2. amps-preamps
  3. 125863-85386

Replace C28 with... ?

In my previous thread regarding a power amp, some of you commented that replacing the McIntosh C28 preamp would make a huge difference. However, what was missing was any elaboration how why you made the recommendation, and with what to replace it.

So, let’s get down to it.
McIntosh C28
HiFiBerry DAC+ Pro (Yes, I know... sacrilege, but it’s all I’ve got for now)
Bryston 4BST
Dahlquist DQ10
Polk PSW650 sub

Need guidance from you guys on whether I ought to be looking at SS, Tube or even a Passive unit. Since I have some skill with a soldering iron, I'm not above entertaining the idea of a kit.

I’ve seen the Tortuga LDRx and that concept looks pretty interesting. My worry is that the DQ10s can be a bit aggressive on the high end with that ribbon tweeter, so I’d like to hear your thoughts.

Thanks again in advance!
parabolic
auxinput
2,920 posts
 

Do you have plans on your future DAC? If you are just using the HiFiBerry as DAC, it may be extremely challenging to plan the proper preamp. In my experience, a preamp is just another tool in shaping the sound from the source.

You went towards a Bryston preamp. This is definitely on solid state side (no Class A, no tube). You are going to want to put some sort of tube or Class A device in your originating equipment. Your HiFi Berry is probably going to put out very weak sound - there is really no power supply capability in this - I think everything runs off USB power or similar. There is no beefy power supply to push bass/midbass weight or punch. I would suspect the sound is very thin. A powerful preamp may help translate more bass, but it will not change the source waveforms much. The type of DAC may influence the type of preamp you’re after. For the HiFi berry or a different solid-state type DAC, I might look at the BAT preamps because of bass translation (BAT is very good at bass). If you are getting a tube DAC, I would lean towards a very solid state preamp - like a Krell or even a Wyred 4 Sound STP-SE (which is almost like a passive preamp with gain voltage).

Most of your suggested preamps are seriously old school. The Krell is from 1992. Most of this stuff will have to be re-capped (electrolytic caps) for them to perform well. From the list, I would probably pick the Conrad Johnson just because of age. Though, if you tried to find a Krell KRC-3 or KRC-HR and then re-cap, that might be extremely nice.

parabolic OP
106 posts
 
Your HiFi Berry is probably going to put out very weak sound - there is really no power supply capability in this - I think everything runs off USB power or similar. There is no beefy power supply to push bass/midbass weight or punch. I would suspect the sound is very thin. A powerful preamp may help translate more bass, but it will not change the source waveforms much. The type of DAC may influence the type of preamp you’re after. For the HiFi berry or a different solid-state type DAC, I might look at the BAT preamps because of bass translation (BAT is very good at bass).
Excellent feedback - this is the sort of information I was hoping for to fill in the gaps of what I haven’t been thinking of, or knowledgeable about.

I have no plans for another DAC right now. So, based on your input, a tube would be the way to go, and I think we can rule out a passive unit because of the minimal power the HiFiBerry puts out.

Old school? Yeah, probably, but not as old as the speakers or current preamp, so that’s not a bad thing in and of itself. I know technology and materials research changes, but I’m not in a position to afford anything new, so I have to pick something that is pre-owned and falls in the area of my budget which is limited, to say the least.

So - in the SS vs Tube debate, what’s the difference in cost and characteristics between recapping or buying new tubes? Heck, talk about ’old school’, so do they even make tubes anymore or must I rely on old stock? I don’t want to paint myself into a corner by spending money on old technology that will be useless when the tubes fail because I can’t replace them.

Thanks in advance!
parabolic OP
106 posts
 
Y'know, one thing we may have overlooked... the Bryston is the PRO model.  Is it possible that a passive might actually work with this amp?

http://www.bryston.com/PDF/Other/STPRO_NOTES.pdf

parabolic OP
106 posts
 
Well, fellas, I just took delivery of a 4BST Pro in a solid 8+/10 condition with 5 years left on the warranty.

Though I'm sure the C28 can be improved upon, in only an hour's time with the new amp I can already hear a decided change over the SAE.

Instruments are more 'articulate'
Imaging is more precise.
Staging is (surprisingly) both higher and deeper.

I can't wait to see what a new preamp will reveal. Though many have admonished me to look at a tube preamp, the diminishing availablility of 1940's technology worries me (i.e., ten years from now when the tubes need to be replaced there won't be any or they'll be a fortune), so I'm inclined to look at a SS unit.

Keep those cards and letters comin'.

Thanks!
auxinput
2,920 posts
 

When I say "old school", I really don’t mean anything negative about it. The circuits are all good. What I’m really saying is that you’ll want to replace all the electrolytic capacitors - they do dry out. The Krell KSL is from 1992!!

Suggestions would be based on what you feel you are missing. Do you feel like you are missing bass punch/weight and low midbass body? Or maybe bass is okay, but you’re missing resolution.

If I had the HiFiBerry, I think my first thought would be to go after the BAT VK3i there’s one for $899. That would give me the bass/body.  The BAT stuff has extremely good bass, but some find it lackluster in the high frequency detail and excitement. You could always start experimenting with tube choices. New tubes are still being made and the industry is not going anywhere.

Otherwise, there’s a Krell KAV-250p for $725. This will probably give you more resolution, but you’ll want to replace all the electrolytic caps.  Maybe look into Conrad Johnson to see what the general sound signature is like (I don't know anything about it)

The McIntosh stuff is generally very laid back and may feel like you are missing resolution. Since you like where the Bryston took you (with more articulate instruments, etc.), you may want to lean towards Krell (or that Conrad Johnson).

What’s your budget for preamp?

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