[rklein]

Hello:

I am assembling a tube based system.  My sources will be an Empire  598TT/AT440MLa cartridge along with a Boulder digital modded SB3 feeding a modded Zhalou DAC.  My room is on the small side (16 x 13).

I would appreciate any comments about the following amps

Dynaco ST-120 Comes in a kit form with links below.

http://www.tubes4hifi.com/bob.htm  (Scroll to down to see ST-120)

VTL ST-85 Triode/Tetrode Amp

I am also having a Mapletree Ultra 4A SE being built for me by Dr.  Lloyd Peppard

http://hollowstate.netfirms.com/ (Scroll down to see the Ultra 4A SE)

This setup will probably be driving some GR Research OB-7's.

Thanks,

rklein

[topround]

Funny,
But I have owned/own or used almost all that stuff.
I had the Vtl St 85, good tube amp, great bass, I replaced it with a Quicksilver amp to move up to higher power and refinement. The high end had a slight solid state sound to it, it is a different circuit in the front end than most VTL amps, but on the whole very good and very well built. I changed caps, but it didn't really help much in my case. I used Seimens and Winged c power tubes, both very good with the edge going to Seimens for their transparency. Experiment with the input tubes, I used some NOS Mullards, but am currently playing with a 6201 from Upscale Audio that I like a lot, and might have been a great addition to that amp.

Dynaco 120, I am borrowing a very old modded version from Frank van Alstine, Mine was modded in the 70's and was one of his first mod efforts with that amp. I like it alot. My amp is very dynamic and punchy and has a delicious tube like sound I love. It lacks a little transparency, but it makes up for it with musicality, and it has that in spades, this little amp can sing. I spoke to Frank about his latest version which is supposed to be many times better and fixes whatever problems the earlier version had.

Mapletree Ultra 4 SE: This is my reference preamp, and Dr Lloyd is a genius, you made the right choice there. Extremely musical preamp, I could go on and on but I won't, be happy you made a great choice.
Try NOS tubes, they will TRANSFORM that pre. I used Sylvania 6SN7 GTA's from the 50's that were great , but now I use Brimars that are just about two levels better than the Sylvania's but are very hard to get, I use a Tungsol rectifier tube.

Fortunately the Mapletree loved the VTL and the Dynaco. If I had to make a choice I would choose a Van Alstine Dynaco 120 with the Mapletree, great synergy, low cost and amazing sound, and you could leave it on all the time.

Gr Research speakers: I have the AV2's , that I use in my son's room, not a bad speaker, but in my son's room they just don't work that well. I brought these to a rave, and they never sounded so good in a big room like at the rave, they just don't work well in my son's smallish square room. But they sounded great at another person's home. I switched to Vandersteen 1c's for my son and they work much better in his room.

Hope this helps, honestly check out the Van Alstine stuff, it is pretty amazing for the money and the synergy with your Mapletree will be great, the Mapletree just gives a very solid sweet tube sound to everything it touches, it also works exceedingly well with digital amps, I have used my pre with Channel Island d200's and Nuforce 9's with tremendous results!!

Mike

[Niteshade]

With the Quicksilvers, you mentioned it had a solid-state like treble response. That can be taken care of by modifying the negative feedback circuit. Less NFB will reduce high frequency roll off.

[topround]

Yes I did some work to the negative feedback on both the VTL and the Quicksilver.

BTW I thought your were talking about the Dynaco Solid State amp, not the Tube version, I replied very early in the morning, sorry, I have the SS st 120.

I have had the ST70 with the Van Alstine board and THAT was great too, probably one of the best sounding amps I ever owned, but I could not use it in my current system.

You might want to try Dr Lloyds board for the ST 70, I know I would if I was using the ST 70.

Sorry for the misunderstanding


Mike

[rklein]

Hi Mike:

Thanks for your input.  One of the reasons I was considering the Dynaco ST-120 was the fact it came in a kit form and was of reasonable price.  Bob Latino offers this kit.  It comes with the VTA PCB board.  Below is a little more info on this unit:

 

The VTA ST-120 is a 60 WATT PER CHANNEL amplifier built on the same ST-70 stainless steel chassis as the amp pictured above.
The VTA ST-120 uses three custom wound USA made transformers and is available as a KIT amp or completely WIRED and tested.
This amp, which comes with a matched quad of 6550A output tubes, has the same quality components as the VTA ST-70 listed above.
KT88 output tubes may also be used in this amp.
The power transformer instead of 360-0-360 secondaries like the ST-70 has 420-0-420 secondaries and puts about 485 volts on the plates
(pin 3) of the output tubes. The ST-70 puts about 420 volts on the plates. The stack lamination on this transformers is about 2.70 inches tall
- my ST-70's power transformer stack is about 2.05 inches high. This transformer weighs about 4 pounds more than the ST-70 transformer
and is rated at 425 milliamps of current flow.
The output transformers have 4200 ohm primaries, 40% ultralinear screen taps and are 3 7/8" tall, 3 1/4" wide and 3 1/8" deep
(about 1/2" taller, 3/8" wider and 1/4" deeper than a stock A-470 output transformer). Each output transformer weighs about
2 pounds more than a stock A-470 output transformer.
The power storage caps have a higher capacity and voltage rating than the VTA ST-70. The supplied WZ68 Weber Copper cap rectifier
has the capacity of two GZ34 tube rectifiers and has an Imax of 450 milliamps.

I will give Frank van Alstine a call to inquire about various options.  I am the first to state that my experience in tube amps is practically nil.   I am coming from an Odyssey Khartago SS amp and in fact have toyed with keeping this amp in order to bi-amp my future speakers.  BTW, I think that the OB-7 is a completely different beast than the AV-2.

Again, I appreciate your responses.

Randy

[topround]

Randy,
Yes the OB 7 is a different beast altogether, and Danny is a great guy making some great stuff, I was just commenting on my speakers and how they work in my system.

Bob Latino offers some nice stuff, I almost bought his new ST 70, but went in a different direction.
I never heard his stuff but if he can improve on a st 70 then he may just know what he is doing!
Louis from Omega speakers has one of his amps and told me he really likes it alot.

Solid State can be great as well, it depends on what you want/need, there are pro's and con's to both sides.
I like tubes for their dimensionality and air. It's the really good stuff that shines, the more mediocre tube stuff is mediocre, just like SS, good SS sounds great but the mediocre is..well mediocre.
It's a crazy hobby...but fun when it starts to come together.

Mike

[Airborn]

Randy,

I can't comment on the 2 tube amps you posted about, but I do remember our prior correspondence about speakers and the similarity of parts of our systems.  I think you will be pleased with the Mapletree Ultra 4A SE, just a great pre at a reasonable price and DR. Lloyd is a true gentleman to deal with.  I guess he must have figured out a way to give you that HT bypass you wanted. 

I would suggest you hang on to the Khartago and try it with the Mapletree, as I find the combo to work very well together.  I haven't bi-amped b/c my speakers don't allow for it, but I bet the OB-7 will sound very nice with the SS Khartago on the bottom and tubes on top.

Btw, the phono stage of the Mapletree 4A grooves with the output of the AT-440 MLa like they were made for each other, so no need for an outboard phono stage either, unless you want to use LOMC.

Steve

[rklein]

Hi Steve:

Thanks for your response to my post and yes, I do remember our conversation.  As you may recall, I ended up buying an SAS Audio 10A pre, which I really liked.  However, it was just a linestage with no phono section.  I almost bought a Graham Slee phono stage but in the end I decided to sell the 10A to a fellow AC'er and put the money towards the Mapletree which included the phono stage.

I also was considering selling the Odyssey Khartago but have had a change of mind.  I plan on biamping my speakers.  I am really torn between building some of Danny's OB-7's or buying some used Emerald Physics CS2's.  My room is on the small side (16 x 13) and the OB-7's actually have a little more leeway in regards to placement than the OB-5's.  However..................., I listen to ALOT of accoustical type music (orchestral, chamber music, jazz - both instrumental & vocals, bluegrass, etc) and I have heard from several different sources that the CS2's just excell at these genres.  Hopefully, I will have a chance to audition them.

Yours,

Randy