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Post by Deleted on Jan 31, 2010 7:26:44 GMT
Perhaps some people, but definitely not the birthday boy !
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Post by PinkFloyd on Jan 31, 2010 14:53:31 GMT
Nice simple circuit , panny FC or even FM may work nice on the cathodes Yes, FC are good in this position Oh yes, I love them Leo Plus I have 250 of the bastards so it's only sensible to use them I've also got a few hundred EVOX PMR 100nF /400V so will be bypassing ALL of the electrolytics with these on the underside of the board. Got a couple of reidons for the PSU resistors.... looking forward to firing this puppy up again once all the work is done
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bullpup
Been here a while!
How much is that doggy in the window?
Posts: 517
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Post by bullpup on Jan 31, 2010 15:12:19 GMT
Mike, I was reading in the link I provided how the transformer has multiple tappings so that the amp can be accurately matched to the headphones. Is this an option that is more hassle than it's worth or could this option be selected via say a front monted selector?
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Post by guadixman on Jan 31, 2010 15:16:31 GMT
Hi Mike, as newbies are always watching threads like this I assumed that you would give a personal opinion on the sound of shunted or non shunted pots.
Same goes for the Dynamicaps v what you like. Reason being of course because those caps are the only ones in the signal path, so they will have a very big impact on the overall sound.
In fact by using PCB pins, which I know you don't like and neither do I but you could have tried out a lot of different caps, that opportunity is now lost. BTW Dynamicaps are not that expensive at all.
I was also taught to never make more than one change at a time. I have broken this rule on occasions and regretted it, since where is your reference point.
Since you don't say, can I assume you don't like shunting a pot. For those that don't know - a shunted pot means the pot is effectively removed from the signal path and all you are listening to is the resistors themselves, they drop 6dB but that should not normally be a problem.
On the old WAD board a lot of members took part in the shunt experiment and many different configurations were used along with an assortment of resistors.
This to me is a very positive way to use a forum, many people get involved and a lot is learned. The upshot of the shunt exercise was that every single person who previously had used attenuators ditched them for the shunted pot. I myself have a Seidon/Welwyn R55Y shunted pot that does'nt hold a candle to an Alps Blue/naked Z foil.
Finally I did'nt realise your opinions on boutique caps/ resistors and so on, since I hav'nt been on this forum very long. It would be helpful if we had a section where regular contributors to the forum could place their likes/dislikes - otherwise others will not know how to 'read' their posts.
Sandy and Robert are exceptions, nobody can be in any doubt about where they are coming from because they are very clear and that is to their credit. Also age changes hearing capabilities - the opinion of someone in their 20s, will be vastly different from someone in their 70s or whatever - an opinion without background reference points is meaningless.
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Post by PinkFloyd on Jan 31, 2010 20:28:49 GMT
Hi Mike, as newbies are always watching threads like this I assumed that you would give a personal opinion on the sound of shunted or non shunted pots. I WILL Stuart! I have had the amp for less than a week and am in the process of tidying the internals up a bit, as soon as I have done this I will comment on shunt V non-shunt. As I've already explained, I like caps that "fit" and that are designed for the job.... I don't like huge caps dangling about inside amps.... sure, they may sound good but my personal taste prefers "neat and tidy" and properly soldered into position. Stuart, you obviously don't know me I am trying to get the amp back to, as close as possible, original spec so I can start from the "beginning".... I will then have a reference point to work from.... were you aware, for example, that R7 and R14 were two totally different values? They should have BOTH been 100 ohm but R14 had 4 x 100ohm Welwyn RC55Y resistors in "parallel" which gave a value of 25ohm ;D Little things like this I need to rectify before I can even begin to start comparing capacitors. The wiring to the pot was barely making contact (dry joints) and just touching them with my finger caused them to fall apart...... C3 should be 100uF, 150uF was fitted..... you'll appreciate it's a wise move to make sure the amp is within spec before I start rolling in capacitors? Same here, I always only make one change at a time but, in this instance, thought it best to make sure the circuit was to spec so it's going to be necessary to pretty much gut the board and fit brand new components.... as much as I like NOS valves, 25 year old BC caps are a different thing..... the Rifa cap (150uF) measured 223uF and the date code suggests it's from 1980!..... sure, they "work" but way out of spec according to my Atlas capacitance / ESR tester.... one of them tested quite a way out of spec with regard to ESR. I like shunting a pot and the shunt will remain, for the time being.... again, I have only had the amp for a "week" and can't do everything at once. I'm sure if you search through the DIY section you'll find similar tests here When I get a "virgin" amp I ALWAYS share my thoughts with forum members, and they share their thoughts. It's a different kettle of fish with a relatively "obscure" amp like the HD-83, not many people here own one..... obviously, if this thread gets popular with HD-83 owners then the games will commence If it's only me talking to myself in the thread then, what the hell..... I'll do my "tweaks", from years of experience, using parts that I know will suit my ears and certain parts of the circuit..... I don't just chuck a handful of parts in Stuart, I have "listened" to hundreds of components over the years, and keep stock of thousands of capacitors from Black Gate to Nichicon to Panasonic to Russian military to Sprague.... I could fill this page with "names" and "pictures" but that wouldn't mean a thing.... basically, I've got a good idea of what sounds good, to my ears, and don't need guidance on what, or how to, listen to components I don't dislike "any" components Stuart, they all have a place.... the secret is choosing the correct part for the job ;D My experience tells me that Allen Bradley carbon composites would be good in this amp so I will be stripping out all the existing resistors and fitting carbon composites in their place..... I may be wrong..... I'll let you know how they sound If you stick around long enough you'll soon become aware of my opinions In the meantime, have a trawl through the DIY section (if you have time) Mike.
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leo
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Post by leo on Jan 31, 2010 21:24:46 GMT
I understand the idea wanting to put an amp back near to stock spec especially if the only version you've heard was tweaked to suit somebody elses ears, lots of flavours can be added to this stuff . BTW, at last those Allan Bradly's are non magnetic unlike most of the newer so called carbons, try sticking a magnetic screwdriver near unused newer carbons, bloody things tend to have metal end caps Lots to do and try with this amp and plenty of fun to be had
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bullpup
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How much is that doggy in the window?
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Post by bullpup on Feb 1, 2010 13:27:55 GMT
What happened to the before and after pics last night?
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Post by miker on Feb 1, 2010 20:24:07 GMT
A bit late to the topic. I have the build/instruction notes for this amp in pdf form if you want them. These are shadow printed with `sample only' so probably come from a time after Nick Lucas left WAD and may be for the MkII version of the amp.
I also have a follow up article on the amp from Hi-Fi World in which the designers (?) apply an upgrade kit changing components for improved sound. That cost GBP170 (ex vat) in 1999, almost as much as the amp GBP200. Can scan those if you are interested.
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Post by PinkFloyd on Feb 3, 2010 11:22:51 GMT
What happened to the before and after pics last night? Sorry BP, there are no "after" pics yet, still awaiting the resistors... I will do the before / after pics as soon as I have some "after" pics to upload
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Post by PinkFloyd on Feb 3, 2010 11:29:08 GMT
A bit late to the topic. I have the build/instruction notes for this amp in pdf form if you want them. These are shadow printed with `sample only' so probably come from a time after Nick Lucas left WAD and may be for the MkII version of the amp. I also have a follow up article on the amp from Hi-Fi World in which the designers (?) apply an upgrade kit changing components for improved sound. That cost GBP170 (ex vat) in 1999, almost as much as the amp GBP200. Can scan those if you are interested. Hi Mike, Any infor would be most appreciated I already have a PDF is it the same as yours? wduk.worldomain.net/acatalog/hd83.pdf ) The follow up article would be great, many thanks. Mike.
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Post by miker on Feb 3, 2010 20:52:18 GMT
No. The PDF I have appears to be part of the assembly instructions, looking at it I now realise it only has diagrams. I though I had more, I'll have look around my pc.
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Post by PinkFloyd on Feb 4, 2010 2:19:26 GMT
What happened to the before and after pics last night? Ok... at last the Allen Bradley (non inductive) resistors arrived so I can now present an "AFTER" pic..... basically, removed everything (apart from the diodes and ELNA Silmic caps) Fitted EPCOS power caps, 220nF Rifa 426, Panasonic FC 100uF...... I have bypassed the power caps with EVOX PMR / 100nF (400V) and may well bypass the 100uF and 470uF with the same. I have also fitted Reidon and Mills non inductive power resistors. (note: The Allen Bradley 1 Watt jobs have thick leads and it's necessary to drill the pads out a tad to accomodate them) The PCB was pretty "dogeared" with quite a lot of pads wiped out but I went PTP on a few of the components / repaired tracks so all is now sound I'll wire her back together tomorrow and have a listen.... I'm looking forward to the "non inductive" experience Before: After:
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Post by PinkFloyd on Feb 4, 2010 21:26:41 GMT
Well...... that's her finally back together (click pics to view full size) Basically, Allen Bradley, Mills and Reidon non inductive resistors. EPCOS power caps, ELNA Silmic and Panasonic FC ( all electrolytics bypassed with EVOX 100nF / 400V PMR film caps). Coupling caps are 220nF EVOX PHE426 bypassed with 18nF / 400V vintage Mullard mustards (I selected the mustards for their superb tone)... Mullard mustard Didn't do a lot else apart from tidy up the wiring a bit (still a bit to do in that respect) and ensure all the connections were 100% sound. I have left the pot in shunt mode for the time being, will try it without the shunt and also a stepped attenuator and decide which is best once all the components have cooked for a few hours. I fired her up and the sound is absolutely SUBLIME! The detail, the soundstage, the tonality.... you name it, absolutely stunning If it gets even better with burn in I think I'll cream my pants the "energy" this amp has is quite simply breathtaking..... now I can see why Rick has always urged me to go down the valve amp with output transformers route..... no solid state amp I have heard has come anywhere close to this presentation.... it's exciting, it's dynamic and it's raw energy gives the impression of "real" sound, rather than pre recorded sound.... it's like "being there" on certain live tracks.... spectacular One thing that was pissing me off, however, was a low level hum...... I traced it to the mains wiring passing the PCB so have decided to do without the front switch and have wired the transformer primary direct to the IEC socket (via a chassis mounted fuse)..... TOTALLY silent now I will report back once she's had 200 hours on her.
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Post by PinkFloyd on Feb 4, 2010 23:21:09 GMT
23:18 GMT.... I have just had an eargasm and it's my first for MANY a long year Oh boy, this is the real deal.... quality on a stick!
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Post by PinkFloyd on Feb 4, 2010 23:50:56 GMT
Bullpup..... I can now do a before and after Before: After:
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Post by PinkFloyd on Feb 5, 2010 0:01:35 GMT
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Post by PinkFloyd on Feb 5, 2010 0:03:59 GMT
Listening to Dire Straits "Alchemy"..... I'm there baby..... The best amp I've heard bar none
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Post by PinkFloyd on Feb 5, 2010 0:23:04 GMT
London rocks
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mrarroyo
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Our man in Miami!
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Post by mrarroyo on Feb 5, 2010 0:31:26 GMT
Nice work there Mike, glad you are enjoying it. Cheers.
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Post by PinkFloyd on Feb 5, 2010 0:42:01 GMT
Nice work there Mike, glad you are enjoying it. Cheers. Enjoying it? best I've heard to date mate...... I am in heaven at the moment
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leo
Been here a while!
Team wtf is it?
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Post by leo on Feb 5, 2010 0:45:06 GMT
Nice! its what this hobbies all about
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Post by PinkFloyd on Feb 5, 2010 1:37:37 GMT
This is truly mind blowing sound! It's gonna keep me up all night....
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Post by PinkFloyd on Feb 5, 2010 2:17:13 GMT
Just thinking................ this is when the UK ruled the world with kit amps What a fantastic kit amp the WAD HD-83 was.... I can't believe what I'm hearing... it feels like heaven
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bullpup
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How much is that doggy in the window?
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Post by bullpup on Feb 5, 2010 9:07:48 GMT
Thanks for the pics Mike.
Did you play around with impedence matching via the different tappings from the transformer? I will email you the notes as supplied by Miker.
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Post by PinkFloyd on Feb 6, 2010 13:10:20 GMT
Thanks for the pics Mike. Did you play around with impedence matching via the different tappings from the transformer? I will email you the notes as supplied by Miker. Hi BP, Not yet but I certainly will do once everything has bedded in and I get fully used to the amp Mike.
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