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Thread: Wanted - First Watt F5 good DIY build

  1. #11
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,869
    I'm Lawrence.

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    Quote Originally Posted by montesquieu View Post
    I've dealt with Kevin at Valab in Taiwan before quite a few times both for bits and pieces and for full components. The last big item I bought was a DHT preamp which I asked to be 240v, and as with this new item, it was modified for UK voltage before shipping. When testing it out for me, Graeme 'Valvebloke' said it was spot on for 240v operation and he said he was quite impressed with how it was done.

    And yes, Kevin did get his supplier to make 240v transformers which he then fitted and tested before shipping out, he said his transformer suppliers were familiar with the procedure as he had just done the same for a regular customer in Australia. At no extra charge incidentally. Genunely impressive. As I say this is Taiwan we are talking about not China, the business aproach is far more like you get in Japan than on the Chinese mainland.

    Just checked the tracking btw I think it's in the UK but not through customs yet, not sure what my chances are for getting it this week.
    That's impressive service, is Kevin the seller of the item you sent the link to, I assumed it was a Chinese seller?

  2. #12
    lordmortlock Guest

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    If it’s tortoise66 or something like that it’s Valab. I agree with Tom, really good service.

  3. #13
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,869
    I'm Lawrence.

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    Quote Originally Posted by montesquieu View Post
    I've dealt with Kevin at Valab in Taiwan before quite a few times both for bits and pieces and for full components. The last big item I bought was a DHT preamp which I asked to be 240v, and as with this new item, it was modified for UK voltage before shipping. When testing it out for me, Graeme 'Valvebloke' said it was spot on for 240v operation and he said he was quite impressed with how it was done.

    And yes, Kevin did get his supplier to make 240v transformers which he then fitted and tested before shipping out, he said his transformer suppliers were familiar with the procedure as he had just done the same for a regular customer in Australia. At no extra charge incidentally. Genunely impressive. As I say this is Taiwan we are talking about not China, the business aproach is far more like you get in Japan than on the Chinese mainland.

    Just checked the tracking btw I think it's in the UK but not through customs yet, not sure what my chances are for getting it this week.
    Excellent service, is Kevin the seller of that item on ebay then? We could support him with purchases if his customer service is that good.

  4. #14
    Join Date: Jan 2014

    Location: Northants

    Posts: 276
    I'm Martin.

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    I bought some anode loading plate chokes from Kevin when he first started on E-bay. They made it to the UK, but Parcelfarce managed to deliver them to someone else and they never arrived at my address.

    Kevin made me another pair for no cost as replacement. Very good service.


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  5. #15
    Join Date: Apr 2008

    Location: Cheshire, UK

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    I'm Clive.

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    The Valab version doesn't look like an exact copy of the Aleph J unless I've not caught up with later versions. The original 2005 version has an input impedance of 242k whereas the Valab one is around 22k. There are a number of other differences but some may be more down to how the circuits are drawn out on ebay vs the Pass circuit shown on diyaudio. I'd prefer an input impedance more like the original 242k but maybe there's a good reason for it being 22k on the Valab...maybe related to the volume control (which isn't shown on the ebay circuit).

    Just casually musing.....

    Oh I now see it's based on the Aleph-M not J. Even so it's still breathed on by Valab, which may well be a good thing in terms of making a reliable product.
    Last edited by Clive; 28-12-2017 at 15:58.
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  6. #16
    montesquieu Guest

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    Quote Originally Posted by Clive View Post
    The Valab version doesn't look like an exact copy of the Aleph J unless I've not caught up with later versions. The original 2005 version has an input impedance of 242k whereas the Valab one is around 22k. There are a number of other differences but some may be more down to how the circuits are drawn out on ebay vs the Pass circuit shown on diyaudio. I'd prefer an input impedance more like the original 242k but maybe there's a good reason for it being 22k on the Valab...maybe related to the volume control (which isn't shown on the ebay circuit).

    Just casually musing.....

    Oh I now see it's based on the Aleph-M not J. Even so it's still breathed on by Valab, which may well be a good thing in terms of making a reliable product.
    I couldn't find out much about the Aleph-M design, well not that I could follow anyway (tech-speak buried in DIY threads). What I did see suggests that although it's single ended, damping factor is still healthy (around 150 - lowish for solid state but fine in the valve world) so it may well be a possible bet for Tannoys.

    Incidentally I did hear a factory Pass Labs F5 with my 12in HPDs .. although it's push-pull, it didn't have the welly to get the low frequencies really running, I bet it would be nice with Golds though. Other than that I liked it. I'd say it's a fine amp but needs careful choice of speaker.

    The Valab will be driving Tannoy DC6 bookshelf dual concentrics, I'm betting it will be a lovely combination. I wouldn't expect it to drive the HPDs in the main system terribly well but I will of course give it a go, you never know till you try something. I'll be running it in the study with a Pass DCB1 so I might have the pot on the front bypassed anyway as it won't be needed ... I'm not expecting any impedance nasties though, the DCB1 should be fine even with 22k. Will also be giving it a try with the Tannoy Eatons (10in dual concentric, HPD295a but in many details, more like a Gold than an HPD).

    (Edit and apologies to Jake for the thread drift this isn't really helping him find one except through regular bumpage!)

  7. #17
    Join Date: Apr 2010

    Location: Bristol, since 1978. Current house since 1996!

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    I'm Chris.

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    The F amps, I think, were initially designed for full range speakers, if I remember all the stuff about them on 6 Moons (which is why I got my F3 for the Ocellias) Perhaps that's why the rather more complex load of a Tannoy doesn't quite make it? They are pretty low wattage.
    Chris.

  8. #18
    Join Date: Mar 2017

    Location: Liverpool

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    I'm Sandro.

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    I have a F5 quite different from the Vanilla version it has been in service for the past 10 years whit not a single problem and would never go back to anyting else, unless I win the lottery and spend mega bucks that is

    I can help you to build one or to source the components.

    PM and we take it from there
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  9. #19
    Join Date: Nov 2008

    Location: belgrade serbia

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    I'm gordan.

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    though aleph series were considered to be predecessors to FW, technically speaking this ain't first watt - although there are similarities with some of the FW units. if i understand correctly aleph M should stand for aleph mini so if you seek for more technical data, it should be related to mini.

    i would be curious to know the final price when it arrives - custom duties, EMS plus unit price. i have a highly improved F5 unit (possibly pushed to the real limits of the circuit without any cuts) here with me which is a tad over 500 pounds.
    Gordan.
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  10. #20
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 766
    I'm Sandro.

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    [QUOTE=

    i have a highly improved F5 unit (possibly pushed to the real limits of the circuit without any cuts) here with me which is a tad over 500 pounds.[/QUOTE]

    Please define highly improved and real limit of the circuit.
    There are so many variation possible from pair of transistors used, balanced and not, turbo and not, psu used for voltage and capacitance.

    I have 2 pairs biased at 2.6 A driving a pair of Polk LSi15 on 24 volts rails whit 150K uF on each rail on CRCLC the Polk are a pretty hard load to drive whit nominal impedence of 4 Homs and 87dB
    I am quite happy volume wise (neighbours no so much so) to push it up to 8 volts but is quite capable to go to 22 V before clipping and the chassis is ready to take a second board and go balanced
    Yes vanilla version may cost about £500 to build I do not see a limit to what can be done whit it

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