Submini Tube Reverb request

[danielzink]

Anyone with familiarity with the submini tubes and laying out amps ever look at doing a submini tube reverb ?

Long ago I took apart a Danelectro Spring King and saw the (genuine) spring reverb tank inside and wondered about using said tank on a true tube reverb.

Here's the tank: https://www.amplifiedparts.com/products/reverb-tank-accutronics-8ab2a1b

10Ω input
2575Ω output

Being as I have a "plethora" of submini tubes hanging around waiting for a new project

Dan

[Kevin Mitchell]

This page is loaded with schematics using subminis and reverb tanks. I've recreated the russian verson on breadboard with mild success (had not used a reliable SMPS with these designs when I was tinkering)

[bluebunny]

Nathan posted a submini reverb a while back using a Belton brick and 6N16B [thread].

[danielzink]

Nathan posted a submini reverb a while back using a Belton brick and 6N16B [thread].

Yeah.

Not sure how the pinout of the Belton translates to a real spring tank - which is my ultimate goal.

Dan

[Kevin Mitchell]

Can you find a compact reverb tank that isn't designed for a solid state preamp/driver?

[danielzink]

Can you find a compact reverb tank that isn't designed for a solid state preamp/driver?

Doesn't say that the (accutronics 8ab2a1b) as posted is specifically designed for a solid state driver so I'm not sure what you're asking ?

[vigilante397]

I've thought about doing a submini-driven spring reverb, may throw that on the list. The 6N16B-driven Belton brick was kind of fun to do, but not a one-size-fits-all solution. I was looking at the Fender 6G15 Fender Reverb unit, it might be fun to try that with a 6N16B, 6P30, and 6N21B instead of the 12AT7, 6V6, and 12AX7 respectively. But with the way things have been going I'll probably draw up a design in the next couple days and build it in 6 months or so

[danielzink]

I've thought about doing a submini-driven spring reverb, may throw that on the list. The 6N16B-driven Belton brick was kind of fun to do, but not a one-size-fits-all solution. I was looking at the Fender 6G15 Fender Reverb unit, it might be fun to try that with a 6N16B, 6P30, and 6N21B instead of the 12AT7, 6V6, and 12AX7 respectively. But with the way things have been going I'll probably draw up a design in the next couple days and build it in 6 months or so

Draw it up and see if you can generate a pcb.

I'll build it !

[vigilante397]

I was just thinking I don't know what PCB project to take on next, may as well take a swing at this one.

[danielzink]

That's awesome.

I have 6N16B's...and some 6111's.

Not sure how the 6111's match to the 6N21B - both are dual triode...

hmm..

[vigilante397]

Not sure how the 6111's match to the 6N21B - both are dual triode...

I've never used 6111 as 6N21B are generally cheaper   It looks like 6111 have a lower amplification factor. A 12AX7 has an amplification factor of about 100, and I usually replace them with 6N21B, which have an amplification factor of 82. 6111 have an amplification factor of 20, which puts them more in the range of a 12AU7 which has an amplification factor of 19. 6N16B have a factor of 25 or so, which is also in the 12AU7 range.

I have heard that despite having a lower gain factor a 6111 gives a better overdriven tone than a 6N16B, making them much better for things like a Valvecaster (or its varients).

[Greenwichpaul]

I was just thinking I don't know what PCB project to take on next, may as well take a swing at this one.

Oh please do! I'll hold off on my surfyverb if so.

[danielzink]

Not sure how the 6111's match to the 6N21B - both are dual triode...

I've never used 6111 as 6N21B are generally cheaper   It looks like 6111 have a lower amplification factor. A 12AX7 has an amplification factor of about 100, and I usually replace them with 6N21B, which have an amplification factor of 82. 6111 have an amplification factor of 20, which puts them more in the range of a 12AU7 which has an amplification factor of 19. 6N16B have a factor of 25 or so, which is also in the 12AU7 range.

I have heard that despite having a lower gain factor a 6111 gives a better overdriven tone than a 6N16B, making them much better for things like a Valvecaster (or its varients).

Got it !

NP - 6N21's are inexpensive enough.

Thanks for the advice !

[thomasha]

It's sad that those 6N*** tubes are really current suckers. 400mA +- 40mA is a lot of heat for a small box to dissipate.

The 6111 and 6021 tubes are more like normal tubes, with 300mA, same as the 12AX7.

[vigilante397]

It's sad that those 6N*** tubes are really current suckers. 400mA +- 40mA is a lot of heat for a small box to dissipate.

I've measured my 6N21B's only pulling 350mA for heaters but it's true, they are current hogs. For anything more than one tube I can't get away with linear regulators because they either overheat and shut down or if they're mounted to the box for heatsinking the box gets uncomfortably hot.

But with my fancy new SMPS I use for heaters total heat dissipation is much lower, and my latest dual 6N21B design only pulls 550mA total on a 9V supply

So a 12AT7 has a gain factor of 60, which is considerably higher than a 6N16B, so I'm thinkning I may use a pair of 6N21B and see if a 6P30B can substitute the 6V6. Also as much as I love doing PCB layouts just for the fun of it, I would feel bad designing something when I don't know if it works, so I would be more comfortable breadboarding it first then doing the layout

[MetalGuy]

Don't forget the 6N17B which has a u of 75 (+/-15). I had very good results replacing 12AX7 in some preamps ut you may need some B+ adjustment. 6P30B and 6P30B-R will give you 1-2W in SE mode but in PP amp with fixed bias I was able to get clean 5-6 Watts out of a pair.

[vigilante397]

It's true, I've used 6N17B interchangeably with 6N21B and they sound great. The only reason I've switched to 6N21B is that my stash of 6N17B ran out and 6N21B seem to be both easier to find and cheaper. So all my older PCBs use 6N17B pinout, and the newer PCBs use 6N21B pinout

[danielzink]

6N21's showed up !

Any headway on the layout ?

Thanks !

Dan

[vigilante397]

Not yet it's still on my list, but I'm finishing up my first 1/2W amp design. It's looking like I may be able to get to it this week though.

[vigilante397]

Sorry I've been putting this off for a million years But i finally started on it today, so I'll keep you posted as progress is made.