Modhouse Tungsten

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Hi all! I apologize for a dumb question, as I probably already know the answer, but this more wishful thinking. I listened to a Modhouse Tungsten at Canjam Dallas and really dug it. I have mostly ZMF stuff and have a Crack and unbuilt Crackatwoa sitting in a box. I was wondering if I would be able to use these amps on the Tungsten and wanted to see if anyone had experience with the pairing. I think it is 150 ohms and that is lower than what is recommended, but I thought I saw somewhere that you can tube roll to slightly lower the usability of the amps. Anyways, any advice would be greatly welcomed. 

[Paul Birkeland]

So I think it is probably worth a shot to plug them into the Crack to see if anything remotely resembling an adequate listening level is possible; I suspect that will not be the case.

I see some recommendations of being able to deliver 20V into the headphones, which are 155 ohms.  This is really not that big of a deal with a tube amp, and you could take a Kaiju and substitute the output transformers for this pair, but ask the winder to stack them without an air gap for parallel feed:
https://www.ebay.com/itm/403212772144?hash=item5de15aa330:g:zVIAAOSwGHFhXdDa&amdata=enc%3AAQAIAAAA0F9DAm%2BkslJTbD%2BtczZVN9Lmz%2Fbe97MjNi1qdRkJnEE5eB4xVcS7HLUeyEQQ8rNCAK2q8UNdnARJvc%2Bb9JyrtbzKUGDjCozRdBy4mLc0yL8QPpmJFBed9mMaAkhqVNc%2BilNfFJex%2FO3HJpHQi83%2BFnbktFIJDrTJc2pStx4xycJ9h%2BO%2BQFNv%2FYTIZwR3UjXE%2FbK18z4r2NV0GqvVVUUnKJHM%2ByQGHcVuXmPTejc2ZB23LxNTGP09tBwbDhjC0sD4t2hQQ70IpPrwmMlXWdMpwX8%3D%7Ctkp%3ABk9SR5z80v_7Yg

The 75 Ohm and 150 Ohm configurations would be worth trying out, and you'd likely want the DC filament upgrade just to be sure the amp is nice and quiet.  7W into 155 ohms is 32V, though you'll get a little less than that since you'd be substituting a 3K transformer with a 5K unit.  I think this could be a fun project though!

[ipetruk]

I am also interested in Tungsten someday and I was considering Kaiju to power it. But I am hesitant to optimize the transformers for one headphone only. I still want to power speakers, I want to power STAX and Raal via respective transformer boxes, so it only makes sense to keep transformers stock. What exactly would be wrong if I don't change the transformers as suggested?

[Paul Birkeland]

I still want to power speakers, I want to power STAX and Raal via respective transformer boxes, so it only makes sense to keep transformers stock.

Each of those applications works best with a very different circuit/transformer.  My recommendation for the alternate transformers is to meet the listed recommendations of the headphone manufacturer.  Not being able to output that much voltage, you may find that there just isn't enough output available for reasonable listening levels.  With the transformer substitution, the amp will put out adequate voltage and the distortion is going to be lower at your normal listening levels since the amp won't be driven as hard.