DRRI and PTP

[NTBluesGuitar]

Been a LOT of talk about the DRRI and I want to ask...

Is there anything that the DRRI does better than a PTP build of the same circuit?

Are there any significant changes in the DRRI that were improved on from the original blackface versions it's based on?

I know the kits are complicated, but I thought this might be an interesting topic to directly compare the two. Since I'm so into tinkering and building, I thought I may add a good ol' Blackface build to my list of wanna-dos.

Thanks in advance.

[brianf]

Other than maybe some upgraded tubes; there is no reason to change anything on a DRRI. They sound great as is. It's so hard to compare to a PTP original because some of those sounded great and today some of them are dogs do to worn parts and old age. There is a 64 or 65 original at the shop I buy my gear at and the DRRI is better sounding.

Whether it will sound better than a new build it yourself depends on parts and the skill of the guy building it.

There are some great sounding silverfaced as well.


brianf


brianf

[NTBluesGuitar]

Oh, I'm the guy that's gonna build it. No problems there.

Just wondering what advantages there are to either a hand-built or new reissue.

[brianf]

I built a tweed princeton about 2 years ago. The step by step build photos are in the forum somewhere if you seach.

They key thing is IT IS FUN!!!! After I did mine I saw some wiring issues that were sloppy. Had fun again tearing it apart and doing a rebuild.


brianf

[JAM]

Is there anything that the DRRI does better than a PTP build of the same circuit?

Are there any significant changes in the DRRI that were improved on from the original blackface versions it's based on?

I don't think there's any significant changes Fender made to the RI compared to the original AB763 circuit. (At lease from just looking at the schematics). I've read posts on other forums where guys have A/B'ed them against originals and they sound pretty similar with some comments that the RI's can be brighter. Maybe just the difference in aged components? BTW, the best DR I've ever played on was a silverface the store I worked at had. One of the best sounding amps I've ever played on. It sold before I could get the cash together to buy it.

[Wilko]

Sounds like a fun project. I'm sure if you search you can find a board assembled and ready to solder in to your DRRI chassis.

They are out there for almost every other amp.

go for it.

[Guitar_Mc]

Just wondering what advantages there are to either a hand-built or new reissue.

Does your kit have reverb and trem?

[NTBluesGuitar]

Sounds like a fun project. I'm sure if you search you can find a board assembled and ready to solder in to your DRRI chassis.

They are out there for almost every other amp. go for it.

I don't have anything for it yet. I'm just in planning stages...before I commit to anything, I like having all my ducks in a row.

As some of you may know, I build my boards from scratch and source out the rest of the parts from various places.

Appreciate the advice! JAM, I'll look at the SF DR schematics and such to see what may be different than the BF.

[Wilko]

For benefits, there are few that are convenient for working on them and access to the parts that can be of whatever quality you want.

My personal feeling is that good old 18AWG wires are better than any PCB trace. All my fenders are hand wired.

I do have a JTM45 RI that will likely get a tag board someday.

[rocknmatchless]

You might want to consider the mid mod for your DR, Guitars live in midrange and DRs dont have a mid control so you can change the capasitor that controls the mids that is soldered to the chasis to a higher value , Fender has set them as though you have the mid control set at 5, I had mine changed with one of higher value so it is like the mid control is set on 15. I changed the speaker with a weber californian this amp sounds great!!!!!! My Dr is a 68 model.

[JAM]

You might want to consider the mid mod for your DR, Guitars live in midrange and DRs dont have a mid control so you can change the capasitor that controls the mids that is soldered to the chasis to a higher value , Fender has set them as though you have the mid control set at 5, I had mine changed with one of higher value so it is like the mid control is set on 15. I changed the speaker with a weber californian this amp sounds great!!!!!! My Dr is a 68 model.

This is really a matter of personal taste, and some guitars (and some styles of music) work better with different values. If you dont want to add a mid control, I think the best way is to hook a pot (25K or so - not too high) in place of the the 6.8K resistor (not a capacitor) and adjust it to where you like the sound the best, and then measure the resisitance value and solder an equivalent value in place.

[rocknmatchless]

Yeah thats a pretty good idea Jam, I was just offering up some suggestions. I play Teles most of the time and this mod works well for me. It would probably be a different story if you were playing a Les Paul

[MMP]

Somebody put a mid control in the second input hole of this 79 PR before I purchased it on ebay. I could put this amp back to original, but have never found a compelling reason to do so.

[mageerc]

Been a LOT of talk about the DRRI and I want to ask...

Is there anything that the DRRI does better than a PTP build of the same circuit?

Are there any significant changes in the DRRI that were improved on from the original blackface versions it's based on?

I know the kits are complicated, but I thought this might be an interesting topic to directly compare the two. Since I'm so into tinkering and building, I thought I may add a good ol' Blackface build to my list of wanna-dos.

Thanks in advance.

I would say build it... your PTP amp will be working years after that PCB was chunked in the dumpster. I'm not saying that the DRRI is a bad sounding amp... it's just that Fender's circuit boards are just plain flimsy. I've worked on so many of them that I've become rather adept at making jumpers for broken traces and such. The boards are just inferior.

[JAM]

I've worked on so many of them that I've become rather adept at making jumpers for broken traces and such. The boards are just inferior.

That's PTP conversion isnt it?

[NTBluesGuitar]

Lots of great suggestions! Thanks again, gang.

In the end, it's a question of whether or not the PCB DRRI had some improvements that makes it so sought after so much now, or if it's just a good job by Fender to capture the qualities of a classic BF PTP circuit.

Still, it's a project-to-be. I've got a Tweed Champ that I almost have all the parts for, a HRDlx that's about to be converted to a 5Ex circuit (the PCB has been repaired too many times and is about to be gutted), and this is just another on the list of want-to-dos.

I just don't want to spend more on a PCB production amp when I can have the same thing for less by building it (besides, building it is so much more rewarding for me). That is, unless there's something in the re-issue that makes it better than its predecessor.

Still, great ideas and input, y'all. Thanks!

[JAM]

AFAIK, the DRRI is the same circuit as the original DR AB763. Fender didnt do any 'improvements'. (They really didn't have to!) The only possible change, and I dont know if it's intentional, is the slightly lower B+ according to some accounts. (Maybe to compensate for the higher AC in the US ?)

[NTBluesGuitar]

AFAIK, the DRRI is the same circuit as the original DR AB763. Fender didnt do any 'improvements'. (They really didn't have to!) The only possible change, and I dont know if it's intentional, is the slightly lower B+ according to some accounts. (Maybe to compensate for the higher AC in the US ?)

Maybe...or maybe it has to do with some of the newer, more economical power transformer production methods?

I read an interesting site on a guy who took his DRRI and had it rebuilt. What makes it noteworthy is his account of his conversations with the tech and with Mercury Magnetics about the differences in the PTs. The site is: http://waynereno.com/ The specific section about transformers is really intriguing. The Mercury, compared with the regular issue, is on the right:

[JAM]

Yeah, I've read that article before. Seems an expensive way to achieve a PTP DR. You could buy the Weber 6A20 and upgrade to MM transformers. Of course, it wont say Fender on it.

[JAM]

I'll bet it was because until the JJ 6V6 came along, new production 6V6's were melting down at an alarming rate.

Hadn't thought about that, but that seems more like it.

[NTBluesGuitar]

Yeah, I've read that article before. Seems an expensive way to achieve a PTP DR. You could buy the Weber 6A20 and upgrade to MM transformers. Of course, it wont say Fender on it.

It's a great article, but he also had a lot of mods done to it. Still, it's an awesome resource for general information, don't you think?

As you probably know, the name on the amp doesn't matter to me. Just the guts.

In the end, as long as the 6A20 would give me the thing as the DRRI, then that's what I'd be after. Just wanted to see what the differences are.

[Guitar_Mc]

The cheapest way to get a PTP DR has got to be...

Go buy a '70s silverface. Then change a couple of caps if you need to.

[Wilko]

Check this out:

http://cgi.ebay.com/BLACKFACE-DELUXE...QQcmdZViewItem

[Don]

I'll bet it was because until the JJ 6V6 came along, new production 6V6's were melting down at an alarming rate.

My Vibrochamp, with the volume and tones set to 10 would devour new 6V6 tubes until the JJ 6V6 came along!