Epiphany Acoustics Evolution Audio  Audio Emotion 
Page 1 of 7 123 ... LastLast
Results 1 to 20 of 126

Thread: 300B pp Build

  1. #1
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No

    300B pp Build

    Thought I'd start a new thread, as future searches based on 'guess what it is' are pretty unhelpful...

    The background:
    Young Kevin (Tel) was kind enough to pay me a visit a few months back, bringing a gift in the form of an afternoon and evening with his amps. These were built by our own Coco and I think it's fair to say that 'spectacular' is an understatement. They have decent power delivery with masses of subtlety, a wonderful tonal range, mids to die for and a really open and deep sound combined with tightly controlled bass and really lucid treble. My current Jadis are better than good, but the 300Bs are better than better. These are right up in la-la-land in terms of what it would cost to buy, but once heard, never forgotten. That left me with only two options. As I'm unlikely to win the lottery and don't have any mega-rich loving relatives likely to pop their clogs anytime soon, that narrowed it down to one option. Build a pair.

    This thread is intended as a help to anyone insane enough to consider something similar. So far there are no pictures, because there isn’t anything to take one of yet. As soon as the soldering iron comes out, I will post stuff.

    The concept:
    As I have learned over the years, at the heart of any decent tube amp are the transformers. Output transformers are crucial, but anything else in the signal path is equally important. The basic design of these is a 1J6 first stage, which powers a pair of 46 tubes. These feed into an interstage transformer, into a pair of 300Bs. As a result, the following iron is required for each mono: One output transformer, one interstage transformer, one mains transformer for HT, one HT choke and one mains transformer for filament supplies. The design incorporates a bias supply for the 300Bs and a constant current source for the 1J6.

    One thing I found out right at the start is fundamental to the build, and not something I had got my head around before. 300Bs, 46s and similar tubes are directly heated triodes. This means that the filament heater is also the cathode. As a result, the power to the filaments is massively important. It needs to be a constant voltage and current, but also should have an extremely high effective impedance to avoid messing up the audio side. Amongst others, Rod Coleman produces small PCB boards which are perfect regulators to supply the filaments. However, every tube needs its own, separate, floating filament supply. Therefore I already need, for each mono, five filament regulator boards and five DC supplies to them. This in turn means an LT transformer with five windings and with rectifiers and smoothing for five supplies. And, of course, cute little rectifiers are a no go. Schottkys are required,so that’s 20 diodes, five caps and assorted resistors, plus the populated regulator boards, just for the filaments.

    The current position:
    I am in component-buying mode at the moment. Thanks to Coco,I managed to steal a pair of Hashimoto HW-60-5 output transformers off ebay. When I say steal, that means these were only cripplingly expensive, as opposed to divorce-territory costly. Nobody makes interstage transforms that meet the required specs, so I’ve ordered a pair of hand-wound ones from DaveSlagle in the US. The mains transformers have to be custom wound, or there will be a mass of small ones all over the place. In the end, I specced one pair forthe HT and other stuff, and a second one for all the heaters. HT caps are a nightmare. High voltage ‘lytics are horrible, but the field is narrow. The HT runs at 400V or so, but a fault or breakage could see it run up to 700V plus for a short while, so a lot of care is needed. In the end I plumped for the Clarity Cap TC range. These are polys rated at 700V, so even if the unexpected happens, they should survive. Then, of course, there are all the odds and ends that are crippling unless you think ahead. I have found a decent Chinese source for things like tube sockets and transformer covers, but these bits all add up…

    The costs:
    In the hope that nobody else at Rab Towers reads this thread, I’m going to try to be as honest as I can about this, as it will hopefully be an indicator for anyone else starting off on this path. I’ve already sold my beloved Jadis monos to attempt to offset some of the cost, but I fear more may have to go. Anyway, to date:
    Filament regulator boards: 」100 from Rod Coleman. Need to be populated, but stupidly cheap frankly and a more helpful guy you could not hope to meet. A beer definitely owed in that direction.
    Mains transformers: 」880 in total for the four.
    Interstage transformers: 」330 so far, but there may be some duty when they arrive.
    Output transformers: 」600 give or take a penny or two.
    HT caps: 」140 (much cheaper than in truth, as I already had a few in the spares pile).
    One matched quad of 300Bs: 」280 at current exchange rates. EH Gold Grid. Cheap, as I had a discount voucher for Tube Depot. May be some duty on top.
    Tube sockets for 46s: 」80. May be some duty on top.


    Breath needs to be taken here. That’s already nearing two and a half grand, and there are no chassis yet, no PSU chokes, none of the rest of the passive components and none of the other tubes, tube sockets, transformer covers, etc. Plus all the bits we tend to ignore, like all the chassis hardware, wire, connectors, etc. Not to mention 40 PSU diodes and all the rest of the caps.
    Frankly, if it lands at less than 」3500 the pair, I’ll have done very well. And that’s with a really major coup for the output transformers and a bit of a deal for the 300Bs. And that's with cooking 300Bs at this stage. In short, these will not be cheap amplifiers by any means and it is a salutary warning for anyone who doesn’t understand why some manufacturers charge serious wedge for products. Bear in mind no development or design costs…

    Next:
    The initial build stuff. Once all the basic bits are here I can work out the fundamental layout and spec the chassis. Some pics will start at that time. I’m fortunate in that I have a source for the chassis plinths. I also have a mate whose parents run a light metalwork company. My initial thought is therefore to go a bit nuts. Build the basic chassis on a piece of 3mm aluminium, with all the bolts, screws and mayhem, then top that off with a piece of 1mm copper to cover it. However, I might just go for a proper copper chassis with a bit more depth and live with some bolts etc.


    Anyway. I’ll start posting pics when there are some more bits here. So far, I only have the output transformers, a heap of oddments and the filament boards.

    Do not expect this to be quick. Expect tears. Expect a visit or two to A&E. Expect unpleasantness with the bank manager and the nearest and dearest. Expect hissy fits. Expect major fuck-ups.

    I have only one aim, which is to have them finished, de-bugged, run in and ready for Scalford next year.
    Last edited by rabski; 29-07-2012 at 10:04 PM.
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  2. #2
    Moderator dom_'s Avatar
    Join Date
     Sep 2007
    Posts
     4,634
    Location
     Lindfield
    Turn Table
     Garrad 401
    Integrated Amp
     Modwright KWI200
    Speakers
     Snell Type A
    In the Hi-Fi industry?
     No
    First.


    Thought I would get my foot in on what should be an epic thread.

  3. #3
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No
    It'll be epic for sure. Picture the first ten minutes of 'Saving Private Ryan' and add a soldering iron, variac and bank manager.
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  4. #4
    Super Dooper Wammer robin's Avatar
    Join Date
     Dec 2006
    Posts
     3,745
    Location
     City of Bradford,
    Real Name
     robin
    Turn Table
     voyd valdi
    T/Arm & Cart
     a/n arm 3 a/n iq3
    SUT/Phono
     SJS
    Digital Source 1
     meridian 500
    Digital Source 2
     moon equinox
    DAC
     chord 64mk2
    Integrated Amp
     cary cad 300bsei
    Speakers
     audio note e
    Pre Amp
     VDH-array a1
    Power Amp
     radford sta 15
    Headphones
     
    In the Hi-Fi industry?
     No
    this is going to be very interesting , good luck richard
    django pre leak st 20 tannoy 15" MG s

  5. #5
    Miserable Git unclepuncle's Avatar
    Join Date
     Apr 2007
    Posts
     11,161
    Location
     Northamptonshire
    Real Name
     Paul
    Digital Source 1
     Italian Stallion
    DAC
     Italian Mare
    Integrated Amp
     Black & Green
    Speakers
     Teeny Tiny
    In the Hi-Fi industry?
     No
    Good luck with this Richard.

    I don't know one end of a soldering iron from the other but you certainly have the speakers and preamp to do them justice so I'm sure it will be worth the cost and man hours in the end.
    'Master of Prescience'

  6. #6
    HiFi Dealer Wammer BD Audio's Avatar
    Join Date
     Jul 2007
    Posts
     13,054
    Location
     Malvern
    Real Name
     Jack
    Turn Table
     J.C.Verdier Platine
    T/Arm & Cart
     IO-Gold + SPU Spirit
    SUT/Phono
     Modwright PH150
    Digital Source 1
     Mac Mini
    Digital Source 2
     Audionote UK
    DAC
     Modwright Elyse
    Speakers
     TuneAudio Anima
    Pre Amp
     Modwright 36.5 'DM'
    Power Amp
     Modwright KWA-150SE
    Headphones
     Phonon
    In the Hi-Fi industry?
     Yes
    What's going to be the technical details Rab? Power output etc?

  7. #7
    Sssshhh Shut The F..k Up It Cost How Much!?!'s Avatar
    Join Date
     Oct 2008
    Posts
     13,401
    Location
     Cheshire, good side.
    Real Name
     Bob
    Turn Table
     Transrotor Fat Bob
    T/Arm & Cart
     Transrotor/Koetsu
    SUT/Phono
     S&B/Hagerman Trumpet
    Digital Source 1
     Esoteric P-30
    DAC
     AS DAX Discrete
    Speakers
     JBL L112 Quad ESL989
    Pre Amp
     Audio Research SP14
    Power Amp
     Primare 928 (white)
    Headphones
     Stax 4040 Beyer 990
    In the Hi-Fi industry?
     No
    How much have you budgetted for croc clips?

  8. #8
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No
    No idea of output mate. I expect 25-35W each, but that's just a mere guess. Too much work at the mo. I wrote that post yesterday, but I thought I might as well stick it up!

    - - - Updated - - -

    Quote Originally Posted by It Cost How Much!?! View Post
    How much have you budgetted for croc clips?
    」1247 each.
    Kondo.
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  9. #9
    Leper Wammer AmDismal's Avatar
    Join Date
     Apr 2007
    Posts
     8,795
    Location
     St Albans
    Real Name
     Adam
    Digital Source 1
     SB3
    DAC
     DitB
    Integrated Amp
     Sony V-FET
    Speakers
     JBL L300 Summit
    In the Hi-Fi industry?
     No
    Quote Originally Posted by rabski View Post
    Bear in mind no development or design costs…
    Have you factored in buying shares in your local curry house? If that gets you a 10% discount it'll be worth it.

    But utter respect, these will be ace. Wasted on those speakers, sure, but just ace nonetheless.

    The only advice I'll give at this stage it to leave lots of room. Either for big foo later or just to make it easier to work with them. Good luck
    Compression drivers twerk my eardrums

  10. #10
    Frugalphile Howlindawg's Avatar
    Join Date
     Mar 2009
    Posts
     3,425
    Location
     Leixlip, Ireland
    Real Name
     Martin
    Turn Table
     Technics SL1210 M5G
    T/Arm & Cart
     A.Note / BA Mantis
    Digital Source 1
     SB Touch
    Digital Source 2
     Meridian 507
    DAC
     dCS Purcell + Elgar
    Integrated Amp
     Devialet 200
    Speakers
     Usher Dancer Mini-2
    In the Hi-Fi industry?
     No
    Well the first post has certainly caught my attention.
    The truth may be out there, but the lies are inside your head.

  11. #11
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No
    Quote Originally Posted by AmDismal View Post
    Have you factored in buying shares in your local curry house? If that gets you a 10% discount it'll be worth it.

    But utter respect, these will be ace. Wasted on those speakers, sure, but just ace nonetheless.

    The only advice I'll give at this stage it to leave lots of room. Either for big foo later or just to make it easier to work with them. Good luck
    Wasted on those speakers eh? Well, I'm factoring in enough room to have a nail-varnish holder built in to the top in case you want to buy them one day
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  12. #12
    In the trade Wammer pure sound's Avatar
    Join Date
     Sep 2011
    Posts
     7,153
    Location
     West Devon
    Turn Table
     STST Motus II
    T/Arm & Cart
     STST Vertex. Io Ltd
    SUT/Phono
     ANS6 Aurorasound
    Digital Source 1
     A8500
    Digital Source 2
     Sony CDP-715E
    Speakers
     Horn
    Pre Amp
     Aurorasound PREDA
    Power Amp
     300B or M845
    Headphones
     Senn HD600. HEADA
    In the Hi-Fi industry?
     Yes
    Nice one Richard, I look forward to seeing/reading about the progress.

    Out of interest, what is the IT spec?

  13. #13
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No
    Quote Originally Posted by pure sound View Post
    Nice one Richard, I look forward to seeing/reading about the progress.

    Out of interest, what is the IT spec?
    Glad you're looking forward to it. I'll likely need your help at some stage

    The interstage is 1:1 10k. Adjustable bias on the 300B side. Pete's design. I'm just a soldering-iron jockey at this point.
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  14. #14
    Deaf Wammer Tel's Avatar
    Join Date
     Aug 2006
    Posts
     26,337
    Location
     Hove Actually
    Real Name
     Kevin
    Turn Table
     Kuzma Stabi S
    T/Arm & Cart
     Stogi, AN Io
    SUT/Phono
     Audio Note S6c
    Digital Source 1
     Rega Saturn
    Digital Source 2
     SBT
    DAC
     Rega
    Speakers
     LV OBX-R2
    Pre Amp
     Audio Note M3
    Power Amp
     CocoSan 300B PP Mono
    Headphones
     
    In the Hi-Fi industry?
     No


    I had better make myself comfortable here, I think I will be visiting this thread quite a lot
    "We could have saved the Earth but we were too damned cheap" Kurt Vonnegut

  15. #15
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No
    Actually, on that note and even this early in the procedings, I need to add a couple of thanks.

    Firstly to Pete, Coco. His design, and his patience in answering my sometimes dumb questions is unending. The last time I scratch-built something was an EL34 PP design that saw me through uni. Even though it was my design from start to finish, that was not yesterday...
    Second, Rod Coleman. 」100 for ten heater regulator boards and all the components is laughably cheap. What counts is that he's incredibly helpful. To the extent of asking me to send him my PSU Design files so he can look at them and give some advice.
    Actually, everyone in the 'DIY' side of this crazy hobby is madly helpful. I have ordered the transformer covers off a Chinese site and have ended up swapping bits of the circuit with the guy and discussing the best source of various bits.
    The world is not always the dump we think it is...
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  16. #16
    Wammer silencio's Avatar
    Join Date
     Feb 2010
    Posts
     2,543
    Location
     Kabul, Afghanistan
    Real Name
     Chris
    Turn Table
     'fraid none
    Digital Source 1
     UnisonResearch Primo
    Integrated Amp
     Prima Luna Dialogue2
    Speakers
     Opera Prima
    In the Hi-Fi industry?
     No
    Good luck, Richard No chance of me attempting something like this, although I'd love to, but I'll be reading with interest.

  17. #17
    HiFi Dealer Wammer BD Audio's Avatar
    Join Date
     Jul 2007
    Posts
     13,054
    Location
     Malvern
    Real Name
     Jack
    Turn Table
     J.C.Verdier Platine
    T/Arm & Cart
     IO-Gold + SPU Spirit
    SUT/Phono
     Modwright PH150
    Digital Source 1
     Mac Mini
    Digital Source 2
     Audionote UK
    DAC
     Modwright Elyse
    Speakers
     TuneAudio Anima
    Pre Amp
     Modwright 36.5 'DM'
    Power Amp
     Modwright KWA-150SE
    Headphones
     Phonon
    In the Hi-Fi industry?
     Yes
    Shocking! You're using Chinese parts Richard! What ever will the Mafia say?!

  18. #18
    Super Wammer russ abbott - royds brother's Avatar
    Join Date
     Jan 2006
    Posts
     18,093
    Real Name
     stu
    Turn Table
     Garrard 301
    T/Arm & Cart
     Dv505 Koetsu
    SUT/Phono
     micromega
    Integrated Amp
     Puresound 2A3
    Speakers
     Coral 15/70 grf cabs
    Pre Amp
     Coral M100 Le cleach
    Power Amp
     Coral H104 Tweeter's
    Headphones
     
    In the Hi-Fi industry?
     No
    Hope it goes well.

    Bet your chuffed you invited kev over.
    Mince pies are not just for christmas - ​Peter kipling 1987

  19. #19
    Cogito, ergo doleo. rabski's Avatar
    Join Date
     Dec 2006
    Posts
     15,575
    Location
     Eat Mudlands
    Real Name
     Richard
    Turn Table
     Well (Bad) Tempered
    T/Arm & Cart
     WT / Dynavector XX2
    SUT/Phono
     Kairsound SUT
    Digital Source 1
     Marantz transport
    Digital Source 2
     Squeezebox
    DAC
     Audiosector NOS
    Integrated Amp
     In the workshop
    Speakers
     Living Voice
    Pre Amp
     Gordon Welford
    Power Amp
     845 nutter
    Headphones
     Nah
    In the Hi-Fi industry?
     No
    Quote Originally Posted by russ abbott - royds brother View Post
    Hope it goes well.

    Bet your chuffed you invited kev over.
    He's such a lovely guy... but there is a part of me that wishes he'd come without those amps...
    I know that you believe you understand what you think I said, but I知 not sure you realise that what you heard is not what I meant.

  20. #20
    Super Wammer russ abbott - royds brother's Avatar
    Join Date
     Jan 2006
    Posts
     18,093
    Real Name
     stu
    Turn Table
     Garrard 301
    T/Arm & Cart
     Dv505 Koetsu
    SUT/Phono
     micromega
    Integrated Amp
     Puresound 2A3
    Speakers
     Coral 15/70 grf cabs
    Pre Amp
     Coral M100 Le cleach
    Power Amp
     Coral H104 Tweeter's
    Headphones
     
    In the Hi-Fi industry?
     No
    Mince pies are not just for christmas - ​Peter kipling 1987

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •