Spring reverb transducer repair possible? (and does it make sense?)

[rock soderstrom]

You can buy replacement Accutronics assemblies from CE electronics.

The coil wires are very fragile. If Molex connectors were plugged onto the leads, unplugging them can often break the magnet wire.

This is my DIY reverb: MicMix MasterRoom XL-305 Spring Reverb Clone - Pro Audio Design Forum

MasterRoom XL-305 Clone Sleds

The XL-305R is now being made by Audio-Scape: XL-305R Equally Tempered Stereo Reverb — Vintage Pro Audio Equipment | AudioScape Engineering Co.

Hi Sputnik, very interesting and impressive project! I had read about it before and build in some of these ideas into my similar test setup with 4 accutronics reverb tanks.

Thanks for info and inspiration!

 

[rock soderstrom]

I used to rewind those hi z reverb transducers, pain I'm the rear. They rivet the coil/core assembly to the plastic carrier
I find that after rewinding and reassembly that the pan sound is weaker. This is probably from the stress the Ni lams go though when bending them to get the coil off. Since Mod pans are cheap, much better to buy new pan. I also like the crazy noisy piezo pans used in the Silvertones.
For some reason, the wire tension got real tight on the accutronics pans, that, coupled with using a different potting compound which hardens real stiff has led to the demise of around 20 pans that I have replaced
Most of the Fender black face twin reverb tanks that I have seen are still kickin, probably due to wax being used.
Man the whole band got drunk tonight and embarrassed the hell out of me being the only straight guy, I don't t know about this rock and roll biz

Thanks CJ for info. I guess if rewinding the coils is a pain in the axx for you, then it won't be right for me. These ultra thin wires and I are not exactly best friends. I think I'll try to organize a replacement coil from Sputnik's source. Thanks again for Info.

 

[Tubetec]

Ive drilled out that brass rivet quite a few times swapped coils and lams , of course you need a small nut and bolt to fix it all back together afterwards , M2 brass nut bolt and washer is my go too , steel bolt maybe not so good .
I think the lams would have to be slightly bent to put the coil on in the first place , I dont think it makes much odds .

For me what really makes a reverb tank worthwhile is at the ultra low levels of decay , it doesnt decimate into square waves like digital reverb at lower levels , its clean reverberation and I find it more absorbing on a synaptic level . Course with 24 bit and higher sample rates Digverb is very good ,but it often still lacks a 'feel' I get from a proper tank . Theres heaps on non linearity when you drive it , but the decay is still flawless .

 

[TimG]

I thought the labor pool required for proper spring reverbs made them cost prohibitive?

 

[CJ]

And let's not forget how much fun it is to resolder those wires that hold the small magnets in the gap. Winding the coils is not bad, no winding machine at work so I just chuck the bobbin on an 1/8 " drill bit and spin some pickup wire on there. The tough part is reassembly and realizing I just spent two hours to make ten bucks,

 

[user 41968]

The Accutronics assemblies as well as the Mod now have the springs glued to the transducers.

Acetone will dissolve the Accutronics glue. The Mod springs are glued with some kind of epoxy. I never could find a solvent for them so they're permanent.

 

[user 41968]

1979 MicMix spring reverb builders

2021 Audioscape spring reverb builders

 

[Tubetec]

Looks like an interesting unit the Audioscape, sounds nice in the demo .
Wow ,seems like there having fun in the pics , Id say say there half tanked

definately seem to be a niche in the market for a real spring reverb .

 

[gyraf]

basically, spring reverbs died because AKG patented all the good ideas in there - most of it implemented in the BX20. But now the patents are void..... (!)

/Jakob E.

 

[Tubetec]

I did fool around with my own transducers based on the moving coil principle like the AKG used , I wasnt able to create such a tiny coil as used in the BX so the high end was rolled off due to the extra inertia/mass hanging off the spring , still sounded good though , hugely powerfull bass end .
Of course in the AKG they have other stuff going on too , they appear to use feedback to change the decay of the springs .
Im surprised Uli B hasnt had a cut off pirating the AKG system , they do a massive amount of analog synth clones and patchbay stuff nowadays . If they can pull off an La-2a or a Pultec or an 1176 for a few hundred , surely a tank reverb wouldnt have to cost thousands .

There lots of other threads here relating to spring verbs , probably worth digging through .
Maybe it would be possible to make a drive/recovery board based on the principles of the AKG but using standard Accutronics tanks ,

 

[mjrippe]

Maybe it would be possible to make a drive/recovery board based on the principles of the AKG but using standard Accutronics tanks ,

Sure, but I would argue that the AKG spring assemblies are responsible for 90% of the "sound" of their reverbs. You might get something like a BX-5, but nowhere near a BX-10 or 20.

 

[Tubetec]

I have one of those folded line short tanks that came out of a Peavey its different to the usual Accu tank , As far as i can tell , its the folded line principle used in the AKG , although with other circuit embelishments added .

 

[CJ]

I see a lot of open coils on amps like the fender blues Jr, they couple u1a tl072 directly to the pan input. If the opamp rails out you get massive current into the pan input coil. Or the chip pops

 

[JohnRoberts]

In linear operation the TL07x only put out 20 mA or less, but if the chip fails all bets are off.

JR

 

[rock soderstrom]

Uncle Doug transplated transducer coils in his latest video.
I probably would have left the old Gibbs coils in because I liked the sound better.
But anyway, the episode is again very good, clear recommendation from my side.
Very interesting video about 6G15 reverb tanks and spring reverbs in general.