Please check my Schimatic

[danotron]

I just drew this up......do you see anything wrong? How badly will the 3M3 resistor for the reverb kill the tone?...is there a better way to implement the reverb?

[danotron]

I guess its ok ....lets build her!

[ayan]

I just drew this up......do you see anything wrong? How badly will the 3M3 resistor for the reverb kill the tone?...is there a better way to implement the reverb?

OK, I just had a quick look and can offer a few comments.

1. You may want to consider using 5uF bypass caps on all 4 preamp stages. You currently show 10uF on V1B and 1uF on V2B, which I don't think will sound as good as 5 all around.

2. If it were me, I would not try to implemente the reverb after the master volume, which is what you're currently doing. That way, you can't turn the amp amp withouth blasting the reverb way too hard.

What you can do is tap the signal at the output of the clean channel (or the overdrive channel, depending on what more you are), pad it down and feed it to the reverb driver. The reverb driver connects to the 3.3Meg resistor you asked about in a Fender type of amp. Anyway, you would go through the reverb driver, the tank, recovery stage (you have two stages in parallel there) and then back to the other end of the 3.3 Meg resistor. One alternative is to sue one recovery stage... and the place another stage after the 3.3 Meg resistor, after which you could put your master volume.

This approach will work and well, I built my first Dumble/Boogie in a Fender chassis that way 10 years ago. However... you may want to pursue a different approach all together, as it takes a bit of tweaking to come up with signal levels that will not be too hot for the reverb and for tone networks that will not spoil the overdrive sound. I know that Dumble had a whole different reverb circuit in his ODS Reverb amps. I cannot go into too much detail, but the guy derived the reverb signal from the 1st clean stage... always, regardless of the mode selected.

Hope this helps,

Gil

[ayan]

I just drew this up......do you see anything wrong? How badly will the 3M3 resistor for the reverb kill the tone?...is there a better way to implement the reverb?

OK, I just had a quick look and can offer a few comments.

1. You may want to consider using 5uF bypass caps on all 4 preamp stages. You currently show 10uF on V1B and 1uF on V2B, which I don't think will sound as good as 5 all around.

2. If it were me, I would not try to implemente the reverb after the master volume, which is what you're currently doing. That way, you can't turn the amp amp withouth blasting the reverb way too hard.

What you can do is tap the signal at the output of the clean channel (or the overdrive channel, depending on what more you are), pad it down and feed it to the reverb driver. The reverb driver connects to the 3.3Meg resistor you asked about in a Fender type of amp. Anyway, you would go through the reverb driver, the tank, recovery stage (you have two stages in parallel there) and then back to the other end of the 3.3 Meg resistor. One alternative is to sue one recovery stage... and the place another stage after the 3.3 Meg resistor, after which you could put your master volume.

This approach will work and well, I built my first Dumble/Boogie in a Fender chassis that way 10 years ago. However... you may want to pursue a different approach all together, as it takes a bit of tweaking to come up with signal levels that will not be too hot for the reverb and for tone networks that will not spoil the overdrive sound. I know that Dumble had a whole different reverb circuit in his ODS Reverb amps. I cannot go into too much detail, but the guy derived the reverb signal from the 1st clean stage... always, regardless of the mode selected.

Hope this helps,

Gil

[Bob-I]

I just drew this up......do you see anything wrong? How badly will the 3M3 resistor for the reverb kill the tone?...is there a better way to implement the reverb?

YES the 3.3M will kill tone and give you a ton of reverb, Dick Dale look out you have competition

First off you don't need parallel triodes to drive or recover that reverb, a single triode will do. I'd drop the 3.3M to about 220K, possibly even lower depending on the amount of reverb you want. I run 150K on one of my amps and the reverb level stays below 50%.

Next, on the "smooth" switch, put the cap first so you don't have 200V across the switch.

On the PI I'd replace the 100k/10K/100K with 110K/10K/91K.

100K going into OD2 is a tad low. I'd go with 180K, 150K if you want it brighter.

Skip the deep switch, it's a waste.

That's my story.

[Max]

I just drew this up......do you see anything wrong? How badly will the 3M3 resistor for the reverb kill the tone?...is there a better way to implement the reverb?

...... I cannot go into too much detail, but the guy derived the reverb signal from the 1st clean stage... always, regardless of the mode selected.

Hope this helps,

Gil

Hi Gil,

As far as I know, this is only valid in regard of the the early "silverface" ODS with Reverb made before 1980.

On page 730 of "The Tube Amp Book, 4th Edition" by Aspen Pittman there is the copy of something like a signalflow-chart of the ODS 150 Watt (1987) where you can see, that (at least in these amps) the OD passes the reverb circuit too.

Cheers

Max

[Max]

I just drew this up......do you see anything wrong? How badly will the 3M3 resistor for the reverb kill the tone?...is there a better way to implement the reverb?

...... I cannot go into too much detail, but the guy derived the reverb signal from the 1st clean stage... always, regardless of the mode selected.

Hope this helps,

Gil

Hi Gil,

As far as I know, this is only valid in regard of the the early "silverface" ODS with Reverb made before 1980.

On page 730 of "The Tube Amp Book, 4th Edition" by Aspen Pittman there is the copy of something like a signalflow-chart of the ODS 150 Watt (1987) where you can see, that (at least in these amps) the OD passes the reverb circuit too.

Cheers

Max

[ayan]

Hi Gil,

As far as I know, this is only valid in regard of the the early "silverface" ODS with Reverb made before 1980.

On page 730 of "The Tube Amp Book, 4th Edition" by Aspen Pittman there is the copy of something like a signalflow-chart of the ODS 150 Watt (1987) where you can see, that (at least in these amps) the OD passes the reverb circuit too.

Cheers

Max

Yep, that is a true observation. Unfortunately, I have never seen the good on one of thos more modern reverb amps.

Gil

[ic-racer]

After reading what I could on this board and the net about reverbs, this is the reverb circuit I came up with.

So, by trial and error I wound up with a 220k resistor and no capacitor to feed the reverb just before the power amp (as you are doing).

As I recall, when I had a capacitor in there, it would bypass almost the whole signal, without feeding the reverb.

I also put a DPDT switch to bypass it entirely if I want. The in-series resistor is really not that bad of a thing for a Dumble style amp as some treble cut can be good. So I found that when my reverb knob is on "0" the DPDT switch then also functions to bring this extra series resistance in and out, as needed to get the good tone from the guitar being played.

So, my opinion is that you may need to do some tweaking of the reverb circuit once you build the amp.