Question for all the Tube Amp fanatics

Steve Spitz · From: New Orleans, LA, USA

Why is it that all the tube fans favor the tone of the point to point wired amps over the printed circuit board amps ?

Let`s forgive and forget the reliability issue of some recent Fender re-issues, I want to better understand why we all think the printed circuit board amp sounds inferior.

I have both.

Actually, several blackface fenders, from my days as a blues bum.

Does the mid 90`s custom Vibrosonic sound dramatically different from the 70`s Vibrasonic ?

If possible, try and keep your responses relative to steel guitar amplification, trying to reproduce a classic steel sound.

To keep it fair, let`s also assume both amp heads are in the same cabinet, thru the same speaker, to eliminate the obvious variables.

Ken Fox · From: Nashville GA USA

I can't hear a big difference I just know which one I will not own or work on!

Steve Spitz · From: New Orleans, LA, USA

Thanks Ken, I was hoping you would respond.

It`s obvious the printed circuit boards were not made to tinker with or repair.

Interesting that you (who most of us consider The tech guru) don`t find much difference in tone.

James Morehead · From: Prague, Oklahoma, USA - R.I.P.

Steve Spitz · From: New Orleans, LA, USA

James,
Point well taken. I know it`s to large of an issue to forgive or forget.

A better choice of words might have been "regardless of the quality issues of some recent Fender re-issues" , how would you compare the sound....

That being said, anybody else want to comment on the tone comparison ?

I know your a real purist with your sho-buds and tube amps. Any experience with tone comparisons ?

John Groover McDuffie · From: LA California, USA

I think there is a lot of mumbo-jumbo and superstition about vintage amps and what makes them sound good, and I suspect the widespread belief that PCB amps sound inferior is at least partially due to that. Mesa Boogie has always used PCBs and people generally accepted their amps as viable instruments.

Of course as Ken implied above, PCB amps are often harder to work on and much less mod-friendly.

Contrary to popular usage of the word old Fenders were not truly point-to-point wired, as most of the components are mounted on an eyelet board.

If you want to see a real point-to-point amp look at the circuitry of a Gibson amp from the late 40s-early 50s (there are many more examples of p-t-p especially from that general era)

Here is a good article on this topic http://www.geofex.com/Article_Folders/pt-to-pt/pt-to-pt.htm

and another one http://www.guitarplayer.com/article/all-about-point/Feb-08/33533

James Morehead · From: Prague, Oklahoma, USA - R.I.P.

Brad Sarno · From: St. Louis, MO USA

P2P is much more fun and worlds easier to work on and tweak, by a longshot. But a well designed circuit board with a real good layout and good copper traces and good glass can easily be as good or better a design with regards to tone and noise issues. Some are even done in a way that makes them very easy to work on. It's just that so many of the reissue amps that use PC boards are also laid out and assembled in a way that makes them extremely unpleasant to get at and work on. Also the general quality of some of the newer stuff is questionable.

Sonically there may be something to the wire inductances and stray capacitances of wires and chassis and whatnot in a P2P amp that may impart some sonic mojo, but I don't think it's as real an issue as some would claim. But it sure looks cool and is easy to get around and do just about anything in there.

The basic circuit design, build quality, and ease of access for servicing is what matters most, and that can easily be done with a PC board if the designer wants to put in the effort. IMHO

Brad

John Groover McDuffie · From: LA California, USA

Actually the price of older, eyelet-board Fenders seems to have surpassed the price of Fender's reissues in some cases - Deluxe Reverb reissues can be found easily in the $700 range, whereas 70s SFDRs now sell for above $1000, and BFDRs sell for over $2000 in the markets I encounter.

James Morehead · From: Prague, Oklahoma, USA - R.I.P.

John, That maybe true with the Deluxes, but my experience is with silverfaced twins and vibrosonics.

Mike Schwartzman · From: Maryland, USA

As mentioned...it's mostly a serviceability issue for me also. Individual components are so much easier to access, replace, or tweak to preferences.

The more recent PCB quality IMO in many amps (not all) can make the entire circuit board disposable when only one or a couple of components fail. Instead of replacing a part the owner has to replace an entire board.
I visited a small amp company (Tone King) a few years back and Mark Bartel (the owner) showed me his PCB for the Tone King Comet model and the quality was unmistakable. The board material/ thickness, and traces were truly impressive and workable...sounded great too. If I ever see one again, I'd love to try a pedal steel thru it. The clean channel was exceptionally nice.
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David Doggett · Posted 13 May 2009 8:21 pm

This is a good question. I think the main reason to prefer the old PTPs is that the circuitry is more reliable and easier to service and mod. And the Silver-Face models preferred for steel are less expensive than the new PCB Twins. So why not pay less and get the real deal?

I don’t know that there is anything inherently inferior about the tone of the PCB amps. But the fact is that many of them are not designed to sound the same as the classic PTPs we love for steel.

The ’65 Twin Reissue is an 85 watt amp meant to sound like a Black Face Twin. Therefore, it has substantially less clean headroom than the 100-135 watt SF PTP Twins that work best for steel.

The ‘90s Vibrasonic Custom may be similar to the ‘65 Reissue, but maybe not, since it is a 100 watt amp. Maybe it is similar to the Evil Twin or Red Knob Twin, which are PCB. What do people think of those for steel? I have never tried one. I have a Vibrasonic Custom, and it doesn’t sound as good to me as my ‘70s PTP 100 watt SF Dual Showman Reverb (through the same external speakers). It has a more bland sound, with less of the complex tube harmonics. But I don’t know the history of my Showman, and maybe it has been modded. But again, that’s sort of the point.

Then there is the new Custom 15. Is that just a ’65 Reissue with a 15” speaker? Or is it something else. How does it compare to a SF Vibrosonic (also a 1x15)?

So the point is that the new PCB Twin-type Fenders are not necessarily reproductions of the old PTP SF Twins, Showmans and Vibrosonics we like, but something else. And maybe it is the “something else” that is less appealing rather than just the PCB aspect.

Scott Appleton · From: Ashland, Oregon

I have both a 90's Vibrasonic and a twin 2 revera P to P and the sound of the
TWINN 2 is much more satisfying to my ear .. The Vibrasonic is nearly as good
and I use it because its smaller and easy to move .. The Twin 2 is a top that is
heavey and unweildly to move about .. but the sound is perfect .. plenty of gain
for a hot tele sound as well .. even through 15" speakers.. I use a 12 and a 15
with the TWIN 2 .. The Vibrasonic is a 15 emminance ..

Mitch Druckman · From: Arizona, USA

I have a 66 Deluxe Reverb and a 65 Reissue. They are 2 totally different sounding amps. The old amp has a depth to the sound, a 3 dimensional quality that is missing in the reissue. The reissue sounds overly bright and harsh in comparison. I've since replaced the tubes, transformers, and speaker in the reissue and it sounds great, but it still does not sound as smooth or deep as the original. I prefer the 66 blackface.

I don't think the difference I hear is in the circuit board assembly as much as the circuit design, component placement, and the components themselves. My favorite amps do tend to be hand-wired, but hand-wired amps are usually well designed and built with the finest components available.

Jim Sliff · From: Lawndale California, USA

Rick Johnson · From: Wheelwright, Ky USA

I had a tech tell me once that
the resistors and tone caps in PTP
amps drift from spec and help
give PTP amps a warmer more
pleasing tone. Thats why some PTP
amps sound better than others.
I don't know at what rate everything
begins to drift, it could be time
or just usage. I don't think that PCB amps will
do that over time.
Of course keeping
fresh tubes in them is important too.

Rick

www.rickjohnsoncabs.com

Bill Hatcher · From: Atlanta Ga. USA

Ben Jones · From: Seattle, Washington, USA

none of the reissues Ive treid would breakup for me, even when cranked, not the champ 600, the deluxe reverb, the tweed deluxe...none of em...and we are talking volume knob maxed.

I am not understanding why I cannot get a tweed deluxe to breakup with the volume maxed out?

b0b · From: Cloverdale, CA, USA

It's a reliability issue. Assuming comparable defect rates in both methods, the point-to-point is more reliable because there's more solder on each connection. It's harder to break.

Tone in any amplifier is the result of the serendipitous combination of small parts with +-10% (or greater!) tolerance values. Any tonal difference attributed to "p-to-p vs circuit board" is minor compared to the effect of the chance selection of individual resistors and capacitors from the parts bin.
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Brint Hannay · From: Maryland, USA

As mentioned, Mesa/Boogie amps are all PCB. Randall Smith of Mesa/Boogie used to (maybe still does) include with the manual of a new amp his self-penned essays on design elements, e.g. his argument in favor of his practice of making the bias in his amps non-adjustable (I'm not convinced), and, relevant here, a rebuttal of the idea that PCB designs necessarily don't sound as good as "point-to-point". For example, he discusses the fact that capacitances occur on PCBs because traces run so close to each other, but the designer just has to take that into account and design accordingly (makes sense to me).

And Mesa gear has the reputation, in my personal experience deservedly, of being very reliable.

Still, like previous posters, I have a fondness for the hand-wired designs, because I can work on 'em myself!

Jim Sliff · From: Lawndale California, USA

Steve Spitz · From: New Orleans, LA, USA

I really appreciate the responses.I`ve learned a few things.

The question was really only about tone, and most of the responses mentioned servicing, tweaking, modding, maintaining, all the things that most of us hate about PCBs.

Unfortunately for many of us, at least for me,I lack the skills to do much more than change tubes, clean the sockets,...minimal maintainance.

To Dave D or anyone who might know: I`m wondering more about the 90s Vibrasonic. 100 watts? and the 65 re-issue twin and Custom 15 both 85 watts? What would be the difference if using the same speaker comparing the 90s Vibrasonic vs the Custom 15? Just the extra 15 watts?

Thanks to all.

David Doggett · Posted 14 May 2009 8:17 pm

It's not just the watts. There's not much difference between 85 watts and 100. But black-face Fenders had some breakup in the top half of the volume range; whereas, the silver-face Fenders were clean to the top. So an 85 watt amp that is modeled after the black-faces is going to have substantially less clean headroom than a clean-to-the-top 100 or 135 watt amp. The '90s Vibrasonic seems closer to the silver-faces than the black-faces.

Jim Sliff · From: Lawndale California, USA

15 watts at that level is imperceptible. To double volume, all else being equal, you have to increase power by a factor of 10.

That's why a Twin Reverb and Pro Reverb are so close in volume - what the Pro has is better tone at lower volume, since it starts to "bloom" at a lower volume level than a Twin (depending, of course, on tubes, speakers and bias).

Anyway, comparing power differences between 85 and 100 watt amps is tonally irrelevant, and many "100 watt" amps simply aren't anyway.
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Paul Sutherland · From: Placerville, California

So what is the most desirable Twin to look for? I take it steelers prefer the silver face, but apparently there were various circuits used through the years: i.e., AB763 (supposedly the old blackface circuit but used on some of the first SFs), then AC568, then ?. Should I want a twin with a master volume knob, or avoid such an amp? What years are best/to be avoided?

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