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Bought a Dynaco ST-70... Need Preamp and tube upgrade recommendation

Dandy said:
If you play vinyl, spend your cash on the best tube phono stage you can afford and experience a really audible upgrade. But, YMMV.
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This is what I need to do. I'll keep the tubes for now and save up for a good preamp. I'm thinking about going with the Conrad Johnson, but need to find one used. $600-$800 could be my budget if I stay with my EL34 tubes. I'm thinking I want to pass on the Pas 2 (no pun intended) because I would want to upgrade it and I feel like it would be a waste. When I decide to change out the Chinese EL34's I'll try out the Gold Lion KT77's.
 
If you can push your budget up for a kit, I recommend the Vacuum Tube Audio (VTA) SP9 kit. I picked up a used one fully assembled with the PH6 phono board off of CraigsList and it really opened up the sound stage in my system. Listening to Dire Straits, one of my reference disc, I was hearing several instruments when before it sounded like one. It's one of the biggest upgrades yet to my system. Highly satisfied.

BillWojo
 
Also what Bill said. I built an SP14, it's very good. The only draw back with the SP14 is no room for a phone stage.
 
Reviews seem good on those, my only concern is that I haven't built a kit yet and would be nervous trying a kit $1000+. That's the main reason I mentioned the Bottlehead or the Pas 2 for experience building/upgrading. I've done work recapping/fixing multiple SS units but not any tube gear yet.
 
That VTA PH16 looks to cost about $700 in the USA. If you are confident with soldering, it should not be a problem to build and the supplier offers good support. (No link, except I have his boards in two of my amps.) Honestly, if your previous experience of vinyl is with an SS amp/phono stage, you'll be amazed at how good a tube phono stage can be. I use mine with an everyday MM cartridge (e.g. Shure M75).

If you're nervous about a kit build, start a new thread here and you'll get some support along the way.
 
For a few hundred more they will sell it completely built. They even have very nice finished aluminum chassis so it looks like a commercial unit and not a home built.
These units are supposed to compete with units costing thousands more and I can believe it. They are a lot of bang for the buck.

BillWojo
 
Dandy said:
That VTA PH16 looks to cost about $700 in the USA. If you are confident with soldering, it should not be a problem to build and the supplier offers good support. (No link, except I have his boards in two of my amps.) Honestly, if your previous experience of vinyl is with an SS amp/phono stage, you'll be amazed at how good a tube phono stage can be. I use mine with an everyday MM cartridge (e.g. Shure M75).

If you're nervous about a kit build, start a new thread here and you'll get some support along the way.
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I think I'll get the PH16, but I'll still have to get a separate preamp/line stage with volume control as I do like to listen off a dac once in awhile and use a tuner. I may end up getting the Schiit Saga to use until I decide to build the sp14 down the road.

Is anyone able to send me pictures of the instructions when building these units so I can read up on it? The ph16 looks very simple to build; my only worry is having to drill my own holes. Would it be a better option to buy the kit without the tubes/transformer for $325ish then add the $40 transformer? I can use the $100 credit I have to buy some of my tubes off Amazon so I can take advantage of saving a bit.
 
Maybe consider a passive preamp, with a nice volume pot and switchable inputs? The ST70 has enough gain to run without a line stage preamp.
 
Cool. I'll purchase the kit version of the PH16 and use my focus rite Scarlett 2i2 to control volume until I decide on the line stage inputs. I currently use the focusrite to record my vinyl as a dac. I can test the volume control tomorrow to see if it would work with the Dynaco.

Turntable-->PH16--->focusrite-->Dynaco

If this isn't a good temporary route, let me know.

Thanks.
 
I think I will go ahead and just build a simple passive preamp with multiple inputs until I decide on exactly what preamp I want. Can someone recommend a good volume pot I should use that would work well with the Dynaco?

I understand how to wire it and the selector switch I need.
 
arts said:
You are quite correct.Presently. But I remember (old fart here!) back when Shuguang power tubes had more in common with flashbulbs than amplifying devices.

My guess is that demand,time,and probably most importantly,competition,are the reasons for their newfound reputation.Unfortunately,back in the day,this company had an absolutely dismal reliability record.
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+1
Shugang has the worst QC record on the planet, CURRENTLY. The only rep they have is quantity, not quality. Had dozens in use and tested over the past 14 years alone. Pure crap. Too many better current production releases in other brand/types to even consider them anymore. They CURRENTLY are still the $2 bottle of wine Chinese factory go-to.
 
Paully said:
Have used the JJ E34L and liked them. Currently have EH 6CA7 and like them a lot too. Personally I have always used Bottlehead preamps with mine and been very happy. Don't know anything about how the Smash would be. I would wait for a a Foreplay II or III on ebay personally.
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Paully - You should really not be using 6CA7 for the ST-70. At 120v + AC line, the grid voltage comes very close and can exceed it's 425v maximum rating. They may work for a while but .......... . Should Use EL34's. I use German RFT's.
 
dneu201 said:
I think I will go ahead and just build a simple passive preamp with multiple inputs until I decide on exactly what preamp I want. Can someone recommend a good volume pot I should use that would work well with the Dynaco?

I understand how to wire it and the selector switch I need.
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I use a 50k Alps pot.

@triode17: surely 6CA7 and EL34 are 'sensibly equivalent'. And the Svetlana datasheet doesn't distinguish between them...
 
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I just retubed my ST 70 with a set of Tung Sol EL34's and a pair of NOS Navy Issued Tung Sol 6U8A with adapters to replace the 7199's. There just starting to break in and sound very good. Total cost shipped to my door for the tubes $160, TubeDepot source. I also purchased a Douk preamp from fleabay, $190 shipped to my door. The pre is nice for the price, point to point wiring, 4 inputs, rectifier and 3 12AX7 tubes. I have replaced 2 of the 12AX7's with JJ gold pin 12AX7's, replaced the 2 output caps with Russian oil caps, and placed a 12AU7 preamp tube in the middle tube socket. The cost for the new AX7's and oil caps was around $85 with 10 minutes of soldering required. I am planning on replacing the Chinese rectifier tube with a NOS Rayathon 6X5GT, $11. In summary for everything, about $450. This is the best setup to date for me since purchasing my ST 70 2 years ago. This combined with a set of RF-82 II makes for a very engaging vinyl listening experience:)
 
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Quick update. I pulled the trigger and just payed Roy for a PH-16X phono preamp from Tubes4Hifi. He was very helpful and quick in responding to help me with using visa gift cards I had received at work for incentives (had to make multiple $100 payments). The case/chasis will take 10-14 days because he had to order another one, but he is going to go ahead and send me my pcb boards to get started on.

For preamp on the dynaco, I ended up unplugging my Yamaha CA-1000iii i was using as a pre and tried out my Focusrite 2i2 as the direct source(dac) playing flac files. I was surprised how tight and more enhanced the bass was. The only issue was I wanted to be able to turn it up a bit louder. I have a tube preamp I built from a cheap kit on Amazon. I will add that and see if I can get to my desired listening level.I plan to use this for a bit until I decide on a new preamp around the $300 range. I may go ahead and buy that Schiit Saga and give it a whirl. I have the modi and magni that I really like.
 
Both boards for the PH-16x have been completed. Roy is sending me the chasis, transformer, and other parts once the chasis is shipped to him. Boards were very easy to piece together; the only issues I had was remembering to put the large parts on the bottom of the boards since they are being mounted to the top of the chasis to expose the tubes.

As for a line stage preamp, I had a spare Sainsmart tube Preamp I had bought off Amazon last year I wasn't using. It has upgraded GE tubes and Jantzen Audio caps. I'm going to put it in a nice wood box (with shielding) and add a selector switch. The preamp will get me by until I can afford a Jolida JD5t, schiit saga, or possibly build a VTA preamp. I like the idea of having a remote, if possible.
 
I just bought this passive preamp and it works very well. Passive volume control with active relay controlled selector. No noise at all. Plus it has a controller chip that remembers your last selection when turned of or unplugged. Ive used the relay boards before and kind of like them. Three inputs and two outputs. One output bypasses the relay selector. 20170617_121026.jpg 20170617_121051.jpg
 
triode17 said:
Paully - You should really not be using 6CA7 for the ST-70. At 120v + AC line, the grid voltage comes very close and can exceed it's 425v maximum rating. They may work for a while but .......... . Should Use EL34's. I use German RFT's.
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Interesting, did not know that. Well, I have lots of chinese EL34s sitting around I can pop in when the Dynaco makes it back into the main system. Thanks.
 
dneu201 said:
No foreplays on ebay right now but I would love to build one of these kits for experience. It would be my first and I would eventually want to build a Bob Latino ST-70 but would need practice first. How are the instructions for a newbie building the Bottlehead?
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Their directions are always stellar, I think that is part of what made their business so successful. But first time build, I don't know... One of the lower kits, sure. Something like the Bee Pre, I would say wait.
 
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