Made my loop serial, still sounds bad.

[Don_Sloan]

I have tried everything. I did patch cable, no patch cable, level max, level min, full wet, full dry, MV high channel low, channel high MV low. Nothing makes it sound the same as with the loop bypassed. It looses so much bass and cut when I have the loop on it's like a totally different amp..

I guess I am just going to have to be without a loop :roll:

I may try that bypass idea posted above. If I go that way I'll report back with the results.

Have you changed that capacitor I recommended yet?
If you haven't, you will always have that bass roll off until you do. The value of that cap sets the corner frequency of that tube stage for the loop. The smaller the cap value, the more low end gets shunted to ground and is therefore removed from your signal. The larger value I recommended allows the full guitar range to pass through the loop. This is actually a mod that Mesa recommended and the value is what they use when they do it. Otherwise, once those bass frequencies are removed from the signal, nothing else you try will add them back.

On the other hand, if you've already replaced it and still have the same issue, then you likely have another problem where something isn't working as designed. But if everything else is working properly, the cap should fix it. At least it has on every amp so far that I've done the mod to.

I have not had a chance yet, I am planning on it. I'll make an updated post once I have it done. I'm sure it will work I just have not been able to purchase the cap and do it yet.

Okay, cool.

Btw, here's a link to the part I used (but you should also be able to find a comparable part at Digikey or most any other electronics component dealer).

http://www.mouser.com/Search/m_ProductDetail.aspx?Kemet%2FT322D106J035AT%2F&qs=lrRQCbJOJcXYrx96%252bOiPyg%3D%3D

 

[Don_Sloan]

Can you please post a picture of the mod?

Thanks a lot!

I will look when I get home this evening and see if I took a picture of it. Of course, mine would be on a Road King I, so if you don'thave the same amp, the location of the cap might be different, but there were a few different models that had the same design mistake.

I'll see what I can find in my pics though.

Thanks a lot!

I have a Triple Recto 3ch. The schematic is really similar to the one of the Dual Recto 3ch.

Did this mod changed a lot the sound of your Road King I using the loop? Do you think that the "tone sucking" is eliminated or reduced? Do you find any difference in sound using or not the loop?

Thanks!

What this capacitor does is stop the bass frequencies from being removed from the loop. The lower value cap that came stock causes a lot of the bass to be rolled of with the loop engaged. Putting in this higher value cap retains the full guitar frequency range. While I'm sure there's still some change when engaging the loop because your still going through tube stages that would be otherwise bypassed, my ears don't hear it. Before the change, it was drastic and unusable to me.

 

[DS-1]

Before the change, it was drastic and unusable to me.

The same for me. The sound with loop on is completely different: too thiny, without basses and mids.

If you find those pictures, it would be amazing!

 

[Chiliphil1]

Okay, cool.

Btw, here's a link to the part I used (but you should also be able to find a comparable part at Digikey or most any other electronics component dealer).

http://www.mouser.com/Search/m_ProductDetail.aspx?Kemet%2FT322D106J035AT%2F&qs=lrRQCbJOJcXYrx96%252bOiPyg%3D%3D

I just placed my order. I got it from Digikey since Mauser wanted $8.00 shipping plus the cost of the part. I got it for around $6.00 shipped.

So, pin 3 of V4A replace the cap that's there with this one and it should be good? Should I make the loop serial in the new amp while I'm at it or will it not matter with this mod and no effects being used?

 

[Don_Sloan]

Okay, cool.

Btw, here's a link to the part I used (but you should also be able to find a comparable part at Digikey or most any other electronics component dealer).

http://www.mouser.com/Search/m_ProductDetail.aspx?Kemet%2FT322D106J035AT%2F&qs=lrRQCbJOJcXYrx96%252bOiPyg%3D%3D

I just placed my order. I got it from Digikey since Mauser wanted $8.00 shipping plus the cost of the part. I got it for around $6.00 shipped.

So, pin 3 of V4A replace the cap that's there with this one and it should be good? Should I make the loop serial in the new amp while I'm at it or will it not matter with this mod and no effects being used?

Yes, that's correct. Just replace the existing cap on V4 pin 3. They should look nearly identical, except of course your new one may be slightly larger. One end will be tapered, which identifies its polarity, so just make sure the new one goes in in the same orientation.

I left my effects loop unmodified other than this cap change. While I typically prefer a serial loop, I've found this loop to function nearly identical as long as the mix knob is set to 100%.
(EDIT: only set to 100% if you have effects plugged into the loop. If nothing is plugged into the loop, setting the mix knob to 0% should bypass the Send & Return jacks completely.)

 

[Don_Sloan]

I had the same issue with my Road King v1 with it losing a ton of lows and low mids with the loop engaged. Looking at the schematics, it appears the loop design is nearly identical in your amp.

There is a 2.2uf capacitor connected to pin 3 of tube V4a (which is the effects loop recovery stage). Changing this to a 10uf tantalum capacitor should eliminate the tone suck or at least reduce it substantially. Just be sure to install it in the right direction with the "+" end connected to pin 3. This worked great for me.

I have a Triple Recto 3ch. The schematic is really similar to the one of the Dual Recto 3ch.

Did this mod changed a lot the sound of your Road King I using the loop? Do you think that the "tone sucking" is eliminated or reduced? Do you find any difference in sound using or not the loop?

Thanks!

I just checked my schematics and the 3 channel Dual and Triple Rectifier amps are the same, with the only exceptions being the triple adds an extra 5u4 and 2 extra power tubes. Anyway, the schematic shows they already have a 15uF capacitor in place on the fx loop recovery stage (which in your case is on pin 8 of V4), therefore no need to change it. The 2 channel Dual Rectifier, however, was like the Tremoverb and RoadKing v1 where it was a 2.2uF, but they changed that before they came out with the 3 channel Dual/Triple Recs. So in your case, this mod does not apply.

So, if your fx loop is thin sounding, you may have another problem. Maybe try replacing V4. Also, like I mention in the previous post, make sure your mix knob is set appropriately, with 100% while effects are plugged in or 0% If no effects are plugged in.

 

[DS-1]

I had the same issue with my Road King v1 with it losing a ton of lows and low mids with the loop engaged. Looking at the schematics, it appears the loop design is nearly identical in your amp.

There is a 2.2uf capacitor connected to pin 3 of tube V4a (which is the effects loop recovery stage). Changing this to a 10uf tantalum capacitor should eliminate the tone suck or at least reduce it substantially. Just be sure to install it in the right direction with the "+" end connected to pin 3. This worked great for me.

I have a Triple Recto 3ch. The schematic is really similar to the one of the Dual Recto 3ch.

Did this mod changed a lot the sound of your Road King I using the loop? Do you think that the "tone sucking" is eliminated or reduced? Do you find any difference in sound using or not the loop?

Thanks!

I just checked my schematics and the 3 channel Dual and Triple Rectifier amps are the same, with the only exceptions being the triple adds an extra 5u4 and 2 extra power tubes. Anyway, the schematic shows they already have a 15uF capacitor in place on the fx loop recovery stage (which in your case is on pin 8 of V4), therefore no need to change it. The 2 channel Dual Rectifier, however, was like the Tremoverb and RoadKing v1 where it was a 2.2uF, but they changed that before they came out with the 3 channel Dual/Triple Recs. So in your case, this mod does not apply.

So, if your fx loop is thin sounding, you may have another problem. Maybe try replacing V4. Also, like I mention in the previous post, make sure your mix knob is set appropriately, with 100% while effects are plugged in or 0% If no effects are plugged in.

Thanks a lot!

I already changed the v4, made the parallel/serial mod and checked the mix pot several times.

Tomorrow I'll try again to "play" with mix knob and some new V4 tubes and I'll let tou know!

 

[Chiliphil1]

Okay, cool.

Btw, here's a link to the part I used (but you should also be able to find a comparable part at Digikey or most any other electronics component dealer).

http://www.mouser.com/Search/m_ProductDetail.aspx?Kemet%2FT322D106J035AT%2F&qs=lrRQCbJOJcXYrx96%252bOiPyg%3D%3D

I just placed my order. I got it from Digikey since Mauser wanted $8.00 shipping plus the cost of the part. I got it for around $6.00 shipped.

So, pin 3 of V4A replace the cap that's there with this one and it should be good? Should I make the loop serial in the new amp while I'm at it or will it not matter with this mod and no effects being used?

Yes, that's correct. Just replace the existing cap on V4 pin 3. They should look nearly identical, except of course your new one may be slightly larger. One end will be tapered, which identifies its polarity, so just make sure the new one goes in in the same orientation.

I left my effects loop unmodified other than this cap change. While I typically prefer a serial loop, I've found this loop to function nearly identical as long as the mix knob is set to 100%.
(EDIT: only set to 100% if you have effects plugged into the loop. If nothing is plugged into the loop, setting the mix knob to 0% should bypass the Send & Return jacks completely.)

I just wanted to update you. I ended up having a meltdown on the ToV, so I returned it to where I got it. I now have a triple rec and there are no loop problems what so ever on this one. Thank you again for all of your advice.

 

[Don_Sloan]

Oh man, sorry to hear about the Tremoverb!!

Glad the Triple Rec is working out for you though.

 

[KevorkianMetal]

For older 2 channels only:

There is a procedure per mesa to mod the older 2 channel dual and triple rec/temoverbs:
It involves replacing the FX return jack with a 12a Switchcraft jack, and then moving the red wire from the mix pot to the new jack along with jumping a brown wire on the send pot to the new return pot. The footswitch to turn the fx loop on / off will still function (only on 2 channel versions). Just wondering if anyone has actually done it this "correct" way. TIA I will be performing this mod soon and am looking for any pics of this exact mod if pics exist anywhere.