Gibson hawk

[menger66]

Picked up a new amp it's a gibson hawk, while I was expecting to see a crappy old PvP this amp is put together very nicely, has some scratchy pots and is lacking in power gonna try a recap and go through everything may convert to something like a a Marshall 18watt with reverb and tremlo

[menger66]

Got chassis out no easy task now I wanna put In grounded cord,, should I get rid of this funky green as recto also?

[Phil_S]

I don't think that rectifier is original. I have two Gibson amps from that period. Both used a pair of traditional looking black diodes. If it works OK, I'd need a good reason to replace it. If it is not the right spec, yes, get rid of it.

I'd recap it and see if the power level comes up. That amp should give you some decent volume. I'm not sure I'd want to convert it to anything, but you should do what you think is best for you.

[menger66]

I noticed the speaker was all jacked up on the connection tabs so I Stuck a Jensen c10q in there and volume and tone changed drasticly sounded, where the Capcan is theres a t-strip with plenty of room for electrolytic caps until I can order correct capcan, amp is full of RCA TUBES. Been waiting to get this amp at right price was real glad when I opened it up and it wasn't a printed board it's really a nicely put together amp

[Phil_S]

Mark:
I looked this up just now. Apparently, there are at least 2 known versions of this amp. I think you must have the 2nd one because you have a solid state rectifier. The date made is 1963-1966. Records indicate 1 was shipped in 1967 ;-} http://www.superiormusic.com/page199.htm

GA-25RVT Hawk (Dated Oct '63 - only one tone-control): 4-6EU7, 12AU7, 2-6V6, 5Y3

GA-25RVT Hawk: 2-6EU7, 3-12AU7 (5814), 2-7591

I hope this helps. Good luck.

Phil

[menger66]

Mine has 2 6bq5 and 3 12ax7

[Stevem]

Most of the Gibson amps that have bird names sound thin due to excess Bass roll of , so don't be surprised if you do not hear much of a change with recapping and new tubes!

[Phil_S]

Take a look at GA15-RVT or GA-20RVT. That seems to match the tube list.

[menger66]

I put a Jensen c10q and it helped a little but am thinking this amp is just a dog, was wondering if messing with the phase inverter would help? I just don't have much use for it the ga-5 I rebuilt blow this amp away

[martin manning]

Might help to adjust the voicing, notably bypassing or taming the notch filter after the volume control (lift the ground on the 0.0047u cap), and trying different values for coupling and cathode bypass caps.

[menger66]

I believe this amp wants to be something else i recapped all the power electrolytics and it still sounds like shit the off on switch is on the tone pot think in gonna move that see if it help,

[Phil_S]

The pot with the on/off switch isn't the problem. It's the circuit. Think about rebuilding it to one of the other Hawk circuits (if the transformers will work) and then sell it as a rebuilt Hawk!

[menger66]

It's one of the smallest power transformer I've seen on a PP . el84 amp, they grounded everything dead center in the middle of the chassis and it's a rats nest most of the orange drops in the preamp are 200v rated. to strip it use new socket and tstrips and rebuild fresh would be a lot easier than rerouting the grounds which must be the problem
One last thing i wanna try is new diodes when check voltages after the rectifier at the first filter cap the voltage fluctuates about 8v could this be my problem? shouldn't the voltage be steady? The output transformer is dinky also i have some new heyboers 15 watt 5.9k on the shelf, I know what a 15watt el84 amp should sound like this thing doesn't put out 5 watts, my ga-5 blows this amp away lucky I paid very little and it had it's original RCA tube im tempted to keep the TUBES and of it as a project sale

[Stevem]

You need to ohm check all the terminal strip post that are used as a gounding point , as those rivets get loose with age and or tarnished or rusted up under the heads a then a poor ground is made.
When I find a bad one I drill it out and replace it with a 6/32 screw , nut and star washer!

[menger66]

Finally got this amp sounding great, but the ss recto is fluctuating about 8v from the recto to the first filter cap and the plate voltage and the bias is also is this normal should I stick some new diodes in there