Help on assembling an Aikido 5687 kit

[machtman]

Hi
I'm a novice to soldering and DIY, having succeeded solely until now at assembling two nixie clock kits (fotos available on request). I then thought I knew how to solder and ordered a 5687 AllInOne Aikido kit from glassware in the US, and am almost totally lost in reaching decisions on which of the options to use.
Nick Gorham pointed me to this forum as including some people (he mentioned simon explicitly) with experience, and who might be friendly enough to help a beginner. The forum prevents PMs until five normal posts have been posted, so this is post 1. Any offers of help would be wonderful.
I'm currently in Cork, IE but am moving to Warwick next month, so also interested in meeting people with interests in audio and DIY after the move.

Thanks in advance
Mark

[simon]

I've played around with Aikidos Mark, both JRB's all-in-one and point to point wired, for line stages and headphones. But I wouldn't call myself an expert. I'm currently using 5687s for the first time in a Broskie Cathode Follower and I like them a lot . You're finished amp should be very nice.

Broskie's PCBs are immense, but there's a little more to coming up with an amp than just simply plug and play for a beginner say IME. The good news is not too much though, once a few basics are understood. And we're good at basic! His PCBs are as good a place as any to start.

What is it you plan to use it for, and with what?

[machtman]

Hi Simon, now I'm up to post 2. At this rate I can send you a PM in three more posts. Your choice whether to prevent that by long, all inclusive comments or accelerate it with brief remarks

I met Nick (initially by email and then in person at Whittlebury) because I was having a problem with the sound from my Linn Renew DS to my 1990's Klyne preamp, which I thought at the time was the unsung best preamp ever made. But the digital streaming sounded somewhat sterile. I suspected the problem might be that the DS was outputting 2.3 V whereas my CJ LP66S had a maximum input voltage of 1 V. And indeed when Nick threw together a simple Alps Blue pot passive, it showed that I was only ever attenuating and didn't ever need any gain. It also sounded dead. But then so did a Rothwell's or Russ Andrews input jack 10 or 20 db attenuator. Nick tried to improve the sound of the Alps by connecting it to a unity gain, which was better, but still nowhere near as good as attentuation through the Klyne. He therefore suggested a TVC-based passive and designed and built an S&B-based passive with magnetic relays, infrared remote control, and Furutech input jacks and wiring. It sounds so good with the Renew DS that I have retired the Klyne and may just sell it at some point.

While this was going on, I made a discovery (possibly a mistake because it ended up expensive) by comparing the sound of a HiRes download of Keith Jarrett's Koeln Concert (Cologne Cocert in english?) with am East German vinyl pressing from the 70s. This was with my Rega Planar 2 from the late 70s with a nondescript Shure MM cartridge. The vinyl blew the streamed music away. I then compared a ripped 1975 Japanese pressing of Dark Side of the Moon on CD with a 1975 vinyl pressing. Same thing. Finally I compared Jan Garbarek's Magico in the original ECM productions on vinyl and CD, and same thing. Since Nick was designing a JFET/5687/RIAA/6922 phono stage for MRCU sale, I had him build me an upgraded version with AN-V internal wiring, and better caps and Furutech jacks. While waiting (donkey's ages), I upgraded the TT to a Nottingham Analogue Ace Space Deck with an SME-IV arm and a Dynavector XX-II catridge with all the tweaks, which blew away the Rega as I had hoped. The phono stage is magnificent in sound and I'm very happy with it. However, I got carried away and bought a used Verdier Platine Nouvelle before Xmas with an SME 3012 arm and an Ortofon 90th anniversary cartridge which is waiting for me in the UK once I move. I consider this insanity because I am quite happy with the Notts and have never heard a Verdier, but there it is. And I'll sell one of the two TTs once I've had a chance to listen.

So what am I hoping to gain with the Aikido? Mostly experience on building my own gear. Secondly a chance to perform comparisons of components. For example I've bought an input and outpair pair of CMC silver plated RCA input jacks as well as one pair of WBT Nextgen silver jacks to see whether I can hear the difference (all the other wiring from the cartridge through to the amp is silver as well). I've bought a tocos volume control and if I'm happy with the Aikido, I might compare that to a DACT stepped attenuator. I was thinking of comparing silver wiring between HT Tx and PCB with copper wiring. All of this is curiosity to see whether it really does make a difference. I might even go overboard and upgrade the caps and resistors on the board over and above what Bronskie recommends. I've ordered a quad of Watford 5687WB Philips Jan cryo-treated valves and would compare them with a quad of original TungSol NOS that I have lying around to see whether they really are as good as Watford claims.

What I don't expect is that the Aikido will sound any better than the S&B passive. I've seem some posts that really good active pres can/do sound better than TVC-based passives with better bass control and clearer trebles. But I tend to hear things differently from other people, including the large number of people who can't hear differences between silver and copper interconnects or different qualities of coax cables or different ethernet cables. So I'm skeptical that this would be an improvement. But maybe it will be equally good and simply different. And maybe miracles happen and valves will sound better than TVCs with the Linn Renew, even though all I need is attenuation. And maybe this will be the beginning of a second system, even though I am already spending so much time on the first.

Thanks and over to you
Mark

[Chopsaw]

I've had a few decent arms over the years and a recent revisit to my 3012 was a revelation. I'm using mine with a Transfig Spirit and it surpasses all expectations. With a Verdier and that Ortofon you should be in for a real treat.

I'm not familiar with the Stevens and Billington transformers but I do have a Django TVC if that's something to go on. I also use a Transcendent Sound Grounded Grid preamplifier in my system with my Jolida Music Envoys and after many attempts with both I prefer the Grounded Grid preamp. There's a delicate touch with the Django but it has no balls. The Grounded Grid has the excitement I desire and is a clear winner. I'd dearly love to hear an S and B pre in my system but I doubt that's going to happen anytime soon!

[machtman]

What country do you live in?
Mark

[simon]

He therefore suggested a TVC-based passive and designed and built an S&B-based passive with magnetic relays, infrared remote control, and Furutech input jacks and wiring.

I think I remember that. Did the TVCs stick out of the top?

Since Nick was designing a JFET/5687/RIAA/6922 phono stage for MRCU sale, I had him build me an upgraded version with AN-V internal wiring, and better caps and Furutech jacks.

Lucky you

Right Mark, there's plenty to go at here, though if I understand correctly this might not be the best solution for you - a 5687 Aikido will give you ballpark 8 or 9 x gain and you really need attenuation. But let's not worry about that, it's a minor detail on the road to audio nirvana which you seem to be a long way down the path of already .

If you've never seen a valve data sheet then it's a good place to start, link here courtesy of everyone's favourite, Franks:
http://frank.pocnet.net/sheets/127/5/5687.pdf

Don't worry too much about understanding everything at first. At the end are some characteristic curves that are really helpful when designing, but you don't really need to understand them at this stage - the Aikido is very tolerant. Further up on the second page are three typical operating conditions (120V, 180V and 250V on the anode (or plate as it's an American sheet)). Below these are typical operating points - the manner in which the valve should be set up to work if you like. You don't have to stick with these, you can go off piste any time you like, they're just handy reference points.

With the Aikido each channel has four valves - usually dual triodes are used, like the 5687, so there are two valves per channel. The first valve is the gain/amplification stage, the second is the white cathode follower which is a load of jargon which means that it's a buffer (and is pretty much unity gain) but does a good job of driving the next stage. This is the bit you're hoping will improve what you already have. And it might, or might not, Nick's stuff is very good.

Back to the first stage, the gain from an Aikido is roughly half of the triode's gain because the two are stacked. Hence the 5687 Aikido has a gain of 8ish.

As Broskie says at various points when he's talking about the Aikido the circuit is exceptionally tolerant of the values of components used. But there are some better options than others. Fortunately JRB produces some fairly good instruction manuals. They are, however, not for complete beginners as even though he describes some stuff in great detail a certain amount of knowledge is required.

So if the above makes a bit of sense the next stage is to have a look at his PDF:
http://www.tubecad.com/2012/01/09/All%2 ... 205687.pdf

On page 7 he gives 4 typical setups, you choose any of the four with confidence of good results. Which would you prefer? You'd only find out by building all 4. And having a memory good enough to remember what each sounded like.

I suppose I should check to see if any of this makes any sense before going further, but the next question is did you just get the PCB or did you get kits with most of the components supplied?

[machtman]

Yes the TVCs stick up out of the top. I asked for an acrylic top so I can see inside.

Everything else makes sense. I had already printed the specs on the 5687 and it also has load curves. I just never knew what they were good for. Thanks for the link to the PDF. I'll study it.

I bought the whole kit with all his recommendations except for the rotary switch between the two caps which is not available. I've bought two Hammond TXs whose numbers correspond to 240 Hz variants of the TXs Broskie bought for himself according to Nick. However I don't understand the schematics nor do I know which would give me the desired voltage. But this gets me going.

Thanks very much for your patience
Mark

[simon]

Didn't he send a paper copy of the manual? That would make it a bit tricky if you weren't aware of its existence.

Which Hammond transformers do you have? We can start to work out your options then.

[machtman]

Hi Simon
The TXs are Hammond 369AX and Hammond 266N12. I haven't yet found the time to study the load diagrams so more on that later. However, your explanation that the choice of voltage depends on studying the load diagrams makes sense out of how to reach a choice. What I am uncertain about is whether to run the heater at 12 or 12.6 V and what the criteria are for that. And the basis for choosing a combination of resistors and capacitors from the table near the end of the pdf.

Sorry, I haven't been totally clear about (at least) one issue. I haven't yet received the kit, which is still in the post, and have been studying the pdf whose link you posted while waiting and ordering the ancillary kit. I had carefully read the pdf twice before I even posted but don't yet know what the printed manual contains and assumed until now that it was identical with the pdf.

This is post Nr 5 so we could continue this via PMs if you think that the topic is too specialised for a general audience. I'm happy to continue to post via the forum if you prefer or think it is of general interest.

What I have already ordered is the TXs, the valves (arrived), wiring (both copper and silver), a tocos volume pot and a Seiden 2 pole 6 way input selector (arrived), a cheap aluminium case, input and output jacks (arrived), an IEC socket and mains on/off switch, an extender to allow placing the Seiden at the back of the case. I've been reading Morgan Jones' book on building valve amplifiers (very educational) and have tried twice to read his book on designing valve amplifiers (over my head). I have a tube tester (built from a kit by Nick) and a multimeter and soldering irons and solder and bits and pieces and am buying other tools for working on the case. And possibly most important given my aging vision, I have an optivisor pair of glasses with LED lighting so I can see what I'm soldering. And I have a basic level of knowledge about valves from tube rolling and testing them and a novice level of soldering and problem solving from putting together the nixie clocks. (Previously I had tinned mains cables and electrical connections for a motorcycle but that is very different from soldering microelectronics)

Oh, one other thing is that I bought an uncased 2 amp variac transformer for which I still have to figure out what sort of cheap box to mount in and make sure that I don't kill myself in wiring it up. Broskie was fairly adamant about slowing increasing the power on first trials. Finally, Nick has agreed to help me do the final wiring of the HT power supplies when I visit him after I've moved to the UK, and wants to come visit me in Warwich and hear my HiFi after the move.

Mark

[machtman]

looks beautiful. The individual bags containing labels for each position will make life very easy. The manual seems to be identical with the pdf I downloaded and had already read.

One very important question: I have the impression that Broskie solders from the top. Is that the correct way to mount the components or can they also equally well be soldered from the bottom.

Mark

[simon]

Ah right, I hadn't appreciated you didn't have the kit yet. It's well put together isn't it?

I'm happy to continue here - someone else might find this useful, and perhaps more importantly others will keep me right!

The variac will be a very handy tool, I really must get one myself. I tend to rely on bottle (and a long stick if I'm short of bottle). This isn't to be recommended. Morgan Jones' books are both excellent reads. You are not alone in finding his design book quite heavy going though - I've been reading and re-reading bits for years. Everytime I re-read something a little bit more falls in to place, usually becasue I've understood something else from somewhere in his book and learnt a bit more from building something. This is why it's such an intriguing hobby for many of us.

You can solder (most) components on either side of the PCB, and indeed Broskie does this himself. So if you want the whole thing contained within a chassis then you can solder everything to the top. If you want the valves sticking out of the top of the chassis then you can mount the PCB to the underside of the chassis top and mount the components on the underside.

BUT, you must bear in mind that whilst resistor and capacitors are easy enough to solder on either side on the PCB, the valve sockets and three pinned regulators must mate up the right way round. So the LD1085 regulator used for the heaters must have the right legs in the right holes, and more importantly the sockets have to go on the top side of the board otherwise the valves just won't work. And if you mount hot things on the underside, particularly heatsinks, the heat will rise through the board as it has nowhere else to go. This isn't ideal.

Starting with the HT supply, your 369AX is 250V centre tapped @ 115mA. Using capacitor input (which JRB's PCB does) means that the raw HT after the rectifiers will be very roughly 250 x 1.4 = 350V. You'll lose the odd volt for for the diodes (which isn't important, but might be for instance if you used a valve rectifier which might drop 20 to 30V). There are then some resistors which will each drop some voltage - R17 is common to both channels, and there is then a split to 12a parallelled with 12b for each channel.

Ohms law is your friend, V=IR. So if you know how much current you want to run through your valves and you know the value of your resistors you can work out how much voltage there is across the each resistor.

Or if you know what voltage you would like on the anode of your valve and the current you would like to pass through it you can work out how much voltage you need to drop and therefore size the resistors accordingly.

Lunchtime is over so I'll have to stop now, but first question is did Broskie supply any resistors for R12a, R12b and R17? And if so what are they?

[machtman]

R17: 10, 20, 100, 200 (one each)
R12a, R12B: 2 each of 1.6, 2, 3, 3.9, 6.8 and 10K

I noticed in the Jones book on building that he first trims the leads and then solders them to prevent distortion of the solder joint during trimming. Clearly this is fiddlier than soldering and trimming. Would you bother to follow his advice or go for the less fiddly route?

The kit is superb. I'm staggered by the amount of space between the components on the board, the enormous sizes of the holes and the general feeling of quality of all the components. Before I start, I intend to actually measure all the resistors to see whether they are in the expected range and to teach me to read the color codes.

One trivial question, some caps do not seem to have + or - indicated on them or on the board. Is the direction irrelevant?

You've already given me room for lots of thought. Let's give this a couple of days to settle while I look things up and do some calculations.

Mark

[simon]

No problem Mark, the working it out is part of the fun. I have no time now till tomorrow anyway. Given your mains transformer and R12s and R17s you're looking for a combination which will match with one of the proposed scenarios in JRB's manual. I'd start by looking at 300V HT, see what the current is and then work back to find the value of the resistors so that you drop the best part of 50V. Don't worry too much, valves are remarkably tolerant beasts.

[Chopsaw]

I'll be following this Aikido thread as I bought the boards from the DiyAudio forum group buy ages ago but never got around to doing anything with them. Mine are for 6SL7/6SN7. I got all the bits together except the mains transformers but could never decide on the right valve combination let alone the resistor values so I gave up.

[machtman]

I'll be following this Aikido thread as I bought the boards from the DiyAudio forum group buy ages ago but never got around to doing anything with them. Mine are for 6SL7/6SN7. I got all the bits together except the mains transformers but could never decide on the right valve combination let alone the resistor values so I gave up.

Hi,
you might be able to learn from Simon but I doubt you can learn much from me because I am such a beginner at DIY. I also know too little to know whether the same TXs would work for your valves as for the 5687s. In my case I chose the TXs listed above as being the 230 V equivalents of some TXs recommended by Broskie in a 5687 blog at TubeCAD in 2012
(Actually Nick chose them after I naively asked what TXs I should buy if Broskie was recommending buying those in the blog). Broskie also recommends some toroidal TXs there and a dual TX for both HT and B+. So if look at that blog you can see what he was recommending for a 5687 board in 2012 in the US.
I've now figured out (again with Nick's help) which leads I should be using on the TXs I bought. I'm happy to pass that information on if anybody else is as naive as I am and needs the information.
In the process of buying the TXs, I ended up fixing myself on a 12.6 V heater (???) configuration because the TX for 12 V has a B in the designation. Somewhere in a newer blog Broskie is mentioning that 12 V is better if one wants to keep the total voltage down, but it's too late now.
I wanted to pass this trivia on now before I forget it because I need to do some serious studying of load diagrams and calculating what the resistances do and all of this is totally new to me.

I've now written more posts in this one thread than in my entire history of reading HiFi fora, and I would feel a bit less like an exhibitionist if other people were to chip in if they're interested in the topic.

Mark