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I just bought my first BRAND NEW tube amp. Dennis Had Inspire SET H.O.

The Inspire “Fire Bottle” SE Stereo Tube Amplifier HO can be a lot of fun in terms of tube rolling. Here’s some of the output tubes I’ve tried in mine:

• Zenith 6V6G (vintage)
• Sylvania 6L6GA (vintage)
• Sylvania 7408 (vintage, 6V6 variant)
• Mullard EL34
• Bugle Boy EL34 (vintage)
• Russian 6P3S-E (Russian military surplus 1980s 6L6GC equivalent)
• Groove Tube Gold Series GT6L6GE (6L6GC)
• McIntosh branded GE 6L6GC (vintage)
• GE 6L6GC (vintage)
• Tung-Sol 7581A (6L6GC variant)
• Tung-Sol 6L6G (6L6GC in a big bottle)
• Gold Lion KT88
• Tung-Sol KT150
• Gold Lion KT66
• Sylvania 5881
 
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ictwoody said:
I don't like it when builders put a passive attenuator in the amps to make them "integrated."
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Personally, I find it absurd that any audio engineer would not put a volume control on any amplifier that has an input sensitivity of 1 Vrms or less. Adding more gain stages, RCA jacks, and cable simply adds noise and distortion. My entire amplification chain from CD player to speakers is two stages driver/voltage amp & output tube/transformer) because I value clean, noise and distortion free, transparent sound over the number of boxes in the signal chain.
 
Palustris said:
Personally, I find it absurd that any audio engineer would not put a volume control on any amplifier that has an input sensitivity of 1 Vrms or less. Adding more gain stages, RCA jacks, and cable simply adds noise and distortion. My entire amplification chain from CD player to speakers is two stages driver/voltage amp & output tube/transformer) because I value clean, noise and distortion free, transparent sound over the number of boxes in the signal chain.
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I would agree with you... but even on my highest sensitivity speakers my Modwright (not a cheap preamp) and Inspire combo makes NO noise. Transparency etc... is FANTASTIC. I don't think those things can be judged by just the number of boxes in the signal chain.

- Woody
 
Palustris said:
Personally, I find it absurd that any audio engineer would not put a volume control on any amplifier that has an input sensitivity of 1 Vrms or less. Adding more gain stages, RCA jacks, and cable simply adds noise and distortion. My entire amplification chain from CD player to speakers is two stages driver/voltage amp & output tube/transformer) because I value clean, noise and distortion free, transparent sound over the number of boxes in the signal chain.
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I agree, yes sometimes you need a preamp if you don't have enough gain but if a pot was added it usually means there is enough gain with line level devices. As long as there is enough gain a extra stage will usually just add noise or push the amp too hard.
 
Dennis Had turns out some fine amps. His Magnavox console pulls like this one "Inspired" him to build a line of tube amps from scratch, hence the name Inspire. This one is a single ended EL84. With all new parts and circuit the only thing it shares with the original is it's iron and chassis.

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Poultrygeist said:
Dennis Had turns out some fine amps. His Magnavox console pulls like this one "Inspired" him to build a line of tube amps from scratch, hence the name Inspire. This one is a single ended EL84. With all new parts and circuit the only thing it shares with the original is it's iron and chassis.

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What were some of the circuit changes made? Did he use a different driver than a 6eu7/12ax7? Prob changed the feedback and tone circuit? Would like to hear how it compares to an upgraded stock maggie.
 
I can't say what circuit changes Dennis made but he switched from the original 12ax7 to the 7308 ( 6922, 6DJ8 ).

He also recommends trying a 6H30 input driver tube but I haven't done that yet. I find myself listening to this amp most of the time while my Bottlehead 2a3 sits idle.
 
Poultrygeist said:
I can't say what circuit changes Dennis made but he switched from the original 12ax7 to the 7308 ( 6922, 6DJ8 ).

He also recommends trying a 6H30 input driver tube but I haven't done that yet. I find myself listening to this amp most of the time while my Bottlehead 2a3 sits idle.
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Thanks for that info, I'm very curious about the bottlehead because it's on my maybe list to purchase soon. Is there a reason it doesn't do it for you, do you not like the 2a3 sound? What are your speakers and what db are they? I'm trying to make a educated buy on this one because it's not everyday that I have 1500 bucks saved.
 
Tubeglowpio said:
Thanks for that info, I'm very curious about the bottlehead because it's on my maybe list to purchase soon. Is there a reason it doesn't do it for you, do you not like the 2a3 sound? What are your speakers and what db are they? I'm trying to make a educated buy on this one because it's not everyday that I have 1500 bucks saved.
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My 2a3 Bottlehead mono blocks take up lots of space on my rack but there's absolutely nothing about their sound that I don't love. They do hum a little with my 98db Lowthers while The Dennis Had EL84 are silent. Glad I have both amps powering two different OB systems as it would be hard to pick one over the other.

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Poultrygeist said:
My 2a3 Bottlehead mono blocks take up lots of space on my rack but there's absolutely nothing about their sound that I don't love. They do hum a little with my 98db Lowthers while The Dennis Had EL84 are silent. Glad I have both amps powering two different OB systems as it would be hard to pick one over the other.

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Did you try out their dc filament supply? I honestly haven't heard a 2a3 yet but I love the midrange I get from a single ended el84 that's why I believe I would love a 2a3 or 300 b amp. I have some 96 db klipsch speakers so they should work ok with a 2a3 but am leaning a bit towards the 300b so far. If I go kit I really may save more and go with the audio note 300b kit.
 
A generalization - the 300b will have more body and warmer mids while the 2a3 is a finesse amp with better resolution. Strength vs sophistication some say.

If you want to save money don't buy a kit but consider a used Bottlehead from an OCD builder/seller who shows off his meticulous wiring with lots of under skirt photos. Kits cost more than used.
 
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Poultrygeist said:
A generalization - the 300b will have more body and warmer mids while the 2a3 is a finesse amp with better resolution. Strength vs sophistication some say.

If you want to save money don't buy a kit but consider a used Bottlehead from an OCD builder/seller who shows off his meticulous wiring with lots of under skit photos. Kits cost more than used.
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I really like when the music has that smooth bass, liquid, deep and 3d mids and a little sparkle up top. I would consider a used one but would have to see their wiring and make sure its neat so I don't have more work by redoing it. On eBay they seem to want to charge more, there is a guy right now trying to sell crack with speedball at around 650 and he must be selling some cause it listed more.
 
I stole the used 2a3 Paramours a few years ago for $200 and more recently the modded Foreplay III preamp for $350.

Just a few months ago I bought the Dennis Had EL84 on eBay for a tad over $400.
 
Poultrygeist said:
I stole the used 2a3 Paramours a few years ago for $200 and more recently the modded Foreplay III preamp for $350.

Just a few months ago I bought the Dennis Had EL84 on eBay for a tad over $400.
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Wow you did real good! I could not pass those up for that price or even double that on the paramours. I'm always looking for good schematics so I can just build it and save some money. I've been looking at the 300b on diy audio, it has a 6sn7 driver tube which is pretty common for a 300b amp but I've seen a lot of people say the 6sn7 barely cuts it as a driver for 300b. I'm hoping to find a well reviewed 300b circuit somewhere.
 
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