Balanced TRS DI Out into Mono Bass Amp Input OK?

[Obrienp]

Hi Knowledgeable Folks,

Looking for some advice. I recently bought an Ashdown Little Stubby 30 watt valve head. It may be loud enough for some very small gigs but I think it will need some reinforcement for larger venues or gigs outside. Now at the moment our PA has 2 EV 12” active speakers and no sub. I wouldn’t normally plan to DI into our desk. The Little Stubby has a TRS balanced DI out. Can I feed this into my more powerful class D solid state head? Would I need some sort of TRS to mono converter? The other head only has jack input.  I know I would need the Stubby to have a speaker load.

Why do I want to do this rather than just use the solid state head? Because I love the tonal options of the Little Stubby and I want to use its preamp and just use the solid state head like a power amp, with all EQ flat. This is trying to avoid shelling out for a separate power amp.

Supplemental question for Little Stubby owners: the manual says it will deliver 30 watts into either 8 or 4 ohms cabs; is that possible? Won’t it be 15 watts into 8 ohms and 30 into 4 ohms, or do valve amps work differently to solid state?

Thanks in advance for any advice.

[paul_c2]

You don't need a TRS-to-mono converter. The 3 pins of TRS are chosen sensibly such that plugging a mono lead in, or plugging a TRS lead into a mono socket, works.

You will probably need to turn the volume very low for it to work okay, but I've done it a number of times and have had no worries.

[agedhorse]

On balanced outputs that are transformer driven (possible with  this amp if the signal is taken from the secondary of the output transformer), a TRS will not work if the ring terminal on the input jack on the amp of the amp is not grounded. It depends on the type of input jack, and the way it is wired into the circuit. 

[hubrad]

What speaker cab(s) are you going into? I'm just thinking back to a borrowed 50W valve head into a 4x12 ages ago, which was both thunderous and tone rich. Possibly the CTM30 into the right cabs will do the trick.

[Merton]

1 hour ago, agedhorse said:

On balanced outputs that are transformer driven (possible with  this amp if the signal is taken from the secondary of the output transformer), a TRS will not work if the ring terminal on the input jack on the amp of the amp is not grounded. It depends on the type of input jack, and the way it is wired into the circuit. 

Pretty sure this will be the case with the Little Stubby. Proceed with caution!

[MichaelDean]

Happy to be proven wrong here!

You might have better luck sending the little stubby out via the effects loop send (still with a load on the speaker) and feed that into the return on your class D head. The manual says that the send comes after the preamp, so accomplishes the same goal and you only need jack cables. 

[Obrienp]

19 minutes ago, MichaelDean said:

Happy to be proven wrong here!

You might have better luck sending the little stubby out via the effects loop send (still with a load on the speaker) and feed that into the return on your class D head. The manual says that the send comes after the preamp, so accomplishes the same goal and you only need jack cables. 

That is a great idea but unfortunately neither of my Class D heads have effects send and return. Still, it might be cheaper to buy a second hand head with a send and return than a power amp.

[Obrienp]

1 hour ago, Merton said:

Pretty sure this will be the case with the Little Stubby. Proceed with caution!

Yes, the balanced out is transformer driven 😱. Do I dare? 

[Obrienp]

2 hours ago, hubrad said:

What speaker cab(s) are you going into? I'm just thinking back to a borrowed 50W valve head into a 4x12 ages ago, which was both thunderous and tone rich. Possibly the CTM30 into the right cabs will do the trick.

It is going into 2 Barefaced One10s, which are pretty loud. Much as I would love to go into a 4x10, or 4x12, I have reached the age where light weight and general portability are key. I think as a combo the Little Stubby and One10s will be loud enough for small indoor pub gigs but probably not for large halls, or outdoors.

[Obrienp]

5 hours ago, paul_c2 said:

You don't need a TRS-to-mono converter. The 3 pins of TRS are chosen sensibly such that plugging a mono lead in, or plugging a TRS lead into a mono socket, works.

You will probably need to turn the volume very low for it to work okay, but I've done it a number of times and have had no worries.

Have you done it with a Little Stubby, or other Ashdown valve head? The manual says you “MUST” connect a TRS cable. 

[paul_c2]

no

[jrixn1]

10 minutes ago, Obrienp said:

It is going into 2 Barefaced One10s, which are pretty loud.  [...]  I think as a combo the Little Stubby and One10s will be loud enough for small indoor pub gigs but probably not for large halls, or outdoors.

Could you get a better PA for these larger gigs?  Even if you rig your Little Stubby into a power amp, how will the audience now hear the drums properly at these outdoor gigs?

[Obrienp]

2 hours ago, jrixn1 said:

Could you get a better PA for these larger gigs?  Even if you rig your Little Stubby into a power amp, how will the audience now hear the drums properly at these outdoor gigs?

Hmm. true that. Maybe I better just get a sub but they are all so big and heavy. Food for thought. Thanks.

[Obrienp]

Thanks to you all for the suggestions and advice. Better PA maybe the way to go:;well at least a sub.

[Obrienp]

4 hours ago, MichaelDean said:

Happy to be proven wrong here!

You might have better luck sending the little stubby out via the effects loop send (still with a load on the speaker) and feed that into the return on your class D head. The manual says that the send comes after the preamp, so accomplishes the same goal and you only need jack cables. 

Just thought, even though my other heads don’t have effects loops, I could still use this basic idea. Just connect a pedal into the effects loop on the Stubby that has wet and dry out. Send the wet back to the Little Stubby and send the dry to the input of the other amp. In fact, I guess the pedal could just be a splitter box.

Then all I have to do is make sure the total volume doesn’t drown the drums.

[agedhorse]

6 hours ago, Obrienp said:

Have you done it with a Little Stubby, or other Ashdown valve head? The manual says you “MUST” connect a TRS cable. 

If you are feeding a balanced input, you must use TRS on the amp’s end but if you are feeding a unbalanced input, you will need to use a TS cable which automatically grounds the ring (to the sleeve)

[Downunderwonder]

What is the second amp supposed to be feeding in this scheme if the Stubby is still on the 110 cabs?

[Obrienp]

6 hours ago, Downunderwonder said:

What is the second amp supposed to be feeding in this scheme if the Stubby is still on the 110 cabs?

It would be another compact cab matched to the second amp. Probably a 12” like the lightweight Ashdown with the white speaker. Now I have spent out on the Little Stubby, I cant afford a Barefaced, or GR 12” but there seem to be quite a few Ashdown 12s on the second hand market.

[Chienmortbb]

8 hours ago, agedhorse said:

If you are feeding a balanced input, you must use TRS on the amp’s end but if you are feeding a unbalanced input, you will need to use a TS cable which automatically grounds the ring (to the sleeve)

Just for clarity is the TS cable just a standard instrument cable?

[Downunderwonder]

25 minutes ago, Obrienp said:

It would be another compact cab matched to the second amp. Probably a 12” like the lightweight Ashdown with the white speaker. Now I have spent out on the Little Stubby, I cant afford a Barefaced, or GR 12” but there seem to be quite a few Ashdown 12s on the second hand market.

It's a real gamble that it doesn't sound lousy with mismatched cabinets. Try before you buy.

[Downunderwonder]

28 minutes ago, Chienmortbb said:

Just for clarity is the TS cable just a standard instrument cable?

It has one end with the XLR 'mic' end wired up unbalanced and the other is standard TS 1/4". Agedhorse will fill you in or you can look up the Rane note for unbalanced XLR.

[Obrienp]

40 minutes ago, Downunderwonder said:

It has one end with the XLR 'mic' end wired up unbalanced and the other is standard TS 1/4". Agedhorse will fill you in or you can look up the Rane note for unbalanced XLR.

OK. In the case of the Ashdown Little Stubby the balanced out requires a TRS jack (no XLR out), so would that require a cable with TRS one end wired unbalanced and TS 1/4” the other? 

[Downunderwonder]

9 minutes ago, Obrienp said:

OK. In the case of the Ashdown Little Stubby the balanced out requires a TRS jack (no XLR out), so would that require a cable with TRS one end wired unbalanced and TS 1/4” the other? 

Yep. See the Rane tech note.

[Obrienp]

3 hours ago, Downunderwonder said:

Yep. See the Rane tech note.

Thanks. Useful to know.

[agedhorse]

13 hours ago, Chienmortbb said:

Just for clarity is the TS cable just a standard instrument cable?

Yes.