Medium delay reverb tank

[dude]

Is there a way to change a reverb tank on a Super Reverb from medium delay to long delay? Of course beside buying a long delay tank.

[HotBluePlates]

Is there a way to change a reverb tank on a Super Reverb from medium delay to long delay? Of course beside buying a long delay tank.

The only way is to buy/use a long decay tank.

However, the stock reverb pan is long decay.  Are you sure you don't already have the stock tank (4AB3C1B)?

[sluckey]

I thought all those blackface amps used a long delay. What is the part number on your "medium" delay tank?

[dude]

OK, sorry I didn't post a schematic, this amp is an Allen Old Flame, based on a single channel Fender BF Super reverb, I built the amp from spare parts and only had a medium delay Accutronics tank 9AB2C1B tank (medium delay). So, no way to change the medium to long delay, thanks.
I had an old Hammond organ reverb tank lying around, tried it in the Old Flame and it works well and has a long delay, I'll use it. Only two springs verses the three in the Accutronic tank. What is the difference between three and two springs?   One spring.. ?   

[sluckey]

Read this... Especially page 4.

Now please post the Allen Old Flame schematic. That's the only one I don't have.
Modify message

[dude]

What I have is 14" x 10" schematic, won't fix my scanner.  It's a killer amp, and has a PPIMV which is different than any I've seen but is "fantastic' and works great, way better than the LAmar, has four separate .1 caps. If I have too, I'll get it copied and send you a copy. Hang on, unless you have suggestions.

[PRR]

> 14" x 10" schematic, won't fix my scanner.

Can you fold it in half (7"x10" twice) and scan each half? Or scan with half in half out of scanner (to avoid fold damage), rotate and repeat? Sluckey or I or lots of folks can paste-together, clean, and export as both GIF and PDF.

[dude]

Ok, l’ll give it a shot with a copy of the layout, schematic is old, 30 years. They don’t make the Old Flame any more. If anyone can put the pages together to one pfd, post the finished schematic and layout. I’m sure others would like a copy, it’s a cool amp.

[dude]

Here’s something l found on my phone, l’ll get a better, full copy tomorrow.

[PRR]

> something l found on my phone

That's a thumbnail. (It renders about 2 inches high). The phone should have a full size. The grey background and small slant are no problem: I can turn dead grass into the whitest snow for Xmas card images, and faded schematics are routine.

I think Sluckey has similar or better skills/tools but if I can help I'm here all week. (Gonna rain rain rain...)

[dude]

> something l found on my phone

That's a thumbnail. (It renders about 2 inches high). The phone should have a full size. The grey background and small slant are no problem: I can turn dead grass into the whitest snow for Xmas card images, and faded schematics are routine.

I think Sluckey has similar or better skills/tools but if I can help I'm here all week. (Gonna rain rain rain...)

Yeah, I'll get something like a PDF file tomorrow

[sluckey]

Remember this?

     https://el34world.com/Forum/index.php?topic=27250.0

When you rescan please use a much higher resolution than 640x480. That's just so old VGA.   

[dude]

Layout, why don't you draw up a schematic and layout, post so I can get a better copy. There have been some changes David made, I have them. David Allen sold the business, a few years ago, but I do know they discontinued the Old Flame. I you want I can get the two schematic's I have and the layout copied and send to you USPS, then if you want you can draw up a schematic and layout.One change David made was the raw pot, he put a 250K dented marked pot for the raw, then he changed it to 100K, 100k works much better.

Those where pictures of the schematic I took with my phone, not scanned. Guess I could retake and post a better resolution but it's readable to me.  I read that tread and I seem pretty naive about servicing an amp at that time, ha.     Much better now, thanks to you and the forum...! The layout and schematic could be transposed to the program you use.., would be nice to share.   

[sluckey]

I stitched the layout file together. Too big to post here. You can get it at my website if you want it. I'll take the file down next weekend.

   https://sluckeyamps.com/misc/Allen%20Old%20Flame%20layout.jpg

[dude]

Thanks
There is a slight error in layout, the bias feed tap is to ground on the bias circuit on the layout, schematic is good, should be to the to the 470 ohm resistor and the positive bias cap goes to ground, just reverse them. The raw pot is nice, 100KL 11 dent. I think one of the reasons my Old Flame sounds so clean and good, is I used a Ruby Tubes (Magic Parts) big OT, 50/60 watts, 2,4 and 8 taps. With the PPIMV, I believe it's a Trainwreck  PPIMV number 1, David copied. I tried this with .047 caps instead of the .1, didn't work well. But this MV works very well as drawn in this layout, very gradual cut in volume when lowered, you notice the change from 2 to 10, every number. Never had any Post MV be so smooth. I used 750 ohm tube grid R's, instead of 470, as I connected pin 8 to ground for EL34's, sounds good but 6L6s are best tone. I know you built a single channel with reverb similar this this schematic, you called it Tweedy Deluxe or something like that, like 20 years ago. 

[HotBluePlates]

... only had a medium delay Accutronics tank 9AB2C1B tank (medium delay). ...

FWIW, I greatly prefer the tank you have now.  Especially when the Reverb knob is a 100kΩ linear as found in Fender circuits (when 100kΩ audio taper would have given a more gradual increase of reverb effect).

The result of the "6-spring" tank and medium decay is a smoother, more diffuse reverb sound that suits more folks when turned up higher.  However, it doesn't do "surf drip" as readily; these days comparatively few folks really seem to want to do the surf thing...

[sluckey]

There is a slight error in layout, the bias feed tap is to ground on the bias circuit on the layout, schematic is good,

Yes and the pencil note about that is clearly readable, thanks to your hi-rez scan.   

[dude]

FWIW, I greatly prefer the tank you have now. 

I agree, unless you're into Dick Dale. Just that I have two of these Allen Amps, one has the long delay, one the medium. I probably would never use reverb past half on but just thought about having the ability. I'll keep the medium delay, thanks for the input. 

[dude]

Here's a shot of that Old Flame layout above, slightly different than the layout posted.  I didn't like that rectifier cap with a tie down, put it on the bd. and ditched the screw down BF eyelet bd.