Blackface Pro Reverb....Lacks Bottom

[Lespaulsignature 74]

Does anyone here find that Blackface Pro Reverbs lack bottom? After having my 66 Pro tweeked by a reputable Tech, new Tungsol 6L6's and 12AX7's, new brite switch, 3 prong plug, the amp still sounds thin to me compared to my 68 Silverface Bandmaster. The speakers are the original/reconed Jensen C12N's, are these speakers known to be brite? The Tech said that the amp didn't need a cap job, do these amps historically have a weak bottom or is there something wrong/missing here?

[darkbluemurder]

Have you tried both amps through the same speaker set up? I would do that first to rule out the speakers.

Fender amps are generally known for their strong and sometimes overbearing bass response. Among many circuit changes there is one noticeable difference between a 66 and a 68. The phase inverter input cap on the 66 is most likely a 0.001uf. This is a small value, blocking a lot of mids and bass from going to the phase inverter. The same cap on the 68 is most likely a 0.01uf, i.e. 10fold higher.

Assuming that the 66 amp works correctly and indeed has the 0.001uf phase inverter input cap, you (i.e. your tech) could incrementally increase this cap until you have your desired low end response. I would start with 0.005uf but 0.002uf or 0.01uf are good also.

Cheers Stephan

[slider313]

Originally Posted by Lespaulsignature 74

The Tech said that the amp didn't need a cap job, do these amps historically have a weak bottom or is there something wrong/missing here?

Are the electrolytic caps original, or is the reason it doesn't need a cap job is because it had been done? If they're original then the lack of bass is a symptom of weak power supply caps. Pro Reverbs do not have a weak bottom. Cross the amp over to the speakers in your Bandmaster as the reconed speakers may be the issue.

[Tomo]

All depends how much bottom you are looking for...

I have several... It's enough bass for me. I can't go over 4 on bass. For me it's enough bass.

Maybe try different speakers... Eminence Legend 121...etc.

Mullard GZ34 (for me) is great overall tightness.

Try really good vintage tube on V2 (make a huge difference).

Tomo

[Lespaulsignature 74]

Originally Posted by slider313

Are the electrolytic caps original, or is the reason it doesn't need a cap job is because it had been done? If they're original then the lack of bass is a symptom of weak power supply caps. Pro Reverbs do not have a weak bottom. Cross the amp over to the speakers in your Bandmaster as the reconed speakers may be the issue.

Hey Slider, the caps had been changed according to the tech and didn't need replacement. The Bandmaster speaker cab has a set of Weber 10F150 and 10F150T. I am away from my apt/amp for the weekend but I'll try running the Pro through that cab ASAP. Thanks

[smolder]

Mine does not lack bottom end, but at the same time, the bottom end is not as strong as say my Route 66. And I often run them in parallel.


.

[buddyboy]

I have a 66 Pro with a 60's and early 70's C-12N in it. It definately lacks a large low end. I run the bass at 7 or so. It's the C-12N's mostly. However, that tone is very much in the classic "Fender" sound.

[Jahn]

hmm, no idea why. my BF Pro Reverb is considerably bassier and warmer than any other blackface or silverface i've owned (brownface and tweed were warmer but not as tight). i have ceramic italian reissue jensen C12Q speakers, Ruby 6L6 and Rectifer, RCA 12AT7 in V6 (phase inverter), V2 has a GE 5751, the rest are russian 12AX7 - actually I just pulled the V1, sounds nicer that way. 3-prong, not sure about the caps, a lot look original tho.

[Tomo]

Originally Posted by Jahn

hmm, no idea why. my BF Pro Reverb is considerably bassier and warmer than any other blackface or silverface i've owned (brownface and tweed were warmer but not as tight). i have ceramic italian reissue jensen C12Q speakers, Ruby 6L6 and Rectifer, RCA 12AT7 in V6 (phase inverter), V2 has a GE 5751, the rest are russian 12AX7 - actually I just pulled the V1, sounds nicer that way. 3-prong, not sure about the caps, a lot look original tho.

I do same way as you do.. pulled V1 in my '66 Pro Reverb.

Very smart to put really good tubes in V2 & V6.. I like GE12AX7/7025 in V4.

Your GE 5751 is grey plate or black plate from 50s?

I love Pro Reverbs!

Tomo

[Lespaulsignature 74]

Originally Posted by Tomo

I do same way as you do.. pulled V1 in my '66 Pro Reverb.

Very smart to put really good tubes in V2 & V6.. I like GE12AX7/7025 in V4.

Your GE 5751 is grey plate or black plate from 50s?

I love Pro Reverbs!

Tomo

What does pulling the V1 tube do to improve the sound? I never heard of this before.

[Tomo]

Originally Posted by Lespaulsignature 74

What does pulling the V1 tube do to improve the sound? I never heard of this before.

If you don't use a CH1 then you can pull V1 tube. This will increase a gain on Reverb CH. Do it and listen... then you can choose what you prefer..

Tomo

[Jack Daniels]

Originally Posted by Lespaulsignature 74

What does pulling the V1 tube do to improve the sound? I never heard of this before.

Essentially it means that one less preamp tube needs to get its power from the power supply. That means more current is available on the other tubes and means less overall sag. It should give a little more headroom and make the amp slightly snappy-er.

J

[Jahn]

Originally Posted by Tomo

I do same way as you do.. pulled V1 in my '66 Pro Reverb.

Very smart to put really good tubes in V2 & V6.. I like GE12AX7/7025 in V4.

Your GE 5751 is grey plate or black plate from 50s?

I love Pro Reverbs!

Tomo

My GE 5751 has long grey plates and a D Getter, identical to this one, including the same white label markings, except mine says 5751, not 12AX7:

[traviswalk]

Plenty of bottom end for me with a '66 that was recapped and original speakers.

[Jack Daniels]

I think the TungSols aren't doing you any favors in this department. Also, the Jensens are not the fullest speaker I have used. Try something like a Tone Tubby Ceramic and you will have all the bottom end you can ever use.

There is two really good threads on Pro Revebs here on the TGP. I started one and Tomo (I think) started the others. Lots of pics, lots of tube and speaker info in both.

Good luck!

J