It is currently Mon Mar 16, 2020 11:40 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 13 posts ] 
Author Message
Post subject: I want more reverb on my Performer 650
Posted: Thu Jan 25, 2018 3:59 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Jan 25, 2018 2:28 pm
Posts: 1
Hello everyone. I recently adquired a 1994 Fender Performer 650 Hybrid, which i really enjoy, because of the simplicity and the sound of the amp itself.
But after a couple of months, i have tested other Fender and not Fender amps with reverb, and i have found that the reverb on my amp is not as loud and endurable as, for example, the reverb on a Fender Frontman 25r, which has an enormous and loud reverb sound.
So i really wanna know how could i improve on the decay and the volume of my reverb! Maybe i could change the potenciometer, or change resistors or maybe change the location of the tank inside the amp?
Please help me out!


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: I want more reverb on my Performer 650
Posted: Mon Feb 05, 2018 2:53 am
Offline
Professional Musician
Professional Musician

Joined: Wed Aug 26, 2009 4:50 pm
Posts: 1339
Location: Denver, CO, USA
That's a relatively uncommon amp, and most of the electronics experts here don't spend much time modifying solid-state amps.

Modifying it is likely to require trial&error experimentation. And might involve replacing/upgrading the reverb tank.

All in all, the best approach is to buy a reverb pedal and plug it into the effects loop.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Mon Feb 05, 2018 8:55 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
That is a interesting amp you have there. The tube for the OD channel has a very unusual circuit that inserts the signal into the plate, takes it out of the grid and sends it to the cathode of the other section. But it doesn't go through that section...???

You can adjust the balance of reverb in a couple places.
R79 is a 470k resistor that feeds the reverb signal back into the main dry signal path. Tack another resistor across it or install a trimpot. Start with 1meg. Don't go lower than 220k.
The other reverb limiting is in the Q4 muting circuit. R76 and R77 are 1meg each. They are used to isolate the muting transistor q4. They could probably be dropped in value as well. Tack another 1meg resistor across them one at a time to increase reverb level. Good luck.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Mon Feb 05, 2018 6:58 pm
Offline
Professional Musician
Professional Musician

Joined: Fri Oct 06, 2017 6:46 pm
Posts: 1209
Location: ʞɹo⅄ ʍǝN
strayedstrater wrote:
most of the electronics experts here don't spend much time modifying solid-state amps.

.... and then there's TimsAudio. :lol:
If the excellent advice above doesn't pan out for you, I would recommend you at least check this pedal out:



Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Thu Feb 08, 2018 12:12 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
TimsAudio wrote:
...The tube for the OD channel has a very unusual circuit that inserts the signal into the plate, takes it out of the grid and sends it to the cathode of the other section...


No, that’s backwards and cannot work that way. From your description, it is a Cathode-follower circuit. The signal comes from the Cathode of the first tube, into the grid of the second tube, and out the Plate of the second tube.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Thu Feb 08, 2018 2:40 am
Offline
Professional Musician
Professional Musician

Joined: Wed Aug 26, 2009 4:50 pm
Posts: 1339
Location: Denver, CO, USA
Different amp, but maybe same principle?

I've always read that the tube in the Roc Pro models was wired as a diode clipper, not as a gain stage. They could have used solid state diodes/LEDs like most clipping circuits, but used a tube so they could market it as a hybrid with a "tube preamp".

Could the Performer be similar?


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Thu Feb 08, 2018 3:56 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Not sure I buy that, about using tubes like a diode. That’s quite an expense, and more complicated to manufacture, as compared to sticking some diodes in there. Using tubes in their normal fashion to drive the preamp section, can give natural tube distortion (clipping), and makes much more sense.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Sat Feb 10, 2018 4:27 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
I just got a copy of the schematic, and I stand corrected, the “preamp” tube is apparently used for clipping. The two triodes of the tube are wired back-to-back, and each will conduct, when the signal voltage is high enough.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Sat Feb 10, 2018 8:50 am
Offline
Professional Musician
Professional Musician

Joined: Wed Aug 26, 2009 4:50 pm
Posts: 1339
Location: Denver, CO, USA
shimmilou wrote:
I just got a copy of the schematic, and I stand corrected, the “preamp” tube is apparently used for clipping. The two triodes of the tube are wired back-to-back, and each will conduct, when the signal voltage is high enough.


Was that a Roc Pro schematic, or a Performer schematic?

Tube-as-diode-clipper is a relatively expensive way to do clipping, but a relatively inexpensive way to be able to market it as a "tube preamp". Borderline deceptive, but there is an actual tube in the preamp section, so...

Like the tube phase inverter in the Super Champ XD. I haven't checked whether Fender outright claims that the SCXD has a "tube preamp", but all the retailers do.

(The SCXD tube PI is perhaps a more defensible bit of marketing since it probably colors the signal and creates overdrive distortion at high input levels. But we can quibble over whether the PI is part of the power amp or part of the preamp.)


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Sat Feb 10, 2018 9:28 am
Offline
Professional Musician
Professional Musician

Joined: Wed Aug 26, 2009 4:50 pm
Posts: 1339
Location: Denver, CO, USA
Back on topic:

When someone asks if moving the reverb tank to a different location within the amp might improve the depth and intensity of the reverb, I jump to the conclusion that the person is inexperienced at modding amps.

I could very well be wrong, but with new posters it's like emergency room triage -- you have to make snap decisions without a lot of in-depth info.

The Fender PCB's I've seen are fairly fragile single-sided things. Even in the ProTube series. Not ideal for novices doing their first experiments. Easy to lift traces and create nightmare repair scenarios. (A lifted trace isn't a nightmare for a gifted tech like Tim, but it can be for a novice.) Just getting them out of the chassis without damaging them can be difficult for the inexperienced.

The PCB in my Orange Micro Terror is more robust than the PCB's in my old Evil Twin.

On top of that, I have no idea what sort of reverb tank the Performer has. I found a Frontman Reverb in the trash (mid '80s metal grille predecessor to the Frontman 15R) -- it has two 6" springs in a cardboard box. I doubt that any circuit tweaking would give it a lush, deep reverb.

So again, there are lots of great reverb pedals available cheap on the used market. Zero risk and guaranteed results.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Sat Feb 10, 2018 10:19 am
Offline
Professional Musician
Professional Musician

Joined: Wed Aug 26, 2009 4:50 pm
Posts: 1339
Location: Denver, CO, USA
And in my first reply, since I was assuming the OP is a novice I was remiss in not mentioning the standard warnings about caps storing voltages.

Caps in solid-state amps won't bite you as hard as in a tube amp, but 30~60 volts running from one hand to the other hand can potentially stop your heart.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Sat Feb 10, 2018 7:05 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Performer 650 schematic.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: I want more reverb on my Performer 650
Posted: Sun Feb 11, 2018 11:03 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
Well, the OP was asking for circuit level mods....

A tube clipper would have a higher switching speed than a diode clipper. Maybe it sounds better.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: