Post by Owen Y on May 29, 2017 10:46:53 GMT 12
Not everyone is into DIY, but if you lean in that direction, building from a good kit, first up, is a good way to start. Usually good sonic value for money & importantly, a good way to learn. IME the most time-consuming part of amp-building is building and/or preparing the hardware & kits take the hard work out of this. So, this is a thread to highlight some kits which look interesting, quality & price-wise. ELEKIT - 6L6GC Single Tube Amp Kit [TU-8200]This Japanese company has caught my eye before. They appear to produce general electronic kits for domestic consumption, but including a few audio amplifier kits. Being Japanese, the parts quality should be good & the chassis quality appears to be esp nice. Pricing looks 'affordable' (JPY 60,000 excl tax). www.elekit.co.jp/en/product/?type=category&q=Amplifier+kitseg. their Elekit 6L6GC tube single-ended amp produces 8wpc (UL/pentode) or 4wpc (triode), switchable, features a nice R-core power transformer, headphone jack & will accept other tubes (eg. KT66, KT88, EL34, 6550) without re-adjustments (via an 'active auto-bias circuit'). RCA & 3.5mm mini stereo inputs. No Input Sensitivity spec given. Not a lot of power, so 88+dB/W lspkrs may be most suitable. Also sold by Tube Depot (USA) & on ebay (fully built up).   
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Post by michaelw on May 29, 2017 11:45:51 GMT 12
a kitset for the 21st century. remember back in the day when many hi-fi makers offered kitsets ? i recall kef speaker kits, ampzilla and dynaco tube amps from the us... and a large catalogue of desirable luxman gear, including diy test gear ! www.thevintageknob.org/LUXMAN/LUXKIT84/luxkit84.html
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Amplifier kits May 29, 2017 13:51:35 GMT 12
- Edited May 29, 2017 13:52:46 GMT 12 by jon
Post by jon on May 29, 2017 13:51:35 GMT 12
Interesting!! Approx $800 from Elekit and $1000 from Tube Audio, postage extra... $800 is very affordable, tho try this: www.elekit.co.jp/en/product/TU-81001/3 the price... and a 1/4 the power
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Post by Owen Y on May 29, 2017 15:38:27 GMT 12
a kitset for the 21st century. remember back in the day when many hi-fi makers offered kitsets ? i recall kef speaker kits, ampzilla and dynaco tube amps from the us... and a large catalogue of desirable luxman gear, including diy test gear ! www.thevintageknob.org/LUXMAN/LUXKIT84/luxkit84.htmlYes, in America I think they called it the "Heathkit generation", in the 1950-70s, electronics kit building was common. In Britain too.  I would have liked to have laid hands on one of those Luxkits 
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Post by Owen Y on May 29, 2017 15:54:03 GMT 12
Indeed jon - here's another Elekit, a bit more fashionable, a bit more $$... ELEKIT - 2A3/300B Stereo Power Amplifier Kit [TU-8233]www.vkmusic.ca/TU-8233.htm - USD 950 (or Can$?) Accepts line level input, with vol control (although the 300B version is less sensitive). Although it looks a bit conventional with 6SN7 front end tubes, it again incorporates some unusual Elekit features - R-core PTX, 'auto-bias' circuit enabling 2A3 or 300B power tube options. Rectification is SS I believe, using a transistor 'capacitor multiplier' circuit for PSU smoothing - saving space & parts cost? 
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Post by Owen Y on May 29, 2017 16:19:52 GMT 12
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Pundit
Post by papahemi on May 29, 2017 17:07:13 GMT 12
Good stuff team, what about ss class A - I have been looking for options for a kit build. Looked at AmpCamp from DIY audio (out of stock), various iterations of the JLH 1969 and the Jean Hiraga Class A. It is all a bit confusing, but if someone had built one of these I would be very interested to hear their experience.
We are what we pretend to be, so we must be careful about what we pretend to be.
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Post by Owen Y on May 30, 2017 10:16:25 GMT 12
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Post by michaelw on May 30, 2017 11:01:16 GMT 12
Yes, in America I think they called it the "Heathkit generation", in the 1950-70s, electronics kit building was common. thanks for the memory jog ! "heathkit" was the name stuck in the depths of my noggin  hafler also made some highly acclaimed kit amplifiers, including the famous dh-101 preamp and dh-200 power amp.
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Post by jon on May 30, 2017 12:05:15 GMT 12
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Post by Owen Y on May 30, 2017 12:21:43 GMT 12
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Post by Owen Y on May 30, 2017 13:01:45 GMT 12
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Post by Owen Y on Aug 1, 2017 12:16:35 GMT 12
I see that there is a new ELEKIT TU8600 300BSET kit - release due in late September 2017. VK Music (Canadian importer of Elekit) announced in June & shown at the LA Audio Show. wallofsound.ca/audioreviews/the-new-elekit-300b-set-arrives-at-wos/wallofsound.ca/uncategorized/quick-update-on-our-most-anticipated-new-amp-of-2017-review/wallofsound.ca/audioreviews/amplification/the-scoop-on-elekits-brand-new-300b-set-amp-introducing-the-tu-8600r/ELEKIT designer, Mr. Fujita, has taken user requests into consideration & the new 300B amp has many improvements from its predecessor (TU-8300R). • Tube Set : 12Au7 X 2 + 12 AX7 X 1 + 300B X 2 • Now compatible with low to high impedance headphones (via an addit. OPT winding I believe) • Frequency response (-3dB) : 10Hz - 80kHz • Max. output (THD 10%) : 8.3W + 8.3W (Input voltage : 250mV r.m.s) • Residual noise : 42uV rms (IHF-A) • Power consumption : 80W when no signal. 80W at max. output • Power voltage : 100V, 115V, 200V, 230V, 50/60Hz) • Dimensions : W385 x H217 x D323 mm, including projections • Weight : Approx. 12kg, excluding AC cord (Lundahl Version 14.5kg)  (Not sure which chassis design will be shipped.)   Also offered: Assembly service, cost is $200.00 Stock resistor - 1/2 W KOA CFS1/J 5% carbon film resistor -2W, 3W KOA CFS1/J 5% metal film resistor Resistor upgrade option -1/2 W TAKMAN Audio Grade Carbon Film Resistor (custom made for TU-8600) (REX 50G 2%) Free before August 21, 2017. $65 after August 31, 2017
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Post by sadface on Sept 13, 2018 18:56:45 GMT 12
I should add these guys: www.tubes4hifi.com/I've had fantastic experiences with both Bob and Roy. They seeem to sell their separate products individually off the one website. Bob bent over backwards to organise custom 230V transformers power transformers on the 110v only big monoblocks. He also accepted something along the lines of a layby plan so I could afford them in the first place, even shipped things as favourably as possible re: customs duty. Roy, I dealt with first on one of his preamps. He too bent over backwards to accommodate me in terms of shipping demands, breaking up one of his kitsets so that I only got the parts I wanted ( I don't think it was a fair request in hindsight, but that's youth for you) email support getting it running. Suffice to say the kits work and sound fantastic.
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Post by Owen Y on Sept 13, 2018 19:37:52 GMT 12
Hey sadface - good one! Good feedback & experience. Any chance of a pic or two? (A pic is worth a thousand words, as they always say  )
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Post by sadface on Sept 15, 2018 9:57:52 GMT 12
Hi Owen,
There was a bunch of photos of the preamp build at an earlier stage on the old audioenz forum.
Here is a photo of the very first implementation.
  
It's been running in various forms for something like 6 years now. Here's a couple of photos from about 6 months ago, when i finally got it 'completed' and the wooden front panel on finally.
Since then it has been rearranged inside, with a bracket to mount the transformers, keeping them as far away from the pcb as possible and allowing a bit more room. Rivet nuts are perhaps the best thing in chassis technology since the tap and die.
It will need rebuilding again eventually, as the signal wire runs could be made shorter by moving the source selector and stepped attenuator to the back of the enclosure.
I'd also like to redo the ground bus bar, as I think I could do it much better now. My toolchest is far bigger than when I originally did the chassis work.
Unfortunately he doesn't make them anymore, which is a shame because they are incredible quality for the prices he use to charge.
I have a matching chassis which will get a DAC put in it soon. I also have a spare wooden front panel which will eventually replace the black steel front panel on my crossover, because the OCD part of me requires that all of my signal end bits have matching wood and knobs.
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Post by sadface on Sept 15, 2018 10:22:29 GMT 12
As for the monoblocks. Here is a photo of one looking pretty while waiting for the other too be completed.  Initial testing of the pair. Notice the early implementation of the preamp.
A couple of under the hood shots.
At some stage I would like to replace the 12au7 driver board with a 6SN7 driver board that they offer at www.tubes4hifi.com. I think it will sound better because Octal tubes. But more importantly means gives tube commonality with my preamp and means I won't have to keep 12au7s in stock.
According to Clarry out in Titirangi, with 2 kt88s and 12au7 drivers; these clip at 40w in trilinear mode, a bit more in ultralinear mode.
I'm not sure I will ever get around to adding a second pair tubes as I have too much gain as it is. I sort of knew that vacuum tube Watts are bigger, but in truth I had no idea. With my inefficient Dynaudio Bookshelf speakers at 86db/w, 40watts is a way to loud for my small listening room.
I'm currently making a gainclone from some Jaycar lm3876 kits to go inside Ipod driven boombox for the missus. It so damn cheap and easy, I will probably make a dual mono gainclone power amp to replace my Rotel backup power amp which at 120watts is just stupid.
In the longer term I would quite like to build something along the lines of 20watts Class A solid state to see how it compares to valves. Something like a Pass design or one of Rod Elliots designs from Aus.
I would also like to build a pair of single ended valve monos to see what the fuss is about.
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Post by sadface on Sept 15, 2018 10:56:50 GMT 12
A couple of other suppliers: Elliot Sound Projectssound.whsites.net/index2.html. Perhaps the best single audio resource on the internet. He also sells pcbs for all sorts of useful things. Only solid state mind you, Mr Elliot doesn't have much time for the tubes.
Tubelab Lots of information. Some really interesting pcbs for various valve amp projects.
Tubecab Inventor the the Aikdio preamp circuit. All sorts of great tube resources, extensive circuits. Has a store with pcbs and kits for valve preamps, headphone amps and power supplies among other things. Some really interesting preamps on here.
I am trying really hard to not pull the trigger on one of these 12VAC 6DJ8 preamp boards for the missus' boombox build. 6DJ8's can be gotten for as little as USD1.50 each from Russia.
Pete Millet Another treasure trove of Tube stuff. Also has an ebay store with PCBS for some interesting stuff, shipping doesn't cheap though. Some excellent looking PSU boards. Analogue Metric A great Hong Kong based source for audiophile grade electronic components and kits. All sorts of quality looking stuff on there, including some very reasonable prices on Iron; chokes, transformers etc. Some of their amp kits look downright bargins.
I've used these guys for a chassis in the past. Shipping was quick and reasonably priced. The chassis was exactly as promised.
I'm looking really hard at their LM3886 boards, delay protection boards and speaker protection boards. Audio Catalogue Another Hong Kong based supplier of audiophile bits. I've not used them by their reputation is excellent. Some exceptional looking Iron on there if you don't mind paying for it. A good source for some rare NOS stuff such as vintage caps and resistors. I've been eyeing up their pure silver wire for a while now. Hifi Collective UK based source of audiophile bits. Possibly the best source for top end European components eg Mundorf Silver/oil caps. Parts Connexion Canada Based. Probably the most comprehensive stockist of audiophile bits on the internet.
Not particularly cheap, not particularly fast, but they almost always stock what you want. I've used their mil spec, silver coated, teflon insulated, multi strand copper wire for all my signal wiring in a few recent builds and found it pretty darn good for the price. I've found that these guys ultimately end up the cheapest as you can get everything from the one supplier which saves a lot of money on shipping.
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Post by Owen Y on Sept 15, 2018 13:59:01 GMT 12
Hi Owen, There was a bunch of photos of the preamp build at an earlier stage on the old audioenz forum. [snip] It will need rebuilding again eventually, as the signal wire runs could be made shorter by moving the source selector and stepped attenuator to the back of the enclosure.
I'd also like to redo the ground bus bar, as I think I could do it much better now. My toolchest is far bigger than when I originally did the chassis work. Unfortunately he doesn't make them anymore, which is a shame because they are incredible quality for the prices he use to charge.
I have a matching chassis which will get a DAC put in it soon. I also have a spare wooden front panel which will eventually replace the black steel front panel on my crossover, because the OCD part of me requires that all of my signal end bits have matching wood and knobs.
Splendid, sadface - I thought that was one of Simon's Design Build Listen boxes, first time I've seen close-ups - shame yes, the'yre ((all?) no longer offered. The pre-punched metalwork is a great idea for DIY. Yes, that spacious chassis allows you to further mod when you gain more expertise & improve the build. (My own tight wood chassis builds have been difficult to update as ideas & knowledge changes ) Riv-nuts - did they come pre-installed on the chassis? We use them on our Ultrasonic Record Cleaner kit plates...  PS. Are the tubes4hifi schematics near-clones of the Audio Research Corp preamps?
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Post by Owen Y on Sept 15, 2018 14:12:26 GMT 12
That's a nice list of suppliers, I have used a few myself. HK suppliers & silver wire - I have used in the past www.vt4c.com - Chung & his wife Sandy are reliable (although I haven't talked to them for a while), they have a myriad DIY tube-related bits & pcs. Their website has become a bit glitchy on my browser but just click 'Online Shop' at the top left. Thanks for showing/sharing!
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Post by sadface on Sept 15, 2018 18:05:49 GMT 12
Hi Owen, The rivet nuts I added myself. Got me a rivet nut set from bunnings. www.bunnings.co.nz/kincrome-blind-nut-riveter-set-85pc_p05910345I used them to add threaded holes mounting holes all over that transformer bracket. The bracket itself was from bunnings. www.bunnings.co.nz/carinya-make-a-bracket-100x600x1mm-flat-galv_p00520682I simply bent it over the corner of my desk with some quick-clamps. m3 rivnuts for mounting the bracket to the chassis. m4 rivet nuts for mounting the screw terminals m6 rivet nuts for mounting the transformers. I've also found the www.v4tc.com website a bit glitchy recently. It was down for a couple of days 2 weeks ago. The tubes4hifi.com preamp kits seem to be a licensed version of an Aikido. Half of the power supply
 signal stage  The power supply is pretty impressive. Independant, regulated 6.3v heater rails for each channel. A single 6x5 rectifier goes into independantly regulated B+ supplies for each channel. Each channel gets its own 6.3v secondary. A single 230v secondary for the B+ supply and the rectifier also gets its own 6.3v transformer. I wouldn't have minded if Roy had gone the extra step of adding a 2nd rectifier so the channels were fully independent but I don't often see kits regulated B+ supplies, let alone the rest.
Here is the aikido circuit off the tubecad website for reference (with additional cathode bypass caps). 
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Post by Owen Y on Sept 16, 2018 19:12:26 GMT 12
I wouldn't stress about dual-mono everything, eg HT rectifier. I think the dual-mono channel separation thing is over played. I always remember Murray Dick (Ecofan) telling me that he found that a single large mono transformer resulted in better bass than 2 mono PTXs - LFs, where the power is in music signal, tends to be mono. However, a separate heater PTX is good, they are high current, so less chance of hum coupling into the HT windings.
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Post by Owen Y on Oct 19, 2018 12:12:26 GMT 12
Elekit (Japan): I see that the USA importer VK Music was showing their kits at RMAF 2018:  This looks like the TU-8600 300B Stereo Power Amplifier Kit, US$1185 + tubes. Note the nice R-core power transformer.  Elekit TU-8340VK amp (centre), with KT150 (or EL34, 6550) tubes. The amp on the LHS looks like a Sun Valley 211/845 SET Tube Amp Kit (Japan).  Elekit TU-8150 6AQ5 amp/headphone amp, TU-8200DX 6L6GC amp/headphone amp, TU-8500 tube preamp (bottom).
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Post by Owen Y on Oct 19, 2018 12:32:44 GMT 12
A better pic of the Sun Valley 211/845 SET Tube Amp Kit, nice huh? 
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Post by deano1974 on Oct 23, 2018 19:07:31 GMT 12
A better pic of the Sun Valley 211/845 SET Tube Amp Kit, nice huh? Very nice!
Manager & Product specialist at Rapallo AV & HI-FI
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Amplifier kits Dec 4, 2018 11:49:37 GMT 12
- Edited Dec 4, 2018 11:50:06 GMT 12 by jon
Post by jon on Dec 4, 2018 11:49:37 GMT 12
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Pundit
Post by papahemi on Dec 5, 2018 16:10:53 GMT 12
Insane alright, have shied away from valves to date, but at this price... anyone had any experience with these? At 3wpc may just be on the low-powered side to drive my Coral 4A-70 at 90db sensitivity - could also be dependent on input sensitivity quoted at 550 mv. The minidsp hd delivers up to 2v and I run it quite high - thoughts on this anyone?
We are what we pretend to be, so we must be careful about what we pretend to be.
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Pundit
Post by papahemi on Dec 5, 2018 16:12:34 GMT 12
Ooh Jon - did you put the AmpCamp Amp together?
We are what we pretend to be, so we must be careful about what we pretend to be.
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Post by sadface on Dec 5, 2018 17:41:50 GMT 12
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Post by Owen Y on Dec 5, 2018 19:43:03 GMT 12
At 3wpc may just be on the low-powered side to drive my Coral 4A-70 at 90db sensitivity - could also be dependent on input sensitivity quoted at 550 mv. The minidsp hd delivers up to 2v and I run it quite high - thoughts on this anyone? 3wpc may be OK for the Corals if (i) listening distance not to great, say <3m (ii) esp if the spkrs are located near a wall/s. You should get 80dB average SPLs with dynamic power headroom to spare. Sounds like your 2Vrms source is plenty to drive this amp to full power. I've little knowledge about the FU32 (also known as 832A apparently) or the kit design. Tube data - www.r-type.org/exhib/aaa0603.htmEdit: The top cap connections are to the anode plates, so a couple or few hundred volts on top there, that's why they are well shrouded
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