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Old 19th December 2002, 09:03 PM   #21
Joel is offline Joel  United States
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Ok, but I still wonder what experience you had with them sounding 'compressive'?
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Old 19th December 2002, 09:06 PM   #22
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Default Direct expierence

Quote:
Originally posted by Joel
Ok, but I still wonder what experience you had with them sounding 'compressive'?
Because I built a preamp with those and some 1h4g once.

Robert Morin
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Old 19th December 2002, 09:08 PM   #23
Joel is offline Joel  United States
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Did you use cathode bias? I always use fixed battery bias for mine, in all postions, and they always sound crystal clear.
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Old 19th December 2002, 09:08 PM   #24
dhaen is offline dhaen  Europe
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Robert,
What was +B in your preamp?
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Old 19th December 2002, 09:20 PM   #25
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Default can't remember

It was so long ago (8years) that I can't remember the B+. The 1h4 was cathode biased. The sound was VERY clear just not lively.

Robert M.
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Old 19th December 2002, 10:46 PM   #26
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Default Re: can't remember

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Originally posted by Robert Morin
It was so long ago (8years) that I can't remember the B+. The 1h4 was cathode biased. The sound was VERY clear just not lively.

Robert M.
Wait!!! What am I saying! the 1h4 is a DHT - IE no cathode I can'y really remember what I did but I remember useing those 2 volt battery tubes and being impressed at first but later not being happy with the dynamic performance. They would make a good "sanitizer" for recording things like Bass and drums though.

Robert Morin
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Old 20th December 2002, 08:27 AM   #27
stigla is online now stigla  Norway
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The first amp I ever buildt was a pre-amp based on a type #30 (UX4 based 1H4G).

This being the first tube amp, I really had it running for a long time. I really liked it.

My amp was a normal cathode biased Resistor loaded RC coupled gain stage. (one 22R resistor from each cathode leg to a common cathode resistor).

The one thing I really learned from that amp, besides how anoying HUM can be, was how much the sound depended uppon the passive components. It was a simple design, and the bypass cap on the cathode alone had a huge impact. Use a crappy BP-cap (or coupling cap..), and it will indeed sound compressed and soaked!
My first choice at the time was a Panasonic Low Impedance type. Later I got some Sanyo OS-CON's, and I was amazed! It seemed like I had been listening to the bypass cap, and not the tube! And even better it got when I got some Elna ARD series caps!

I guess one needs top-of-the-line parts if one wants to make these tubes sing.

My first sound test with that amp was on a NAD 340, connected it straight to the power amp, on to B&W monitors. I never used the transistor preamp inside the NAD again (well, not as long as I had that NAD... I would describe it as very clear from top to bottom, sparkling and veil-lifting. Far from 'compressed'.

But, with that said, must admit I have never heard other DHT's like the 26, or IHT's like the 27... so... heh.... bye!

stigla
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Old 20th December 2002, 11:47 AM   #28
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Default CRAPPY CAPS

Hi,

Quote:
Use a crappy BP-cap (or coupling cap..), and it will indeed sound compressed and soaked!
My experience exactly.

If you want to find out what a big electrolytic cap sounds like put one over the cathode R in a preamp and you'll hear the sound and transient response go down the tubes (pun intended)

For bias I much prefer fixed bias (several ways possible) over cathode bias.

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Old 20th December 2002, 02:14 PM   #29
Joel is offline Joel  United States
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Oh god, are we getting into a cap discussion again????

Back to the tubes...
a) Let me say this - usually, when I hear someone say "all ____ tubes sound _____" they are wildly generalizing, often from a single experience. I've breadboarded #30's, #112's, #01's, #31's many times now, and never had a bad experience.
Hum is a non-issue, since they have such low gain, and use DC filaments. And the sound was as full-range as any other tube I've wired up. I think they're relatively tough, very forgiving tubes, and easy to work with. This is contrary to the popular belief - 90% of whom don't own any of these tubes.
b) All the early tubes were designed to be operated with fixed bias, and you will do yourself a big favor by running them this way.
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Old 20th December 2002, 02:24 PM   #30
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Default I KNEW IT.

Hi Joel,

Quote:
b) All the early tubes were designed to be operated with fixed bias, and you will do yourself a big favor by running them this way.
Somehow I knew there must be something out there we can agree on.

Cheers,
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