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Inspire IHA-1 tube headphone amp

Discussion in 'Headphone Amps (full-size)' started by burn1, Oct 18, 2014.
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  1. grizzlybeast
    Is this including the one at moon audio?
  2. Xcalibur255
    Both are 5V rectifiers with 3 amp heater current ratings, in line with a typical 5U4G, so using them should not be a problem.  The amp's B+ requirements are pretty modest, the worst case scenario is around 80mA when using 6BX7 I believe, so there are no off-limits tubes in terms of capacity.  The heater current requirement is the only thing you need to watch, going over 3 amps means putting too much load on the power transformer.
    Personally I think the IHA-1 really sings when using 5R4GY type rectifiers.  The Brimar and Philips are both excellent and produce the best sound I've heard from the amp.
  3. Rossliew

    Thanks for the explanation. I suppose the 5R4GY tubes are relatively cheaper to roll as compared to the other top tier rectifiers as seen in Dubstep Girls listing.
  4. Xcalibur255
    The NOS Philips 5R4GYS they sell over at Upscale Audio is outstanding, IMO the only rectifier you really need for the Inspire.  I've tried a variety of tubes and this one is the best without spending insane money on something like a Marconi/GEC U52.  It's not super cheap, you can find US made 5R4 tubes for a lot less but they don't perform quite as well.
    A nice little side effect of using 5R4 tubes is they only have a 2 amp heater so it actually makes the amp run cooler, just as it would while using a 5Y3 tube.
    One thing to keep in mind about Rectifier reviews like the one Dubstep Girl did is that her results are specific to the amplifiers she was testing in.  The same tube can and will sound different in a different amp, for a variety of reasons.  I think the 5R4 suits the IHA-1 extremely well and brings out the amps strengths.  If we were talking about another amp I might not make the same recommendation.
  5. Rossliew

    Once again, thanks for the tip :thumbsup: Will keep that in mind if and when I purchase this amp. Am curious how the other non branded Russian rectifiers would sound with the amp. Sometimes nuggets of brilliance may be found with the less famous/popular makes.
  6. Xcalibur255
    I know a lot of tube amp guys hate on new production tubes.  There are some good ones, but IMO the run of the mill Russian stuff that ships with many new amps are not that great.  You don't have to spend a lot on NOS tubes if you're careful.  Even the non "legendary" ones are usually much nicer sounding than new production Sovtek tubes.
    smitty1110 likes this.
  7. Rossliew
    Shall take your advice to heart, sir. Will check out Upscale Audio when required. 
  8. Mobiustereo
    Hello! Does anyone have Dennis Had's e-mail address they can please pass on to me? Thanks.
  9. jelt2359 Contributor
    Message him on eBay, that's what I did..
  10. svmusa
  11. Rossliew
    Can the Dragon use 6C8G/6F8G tubes in place of the 6SN7s?
  12. Xcalibur255
    6F8G definitely yes.  They are identical to the 6SN7 electrically.  The 6C8G I'm less familiar with.  I looked at the datasheet and I see no reason why it wouldn't be okay to use one.  All the important electrical specs are compatible, but it's pretty different from a 6SN7 or 6BX7 in other ways such as plate resistance and transconductance so I have no idea if the tube would perform well in the amp.  They draw a mere 3mA of plate current, that's a very different bias than the tubes the amp is designed to use.
  13. Rossliew

    Is the 3mA of current draw too much for the amp? Also where would be a good place to obtain the 6sn7 to 6f8g adapters ? I found loads on eBay but somehow unsure of the quality..
  14. Xcalibur255

    No not too much, rather the opposite:  it's far below that of the tubes the amp is designed for.  The 6BX7 draws 40mA and the 6SN7 nominally draws 9mA per section. 
    You aren't going to hurt anything, I'm just saying it might not sound good when you try it.
    My trusted source for adapters is 2359glenn who can be found on this forum.  He's pretty busy these days with requests so I have no idea how what kind of wait time there is I'm afraid.
    I would recommend trying the 6BX7 before exploring lots of tubes.  They sound wonderful and are pretty cheap to get ahold of.  As long as the amp has enough volume that is, though I hear the design was changed a bit recently to resolve that issue.  I'd love to know the details of that actually.  I'm no amp designer but I've absorbed some knowledge over the years and it seems to me that the obvious way to give the amp more gain would be to change the design so each section of the 6SN7/6BX7 was no longer parallel wired but instead are each treated as a separate gain stage.  This would definitely give the amp more volume, but would reduce it's ability to drive difficult to power headphones and would have a slightly negative effect on the amps resolution.  But that's not necessarily what was done, it could have been changes in the transformers or any number of other design tweaks.  If you have any communication with Drew or Dennis when you order you should ask and see if they'll tell you.
  15. Skooks
    Has anyone used the Inspire IHA-1 to drive the HE-1000's?
    Or, do you know of a thread that addresses the combination?
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