Dennis Had Inspire Amps

[Isaacc7]

Huh, those are much smaller than I anticipated. How sensitive are they? I would think porting would boost that number.

[BlackBess]

Thanks for the update on the ongoing development of Mr. Had’s new speakers. Now how about a little info on that black & gold 9-pin amp with the WE396a. Will this be a Pgh. Pa. Sports team themed piece or is it more Marshall “inspired”?

[Analog Addict]

Originally Posted by Isaacc7

Huh, those are much smaller than I anticipated. How sensitive are they? I would think porting would boost that number.

Dennis anticipates that these speakers will be ~ 92db/w/m or so. All I can tell you is that they produce an amazing amount of sound for their size.

Originally Posted by BlackBess

Thanks for the update on the ongoing development of Mr. Had’s new speakers. Now how about a little info on that black & gold 9-pin amp with the WE396a. Will this be a Pgh. Pa. Sports team themed piece or is it more Marshall “inspired”?

Which amp are you talking about?

[BlackBess]

Please keep us current on the speaker development, especially how low will those little drivers dig? I saw the pictures of the amp below & was curious.

[Analog Addict]

Originally Posted by BlackBess

Please keep us current on the speaker development, especially how low will those little drivers dig? I saw the pictures of the amp below & was curious.

Heh, that little amp is a one off, a side project of mine. Notice no Inspire logo.
The color scheme is just a continuation of a theme that has been running through a few of my last personal builds, i.e. copper accents.

I wanted to use the WE 396a as a driver tube, and instead of 6BQ5s, I went with an equivalent tube electrically, the 6GK6. The nice thing about the 6GK6 is that it is essentially the same tube as a 6BQ5, other than a different pin out and internal connections.

I've used them in a similar manner about 10 years ago and wanted to try them again. The kicker is that they are essentially dirt cheap, with good old stock, or NOS examples running $20 a pair. OK so the WE 396a isn't cheap, but other examples of this tube, the 5670, can be found quite cheap as well.

Anyway, I finished the build earlier this week, and went by the shop to let Dennis put it through it's paces. We made a few adjustments, and it's a strong 4.5 wpc with some impressive bass response.

Dennis liked it a lot, enough to want to take it home tonight, but I have some friends coming by Friday I wanted to show it to, so I told him he could have it Monday.

Adjusting....

Untitled by analog addict, on Flickr

Measurements...

Untitled by analog addict, on Flickr

Untitled by analog addict, on Flickr

The distortion measurements really surprised me. At 1 watt/1KHz, there is almost no third order distortion and the second order distortion was -55db, which is really good.

Untitled by analog addict, on Flickr

Untitled by analog addict, on Flickr

Untitled by analog addict, on Flickr

So, I'm happy it turned out as well as it did.

As far as the speakers, Dennis didn't bring them to the shop today, but told me he has decided on a port configuration, so he will be doing some woodworking later this week....

[Analog Addict]

Oh and BTW, that 300b-v in the middle of the table is heading out to it's new owner in CA tonight...

[Isaacc7]

I have some 16gk6 tubes that I have been trying to ID. One is labeled GE "Great Britain" and the other is labeled International but have the GE dots and "Made in Japan." They are identical otherwise. Have also seen the same tube labeled Siemens and made in Canada lol.

Other than the labeling they look identical to the 10gk6 seen here:
https://www.radiomuseum.org/tubes/tube_10gk6.html

My push pull amp uses external supplies for the heaters so I can use 16v tubes with no trouble. Was excited to get some adapters because at first I thought I had the equivalent of GE 6bq5. Then I thought I had the Mullard made el84. Now I don't know what I have and I'm not sure it's worth getting adapters at all lol.

Edit to add that I have now just seen another identical 16gk6 labeled International made in Korea. SO that's 4 different countries. I'm willing to bet they were all made in the same place.

[Analog Addict]

Rumor has it that Dennis has just purchased a sleeve of NOS 6GK6s....
;-)

[BlackBess]

That little “side project” with a volume control would be pretty cool, even if that means it’s necessary to add another 5670.

[Analog Addict]

Originally Posted by BlackBess

That little “side project” with a volume control would be pretty cool, even if that means it’s necessary to add another 5670.

I may be wrong, but I thought a volume control is nothing more than a pot in place of the normal voltage divider coming from the signal input. Shouldn't require an additional tube...