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-   -   pentode in triode mode SE vs a DHT SE like 2a3/300b (http://www.diyaudio.com/forums/tubes-valves/99957-pentode-triode-mode-se-vs-dht-se-like-2a3-300b.html)

jarthel 13th April 2007 12:41 AM

pentode in triode mode SE vs a DHT SE like 2a3/300b
 
has anyone compared/listened to a pentode connected as triode in SE vs a dht SE?

feedback please

thank you.

Wavebourn 13th April 2007 01:01 AM

Re: pentode in triode mode SE vs a DHT SE like 2a3/300b
 
Quote:

Originally posted by jarthel
has anyone compared/listened to a pentode connected as triode in SE vs a dht SE?

feedback please

thank you.

I compared strapped 50L6-GC vs 6N13S triode, the strapped won (power, linearity, price/performance factor) in application of a driver for solid state Pillar output stage. Also, it is convenient to power filaments from solid state power supply.


phn 13th April 2007 01:07 AM

A pentode strapped as a triode is a triode. It has the same characteristics as a triode. It behaves like a triode.

jarthel 13th April 2007 01:19 AM

Quote:

Originally posted by phn
A pentode strapped as a triode is a triode. It has the same characteristics as a triode. It behaves like a triode.
I somehow missed the point of the reply. :)

300B and 2a3 are both triodes but that doesn't mean they sound they same.

so how is the sound compared to a DHT triode in SE?

jarthel 13th April 2007 01:20 AM

Re: Re: pentode in triode mode SE vs a DHT SE like 2a3/300b
 
Quote:

Originally posted by Wavebourn


price/performance factor


this is main reason why I created the thread :)

phn 13th April 2007 01:32 AM

If the 2A3 and 300B don't sound the same, then it's not very likely any other tube will. But it's not related to if it's a pentode strapped as a triode or if it's a real triode. I have nothing to say about taste since I consider taste to be personal.

jarthel 13th April 2007 01:36 AM

well I believe it doesn't involve personal taste at all. I wasn't asking which is better.

maybe I should have been clearer.

feedback on the type of sound. like more bass, high are exagerated. things like these. And these description doesn't involve personal taste at all. these are facts that someone can hear.

ilimzn 13th April 2007 01:46 PM

Very strange question - a tube doesn't 'sound', an amplifier as a whole does. There are far too many variables, otherwise we'd be just changing the output tube and never mind all the other parts (like drivers, caps, transformers, not to mention the eternal musings over cables, 'magic' capacitors and resistors). Every tube has it's own peculiarities (at the very least regarding different major specs), that have to be taken into account when designing an amp as a whole, so it is impossible to compare on truly equal grounds. When you change a design from a popular DHT to a triode strapped pentode or BPT, you usually have to change the power supply, output transformer and driver circuit, all of which heavily influence the sound. Compared tot hat the fact that the output device is a DHT or a strapped pentode is actually of lesser signifficance, witness that all 300B amplifiers do not sound teh same even with the same actual 300B. Other than that, a pentode strapped as triode is a triode, as one member already wrote in this thread. After that you have to contend with it's triode parameters, just like you would with any other triode.

Salas 13th April 2007 02:29 PM

All tube types and their brand, vintage, have a characteristic tone. A well known trait. Quality and attention to cathode chemicals and metals, assembly precision and vacuum formation all count. A vintage 5 star Amperex is by no means an early 90's Shuguang.
Apart from that a design can incorporate, exemplify, offset, bypass some traits in an up to spec tube. But it can never add some missing intrinsic linearity. An excellent design manages better with an excellent tube element invariably. As for DHT vs Triode strapped beam tetrode or pentode, there are findings of an even more benign distortion amount and pattern in low gain DHT tubes. They certainly sound a bit more open and natural. The law of diminishing returns strikes heavilly, so choosing to depart from a triode mode KT88 to a 300B in SE or PP is rather a purist choice. DHTs require some care and cost for filament powering also, since hum appears easier in their case..

Klimon 13th April 2007 02:54 PM

Quote:

A pentode strapped as a triode is a triode. It has the same characteristics as a triode. It behaves like a triode.
NOt really. Compare a default pseudo-triode with a pseude-triode with additional screen circuit to separate ac and dc paths -- not a subtle difference in sound; I'm too untechnical to give you an explanation but this could point the way: http://www.vaughnaudio.com/carina-FAQ.html#Q14

Simon


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