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Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 2:02 am
by Dr.HI-TONE
no that wire should be there.
I don't think Mark has a layout for a mid 1970s DR201.
the only issues I saw with your amp are related to V1 which are those mallory 150 series caps at the left end of the preamp board.
replace that .001 with a .022 and see how the amp sounds.
if it is still excessively brittle, upgrade the tubes and if you want it even more musical and less brittle, recap it with F&T caps.
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 2:08 am
by teethdream
Dr.HIWATT wrote:no that wire should be there.
I don't think Mark has a layout for a mid 1970s DR201.
the only issues I saw with your amp are related to V1 which are those mallory 150 series caps at the left end of the preamp board.
replace that .001 with a .022 and see how the amp sounds.
if it is still excessively brittle, upgrade the tubes and if you want it even more musical and less brittle, recap it with F&T caps.
I only asked about the blue wires and the red wire because it seems as if there is solder on the empty turret (like something was there at some point), just kind of made me wonder you know?
Already noticed a difference since I took the .047uf cap at the very left off and the .001 will be replaced with a .022 shortly. I'd kind of like to put an actual mustard cap back in there.
Thank you for your patience with me! This message board is a wealth of knowledge when used with Hiwatt.org
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 2:09 am
by mhuss
All those white caps are Mallory replacements and not original. The .001 in place of the .022 will definitely roll off the low end a bit and make it sound thinner.
The original layout had plain (uninsulated) jumper wires going across the board, and the red wire connects underneath. It looks like someone mickeyed around with it a bit, but it looks functionally correct.
--mark
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 2:12 am
by Dr.HI-TONE
you are welcome!
We love Hylight era HIWATTs, this is why we are here.
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 2:30 am
by teethdream
mhuss wrote:All those white caps are Mallory replacements and not original. The .001 in place of the .022 will definitely roll off the low end a bit and make it sound thinner.
The original layout had plain (uninsulated) jumper wires going across the board, and the red wire connects underneath. It looks like someone mickeyed around with it a bit, but it looks functionally correct.
--mark
I see what you mean after finding a picture of the internals of another DR201 , there would have originally just been two wires going across at those two points. The way this is wired now is basically the same function?
Dr.HIWATT wrote:you are welcome!
We love Hylight era HIWATTs, this is why we are here.
I can see why you do! I find it very interesting to look around inside this unit as it is my first non pc board amp. Just makes me want to learn more haha.
Also - would I want a 160v or 400v .022uf Mustard cap in place of that .001uf?
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 10:46 am
by mhuss
400v in that position.
--mark
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Thu Feb 28, 2013 12:55 pm
by Dr.HI-TONE
mhuss wrote:All those white caps are Mallory replacements and not original. The .001 in place of the .022 will definitely roll off the low end a bit and make it sound thinner.
The original layout had plain (uninsulated) jumper wires going across the board, and the red wire connects underneath. It looks like someone mickeyed around with it a bit, but it looks functionally correct.
--mark
I have seen at least 3 if not 4-5 1976-1977 EL34 version DR201s wired just like this. I suspect the uninsulated jumper wires were only used with the KT88/early 1970's preamp versions.
I am confident that the red wire in this amp is original.
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Fri Mar 01, 2013 11:24 pm
by teethdream
Great. I'll just have to get a replacement cap for that spot and I'll have my tech switch it out when I get some EL34s to replace the 6550s.
Speaking of EL34s - I've narrowed it down to the Groove Tube EL34M or the Winged C EL34. I've read good things about both of these tubes in Hiwatts. Any opinions on these? I want a tube that's going to last a long time AND sound good, without breaking my bank on NOS Mullards (someday though....
)
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Sat Mar 02, 2013 2:11 pm
by mhuss
Either of those choices should work well, but (in the US at least) the =C= cost a lot more.
--mark
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Sat Mar 02, 2013 2:15 pm
by Dr.HI-TONE
i think the =c= sound a little better, but the GT's may be more durable.
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Sat Mar 02, 2013 2:21 pm
by ak-47
+1 on the =C='s I love them in mine
My other hylight has a mix of EH and JJ's which I quite like too
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Sat Mar 02, 2013 9:44 pm
by teethdream
I've had great results with the Winged C 6550 for a SVT in the past so I'm kinda leaning towards their EL34 I think
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Sat Mar 02, 2013 10:08 pm
by Dr.HI-TONE
The =C= quality isn't quite as good as it was 3-4 years ago, so it may be in your best interest to get a burned in set.
Let the distributor cull the duds, not you.
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Sun Mar 03, 2013 7:44 am
by ak-47
Dr.HIWATT wrote:The =C= quality isn't quite as good as it was 3-4 years ago, so it may be in your best interest to get a burned in set. Let the distributor cull the duds, not you.
I agree... I got my 1999 St.Petersberg C's over here:
http://www.tubeampdoctor.com/product_in ... 3Fhymolne3 An investment I am glad I made
Re: What tubes should I use in my DR201 6xEL34 amp
Posted: Fri Jul 19, 2013 4:28 am
by teethdream
Finally got this amp fixed up by my tech. Went with Winged C El34s and got that cap changed back to what it should be and wow... it sounds like a different amp. As in, it sounds like it's supposed too.
Just wanted to check back in and thank everyone on here for their help, without y'all I probably would have just given up on it, sold it and never really got to truly experience this amp. Y'all are good people.