Gallien-Kreuger 400B question

[RSNG]

I have an old GK 400B that I'm using for a practice/backup amp. It has volume and master volume controls. I've always had the master volume up all the way, and used the volume to adjust volume.

I never gave it much thought before, but now I'm wondering how these two controls were intended to be used. Can anyone shed some light on this?

Thanks.

[RickenBoogie]

Well, the other way around. Use the Master volume to set your overall volume, and the first volume, usually called gain, as high as possible before it clips.

[Razman]

I recently picked up an 800rb and noticed that if I want the clearest, brightest sound I have to turn the master volume to max and use the input gain to get the volume I need. Never had another amp that was like that. The manual states this; it's probably the same for the 400rb.

[RSNG]

Originally Posted by Razman

I recently picked up an 800rb and noticed that if I want the clearest, brightest sound I have to turn the master volume to max and use the input gain to get the volume I need. Never had another amp that was like that. The manual states this; it's probably the same for the 400rb.

Mine is the 400B, not the 400RB. I'm not sure how much difference that makes.

[Razman]

Originally Posted by RickenBoogie

Well, the other way around. Use the Master volume to set your overall volume, and the first volume, usually called gain, as high as possible before it clips.

This is what I would call "normal" or "mainstream" when setting an amp but not so with the GK. When I set my 800rb in this fashion it was not as clear sounding (some would refer to that as "warmer" sounding).

Oops, sorry about missing the "r". In the absence of a manual, use your ears.

Raz

[RSNG]

Thanks for the info. I found the 400RB manual, but not one for the 400B. The 400 RB manual mentions the "boost" control too, which my 400B also has. It suggests adjusting this along with the two volumes. I've never used the "boost", because it seemed like all it did was turn up the volume.

[1958Bassman]

Originally Posted by RickenBoogie

Well, the other way around. Use the Master volume to set your overall volume, and the first volume, usually called gain, as high as possible before it clips.

But, for highest clean level, setting the master higher is the way to go.

[1958Bassman]

Originally Posted by RSNG

Thanks for the info. I found the 400RB manual, but not one for the 400B. The 400 RB manual mentions the "boost" control too, which my 400B also has. It suggests adjusting this along with the two volumes. I've never used the "boost", because it seemed like all it did was turn up the volume.

You saw the jack for the footswitch, right? That would be like a "solo" setting. You get to decide how much louder than normal it would be, rather than use the volume control on the bass.

[1958Bassman]

I just put a deposit on one of these at Music-Go-Round after taking my GK 400GT to see how much they would offer as trade-bait. Unfortunately, not enough to use it on a trade.
I asked if they had any 400RB and he checked their website to see if the other store had one, but said they didn't. I decided to take a walk to the back of the store and saw one sitting on a 410 cabinet (I didn't notice the name), so I tried it out. Went to make the payment and he said the price had dropped to $179. I have been selling things I don't need/want and just shipped a '63 Standel Reverbalux oil can delay, so I'm 2/3 of the way there without anything out of pocket.

A couple of observations- I messed with the controls and, with the cable plugged into the amp but not the instrument, I heard a high pitched oscillation when I turned up the boost & both volume controls. I also heard a fair amount of hum when I boosted the Mid and Low-Mid controls. I think this was because of the instrument (Fender Fretless), though. The knobs were mix-n-match, no two alike, so I assume the previous owner messed with things they didn't know about, or was just careless. Anyone else hear these things?

[will33]

The B or the RB? The 400B is a '70's - very early '80's predecessor to the 400 and 800RB's we've all seen. There was one for sale here a while back, I didn't pick it up but sometimes wish I would've just to have something everybody doesn't have...and a little bit of GK history. They are pretty large amps, 3 or 4 rackspaces tall and maybe a couple hundred watts. Has the GK eq and boost.

Anyway, whatever noises with the cable plugged in bit no instrument attached could likely be just due to that. Touch your thumb on the end of the plug and things will make noise.

With a known to be good bass plugged in, noises could indeed indicate amp problems. As far as the knobs, those old GK's are notorious for missing the knob centers. If some knobs came off, they could've easily been replaced with whatever someone had laying around. I've often thought of replacing mine with numbered knobs, or chicken heads, or whatever with clearer markings. Grey on grey on grey can be hard to see on dark stages.

My biggest concern would be making weird noises with both a good bass and good cab plugged in. Those are old enough, a power supply and general electrolytic re-cap should be considered.

[will33]

Originally Posted by 1958Bassman

I just put a deposit on one of these at Music-Go-Round after taking my GK 400GT to see how much they would offer as trade-bait. Unfortunately, not enough to use it on a trade.
I asked if they had any 400RB and he checked their website to see if the other store had one, but said they didn't. I decided to take a walk to the back of the store and saw one sitting on a 410 cabinet (I didn't notice the name), so I tried it out. Went to make the payment and he said the price had dropped to $179. I have been selling things I don't need/want and just shipped a '63 Standel Reverbalux oil can delay, so I'm 2/3 of the way there without anything out of pocket.

A couple of observations- I messed with the controls and, with the cable plugged into the amp but not the instrument, I heard a high pitched oscillation when I turned up the boost & both volume controls. I also heard a fair amount of hum when I boosted the Mid and Low-Mid controls. I think this was because of the instrument (Fender Fretless), though. The knobs were mix-n-match, no two alike, so I assume the previous owner messed with things they didn't know about, or was just careless. Anyone else hear these things?

I see from the CL find thread it's a '90 400RB at a nice price.

Same stuff applies except it may not need the cap job.

I'd just check it out with a known to be good bass, cables and cab.

They're great amps. Much louder than the 200 watts would lead you to believe. They are one of a relatively few solid state amps that sound good run up near the edge. I've been using mine more because I can do precisely that and not end up too loud for small bar/club gigs.

My 800RB is the only old GK from that era I've seen that still has all it's original knobs fully intact. I wouldn't worry much about the knobs and just make sure the amp functions properly.

[Marton]

I always set my 400RB like that :
Boost at max.
Gain high enough to get a dirty enough sound
Master to control my volume

[will33]

Originally Posted by Marton

I always set my 400RB like that :
Boost at max.
Gain high enough to get a dirty enough sound
Master to control my volume

It does sound way cool like that, though, it's a little too dirty for some of the lighter songs our cover band does. I've been generally running my gain and boost around 1:00, and then run the master up to about 3:00 and make the amp "work". That lets me make it snarl, bit can still hold back and get a fat clean with a hint of the growl for mellower stuff.

Pair of 12" Deltalites here so roughly 100db/1w worth of speakers with an emphasis in the upper mids and that seems to be just right for filling a smaller bar room on it's own or covering a larger stage.

Of course, YMMV and I'm sure yours sounds great for how you play it.

[1958Bassman]

Originally Posted by will33

I see from the CL find thread it's a '90 400RB at a nice price.

Same stuff applies except it may not need the cap job.

I'd just check it out with a known to be good bass, cables and cab.

They're great amps. Much louder than the 200 watts would lead you to believe. They are one of a relatively few solid state amps that sound good run up near the edge. I've been using mine more because I can do precisely that and not end up too loud for small bar/club gigs.

My 800RB is the only old GK from that era I've seen that still has all it's original knobs fully intact. I wouldn't worry much about the knobs and just make sure the amp functions properly.

The amp I was trying to get a value for is a GK GT400, which is rated at 200W into 4 Ohms. I went to high school with someone who was in a '70s fusion band and he used two of these, each with a 412 cabinet loaded with JBL speakers. Got a great sound with it, even though I usually like tubes more for guitar.

I know these are regarded as loud amps- that's one of the reasons I decided that a 400RB would be enough for most times. If I need more, I can always buy another. The one I'm buying is very clean- only a few small-ish scratches and not banged up. Knobs are all intact.

Thanks.

[will33]

I don't know anything about the GT400. Sounds similair though, the regular GK frontend, 200 watts, fairly large compared to similair powered amps nowdays ( before the micro craze ).

The 400B here, not "RB" was asking I think $235 or $285, can't remember. I didn't follow up on it although the ad was gone in 2 or 3 weeks. Don't know if that means they sold it or pawned it or just took it off the market.

Sorry...can't be of anymore help on that one.

[1958Bassman]

Originally Posted by will33

I don't know anything about the GT400. Sounds similair though, the regular GK frontend, 200 watts, fairly large compared to similair powered amps nowdays ( before the micro craze ).

The 400B here, not "RB" was asking I think $235 or $285, can't remember. I didn't follow up on it although the ad was gone in 2 or 3 weeks. Don't know if that means they sold it or pawned it or just took it off the market.

Sorry...can't be of anymore help on that one.

After reading the interview with Bob Gallien, I wonder if the 400GT (I screwed up the model in the other post) is a follow-up to the one he was making in the late '60s, used by Santana at Woodstock. That one was 270W, so it may have been scaled down. Other than mine having hum in the reverb, it's very quiet for an amp that puts out so much power. I bought it in the early '80s, when the rectifier of my '58 Bassman died and I needed an amp, but didn't know anything about how to diagnose. Good thing I kept it- nobody I talked to knew much about old amps at the time and about the only things I read were about the differences between the 5F6a and 5E6 and the caps needed to be replaced.

I figured that the reputation for good sound and reliability were true WRT the bass amps and I know others who have used GK but haven't seen them lately, so it's not too easy to ask.

[will33]

If it has reverb, it's a newer revision of the early GMT guitar amp. (The Santana Woodstock one). That might explain the "GT" moniker, just guessing there though.