Amplifier suggestions

[David Deratany]

I have been using a pair of restored and upgraded DYNA ST70s to power my 416/511/902s, and they have been serving me well. I am thinking now that some day I might want to move on to something a little better.

I would appreciate whatever thoughts anyone would like to share as to what amps (tube) I might want to consider. I sometimes listen at substantial volume and don't want to try to get by with only a few w/ch, but I certainly don't need more power than I have with the ST70s.

My budget constraints, and sensibilities, will not permit trendy - and maybe even good- highest priced choices. I can do kits if the savings would be more than nominal.

TIA

[Roland N R]

Congratulations your ST 70s with excellent OPTs will provide the basis for modifications which will match very expensive amplifiers indeed. You DO NOT need to expend much to get there. Already with high efficiency speakers and updated but unmodded they compare very favorably to others but mod if you will. Look back at Glass Audio Mag and check the internet for many available mods. I remember in particular a triode connected PP output in Glass Audio that was easy and excellent. DO NOT go crazy expending money uneccessarily on "better" you likely will be disappointed. Additionally since obviously biamping consider passive crossovers between the pre and power amp as a way of limiting the freq of signals going to different drivers.

[David Deratany]

Thank you, Roland,

Way back when, I did look into several of the mods that were popular. There seemed to be little concensus. They were different but not necssarily better. Throughout all of the reviews was the recurrent theme that Haffler did quite a good job trading off between design and cost.

My "renewing" consisted of replacing just about everything, trannies excepted, with high quality, very low tolerance parts. I think the units have a certain charm, as well as value, being "stock", sort of.

One thing you said confused me: Since I am biamping, I didn't understand the part about installing passive xovers between the preamp and amplifiers. That is where I have the active crossovers. Am I missing something?

Dave

[Fitts]

From what I have read and recalling the last time I heard an ST70 in operation, I have a hard time imagining anything much better. I have only heard a MacIntosh tube amp once and was very impressed but a pair of them or 4 monoblocks to replace your ST70's are going to be a bank breaker.

May I suggest trying a MOSFET amp for your LF and one ST70 for the HF. MOSFETs have characteristis that are very similar to tubes but usually have a lot more damping than tube amps. The Hafler MOSFET amps are very nice and from the same lineage as the ST70's.

Just some thoughts,

[Roland N R]

Dave:

Forget about passive in between pre and amp XO if already satisfied with active XOs.

If you have read Jim's recommendations notice he says with today's SS amps with higher damping etc you should reduce the internal cab volume... for tube amps as you are using you may not need to do so. I would experiment by placing a sealed box in that space to in effect reduce the volume and see if you like the bass with the amp you are using.

I would also likely not bother with mods for the ST70 but if have a chance look up the triode connected mod as I remember if was really simple and would be the only one I would consider.

[David Deratany]

This is all very reassuring. Seeing and hearing from people caught up in extremely high end equipment, not unlike those espousing interconnects costing even more than some of that equipment, can be distracting. The responses in this thread have served to help me keep my feet on the ground, and I am most appreciative of them.

I do occasionally hook up the lf to the amplifier section of my SS YAM RX770 receiver (not their typical stuff) which has damping in the 240 range and maybe even MOSFETS. I haven't as yet done it with the 416s. I think it is time. It may prove to be quite interesting and rewarding, what with their deeper bass than the 604's I was using.

[radiolee]

I would strongly urge you to try out some single ended amps. I've been playing with the old stuff for a while and SE offers, to my mind, the biggest actual sonic difference (apparent to me anyway) compared to any push pull amps. Keep your eye out for old consoles and the like with SE amps. The amp I listen to most came out of a 25 dollar junk store Silvertone console. it'a a SE 6BQ5 amp.

I actually much prefer the sound of 6BQ5 PP amps to 6CA7 amps, but amps like the ST-70 do provide more ballsy bass. I did Trode Electronics mod on one and it improved the mids audibly.

I did make up some passive XO's once and ran two different SE amps and it sounded fabulous, but the insertion loss was significant.

I guess the bottom line is that every time I reduce the amount of circuitry in the amplifiers and crossovers, the better the music sounds.

Ain't audio fun??

Lee