Who makes a GM-70 based SET?

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.

Thanks for the response guys. For some time now I have been contemplating using a good tube amp with my ATC SCM40 but most people discourage me trying mate an 85db 8 ohm speaker like ATC with tubes. I knew about SAC Thailand and their products. I always thought their big GlowMaster based on GM70 which delivers about 70 watts per channel should work in my case. My room is little less than 200 sqft, which should not be difficult to fill. As usual there were no reviews about this amp and I could not gather courage selling my Symphonic Line RG1 MK4 power amp and buy the 70 watter tube power amp.