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Post subject: Re: 1965 Pro Reverb
Posted: Thu Mar 27, 2014 5:32 pm
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I'd say as long as you are not over the magic 70% dissipation, your ears will tell you the best place to be.

I have noted at higher volumes the difference in overall tone of the amp (regarding a different bias settings) is more noticeable (pass Vol. 5) :lol:


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Post subject: Re: 1965 Pro Reverb
Posted: Thu Mar 27, 2014 6:38 pm
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Milton555 wrote:
Just found this thread. I have a 1966 Pro Reverb and have just started biasing my own amps as well. I recently installed JJ 6L6GC and found 35ma to be right for my ears. Can still get some nice hair if chunked. Anything over 40 and I was getting a little too much compression and choking on my notes.


It kinda all depends on the plate voltage, too. Maybe, your PR runs a bit hotter plate voltages than our AC-voltage buddy (Tesla ... :lol: ).

JJ tubes also take a bit to break-in, so it may "loosen" up, tone-wise --- in a month or two. May want to check the bias after a few sessions, too.

Good luck! Great amp! :D


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Tue Jun 17, 2014 4:15 am
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:shock:

After replacing all the original (1965) tubes with a new ones (except for the Mullard GZ34), I have installed the old tubes back into the amp .. :mrgreen: one by one, to see if there are any issues with any of the old tubes.

Looks like all the old tubes are still performing fine :lol: .. (even after nearly 50 years :idea:

With the V6 (phase inverter) tube - it appears that the old one (Telefunken) performs differently to to the 'new' Jan at7. Its maybe my imagination, but it seems that with Telefunken the amp sounded a bit muffled and lacked power.

Is it me or an 'old' phase inverter tube may cause the above symptoms? :?: :oops:

:wink:


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Tue Jun 17, 2014 8:08 am
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Nikola Tesla wrote:
:shock:

With the V6 (phase inverter) tube - it appears that the old one (Telefunken) performs differently to to the 'new' Jan at7. Its maybe my imagination, but it seems that with Telefunken the amp sounded a bit muffled and lacked power.

Is it me or an 'old' phase inverter tube may cause the above symptoms? :?: :oops:

:wink:



This is a classic sign of a weak tube. Do you have access to a tube tester? I like to put the highest testing, quietest, & most balanced (between triode sections) 12AT7 into the PI position. It's a critical position for most amps.


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jun 18, 2014 3:38 am
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Thanks Beemer for the answer. :wink:

I have no tube tester of mine. 8)


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jun 18, 2014 6:41 am
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Nikola,

Actually, your ears are pretty good testers. BTW, by pushing the output tubes to greater than 75% wattage of dissipation, at idle, you are starting to approach Class "A" region. Not that this is bad, but you'll notice a distinct change in the amp's tonal response and heat produced, at idle.


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 2:36 am
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Beemer,

would you know how similar the 1964 Vibroverb is to 1965 Pro Reverb (apart from speaker{s} configuration)?!?!?

Image


:wink:


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 7:23 am
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Nikola, the VV (AB763) is pretty close to the PR (AA165). PT is the same model. Output trannies are different, prolly to account for impedance load as anything else (just a WAG). VV has the 125A7A. And the Pro Reverb with the 125A6A.


http://www.ampwares.com/schematics/vibroverb_ab763.pdf


http://ampwares.com/schematics/pro_reverb_aa165.pdf



Hammond has no replacement listing for the 8-ohm VV output tranny.


http://r.search.yahoo.com/_ylt=A0SO8yEp ... JoIrOXkgg-


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 8:08 am
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Same circuit as in DeLuxe reverb ..

Image


Very pricey those V.Verbs .. ($5K)
http://www.ebay.com/itm/301230890274?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/1964-Fender-Vibroverb-Guitar-Amplifier-/221480140114?pt=LH_DefaultDomain_0&hash=item33913ebd52


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 9:15 am
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Think we can thank all those SRV fans out there & the limited run of VV, for the high resale price.

The VV has two 6L6GC not 6V6GT (as in the DR). The AB763 has the heftier PSU setup with the two 70mfd/350VDC caps in the first stage. Not like the VV AA763 and the VLR which runs a PSU cap setup similar to the DR.


http://www.ampwares.com/schematics/vibroverb_aa763.pdf

http://www.ampwares.com/schematics/vibroverb_ab763.pdf


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 9:35 am
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BMW2002Ti wrote:
Not like the VV AA763 and the VLR which runs a PSU cap setup similar to the DR.


???

The AA763/AB763 Vibroverb's PS is near identical to the AA165 Pro Reverb -- not the lower-powered Deluxe Reverb or the Vibrolux Reverb. The principal circuit differences between the VV and the PR lie in the resistors used in the NFL and the reverb's RC coupling network. Were these changed to the values used in the Vibroverb (in conjunction with an output tranny swap to the 125A7A) the Pro Reverb would be transformed for all intents and purposes into an ersatz Vibroverb.

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 11:53 am
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Seem not the AA165. It has the parallel 20mfd caps in the first stage. Unlike the AB165 which has the series 70mfd caps (like in other 6L6GC Fender amps).

VV AA165:

http://www.ampwares.com/schematics/vibroverb_aa763.pdf


VV AB165:

http://www.ampwares.com/schematics/vibroverb_ab763.pdf

The AA763 PSU cap arrangement is a lot like the DR, first stage in parallel. Note mfd/voltage ratings. And the VLR.


DR:


http://bmamps.com/Schematics/fender/del ... _schem.pdf


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 11:58 am
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And VLR:


http://bmamps.com/Schematics/fender/vib ... _schem.pdf


Note: only three URL per post.


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 2:40 pm
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I have no idea WTF you are talking about or what schematics you are referring to. The discussion's topic was similarities/differences between the AA165 Pro Reverb Amp and an AB763 Vibroverb Amp. Your totally-off-the-wall references to a Deluxe Reverb and a Vibrolux Reverb have absolutely nothing to do with the question.

Adios

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 1965 Pro Reverb Amp
Posted: Wed Jul 09, 2014 4:30 pm
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Sorry Arjay, Just responded to this post by Nikola. The topic of the PSU cap layout of the DR and the VLR is similar to the VV AA165. The layout of the VV AB165 is similar to the layout of the Pro Reverb. That's all.


Nikola Tesla wrote:


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