[busseysound]

Ha! I saw that and was close to pulling the trigger myself (great deal! Congrats!!). I had that in my alerts, but when the moment came I realize the I’ve tubed my MK2.5 (which uses 12au7 gain tube, it changed with MK3) and also has single vol knob (the change to double vol knob I find mildly annoying though no biggy). So I exhaled, and decided to be content… happy this went to a good community member!

I don’t think you can use 5687 instead of EL84 - but you should try the 5687 in the OTL (perhaps you have already, I forget, sorry). There are ton of great EL84 options that are fairly easy to source. I settled on the Reflektor 6P15P which is an equivalent that can be rolled in (also tried the RCA 6BQ5 EL84 that worked great)

The combo is just terrific, you’ll have a blast fine tuning it!

Great thanks! Yeah I went with your suggestion awhile back and am using the 5687 on the OTL - great upgrade. I think I'm going to try Telefunken EL84s. I'll look for the 6P15P you mentioned as well.

Yeah the dual volume knob is a bit of a bummer, but hey it's a pretty new MK IV and I'm thrilled just to have one. How big of a deal is it to use the OTL pre's volume control instead?

 

[Marutks]

EL84 options that are fairly easy to source. I settled on the Reflektor 6P15P which is an equivalent that can be rolled in

Isn't 6P14P EL84 equivalent?

 

[goldwerger]

Isn't 6P14P EL84 equivalent?

Yes you are correct. The 6p14p is the equivalent of EL84

The 6p15p is the equivalent of EL83

The Taboo - at least the old SE84TS+ version that I have - works with EL84, 6515P, and SV83 as substitutes (with SV83 need to use only NOS Svetlana with the large logo per Steve)

 

[heliosphann]

As my addiction has grown, I’ve started creating additional listening stations. My bedroom setup is for speakers, headphones, and IEMs. The line out on the A20 simplifies the setup so no switching required when using PMax. Aeolus is great from either one.

The power cords underneath are cordoned off with copious amounts of cardboard, but only do a fair job as cat deterrent. This is nestled between one speaker and my quilt covered chair.

The signal passthrough on the A20 is a very nice feature. On my secondary setup, I usually have it going to my Pietus Maximus or another amp like it's big brother, the A2.

 

[AnamCeoil]

The signal passthrough on the A20 is a very nice feature. On my secondary setup, I usually have it going to my Pietus Maximus or another amp like it's big brother, the A2.

Can I jump in with a quick question:

I didn't realize this feature of the A20 - couks I use the LO feature from my A20 to feed another amp, without the A20 interfering with the signal? Or am I missing something....if that's the case this will greatly simplify my setup...

Thanks in advance!

 

[cats4cans]

Can I jump in with a quick question:

I didn't realize this feature of the A20 - couks I use the LO feature from my A20 to feed another amp, without the A20 interfering with the signal? Or am I missing something....if that's the case this will greatly simplify my setup...

Thanks in advance!

Exactly. The Line Out is like a bypass. The A20 doesn’t even need to be on.

 

[Honeypot]

Remember a few days back I asked about this?

Thanks everyone for the suggestions. I will definitely look each of them once I rest a bit. It was a veeeery long Friday and Saturday partying hehe

I know using echo as preamp is a nice option, but the Echo uses a solid state rectifier power supply, which won't get most of the tubes and I want to experiment with rectifier tubes as well. Also, the echo uses ecc88 as driver tubes which work at 6v, the 12au7 is a 12v tube, which can also work at 6 for backward compatibility, but it will not get the best of the 12au7 tubes.
The ecc88 tubes were used mainly for UHF amplification. And 12au7 is an evolution from the ecc88 or 6922..

6sn7 is also on my radar. Would love to get some nos tubes and try the very old tubes.

6sn7 - 12au7 and a rectifier. Any amp with these options I will consider.

Thank you so much for all the answers!

I will really look at the options proposed

I get it, and if that’s you goal, go for it!

Rectifiers can definitely help shape sound, in some amps (in some, they make little difference). FWIW, one of my tube amps comes with a SS rectification (the Auris Nirvana) and I can get plenty of tuning from rolling the gain and output tubes.

As far as ECC88 family there are some great tubes. My favorite is the RCA 6BQ7A and 5687 (where can be used with adapters) - I use both with the Decware/ZMF OTL and they are just fantastic tubes.

That said, I do agree there is a ton of 12AU7 options (like those I mentioned in my prior post). Both of these models are some of the most common tube types to source and roll, so great choice either way!

After much reckoning, I ended up eyeing the cayin ha-3a.
What are your thoughts about this pairing with caldera? Had anyone tried it?
The main thing is the usage of 12au7 plus the possibility of changing rectifier tube.
Link to review

Edit: something I can't still figure out for the best solution possible it's how to connect the only RCA out of my DAC to two amps, the otl and the otc. I am actually using pretty nice cables and the connection is direct from DAC XLR to SS XLR and from DAC RCA to otl RCA.
I know some kind of device to switch between outputs could work, but I don't want to lose the quality of a direct connection. Would be better to just swap cables when I want to use one amp or the other (it sounds a bit inconvenient or me). For instance a goldpoint sw4 but it's 4 out. I only need two. And I don't want any preamp or any kind of volume control.

Any ideas? I know it's too much of asking. The RCA split and the cayin ha-3a. But I would really appreciate some inputs.

Thanks everyone

And have a good Monday

 

[AnamCeoil]

Exactly. The Line Out is like a bypass. The A20 doesn’t even need to be on.

Fantastic, appreciate the quick reply. This is great to hear and will really help my setup. Cheers!

 

[VanHai]

McChanson's amp. The Super UltimatE.

 

[michael2v]

Edit: something I can't still figure out for the best solution possible it's how to connect the only RCA out of my DAC to two amps, the otl and the otc. I am actually using pretty nice cables and the connection is direct from DAC XLR to SS XLR and from DAC RCA to otl RCA.
I know some kind of device to switch between outputs could work, but I don't want to lose the quality of a direct connection.

I find that an RCA splitter cable works well, 1 male / 2 female connectors.

Just get two of those (one for each channel) and then pair with your favorite RCA cable to complete the connection to each amp.

 

[tutetibiimperes]

McChanson's amp. The Super UltimatE.

Are you running double adapters on some of those tubes?

 

[JerseyD]

Edit: something I can't still figure out for the best solution possible it's how to connect the only RCA out of my DAC to two amps, the otl and the otc. I am actually using pretty nice cables and the connection is direct from DAC XLR to SS XLR and from DAC RCA to otl RCA.
I know some kind of device to switch between outputs could work, but I don't want to lose the quality of a direct connection. Would be better to just swap cables when I want to use one amp or the other (it sounds a bit inconvenient or me). For instance a goldpoint sw4 but it's 4 out. I only need two. And I don't want any preamp or any kind of volume control.

Any ideas? I know it's too much of asking. The RCA split and the cayin ha-3a. But I would really appreciate some inputs.

The Pine Tree Audio “Transparent Selector” is a less expensive and probably higher quality switching box.
https://sites.google.com/view/pine-tree-audio/devices/transparent-selector?authuser=0

 

[VanHai]

Are you running double adapters on some of those tubes?

No, they are single adapters. At the bottom are socket savers.

 

[tutetibiimperes]

No, they are single adapters. At the bottom are socket savers.

How do you like that amp overall? How quiet is it? Any hum/buzz in the output? Are the output transformers wideband enough you don’t lose any sub-bass?

 

[VanHai]

How do you like that amp overall? How quiet is it? Any hum/buzz in the output? Are the output transformers wideband enough you don’t lose any sub-bass?

Love the amp. One of the most versatile amps that I ever own, there are so many combinations of tubes that you can use. Almost endless, very quiet if you use native tubes. It has an excellent bass and I have Merason Dac 1, well known for the base.