• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

3 Grommes Precision G 101 A, 100 watt mono block tube amps

TENER

Well-Known Member
I just got these about 3 hours ago for free. They where in a trailer park down the street from my brothers house. 3 Grommes Precision G 101 A Power Amplifiers (Pretty long story about how I found out about them). Not in the best shape but at 100w mono on each and the free price tag how could I leave them to go in the trash. I was glad I could save them. Any opinion on these? are they worth the time to fix? 100 watt mono block tube amps sound interesting. Thanks
 

Attachments

  • CIMG3778.JPG
    CIMG3778.JPG
    71.7 KB · Views: 264
  • CIMG3777.JPG
    CIMG3777.JPG
    64.4 KB · Views: 242
  • CIMG3779.JPG
    CIMG3779.JPG
    75.2 KB · Views: 253
  • CIMG3780.JPG
    CIMG3780.JPG
    65.6 KB · Views: 234
  • CIMG3781.JPG
    CIMG3781.JPG
    64.4 KB · Views: 229
  • CIMG3782.JPG
    CIMG3782.JPG
    68.4 KB · Views: 226
  • CIMG3784.JPG
    CIMG3784.JPG
    67.6 KB · Views: 227
  • CIMG3785.JPG
    CIMG3785.JPG
    85.5 KB · Views: 244
Register to hide this ad
I just got these about 3 hours ago for free. They where in a trailer park down the street from my brothers house. 3 Grommes Precision G 101 A Power Amplifiers (Pretty long story about how I found out about them). Not in the best shape but at 100w mono on each and the free price tag how could I leave them to go in the trash. I was glad I could save them. Any opinion on these? are they worth the time to fix? 100 watt mono block tube amps sound interesting. Thanks
Looks like PA type amps with 4 x 6l6gc? just guessing. Grommes is good stuff. They look like they have not seen any power in a long time so you need to do all those procedures for a slow power up and voltage checks, etc.
 
Looks like PA type amps with 4 x 6l6gc? just guessing. Grommes is good stuff. They look like they have not seen any power in a long time so you need to do all those procedures for a slow power up and voltage checks, etc.
Thanks. The 4 tubes are actually 6GT5's. I am kind of happy I have 3 of them (One for parts).
 
Hell yeah you gotta fix those suckers up! If not, can I send you a check? :D
:eek2:
You would not believe the crap I went through to get these. I first saw them on offer up and the guy wanted $25 for all 3 of them. That was 3 weeks ago. So I messaged him that I would take them but never heard anything back. I kept messaging him at least 2 times a week and yesterday he contacted me. He told me he no longer had them that he had to move quick and had to leave them when he left. That was 2 weeks ago when he moved. I asked him if he thought they might still be where he left them. He sent me the address of a rundown trailer park and said that they might still be there because the trailer was so bad that it could have been condemned. So i went to the trailer park at 8:00 yesterday night and after talking to the neighbors i found out who was in charge of the place. I knocked on his door and told him that the former tenant said I could get something from the trailer. He said that the trailer had been cleaned out. I then told him specifically what I was after, he said give me a minute and then came out. He walked down to the trailer and opened the front door and there they where. All 3 sitting right inside on a counter of a trashed out trailer. He said if you want them go ahead they are yours. He couldn't understand why I wanted those pieces of junk and thanked me for taking them so he did not have to carry them to the trash lol. I loaded them up thanked him. Just think how close these where to the trash can :yikes:
 
Great story! :thumbsup:

Those things should sound awesome when brought up to par. They remind me of those Dynaco mono block amps which use push / pull / parallel tubes. I think they used 6AV5 tubes but I am not sure. :dunno:
 
Last edited:
They use 4 6gt5's and 2 12au7's.I have a few of these myself.I replaced the caps and they sound fine.
 
Looks like those tubes are decently available so thats nice. Hopefully the transformers have a nice wide frequency response. They certainly look like something worth saving. They're pretty nice looking for what is apparently industrial gear too, the rack mount face is a nice clean look. Nice score indeed.
 
Yep. TV Horizontal Output sweep tubes. Grommes made very good stuff -- I would expect very good performance from them when properly restored.

Congrats on a great find!

Dave
 
Amazing sweep tube amps, and that's some serious looking iron as well. Nice find and your persistence definitely paid off!
 
They use 4 6gt5's and 2 12au7's.I have a few of these myself.I replaced the caps and they sound fine.

What do you use yours for? Are these good for music? I have a pair of 1976 Magnepan tympani 1D's that I thought these would be great for.
 
More pics of the back of one. I have never owned a amp like these before so I am not exactly sure how to hook it up. I am sure I need some jumpers in certain places.
 

Attachments

  • CIMG3793.JPG
    CIMG3793.JPG
    251.9 KB · Views: 99
  • CIMG3794.JPG
    CIMG3794.JPG
    282.8 KB · Views: 89
  • CIMG3795.JPG
    CIMG3795.JPG
    277.9 KB · Views: 87
  • CIMG3796.JPG
    CIMG3796.JPG
    272.4 KB · Views: 89
First of all to the OP congrats on your find, Secondly I'm still trying to figure out how they put out 100 watts?
 
First of all to the OP congrats on your find, Secondly I'm still trying to figure out how they put out 100 watts?
I don't know but that is what I have read about these, Here is a link to the radio museum that says that they are 100wpc. They also say 1960 for a date but I have read other places that say they where made around 1970? I know one thing, They are heavy. About 35lbs each.


https://www.radiomuseum.org/r/grommes_power_amplifier_g_101_a.html
 
HiZ input and 25v output are likely the connections. Usual warnings about old tube gear apply.

http://www.4tubes.com/SCHEMATICS/BY-BRAND/Grommes-Precision/g101a.gif

looks to be the schematic. Surprisingly reasonable plate voltage, only 440v.

Interesting driver circuit. Cascode stage I think? Or is that a grounded grid stage? Not something you usually see in an audio amp circuit. Long tail pair / diff amp phase inverter is a good thing.

Full wave bridge rectifier with a choke in the supply, good deal.
 
Last edited:
HiZ input and 25v output are likely the connections.

Okay for the input why would it look like a stereo input on a mono amp? Look on the corner at the "RCA" style HiZ input
 

Attachments

  • CIMG3787.JPG
    CIMG3787.JPG
    77.4 KB · Views: 55
Just look underneath to see if they are connected together. If not, I might surmise the other one might be a "LowZ input? :dunno:
 
Back
Top Bottom