Rerurn to Romy the Cat's Site


In the Forum: Melquiades Amplifier
In the Thread: Single-stage Melquiades vs. DHT amps
Post Subject: ..are lacking in power, dynamics and bandwidth.Posted by Romy the Cat on: 12/1/2008
fiogf49gjkf0d
 tuga wrote:


 nl wrote:

In general, DHT amps are lacking in power, dynamics and bandwidth.
Would this be the result of poor implementation or rather a feature of such technology?
If the latter is true, then it might only make sense to use DHT for Injection purposes... 


I do not think that it has anything do with implementation, though dynamics might be a factor of bad implementation. The bandwidth is not the problem of DHT but all SETs. I do not see why DHT shell has the less bandwidth at the same power then IDHT. Many DHT have very high plate impedance that requires transformers with huge ratio. This of course affects bandwidth but I do not think about SET in terms of “full-range SETs” but rather in terms of DSET. So, as the intentionally bandwidth-limited SET I think the DHT shell not see any problems deriving from higher plate impedance. As far as power concern the DHT that we use in audio have little power and little gain. It does not mean that it is imposable to get a lot of power on DHT, look at the DH transmissions tines with a few kW of pate dissipation. My problem with DHT is not power but gain and anode impedance. Whatever “small” tube has a gain of 10 has the anode impedance of those Ohm that require wasting a lot of gain in transformer. The DHT tubes that have good sub 1K plate impedance has gain of 3-4 – what to do with it. Those DHT have very limited cathode’s surface and juts very few electrons might run from it, here is what they have no gain. If to have a tube with 1K on anode and with gains of 25-30 let say then it would be so much fun to try it as single stage DHT without any input transformers, driver stages or couplings…

The Cat

Rerurn to Romy the Cat's Site