DIY echo - PT80 or DH echo

[Roobin]

Yes i have searched here...

Anyway, i wanted to build a diy echo, im not really worried about analog/delay, but i would like a lot of flexability, so long (ish) delay times, but little distortion on echos. The pt80 is a bit short delay for me (only 500ms) and high notes apparenlty distort (ive heard a sound sample), but it sounds really good. The DH echo looks better, with 800ms delay, but a) the main chip is out of production and so i'd need to find a replacement, and b) its not raved about as much as the pt 80.

Any advice?

[geertjacobs]

General thought: even though I've built a PT-80, when it comes to delay pedals I would seriously consider buying instead of building.
Even a Line 6 Echo Park (lots of settings, gets great comments around here) is 150$...

That aside, I really like my PT-80. It doesn't do a lot of tricks, but it does them well. Don't know the DH Echo.

edit: This thread came up in the search:
http://www.elixant.com/~stompbox/smfforum/index.php?topic=39429.0

[Mark Hammer]

I'ver made Dean's delay circuit, and with a couple of changes, it's useful enough.  I think he'd be the first one in line to say that the bandwidth and noise specs are nothing to write home about.  The 800ms delay time IS nice to work with and presents a broader range of possibilities for using a delay pedal than the more traditional 330-400msec delay time (found in most MN3005-based pedals), so I can see why you are drawn to it.

Having said that, the PT2399 chip, while shorter on delay, is a noticeably better chip, and should provide better quality sound than the HT8955.  Scott (Swartz) also included a compander chip and better filtering in his design, which should yield performance similar to what people normally get in a Memory Man type pedal.  Indeed, most folks who have reported back on their PT-80 build have good things to say about it.

Princeton Tech also makes a chips which uses outboard DRAM like the Holtek chip does to achieve 800msec delay time, but it will not simply retrofit on the PT-80 layout.

This is going to sound kind of dumb, but if you want 800msec, chances are you'll want more than that.  Why?  Because 4/5 of a second invites you to play riffs to harmonize over, and not every riff will fit into 4/5 of a second.  Consequently, I'd suggest building a PT-80, and saving your pennies for a more substantial digital delay that will do the job with the features and conveniences you'll want.  The one will make you happy until the second one comes along.

[Herr Masel]

There was a mod on moosopotamus for longer delay time on the PT80 but the site is down.. however I remember it was something very simple, I think it was just changing a resistor.

[runmikeyrun]

yes, you add a resistor to the output lug of the delay time pot.  100K will effectively double the delay time.  I put mine on a switch so i can switch it in and out.  The sound quality suffers big time though.

[Dean Hazelwanter]

I'ver made Dean's delay circuit, and with a couple of changes, it's useful enough.  I think he'd be the first one in line to say that the bandwidth and noise specs are nothing to write home about.  The 800ms delay time IS nice to work with and presents a broader range of possibilities for using a delay pedal than the more traditional 330-400msec delay time (found in most MN3005-based pedals), so I can see why you are drawn to it.

Well, I *would* have been the first to admit it, but you beat me to the punch!   
But Mark is 100% correct. Scott's use of the compander chip and extra filtering means the PT-80 *is* considerably better than mine. When I designed it, it was more of a 'circuit snippet' (to steal Tim E's term) that I released just as I was transitioning between careers. As they say, designing (hardware or software) is like using the rhythm method of birth control - one slip and you're supporting it for a lifetime.   

[Roobin]

Thanks for all the feedback guys.

Im probably gonna save up, since i play mostly Pink Floyd or Vai (yes, completely different!) as well as my own stuff. So theres my reasoning for flexability.

The Line 6 echo park looks pretty cool...thanks for the link geertjacobs

Soory, a bit OT, but what is the difference between the DD-6 and the DD-3? They seem roughly the same...

BTW i have moosapotmus' webpage saved on my pc. i found it some time ago, thought it looked good and got it. he put on a 47k

the sound samples for long delay werent long enough for my use (but sounded nice and juicy!)