my Rig and question on old Rocktron and ADA tube amp

[SalsaNChips]

Wanted to show what I am currently using as my main amp rig and ask a couple questions.

This is what I have been using for the last 15 years or so:

Pretty simple and self-explanatory from the pic. Early-mid 90's Rocktron Piranha pre-amp into a late 80's (?) ADA T100S stereo 50W/channel tube head, with a Alesis Midiverb 4 in the EXF loop on the Rocktron pre-amp.

I use this to switch it by MIDI:

Which has worked fine up until recently when one of the button pads went south. That is a Rolls unit I believe and I think they still make them (saw one new on eBay recently). It lasted me for about 15 years so not complaining.

The cabinet is your basic "brand M" 2X12 closed back in stereo. I do run stereo off the ADA head.

It stays pretty much parked in my studio -- I don't play out much and when I do I have taken to using a little Fender Mustang I solid state amp (which is a pretty neat little amp; thin sounding but does what it does very well thank you). I use The Rig for practice and recording or on those rare occasions when I need serious tone and volume.

Three pre-amp settings, clean, tube overdrive and tube/solid-state overdrive. The Clean with the gain down and output level raised is pristine (that is, once I figured out the right EQ settings for my Strat and the matching of signal levels to the Alesis). The Tube Overdrive – it’s “okay”; useful for blues, SRV, ZZ Top, Hendrixy stuff. Kind of mushy, okay for rhythm. Prefer the Clean setting with the gain cranked up. The Tube/Solid-State Overdrive? What can I say. IT BARKS. Not Of This Earth, late 80’s, Satriani’ish, early EVH, Gary Moore, etc., endless sustain – adjectives fail me. Needless to say, I rather like that setting

I actually quit playing guitar between 2001 and 2011 (long story) and this rig sat in a corner for 10 years gathering dust. When I got back into playing in 2011, I changed out the Rocktron tubes with GT’s, cleaned the pots, upgraded the cabling and re-did all my patches. The main gain stage tubes in the ADA are still originals; I thought about replacing them but they sound fine so figured not to mess with it.

I was actually thinking about selling the entire rig and replacing it with one of the new Rocktron VooDoo tube pre-amp units and a Rocktron 100 watt solid state stereo amp to reduce weight, save space and make it more portable for playing out – but came to my senses. I had a MosValve solid-state amp before I got the ADA tube head and never liked it (that was why I got the ADA). That was a long time ago, maybe the tech has improved since then. Whatever, too many other priorities.

The only real problem I have at this point is – the fan in the ADA is ridiculously loud. Lousy for recording in that I pick up the fan noise unless I seriously CRANK the amp and back off the gain on the cabinet mic (SM57) thus lowering the overall noise floor. Seriously -- cranking that amp is fun, but it takes my cats a couple days to get over the trauma and re-appear. That and makes monitoring in the phones difficult (I have a small home studio with little to no isolation).

So, my question – wanted to see if anybody has any suggestions on changing out the fan for an old ADA tube head with a durable replacement that is dead quiet? Also, any comments/suggestions from those who have a similar set-up or are using/have used the Rocktron Piranha pre-amp (you don’t see them around much these days).

THANKS.

 

[bagman67]

Totally guessing here, but you could probably find a quiet replacement fan at a computer retailer or online source - try frys.com or microcenter.com as starting points.  The spec for the fan has gotta be printed on it somewhere, if you feel up to opening the box, otherwise find a good local tech.



Maybe the schematic is available online, too - Google is your friend.



I have a similar issue with my Yamaha T100C combo - it has a fan that's obnoxiously loud.  I had my amp guy (Val King at King Amplification in Los Gatos, California, if you happen to be local) install a switch to turn it on and off.




Good luck -


Bagman

 

[Cagey]

Those little muffin fans are notoriously loud while barely moving any air, and generally have the life expectancy of a fruitfly. You need to spend a few extra dollars and buy either a Papst, Scythe, Sharkoon, or Noctua fan. They're not terribly expensive, but they'll run $15-$20 while your standard fans will often be $5 or less. They're quiet, though. All but silent, usually under 25dBA, and they typically use ceramic bearings so the MTBF will exceed 100,000 hours. Find out the size you need, and go here.

 

[Patrick from Davis]

We replace fans a lot around here at work.  I essentially work in an over glorified barn, so it is not the nicest on some equipment.  You just have to get the proper voltage, air movement, and noise level.  One trick that people used to use was a 24 volt fan run at 12 volts to drop the noise.  You get half the flow, but...  With todays fans for computers, you should be able to get something to fit that is a lot better than the old stuff, with regards to both noise and airflow.
Patrick

 

[Cagey]

We used to replace fans a lot, too. At least, until we started using some of the fans I mentioned above. Then, we got the double benefit of long life and low noise.

Used to build a lot of computers, and almost without fail the first thing to go was a fan. Of course, once a machine is built, changing a fan is often a major league pain in the ass, so it was cheap insurance to use the better parts. We'd even void the warranties on brand new power supplies by opening them up to replace the fans in those. That they were quieter was icing on the cake. Considering many of these machines were high-performance units, there were usually a number of fans in them, so the cost added up. But, adding $50-$70 to a $$3,000 machine isn't really noticeable, while wasting half a day replacing a bloody fan is.

Highly recommend the Noctua parts.

 

[SalsaNChips]

Find out the size you need, and go here.

Thanks for that link, I remember when I had it open a year ago to clean the volume pots I looked at the fans -- I think there were two of them bolted together, pushing air out of the front of the chassis. Don't remember the size, voltage (probably 24V) or cubic FPM spec, have to open it up again and check, which is easy to do once I get get that monster out of the road rack (it weighs like, 40 lbs or something).

I'm thinking maybe I will get two fans of identical spec (same FPM) except quieter and find a way to mount one in the front of the chassis pulling air, one in the back pushing. One of those things that's not particularly difficult but you keep putting if off, you know?

I'll post a pic of the innards when I get it open. The transformer in that thing is awesome

 

[Patrick from Davis]

Most every amp has a 6 volt tap for the heaters on the tubes.  If you get a 12 volt fan that moves enough air, you can run it at half power.  Since it already has the fans, they should have isolated them so they don't make a ton of electrical noise.  Other than moving in and out of the rack, it sounds like a fun thing to do.
Patrick

 

[Cagey]

I'm thinking maybe I will get two fans of identical spec (same FPM) except quieter and find a way to mount one in the front of the chassis pulling air, one in the back pushing. One of those things that's not particularly difficult but you keep putting if off, you know?

That's the secret: flow. Lotta guys (and some manufacturers) will put in a half-dozen fans, but all they do is blow around the hot air. The hot air has to be removed and replaced with fresh air. Turbulence does nothing. You've got to have makeup air and exhaust, or you're not getting anything done.

 

[SalsaNChips]

Follow-up, I opened the ADA T100S head and took a look:

It's a 80mm 115VAC fan by FlowMax who are no longer around. But, I located a fan with identical form factor and specs here:

http://www.acinfinity.com/115v-ac-fans/80-mm-fans/115v-ac-cooltron-fan-80mm-x-38mm-ls/

which is a 28dba fan, slightly reduced speed but quieter and I don't think the lower speed is going to cause a heat problem. I have a temperature probe on my multimeter, I am going to measure it before and after and see how much of a difference it makes.

 

[Cagey]

28db is pretty quiet. Looks like there's room in the front to mount a makeup air fan as well. Make sure the rear is actually an exhaust and that would get a forced cross-flow going, which would be a Good Thing.