speaker question

mellowgerman

Senior Member
Joined
Sep 21, 2008
Messages
4,100
Reaction score
1,505
Location
Orlando, FL
Just as a fun experiment, I'm thinking of trying out some different speakers in my old Guild Model Three solid state 1x15 bass combo (late-70s to early-80s I believe). I know these aren't the greatest amps, but I imagine the sound will improve with the right speaker and that I could end up with a nice little practice rig. The old one in there right now sounds very stiff and mid-heavy to my ear (for lack of better terminology).
So now I'm wondering if anyone has any insight into how many ohms the original may have been? I haven't been able to find specs or much info at all about it on the greater web. I'm assuming it was probably 4 or 8, but if I hit a wall in this investigation, it should be safe to try 8ohm speakers, right? My understanding is that with solid state amps speaker impedance is less important as long as you don't go below the minimum, no?
Any input/thoughts are appreciated!
 

matsickma

Senior Member
Joined
Jun 21, 2005
Messages
4,280
Reaction score
1,028
Location
Coopersburg, PA
Anyone know if the transistor bass amp is any different from the Model One or Model Two other than speaker type and size?

I know the Guild Maverick tube amp for guitar and bass used a pair of 7591 tubes, which are not known for use in bass amps, had differences more than just different speakers to enhance bass performance. The obvious Reverb and Tremelo circuits were removed but my memory says other changes to the preamp were also made.

M
 

Default

Super Moderator
Platinum Supporting
Joined
Jul 30, 2007
Messages
13,595
Reaction score
3,008
Location
Philly, or thereabouts
Guild Total
11
Just as a fun experiment, I'm thinking of trying out some different speakers in my old Guild Model Three solid state 1x15 bass combo (late-70s to early-80s I believe). I know these aren't the greatest amps, but I imagine the sound will improve with the right speaker and that I could end up with a nice little practice rig. The old one in there right now sounds very stiff and mid-heavy to my ear (for lack of better terminology).
So now I'm wondering if anyone has any insight into how many ohms the original may have been? I haven't been able to find specs or much info at all about it on the greater web. I'm assuming it was probably 4 or 8, but if I hit a wall in this investigation, it should be safe to try 8ohm speakers, right? My understanding is that with solid state amps speaker impedance is less important as long as you don't go below the minimum, no?
Any input/thoughts are appreciated!

Take the speaker out and get an ohm meter. Measure with the probes, one on each terminal. It will read slightly less than the impedance. 6 ohms, means a 8 ohm speaker. 3.4 means a 4 ohm speaker.
 

mellowgerman

Senior Member
Joined
Sep 21, 2008
Messages
4,100
Reaction score
1,505
Location
Orlando, FL
Take the speaker out and get an ohm meter. Measure with the probes, one on each terminal. It will read slightly less than the impedance. 6 ohms, means a 8 ohm speaker. 3.4 means a 4 ohm speaker.

Yeah I was trying to get around buying another ohm meter... but as I write that statement I see how silly it sounds. I lost mine a few years back during a move and it's a good thing to have around so I should just scoop up another. Still though, even if I do the ohm meter test, I'm still not convinced the speaker is original. I was hoping maybe someone would have some wisdom to offer along the lines of "all guild combo 15's were 8 ohm" or something like that. I remember my Thunderstar bass head was for use with an 8ohm cab only
 

mellowgerman

Senior Member
Joined
Sep 21, 2008
Messages
4,100
Reaction score
1,505
Location
Orlando, FL
Well, I scored a gorgeous vintage 8ohm JBL locally today and the amp was immediately transformed into a whole different animal. Sounds 10x better than I ever imagined this little shallow-box, solid-state black sheep could!
 

mellowgerman

Senior Member
Joined
Sep 21, 2008
Messages
4,100
Reaction score
1,505
Location
Orlando, FL
I'm not sure to be honest. It was starting to get late when I got home and I wanted to try it out still so I didn't waste any time putting it in out of courtesy to the neighbors. It came out of an old JBL 1x15 PA cab with a blown horn. Has a 3 inch voice coil and a nice beefy magnet, but there was no printed label on it listing a model number. Some fading/faded code stamps, but again, I was eager to see how it sounded in the amp, so I installed it without trying to decipher and research.
I'm bringing the amp to a jam tonight right after work. First block of free time I get I'll try to get you a model number on it though
 

matsickma

Senior Member
Joined
Jun 21, 2005
Messages
4,280
Reaction score
1,028
Location
Coopersburg, PA
If it is a JBL with a 3" diameter then it isn't a D or K 120 or D131 model as they have 4"diameter voice coils.
 

dbirchett

Member
Joined
Oct 2, 2006
Messages
938
Reaction score
90
It probably isn't designed for musical instrument use so take it easy on the volume and the boominess.
 

mellowgerman

Senior Member
Joined
Sep 21, 2008
Messages
4,100
Reaction score
1,505
Location
Orlando, FL
Yeah it's just a nice little practice amp for when I play with my buddy. No pushing. Sounds fantastic!
 
Joined
Mar 9, 2011
Messages
580
Reaction score
94
I put a JBL D-130F speaker in a 1966 Ampeg Gemini II I recently bought. The amp came with a Jensen C15N that had been re-coned with a new heavy ribbed cone and sounded dull and mid heavy like you describe. The difference with the JBL is like night and day. Now to get the original C15N re-coned with a period correct cone. I have been told that original style Jensen 15" cones are out of production but I found a local guy the rebuilds organs and he has 3 original style ribbed cones for Jensen 15's. But it's hard to beat a JBL and it's 4" voice coil.
Thanks John
 
Top