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Non ADA Gear => Amps => Topic started by: Systematic Chaos on July 11, 2017, 01:53:36 AM

Title: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 11, 2017, 01:53:36 AM
Did I mention that you gotta love Japan  ;D ;D ;D

Just scored a '93 Carvin Tube 100 off Yahoo Auctions here in Japan for a blasting 85€.
Nice 2U rack poweramp from the early 90s with the even nicer feature of a 120/240V switch.
Other than that it's a basic 2x50w stereo tube poweramp. Gotta check how it sounds once it's delivered.
I'm not too fond of EL34 sound though....gotta wait and listen.
(http://i992.photobucket.com/albums/af41/MagnusBausW/tube100_zpsa2wjcxki.jpg)
(http://i992.photobucket.com/albums/af41/MagnusBausW/CarvinBack_zps6g46cnps.jpg)
Title: Re: NAD 90s Carvin Tube 100
Post by: rnolan on July 11, 2017, 03:08:18 AM
Hey SC, great score, I'm pretty sure you'll like it.  I suspect the new version which I have is very similar, they put the presence knobs on the front but apart from that it looks the same(ish), now mine can run 6L6 (which is how it came) or EL34, may be so can that one ?
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 11, 2017, 05:27:33 AM
I’ve briefly compared the schematics and there’s quite some differences. My “old” one seems EL34 only. Big win though is the voltage selection switch so I can use it both here and in Europe.
Everything else is pretty straight forward and simplistic. Maybe the circuitry can be modded to accept 6L6/5881....will have to check with MJMP on that

http://carvinimages.com/schematics/Tube100%20Output%20Schematic.pdf (http://carvinimages.com/schematics/Tube100%20Output%20Schematic.pdf)
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on July 11, 2017, 09:02:57 AM
Great find SC!  :thumb-up:

    I see the Presence knobs on the back of it for each channel.
    Don't they run 100V in Japan?

    In any case, what I was looking for on the back and don't seem to see, is a voltage bias for tube replacement. Hopefully there is one on the inside on the PCB. That would definitely cut the cost on a tube change.

    Who knows? You might like the tone of this one with EL34's.
Title: Re: NAD 90s Carvin Tube 100
Post by: rADAr on July 11, 2017, 09:51:13 AM
This is a what I currently have with my AXE-FX II. This early version can only use EL34 tubes, I think. It sounds good to me, but I find the clean sounds can be a little lacklustre - after having owned the Mesa 2:90 with 6L6's for comparison, that is. Enjoy, look forward to hearing how you like it...!
Title: Re: NAD 90s Carvin Tube 100
Post by: MarshallJMP on July 11, 2017, 02:41:24 PM

Everything else is pretty straight forward and simplistic. Maybe the circuitry can be modded to accept 6L6/5881....will have to check with MJMP on that

http://carvinimages.com/schematics/Tube100%20Output%20Schematic.pdf (http://carvinimages.com/schematics/Tube100%20Output%20Schematic.pdf)

Let me know if I can help out.
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 12, 2017, 03:23:29 AM
Great find SC!  :thumb-up:

    I see the Presence knobs on the back of it for each channel.
    Don't they run 100V in Japan?

    In any case, what I was looking for on the back and don't seem to see, is a voltage bias for tube replacement. Hopefully there is one on the inside on the PCB. That would definitely cut the cost on a tube change.

    Who knows? You might like the tone of this one with EL34's.

Yeah, JPN is 100V but there's lots of US-Voltage gear operated and running here with no problems.
While rechecking the schematics there's bias pots for each side (l & r), so no biggie re-biasing after a tube change.
I've modded various Boogie fixed bias amps in the past so even if this would've been fixed I would've had no headaches with it ;-)


Everything else is pretty straight forward and simplistic. Maybe the circuitry can be modded to accept 6L6/5881....will have to check with MJMP on that

http://carvinimages.com/schematics/Tube100%20Output%20Schematic.pdf (http://carvinimages.com/schematics/Tube100%20Output%20Schematic.pdf)

Let me know if I can help out.

@MJMP: Thanks bro! I was wondering if there was a way (maybe by tinkering with/modding the circuitry) to run 6L6/5881 tubes in the amp. I've linked the schematic above and attached all revision schematics...
Will post gut-shots once I have the amp on hands
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on July 12, 2017, 05:42:32 AM
Hey SC,

     Tell me you are at least going to check the amp out as is with your rig before you start tinkering with the circuitry.
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 12, 2017, 06:30:16 AM
No worries Harley, I’ll give it a thorough check. But there’s a reason I’ve ditched all EL34 based poweramp stages in favor of 6L6/5881 ever since. The only exception is when running 6L6 in Class AB and 34 in Class A simultaneously (Boogie Mk SimulClass)
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on July 12, 2017, 07:34:40 AM
Hey SC,

     If you don't mind me asking, what's the reason?
     I've been using 6L6 power tubes for years, and I feel the need to try something different, so this is why I went with the power amps I have now. I'm definitely getting a pronounced, and articulated bottom end response from these with a nice midrange, so I'm pretty happy with them.
Title: Re: NAD 90s Carvin Tube 100
Post by: MarshallJMP on July 12, 2017, 08:35:28 AM
Well looking at the schematic you should be able to put 6L6's in it. Bias range goes to -57V so that should be enough for 6L6's.Heater current is less with 6L6's so that should be a problem either. Raa is a bit higher with 6L6's but not much so should be a problem either.
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 12, 2017, 09:13:17 AM
Hey SC,

     If you don't mind me asking, what's the reason?
     I've been using 6L6 power tubes for years, and I feel the need to try something different, so this is why I went with the power amps I have now. I'm definitely getting a pronounced, and articulated bottom end response from these with a nice midrange, so I'm pretty happy with them.

No problem asking....
My preferred sound typology is Boogie Mk (IIC+, IV) which is mid heavy by itself. I tried it paired (Studio Preamp, Quad Preamp, Triaxis) with various EL34 power stages and it simply sounded meeeh. For my tastes it works best with either pure 6L6(W)GC, 5881 or in SimulClass mode (2:90, 295).
Since I don't gig out that often atm (mostly Madison Square bedroom and only some "Open Stage" events and maybe a hired hand job every 2-3months) I left the big WOMS in Germany in storage and only took the AxeFXII with me to Tokyo....(I nevertheless gave in to GAS and got myself a JP2C head).
Main aim for the Carvin Tube 100 now is ti pair it with the AxeFXII...and for that I wanna keep it as clean as possible, which is where the 6L6 excels over the EL34.

Well looking at the schematic you should be able to put 6L6's in it. Bias range goes to -57V so that should be enough for 6L6's.Heater current is less with 6L6's so that should be a problem either. Raa is a bit higher with 6L6's but not much so should be a problem either.

Thanks for that quick reply...I´ll give it a go once I've checked how it sounds with the EL34. Re-checking the schematic I couldn't find an Input 12AX7, just 2 PIs, correct?!
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on July 12, 2017, 09:40:33 AM
Hey Sc,

     So basically, you are thinking about upgrading this old Carvin to the specs of the newer ones with no amp character added to it, if I'm following you correctly.
    It seems you prefer that 6L6 punch over the softer EL34 compression.
    I was looking for a Simul-Class power amp because I kind of get the impression that you can get the best of both worlds with those, depending if you run Class AB or Class A. I could be misunderstanding that difference in those amps though. In any case, I'm going to be sticking with tubes for the power section whenever it's reasonable to do so.
   I'll still keep the B200S for situations where the tube amps would be too much.
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 12, 2017, 10:07:28 AM
With the SimulClass amps I had I only used them in SimulClass, running AB and A simultaneously. It adds something to the sound that’s hard to describe...more complexity.
Check out a 2:90 if you get the chance and you’ll know what I mean.

With this Tube 100 I am just trying to find easy workable possibilities if I come to the conclusion that the EL34s won’t do it for me. Dropping a quad of 6L6s in there and just re-biasing sounds easy enough  8)
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on July 12, 2017, 12:01:30 PM
Okay,
   the 2:90 is basically two 6L6 power amps side by side, correct?
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on July 12, 2017, 12:52:04 PM
Okay,
   the 2:90 is basically two 6L6 power amps side by side, correct?
Yeah, it's 2 MkIV power sections running in SimulClass continuously. You can swap the Class A pair of 6L6 on each side for a pair (quad since you gotta do both sides) of EL34s.
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on July 12, 2017, 01:35:07 PM
Oh, I get it now. You don't have a choice between class AB and class A like you do in the 2:95.
    I'd have to audition a 2:95 to hear the difference. They might get one in at the local music shop down the street from me. I'll bring a preamp when they do and check it out.
Title: Re: NAD 90s Carvin Tube 100
Post by: MarshallJMP on July 12, 2017, 02:21:01 PM

Thanks for that quick reply...I´ll give it a go once I've checked how it sounds with the EL34. Re-checking the schematic I couldn't find an Input 12AX7, just 2 PIs, correct?!

Looks that way but I think this is not the complete schematic. But it could be like this just 2 PI.
Title: Re: NAD 90s Carvin Tube 100
Post by: rnolan on July 13, 2017, 04:05:42 AM
In the newer TS100s (like I have) they have both buffer 12AX7s and Phase Inverters (PIs), also a switch to change the circuit (in whatever way is required  :dunno: ) for each channel to go from EL34s to 6L6s and also biasing instructions (have a quick look at the manual), so if you get to modifying it, it would (no doubt) be a good reference as it's obviously a later revision of the one you have.  The TS100 is a great amp, works really well with the MP-2 and split cabs, it's just a brick  :facepalm: , but then no where near as heavy as some of the older tube amps. Compared to a B200s, it's super clean and transparent (as is the B200s) I found it adds a tiny bit of tube warmth to the sound and heaps of good tube grunt  >:D .  I don't use the presence knobs at all, I have all the presence I want/need in the MP2 and also the MP2 room eq sorts out the rest for various stages (dead through live reflections). For those who want to chase power tube distortion (which I don't), you could change the PIs to 12 AT7s. I bought the TS100 because my B200s was farting and I needed an amp, I still prefer the B200s (and being a tube nerd  :facepalm: ...).  In my current live rig I have the Carvin DCM200L, one RU, super lite, and also a great option.
Title: Re: NAD 90s Carvin Tube 100
Post by: Systematic Chaos on October 17, 2022, 07:04:53 AM
Necrobump on this old thread....and thought I'd kick it off almost where I left before I went on a hiatus.
Long story short - life in combination with all them worldwide sh!t sandwiches going on currently had me pretty busy job wise so I had to put hobbies etc on back burner in favour of family and work.
Finally early this (2022) summer I found the time to unpack some more stuff (that was still all in storage after we relocated back from Japan to Germany) and get to it....

So I got this old Carvin Tube100 power amp for dirt cheap in 2017...and finally did a complete one-over. All new resistors/caps/sockets etc....also added a choke. And this thing really smokes now. Dead quiet noise wise an glorious tube sound.
As mentioned earlier in this thread, I've never been a big fan of EL34 and this again proved it true. Biased properly with 6CA7 though I get the (almost) best of both 6L6 and EL34 worlds....
Pics for your viewing pleasure:

(https://i.postimg.cc/Wphy81MJ/IMG-6540.jpg)
(https://i.postimg.cc/Qx7yLYY8/IMG-6357.jpg)
Title: Re: NAD 90s Carvin Tube 100
Post by: Harley Hexxe on October 17, 2022, 01:04:14 PM
Het There SC,

      Welcome home, and welcome back to the Depot. It's good to see you again.

      Pretty neat trick, I didn't know those amps could take 6CA7's

Harley 8)
Title: Re: NAD 90s Carvin Tube 100
Post by: Dante on October 17, 2022, 03:43:05 PM
Welcome back my friend! So good to see you, thanks for checking in

Don't be a stranger
Title: Re: NAD 90s Carvin Tube 100
Post by: rnolan on October 18, 2022, 01:44:59 AM
Hey SC, nice  :thumb-up: , those JJs look sweet. So as far as I remember, 6CA7s are much the same as EL34s, and what I used to put in my '73 Marshall 50. 

quote (The differences are nearly negligible. The 6CA7 was a North American built version of the Euro EL34.... If you find an original Sylvania 6CA7 you will find that it is built more like an American "Beam Tetrode" (like 6V6, 6L6) as opposed to a pure Pentode (EL84, EL34).

But then as we all know, even tubes of the same designation (e.g. 12AX7s) all sound different.