus I'd like to tidy the wiring inside a little. To your questions specifically: Power Supply shielding - I decided not to because the transformer has an electrostatic shield, plus there is no switching in this power supply it's all completely linear and unregulated. So there shouldn't be any RF spuriae RF Protection on AC input: With tubes, they have an effect called "miller capacitance" which - long story short - if you add a grid-stopper resistor right near the Grid pin, forms a strong attenuator for RF. I scoped it up to 20MHz and there's nothing going on other than expected harmonics of input signals, there's a dominant pole at 46KHz so I have decided to assume, naively maybe - that RF is not going to be a problem. My NFB has filtering to damp oscillation also. I'm gonna keep refining the design of this one as long as I can find people that want them. This one sounds incredibly easy on the ear to listen to, I've been delighted with the sound from it.
  15. Black adhesive vinyl sheet affixed to front panel. Laser cutter used to etch the outlines of the letters by cutting through the vinyl. The vinyl was then peeled off carefully, then the tweezers were used to peel off the enclosed parts in the letters (like the letter o, e p, d, etc) Then I sprayed three coats of clear lacquer over it to protect the letters and ensure they stayed on.
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