Who makes a GM-70 based SET?

Build quality and cosmetics exceeded my expectation for the price. The chassis is the same as the Glowmaster GM-70 on their website. Difference being my amp is modified for a single, not parallel GM-70.I was also offered the option of a wood chassis at the same price if I wanted that aesthetic (it would have taken a few more weeks to build). I mean it's not a piece of modern art or anything but I think it represents a pretty darn good value for those of us who want to see what the GM-70 is all about and are not (a)wealthy or (b) into the DIY scene. I was on the fence about using SAC Thailand because I could not find out much about them on the web and did not want to get ripped off. Just wanted to let people know that it really is a legit business.

Has anyone compared the sound of GM-70 vs 845 tubes ?
Seemingly they both are used to build tube amps with high power, but both have different origins hence should have a different signature sound. Can someone shed some light here ?

Sibelius, does your amp have negative feedback ? What preamp are you using with this amp ?
Can you give a comparison of this amp with another popular tube amp you might have heard ? That would give a clearer perspective. I have been looking at these guys for sometime but lack of reviews have kept me at bay.

Pani,

Kara Chafee at Dehavilland would be the expert to answer your question. Dehavilland has been focused on making amps with 845s and GM-70s for quite some time.

FWIW, I can't say enough good things about my experience owning Dehavilland amps (in my case Aries 845G monoblocks).

From my own experience previously owning many types of tube amps, here is a broad stroke attempt to help you. Both the 845s and GM70s give you the magical midrange that is often associated with tubes like the 300B, but they don't sacrifice roll-off at either freq. extreme to nearly the same degree. Even more importantly, they provide more power to allow you to drive many different real world speakers that would sound terrible if paired with low powered SET amps.
They provide transparency that I've only heard equally with OTL amps or a few 6C33 designs.
Their bass might not be quite as punchy as big EL34-based amps, but the are surprisingly dynamic.
My 92db/8ohm Silverline La Folias are a pretty easy load, but most people can't believe it when I tell them that they are listening to only 30w amps. Most 845 or GM70s would probably elicit the same type of reaction in that regard. Hope this helps. Cheers,
Spencer

Pani:

I agree with Sbank's assessment. In addition to the GM-70 I also own 45, 2A3 and 300B SET's, an Atma-sphere OTL, and a refurbed Dynaco ST-70 (EL-34). I find the GM-70 gives me most of the benefits of the lower powered SET's while enjoying greater dynamics over a wider variety of musical genres. As much as I enjoy the low powered tubes, they have a hard time (in my system) doing justice with large orchestral recordings.

I don't have a lot of experience comparing the GM-70 with the 845. Hopefully some one else can chimn in here on that. The GM-70 has more power than the 845. Also, in comparison there are fewer manufacturers making GM-70 amps. Because of this you are limited to NOS tubes. Good news is that they are (comparatively speaking to other SET tubes) not that expensive.

The preamp I'm using with all my amps is the Shindo Masetto.

Pani - Forgot to answer one of your questions. The GM-70 amp I have from SAC Thailand does not employ negative feedback.