Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on August 07, 2012, 08:40:39 am

Title: 4AB3C1B vs 9AB2C1B
Post by: LooseChange on August 07, 2012, 08:40:39 am
I find that the Reverb tank length is crucial. 4AB3C1B seems to be too long.
Which one do you prefer.
FWIW, I am not a fan of the Dwell control... Does not really shorten only reduce the effect. I like the pan to be hit hard for the shimmer effect.
Thanks!
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: Fresh_Start on August 07, 2012, 08:47:53 am
Depends on whether you want to shimmer or surf I guess.

 I'm kind of disappointed with the Dwell control on my PR build.  Does just what you say so why have two controls for the reverb return level.

Cheers,

Chip
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: LooseChange on August 07, 2012, 08:55:36 am
I want nice tone and just not too long.
Problem is that the length does vary with each pan with the same part number.
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: Fresh_Start on August 08, 2012, 09:52:52 am
I want nice tone and just not too long.
Problem is that the length does vary with each pan with the same part number.

Big time!  At one point I tried 3 different Accutronics pans in the same amp.  All the same part # and no two sounded exactly the same.  Much bigger variations than swapping tubes.  Biggest difference was reverb output level.

Cheers,

Chip
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: HotBluePlates on August 08, 2012, 04:24:35 pm
Which one do you prefer.

I very much prefer the "6 spring" medium delay 9AB2C1B.

The shorter delay time allows you to use more of reverb pan's output without getting into novelty-effect territory. You can also realistically use a dwell control to get actual reduced reverb density.

I replaced the stock reverb pan for a 9AB2C1B in a reissue 6G15 Reverb I used to own. Suddenly all the range of dwell and mix settings became usable. I don't play surf, but you could still get all but the most extreme surf-drip reverb sounds.
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: LooseChange on August 10, 2012, 06:27:05 am
I collected three of each and I am going to hook each one up for a tone test.
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: HotBluePlates on August 10, 2012, 06:18:23 pm
It would be cool if that were 6 springs but it's only 3.  Is there a 6 spring model? 

The tank starting with "9" is what Accutronics/Belton calls a "6-spring reverb".

Yes there are only 3 delay lines. But there are 6 individual springs, with 2 springs joined in the middle by a brass rivet. So three pairs.

Once upon a time, Thunderfunk (http://www.thunderfunk.com/History.html) amps used to build guitar amps with the "12-spring reverb". This connected two 6-spring tanks in a kind of humbucking fashion to generate a more complex reverb sound. According to Dave Funk, one of the tanks was the standard Accutronics 6-spring tank, and the other was special-made for his arrangement with different delay lengths to complement the stock 6-spring tank.

I don't think even Thunderfunk still makes a 12-spring setup though.
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: Willabe on August 10, 2012, 10:19:14 pm
The tank starting with "9" is what Accutronics/Belton calls a "6-spring reverb".

one of the tanks was the standard Accutronics 6-spring tank, and the other was special-made for his arrangement with different delay lengths to complement the stock 6-spring tank.

The other tank is a "99" tank. I called Accutronics one time years ago and they said it was their idea/design and that they don't make it any more. But would if you ordered a run of, was it 100 tanks?


                         Brad       :icon_biggrin:
Title: Re: 4AB3C1B vs 9AB2C1B
Post by: plexi50 on August 11, 2012, 04:34:37 pm
I just got a 8AB2A1B 3 spring reverb tank and the decay rate is way too long. Now my Dwell pot makes hardly any difference in taming the decay rate.  I had better results using a Solid State reverb tank i was playing around with a few days ago