Putting one tube reverb in a Bluesmaster clone.

[Mark]

Hi

I thought I'd ask the question before I wade through thousands of posts.

I have noticed one tube reverb circuits that use both 12AX7's and 6BM8's. So obviously a decision has to be made with regard to valve choice.

What have you tried and what works bets for you.

Thanks for your assistance.

[TPL]

I used a 12ax7 but found I like the 12at7 better. Not as strong but sounds sweet.

Tony

[Mark]

The 6BM8 would have a ton of gain from the pentode, but I think voltage gain isn't the key to the send side, I suspect a 12DW7 with a AU7 and AX7 in the one package would also be interesting.

[markusw]

I suspect a 12DW7 with a AU7 and AX7 in the one package would also be interesting.

Just tested a 12DW7 I bought 2 or 3 years ago for exactly this purpose.
With the AU7 section for driver the reverb is clearly much weaker than with a 12ax7. I will stick with 12AX7.

Peace,

Markus

[wjdunham]

Hi

I thought I'd ask the question before I wade through thousands of posts.

I have noticed one tube reverb circuits that use both 12AX7's and 6BM8's. So obviously a decision has to be made with regard to valve choice.

What have you tried and what works bets for you.

Thanks for your assistance.

Having experimented with many different one tube and two tube configurations, my experience is that the recovery amp gain is a very critical factor in getting a balanced reverb. The drive side is a bit less critical and adequate drive can be achieved with a single 12AX7 or AT7 Triode. I have found that a single return stage amp just doesn't cut it though, and that 2 x 12AX7 stages are really required to get a good full verb. I have built plenty of single tube amps, the verb is good for low volume, small room/bedroom environments, but falls way short in a larger setting.

All that said, my experience is that 12AX7 is the best choice for a simple single tube reverb. The lower current on the drive side is more than compensated by the higher gain return amp.
Bill

[Mark]

Thanks for the advice on reverb.

Could I also ask for favourite circuit diagrams that work well in these amps?

Also does the reverb, take anything away from the amp?

I am very happy with the tones that I'm getting.

[martin manning]

https://tubeamparchive.com/viewtopic.php?p=9999#9999

[Mark]

Thanks Martin, much appreciated.

I had a listen to the clip, the song is very nice, great playing, but the reverb isn't all that apparent.

The question that immediately came to mind whilst I was listening was, is there more reverb on tap from this circuit than the amount demonstrated in the clip?

I don't want to use the reverb tastelessly, but I like to surf every now and then.

I think I would have liked a clip where the depth of the reverb was demonstrated.

Thanks again for showing me this circuit Martin.

[martin manning]

I haven't built that circuit (several people here have), but as suggested by Gary the 100k mix resistor could be tweaked to adjust the balance of wet and dry signal. That thread I linked has some discussion on 6BM8... have you seen circuits using that tube somewhere?

[Mark]

I saw the 6BM8 circuit at Hoffman amps forum. The specs on the 6BM8 makes me think this would be a better tube for a single tube reverb. The pentode seems quite rugged.

More to experiment with.

The other question related to reverb tanks; which brand MOD or the new Accutronics?

I've heard the new reverb springs aren't much good any more what are the findings on this issue?

Then there is the type of reverb unit long delay, medium delay, 4 springs or six springs?

[10thTx]

Like the 6BM8, the ECL84 is a pentode/triode also and might be worth considering? It has a little less output than the 6BM8.

I have built an amp using the 6BM8 triodes as a LTPI into the 6BM8 pentodes.

And now I have done the same thing with ECL84 triodes into the ECL84 pentodes. I like the tone that the ECL84 has. (ECL84 = 6DX8)

http://tdsl.duncanamps.com/show.php?des=ECL84

I have not tried the ECL84 as a reverb tube, but perhaps it would be a reasonable choice? Maybe it would sound great?

With respect, Tubenit

[Mark]

Thanks for the tip.

Does anyone have advice on which spring works best?