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Tuesday, July 2, 2013

Two DHT Phono Stages


Just finished two phonostages with all directly heated triodes. Here some photos:

Both preamps share the same circuit which has already been presented here.

Also the internal construction is identical as shown here and here.

There is onlyone difference. The phono stage with the black covers uses a silver wound output transformer, the LL1660Ag.

Both preamps will be used with external MC step up transformers. Also the LCR RIAA will be in separate chassis.

The preamp with silver output transformer will be used with a silver MC step up transformer and the recently shown silver LCR RIAA.

Both preamps share the same sound character of all DHT amplification which has already been described here. The silver in the output transformer again make a remarkable difference. Stay tuned for a report on the sonic differences between the standard LL1660 and the silver version.

Best regards



  1. Hi Thomas,
    are the black transformer covers left overs or is there finally a new batch from cubesfortubes?

    Best regards,

  2. Hi Daniel,

    I am working with a new supplier for covers. I will offer a full range shortly. If you have needs for specific covers, drop me an email. I have some left and also some new ones already


  3. Hi Thomas
    Your all wood enclosures phono DHT with white caps
    look dream gorgeus :-) great work congratulation!
    Sonic differences between the Lundahl LL1660 and the silver version
    yeah is a very interesting topic beacause not many manufacturers &
    talkers about this high fidelity research.Hope maybe in future
    can i meet you on European Triode Festival to taste sound like
    Have a nice day

  4. Hi Krzystof,

    Thanks :-)

    Yes these differences the silver makes in transformers is remarkable. I will report on this in another post this week.

    I'll try to make it to ETF this year!

    Best regards