C.H. Diamond 6SN7 Tube Preamp

Clipdat
Clipdat Posts: 12,589
Check out this awesome looking tube preamp that I just came across on eBay: https://www.ebay.com/itm/C-H-Diamond-6SN7-Tube-Preamp-Khozmo-Attenuator-Goldpoint-selector-switch/272887717384

"C.H. Diamond 6SN7 Tube Preamp"

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The description sounds like this thing is no joke:

"The circuit is all direct coupled from the first tube to the last. The only coupling capacitor is at the output, where having one is unavoidable.
For that, I chose an Audyn True Copper Max.
The Max version is only available directly from the manufacturer in Germany at this time, but given the high rating it received from humble homemade hifi, I had to try it.
It took quite a while to arrive, but was well worth the wait. This is by far the best sounding capacitor I've heard.

The attenuator is a Khozmo series 100K.
This is an exceptional volume control, with 48 steps, which gives plenty of fine adjustment (1 db per step at the lower end), and an outstanding sound.

The signal path wiring is all solid OCC copper.

The power supply begins with a hexfred rectifier, choke filtered, then branches off to separate filter sections for each channel (to reduce crosstalk), ending with the last two filter sections using Solen film caps.
They took up a lot of room in the chassis, but I think they improve the sound over electrolytics in that critical final filter section which interacts with the signal path. No electrolytic, no matter how nice, will ever sound as good as a film cap."

@tonyb @pitdogg2 @kharp1 @mikeyb128 @mhardy6647 - What say you?

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Comments

  • pitdogg2
    pitdogg2 Posts: 24,548
    All I can say is I'd find a way to get those Solen's gone.....
    I see you can buy with out the EH tubes. I'm not a big fan of those
  • Clipdat
    Clipdat Posts: 12,589
    Get those Solens gone? What do you mean?
    pitdogg2 wrote: »
    All I can say is I'd find a way to get those Solen's gone.....
    I see you can buy with out the EH tubes. I'm not a big fan of those

  • mikeyb128
    mikeyb128 Posts: 2,885
    I’m sure it doesn’t sound too bad. It’s a little
    Pricey in my opinion. You could get something tried and true on the used market for much less. Like that joule lurking in the FS section.
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • Clipdat
    Clipdat Posts: 12,589
    Thanks for your thoughts!

    I think you meant the Modwright, the Joule is sold.
    mikeyb128 wrote: »
    I’m sure it doesn’t sound too bad. It’s a little
    Pricey in my opinion. You could get something tried and true on the used market for much less. Like that joule lurking in the FS section.

  • mhardy6647
    mhardy6647 Posts: 33,020
    FYI and FWIW, this is a (another?) nice option in a cost-effective, 6SN7-based preamplifier.

    http://www.tubes4hifi.com/pre11.htm (the "SP-14" kit).

    8eycja9y4wft.png
    ekas3qvt7sa1.png


    PS I'd agree about the Solens -- kind of 'entry level' decent-quality capacitors. Such a circuit deserves better. The cost differential doesn't have to be huge, either (Solens are pretty inexpensive and not the best sounding).


  • pitdogg2
    pitdogg2 Posts: 24,548
    edited March 2018
    mhardy6647 wrote: »


    PS I'd agree about the Solens -- kind of 'entry level' decent-quality capacitors. Such a circuit deserves better. The cost differential doesn't have to be huge, either (Solens are pretty inexpensive and not the best sounding).

    This^^^ Solens just hurt my ears. They're much better caps that are MUCH better sounding that do not cost but just a little more.

  • Clipdat
    Clipdat Posts: 12,589
    That looks sweet! I want it!
  • Clipdat
    Clipdat Posts: 12,589
    I guess that's a strange design decision then by the maker of that preamp. Curious as to why he would go that route if there are improvements for a minimal price increase.
    pitdogg2 wrote: »
    This^^^ Solens just hurt my ears. They're much better caps that are MUCH better sounding that do not cost but just a little more.

  • mhardy6647
    mhardy6647 Posts: 33,020
    edited March 2018
    I am somewhat late to the party, but I've become something of a fan of the 6SN7 and (more to the point) its forebears in the last couple of years. :)

    http://vinylsavor.blogspot.com/2014/02/tube-of-month-6sn7.html

    erjjdqd8zgr0.png

    http://www.effectrode.com/signal-tubes/the-6sn7gt-the-best-general-purpose-dual-triode/
    http://www.fourwater.com/files/hist6sn7.txt
  • mikeyb128
    mikeyb128 Posts: 2,885
    Bang for the buck comes to mind with 6SN7’s :smile:
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • Clipdat
    Clipdat Posts: 12,589
    Another cool eBay find: https://www.ebay.com/itm/PM-Audio-PM-201-6SN7-linestage-preamplifier/152950427522

    "PM Audio PM-201 6SN7 linestage preamplifier"

    s-l1600.jpg

    s-l1600.jpg
  • mhardy6647
    mhardy6647 Posts: 33,020
    Looks like that one has better coupling capacitors in it :)

    Are those 7N7s in socket adaptors?


  • Clipdat
    Clipdat Posts: 12,589
    Yep! From the auction description: "Also included is a pair of 7N7 to 6SN7 tube adapter along with a pair of Raytheon 7N7"
    mhardy6647 wrote: »
    Are those 7N7s in socket adaptors?

  • mhardy6647
    mhardy6647 Posts: 33,020
    edited March 2018
    There was a time that the 7N7 was the cheap NOS option for 6SN7s, but
    1) I think virtually all (if not all) Loktal tubes (and, thus, 7N7s) were made by one manufacturer (Philco, if memory serves). In other words, the tube rollers won't really have a lot of options in "7N7 space" :p

    and

    2) The secret got out pretty quick, and consequently the hyper-cheap 7N7 supply dried up pretty quick.

  • Clipdat
    Clipdat Posts: 12,589
    I don't know why but I want to try different preamps. Ideally I would have several that I could cycle through depending on my current mood/taste.

    I need serious professional help.
  • mikeyb128
    mikeyb128 Posts: 2,885
    Buy one good preamp that has some resale. That way you can sell it to try others. My Cary lasted 2 years, and has to be a personal record of mine.
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • Clipdat
    Clipdat Posts: 12,589
    But that's the thing, I don't want to sell them. I want to keep them. :)
    mikeyb128 wrote: »
    Buy one good preamp that has some resale. That way you can sell it to try others. My Cary lasted 2 years, and has to be a personal record of mine.

  • mhardy6647
    mhardy6647 Posts: 33,020
    edited March 2018
    Have you seen a picture of my house?

    ... and I avoid collecting preamps because I've heard so few that I actively (pun intended) liked (and that I can reasonably afford)!
  • Jstas
    Jstas Posts: 14,711
    I only have 2 pre-amps. Unloaded anything else I had.

    I have an Adcom GFP-750 "blue board" that I picked up from someone here and an Onkyo P-301 which is way better than anything that inexpensive has any right to be.

    Neither are super high-end but the Oinker serves to impress every time and that Adcom can stand toe to toe with anything at any price point and hold it's own. I love both of them and have had no desire to replace either one.
    Expert Moron Extraordinaire

    You're just jealous 'cause the voices don't talk to you!
  • Clipdat
    Clipdat Posts: 12,589
    That Adcom has been on my radar for a while, would love to give it a try!
  • kharp1
    kharp1 Posts: 3,453
    If it doesn't have a 2nd set of pre outs its destined for the scrap heap.
  • Clipdat
    Clipdat Posts: 12,589
    No sub out?
    kharp1 wrote: »
    If it doesn't have a 2nd set of pre outs its destined for the scrap heap.

  • kharp1
    kharp1 Posts: 3,453
    Clipdat wrote: »
    No sub out?
    kharp1 wrote: »
    If it doesn't have a 2nd set of pre outs its destined for the scrap heap.

    IDK.
  • Clipdat
    Clipdat Posts: 12,589
    No, I mean is that why it would go in the scrap heap if it doesn't have a second set of outputs? Because then you wouldn't be able to hook up your subs?
    kharp1 wrote: »
    IDK.

  • mhardy6647
    mhardy6647 Posts: 33,020
    It's (apparently) OK to use Y-connectors for preamp outputs to split signals. It's not like mixing two channels to one with a Y-connector "the other way".

  • txcoastal1
    txcoastal1 Posts: 13,132
    mhardy6647 wrote: »
    It's (apparently) OK to use Y-connectors for preamp outputs to split signals. It's not like mixing two channels to one with a Y-connector "the other way".

    That's how it would be wired inside the pre with dual outs

    Doug made me custom cable to do mine
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
  • Clipdat
    Clipdat Posts: 12,589
    Got a pic? Trying to visualize what you are describing.
    txcoastal1 wrote: »
    Doug made me custom cable to do mine

  • txcoastal1
    txcoastal1 Posts: 13,132
    All male Y-cable from my W4S Dac/pre to my Ampino amp and to my sub

    It's my desktop rig with LSi7, no crossover setting all full range near field
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
  • kharp1
    kharp1 Posts: 3,453
    edited March 2018
    I would have to believe that a pre with dual outputs would have some resistance added. Been several years since I was in that class, and, we don't do much of that here. Lot of plug and play components (proprietary) and logic changes (which is what we do mostly).

    Not saying that a splitter won't work, we all know it does, but, I think proper utilization would require modest circuit changes.
  • mhardy6647
    mhardy6647 Posts: 33,020
    kharp1 wrote: »
    I would have to believe that a pre with dual outputs would have some resistance added. Been several years since I was in that class, and, we don't do much of that here. Lot of plug and play components (proprietary) and logic changes (which is what we do mostly).

    Not saying that a splitter won't work, we all know it does, but, I think proper utilization would require modest circuit changes.

    Well -- buffers are nice, but, no it's not actually strictly necessary.

    http://www.rane.com/note109.html
    Introduction
    Wye-connectors (or "Y"-connectors, if you prefer) should never have been created.

    Anything that can be hooked-up wrong, will be. You-know-who said that, and she was right [I have no idea what this is meant to refer to :p ] A wye-connector used to split a signal into two lines is being used properly; a wye-connector used to mix two signals into one is being abused and may even damage the equipment involved.

    Here is the rule: Outputs are low impedance and must only be connected to high impedance inputs -- never, never tie two outputs directly together -- never. If you do, then each output tries to drive the very low impedance of the other, forcing both outputs into current-limit and possible damage. As a minimum, severe signal loss results.

    Monoing Your Low End
    One of the most common examples of tying two outputs together is in "monoing" the low end of multiway active crossover systems. This combined signal is then used to drive a sub-woofer system.

    Since low frequencies below about 100Hz have such long wavelengths (several feet), it is very difficult to tell where they are coming from (like some of your friends). They are just there -- everywhere. Due to this phenomenon, a single sub-woofer system is a popular cost-effective way to add low frequency energy to small systems.

    So the question arises as how best to do the monoing, or summing, of the two signals? It is done very easily by tying the two low frequency outputs of your crossovers together using the resistive networks described below. You do not do it with a wye-cord.

    (etc., etc., etc.)