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Old 3rd November 2006, 07:48 AM   #1
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Default World' smallest GM-70 set

I just finished my mighty little amp using GM-70 last week,am a newbie in this forum,any comment pls advice.
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Old 3rd November 2006, 08:33 AM   #2
Tweeker is offline Tweeker  United States
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A link to your project or more details about it please?
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Old 3rd November 2006, 10:40 AM   #3
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Hi.Tweaker
I do not have a link to my project,i use 12HG7 as a driver thru 100H. choke load and feed thru GM70,the chassis size is 12x19 inch.,i 'll post some photo.
Arth.
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Old 3rd November 2006, 11:23 AM   #4
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The look inside my amp
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Old 3rd November 2006, 04:33 PM   #5
kevinkr is offline kevinkr  United States
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Looks very nice. How about a little more description and some schematics?
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Old 3rd November 2006, 04:52 PM   #6
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Default Re: World' smallest GM-70 set

Quote:
Originally posted by Triod lover
I just finished my mighty little amp using GM-70 last week,am a newbie in this forum,any comment pls advice.

Really nice job there! What output xfmers did you use? What is the plate load Z? You are using ultralinear G2 connection to OPT yes?
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Old 3rd November 2006, 05:04 PM   #7
kevinkr is offline kevinkr  United States
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Hi rcavictim,
The GM70 is a triode so he obviously won't be running it in UL as there is no screen grid.. I've included the data sheet as an attachment.

I'm actually thinking about getting a pair of these at some point to design and build an amplifier around.

I have heard a lot about a supposedly better sounding copper plate version of this tube. Standard plate afaik is graphite. Anyone have any thoughts on this? Triod Lover which version of GM70 do you use?
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Old 3rd November 2006, 05:13 PM   #8
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Very nice construction and wiring job. I like the combination of wood and metal for the chassis too.

Quote:
You are using ultralinear G2 connection to OPT yes?
I thought GM-70s were triodes.

Victor

PS, yup, Kevin confirmed it. If I didn't have as many tubes as I do, I'd buy a few of these too. They sure look cool.
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Old 3rd November 2006, 06:27 PM   #9
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Hi..RCAVICTIM,KEVINKR,HOLLOWSTATE
Thank you all for the compliments,GM-70 is a very stable and tough like a tank it is a pure triode no G2,the output is the Electra-print load impedance is 5k.,the sound is very sweet and has a very good bass,the sound stage is just like watching the concert!!!,anyhow,i just burn-in for two weeks i think this tube will need another week or so to get it ready to rock n roll.One con about my amp is it so hot,especially living in Thailand that the temperature quite hot all year!!.I wish i lived in U.S.A or CANADA to get my amp as the heater as well.
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Old 3rd November 2006, 06:27 PM   #10
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Hi...Kevinkr
The GM70 that i used is a copper plate,i test both graphite and copper plate and prefer copper plate much more!!! it has a better tonal balance for me(my opinion anyway).
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